Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Boriding kinetics and mechanical behaviour of aisi o1 steeluaeh
Boriding is a thermochemical treatment in which boron atoms are diffused into the surface of a workpiece and form borides with the base metal. Apart from constructional materials, which meet these high demands, processes have been developed which have a positive effect on the tribological applications including abrasive, adhesive, fatigue and corrosion wear of the component surface.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A simple kinetic model for the growth of fe2 b layers on aisi 1026 steel duri...uaeh
Boriding is a thermochemical treatment in which boron atoms are diffused into the surface of a workpiece and form borides with the base metal. Apart from constructional materials, which meet these high demands, processes have been developed which have a positive effect on the tribological applications including abrasive, adhesive, fatigue and corrosion wear of the component surface.
Kinetic investigation and wear properties of fe2 b layers on aisi 12l14 steeluaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Diffusion model and characterisation of fe2 b layers on aisi 1018 steeluaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Boriding kinetics and mechanical behaviour of aisi o1 steeluaeh
Boriding is a thermochemical treatment in which boron atoms are diffused into the surface of a workpiece and form borides with the base metal. Apart from constructional materials, which meet these high demands, processes have been developed which have a positive effect on the tribological applications including abrasive, adhesive, fatigue and corrosion wear of the component surface.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A simple kinetic model for the growth of fe2 b layers on aisi 1026 steel duri...uaeh
Boriding is a thermochemical treatment in which boron atoms are diffused into the surface of a workpiece and form borides with the base metal. Apart from constructional materials, which meet these high demands, processes have been developed which have a positive effect on the tribological applications including abrasive, adhesive, fatigue and corrosion wear of the component surface.
Kinetic investigation and wear properties of fe2 b layers on aisi 12l14 steeluaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Diffusion model and characterisation of fe2 b layers on aisi 1018 steeluaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Pack boriding of aisi p20 steel. estimation of boron diffusion coefficients i...uaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Effects of thermo mechanical simulation on the corrosion of steelJaideep Adusumelli
Performed numerous stress-strain elasticity tests along with impact test under controlled temperature and stress factors.
then the corrosion properties were studied based on the microstructures and corrosion current graphs.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
Growth kinetics and mechanical properties of fe2 b layers formed on aisi d2 s...uaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Growth kinetics of the fe2 b coating on aisi h13 steeluaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Pack boriding of aisi p20 steel. estimation of boron diffusion coefficients i...uaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Effects of thermo mechanical simulation on the corrosion of steelJaideep Adusumelli
Performed numerous stress-strain elasticity tests along with impact test under controlled temperature and stress factors.
then the corrosion properties were studied based on the microstructures and corrosion current graphs.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
Growth kinetics and mechanical properties of fe2 b layers formed on aisi d2 s...uaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Growth kinetics of the fe2 b coating on aisi h13 steeluaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Kinetics of boron diffusion and characterization of fe b layers on aisi 9840 ...uaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Characterization and boriding kinetics of aisi t1 steeluaeh
Boriding is a thermochemical treatment in which boron atoms are diffused into the surface of a workpiece and form borides with the base metal. Apart from constructional materials, which meet these high demands, processes have been developed which have a positive effect on the tribological applications including abrasive, adhesive, fatigue and corrosion wear of the component surface.
Boridign kinetics fe2 b layers formed on aisi 1045 steeluaeh
Boriding is a thermochemical treatment in which boron atoms are diffused into the surface of a workpiece and form borides with the base metal. Apart from constructional materials, which meet these high demands, processes have been developed which have a positive effect on the tribological applications including abrasive, adhesive, fatigue and corrosion wear of the component surface.
Growth kinetics of the fe2 b layers and adhesion on armco iron substrateuaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Simulation of growth kinetics of fe2 b layers formed on gray cast iron during...uaeh
Boriding is our favourite method to harden steels. That is also why we have developed a special boriding treatment that works even better than regular boriding, called BoroCoat®.
Boriding is a thermochemical heat treatment that diffuses boron into the surface of a workpiece. The boride layer that is formed on top is extremely wear resistant and protects the workpiece from chemical attacks as well as abrasive wear and cold welding.
Boron can be applied as a powder, as a paste and as granules, making possible the treatment of almost any type of workpiece, no matter their design. Boriding is extremely effective when it comes to corrosion resistance and can be applied to workpieces in mechanical engineering, for valves and for power tools.
Gamma TiAl alloys are of considerable interest as potential material for aerospace turbine engine applications. The ability to join these alloys usually using conventional welding techniques, such as, electron-beam(EB) method, is of great importance. In this investigation, five EB weldments, containing Al range from 46.3 to 48.3 at% produced with two heats, were examined at conditions of as-stress-relieved(SR) and post-welded heat treated(PWHT) at temperatures of 1050, 1150 and 1250°C. The microstructures of SR and PWHT of EB weldment were characterized in detail using Light(OP), Scanning Electron(SEM) and Transmission Electron(TEM) Microcopy. All EB welds exhibited a predominantly lamellar γ/α2 fusion zone(FZ) microstructure in the SR condition, with increasing proportions of equiaxed γ grains, and a decreasing volume proportion of intergranular α2 phase, observed with increasing Al content. Although PWHT did not affect base metal(BS) microstructure significantly, it promoted further recrystallization and growth of the γ grains at FZ. Increasing the PWHT temperature resulted in an increase in the volume fraction of α2 phase in the FZ. At the highest temperature, 1250°C, the presence of B2 phase was detected in FZ containing 47.1 at% Al or less.
Low grade iron ores are often contaminated with relatively high percentage of different
impurity gangue minerals. The iron ores contaminated with manganese oxide and silica are hardly reducible
and consume more energy in the integrated steel plant. Therefore it is important to estimate and predict the
influence of manganese oxide, silica and temperature on the reduction yield of iron oxide using mathematical
model approach. In the current study, a 23
(three-parameters, two-levels)factorial design is applied on the
gaseous reduction experimental data of mixed oxides (Fe2O3-MnO2-SiO2) to build a linear regression model.
The calculations have been performed using Matlab program. The developed mathematical model indicated that
SiO2 and temperature have positive effect on the reduction yield of iron oxide. On the other hand, MnO2
exhibited the highest negative impact on the reduction yield of iron oxide followed by the interaction coefficient
of MnO2, SiO2 and temperature. The results of the developed mathematical model are fitted to the experimental
reduction data of mixed oxides.
Mass and heat balance for duplex stainless steel production by conarc processIJESFT
Mass balance and heat balance calculations are carried out for estimating inflow and outflow of materials and energy respectively in a process. Such calculations are required to get accurate composition of product with available raw materials. CONARC is a new electric steel making process using a twin shell electric arc furnace (EAF) which can handle raw materials input of solid steel scrap and hot metal in varying proportions.
In the present study an attempt has been made to develop a mathematical model for mass and heat balance for duplex stainless steel production by CONARC process. Case studies have been carried out by varying the amount of hot metal in the charge from 0% to 100%. Such variation shows proportionate increase in the amount of oxygen required, lime consumption and amount of slag formed along with the increase in chemical energy available for the process. However, electrical energy consumption reduces for SAF 2205 and 3RE60 duplex stainless steel production.
On the basis of the above case studies, it has been found that increased amount of hot metal increases the available chemical energy for the process and in turn it reduces the electrical energy requirement of CONARC process, ultimately leading to reduction in the power consumption and overall production cost.
Characterization of expanded austenite developed on AISI 316L stainless steel...Javier García Molleja
Authors: J. García Molleja, L. Nosei, J. Ferrón, E. Bemporad, J. Lesage, D. Chicot, J. Feugeas.
Surface and Coatings Technology 204 (2010) 3750-3759 (August 25th 2010)
Because Elsevier copyright policy only the first page -of ten- is shown. Available at: http://dx.doi.org/10.1016/j.surfcoat.2010.04.036
Effects of Continuous Cooling On Impact and Micro Structural Properties of Lo...IJMER
Some mechanical properties and microstructural analysis were conducted on shielded
metal arc weldments of low carbon steels in some simulated environments. Specimens were prepared
and subjected to welding and continuous cooling at the same time at various positions. Results obtained
for impact strength using Charpy impact testing machine showed that impact strength of water cooled
samples were higher compared to salty water cooled samples. This is due to the increased formation of
martensitic structure and finer pearlite grains. The microstructure of the samples was studied using
photographic visual metallurgical microscope. For low cooling rate as in the air cooled sample, the
austenite was observed to transform into ferrite and pearlite. Ferrite is a body-centred cubic crystal
structure of iron alloys. For higher cooling rates of water and salt water cooled samples, low
temperature transformation products like bainite (an acicular microstructure which is not a phase) or
martensite (a very hard form of steel crystalline structure) were formed. The salt water cooled samples
had more martensite regions because of the increased cooling rate
Stability of expanded austenite, generated by ion carburizing and ion nitridi...Javier García Molleja
Authors: J. García Molleja, M. Milanese, M. Piccoli, R. Moroso, J. Niedbalski, L. Nosei, J. Bürgi, E. Bemporad, J. Feugeas
Surface and Coatings Technology 218 (2013) 142-151 (March 15th 2013)
Only the first page is uploaded because Elsevier's copyrigth policy. Available at: http://dx.doi.org/10.1016/j.surfcoat.2012.12.043
. One of the methods used to surface hardening of ductile iron is chilled cast iron. Chill as the fast cooling rate in the mold during solidification and chill thickness greatly affects the thickness of the hardness layer. The main material used is ductile iron, and the chill material is SS 304. Casting uses the sand casting method. Before pouring, the chill plate has been inserted onto the surface of the pattern that has been formed in the mold, then the chill plate is preheated at 700OC. Pouring was carried out at a melting temperature of 1400OC, and then cooled with argon and O2 sprays into the mold in solidification conditions at exactly 700OC. The results analyzed were the microstructure, hardness value, and the hardness of the thickness layer. This chill coolant will absorb heat very quickly and the Cr and Ni alloy will diffuse to the specimen surface to stabilize the ferrite and austenite phases in the final solidification. The particles on the hard surface have Ferro carbide M7C3, which is in the form of cementite and martensitic phases so that to categorized as white cast iron structure formed on the surface with an area around 1.5-3mm has a hardness of 61-65HRC. But in the center area is 31-49HRC
— Heat exchangers included in air conditioning systems for aircraft are produced by brazing stamped thin alloys sheets made of nickel-based alloys, Alloy 600 and Ni 201, or stainless steel, AISI 444. Separation metal sheets and locking bars of Alloy 625 are used to complete the system. The brazing filler metal, mainly composed of nickel, manganese, silicon and copper, is referred as BNi-8. In order to control brazing process, a good knowledge of both the brazing filler metal metallurgical behavior and of the interaction with the base metal is essential. The study of the brazing filler metal melting behavior in itself reveals that the melting point is highly dependent on the chemical composition and especially on silicon content. Microstructures analysis showed the presence of several phases with significant differences in terms of mechanical properties at a small scale which could induce local embrittlement. Interactions between the brazing filler metal and the different alloys constitutive of the assembly induce chemical composition evolutions related to the local configuration of the assembly. Dissolution and interdiffusion processes as well as chemical exchanges with the furnace environment occur. Finally, due to this set of phenomena, significant brazing defects can affect the mechanical integrity of the component.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
But there’s more:
In a second workflow supporting the same use case, you’ll see:
Your campaign sent to target colleagues for approval
If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
Join us to learn more about this new, human-in-the-loop capability, brought to you by Integration Service connectors.
And...
Speakers:
Akshay Agnihotri, Product Manager
Charlie Greenberg, Host
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
I have heard many times that architecture is not important for the front-end. Also, many times I have seen how developers implement features on the front-end just following the standard rules for a framework and think that this is enough to successfully launch the project, and then the project fails. How to prevent this and what approach to choose? I have launched dozens of complex projects and during the talk we will analyze which approaches have worked for me and which have not.
"Impact of front-end architecture on development cost", Viktor Turskyi
Kinetics of formation of fe2 b layers on aisi s1 steel
1. DOI: http://dx.doi.org/10.1590/1980-5373-MR-2018-0173
Materials Research. 2018; 21(5): e20180173
Kinetics of Formation of Fe2
B Layers on AISI S1 Steel
Jorge Zuno- Silvaa
, Mourad Keddamb
* , Martin Ortiz-Domíngueza
,
Milton Armando Elias-Espinosac
, Felipe Cervantes- Sodid
, Joaquín Oseguera-Peñae
, Libia Daniella
Fernández De- Diosf
, Oscar Armando Gomez-Vargasf
Received: March 07, 2018; Revised: April 25, 2018; Accepted: June 05, 2018
In the present work, theAISI S1 steel was pack-borided in the temperature range 1123-1273 K for
2- 8 h to form a compact layer of Fe2
B at the material surface. A recent kinetic approach, based on the
integral method, was proposed to estimate the boron diffusion coefficients in the Fe2
B layers formed
on AISI S1 steel in the temperature range 1123-1273 K. In this model, the boron profile concentration
in the Fe2
B layer is described by a polynomial form based on the Goodman’s method.As a main result,
the value of activation energy for boron diffusion in AISI S1 steel was estimated as 199.15 kJmol-1
by the integral method and compared with the values available in the literature. Three extra boriding
conditions were used to extend the validity of the kinetic model based on the integral method as well as
other diffusion models.An experimental validation was made by comparing the values of Fe2
B layers’
thicknesses with those predicted by different diffusion models. Finally, an iso-thickness diagram was
proposed for describing the evolution of Fe2
B layer thickness as a function of boriding parameters.
Keywords: Incubation time, Diffusion models,Activation energy, Growth kinetics, Integral method.
*e-mail: keddam@yahoo.fr
1. Introduction
The boriding process is a thermochemical treatment
in which the boron atoms are diffused into the surface of a
workpiece to form hard layers composed of iron borides and
metallic boride in the case of high alloy steels1
. For carbon
steels, two kinds of iron borides can be formed by boriding
in the temperature range 800-1050°C.
The iron borides are interesting phases because of their
high hardness. Nevertheless, the Fe2
B phase is preferred to
FeB, when the resistance to wear under impact was required,
since the doublé boride layer (FeB and Fe2
B) is prone to
cracking during service.Among the boriding processes, the
powder-pack boriding is widely used in the industry because
of its easy handling and low cost2
. In this boriding method,
a mixture of powders that consists of a boron yielding
substance, an activator and a diluent is used. The samples
to be borided are then packed in a stainless steel container
and placed in the furnace.
In the literature, no kinetic study was reported on the
boriding ofAISI S1 steel. The modeling of boriding process
can be used as a tool to optimize the boriding parameters to
produce boride layers with sufficient thicknesses that meet
the requirements during service life.
From a kinetic point of view, several approaches have
beeen developed to study the kinetics of formation of Fe2
B
layers on Armco iron and steels as substrates3-12
.
All these diffusion models considered the principle of
the mass balance equation at the (Fe2
B/substrate) interface
under certain assumptions (with and without boride incubation
times).For instance, Ortiz-Domínguez et al.5
have developed a
kinetic model for studying the growth kinetics of Fe2
B layers
on gray cast iron by introducing a kinetic parameter that
depends on the values of upper and lower boron concentrations
in Fe2
B and on the boride incubation time.Elias-Espinosa
et al.6
have modeled the growth kinetics of Fe2
B layers on
AISI O1 steel by using a diffusion model that assumes a
nonlinear boron concentration profile with the presence of
a
Escuela Superior de Ciudad Sahagún-Ingeniería Mecánica, Universidad Autónoma del Estado de
Hidalgo, Carretera Cd. Sahagún-O tumba s/n, Zona Industrial CP. 43990, Hidalgo, México
b
Laboratoire de Technologie des Matériaux, Faculté de Génie Mécanique et Génie des Procédés,
Université des Sciences et de la Technologie Houari Boumediene - USTHB, B.P. No. 32, 16111 El-Alia,
Bab-Ezzouar, Algiers, Algeria
c
Tecnológico de Monterrey, Campus Santa Fe, Av. Carlos Lazo No. 100, Del. Álvaro Obregón, CP.
01389, México City, México
d
Departamento de Física y Matemáticas, Universidad Iberoamericana, Ciudad de México,
Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, CP. 01219, México City, México
e
Tecnológico de Monterrey, Campus Estado de México, Av. Lago de Guadalupe KM 3.5. Col. Margarita
Maza de Juárez, Atizapán de Zaragoza, CP. 52926, Edo. De Méx., México
f
Instituto Tecnológico de Tlalnepantla-ITTLA, S/N. Col. La Comunidad, Tlalnepantla de Baz, CP. 54070,
Estado de México, México
2. Silva et al.2 Materials Research
a constant boride incubation time. They have introduced a
non dimensional kinetic parameter to evaluate the boron
diffusion coefficients in the Fe2
B layers in the temperature
range 1123-1273 K. Similarly, Nait Abdellah et al.7
have
also suggested a kinetic model based on the mass balance
equation at the (Fe2
B/Fe) interface by assuming a nonlinear
boron concentration profile through the Fe2
B layers onArmco
substrate. They introduced the β(T) parameter that depends
on the boriding temperature. Flores-Rentería et al.8
have
modelled the kinetics of formation of Fe2
B layers on AISI
1026 steel by using a kinetic model. In their model, they
introduced a kinetic parameter called ε which is independent
on the boriding temperature with a linear boron concentration
profile in the Fe2
B layer.
In the present study, a recent kinetic approach based on
the integral method 3,4
has been suggested to investigate the
boriding kinetics ofAISI S1 steel by taking into account the
presence of boride incubation time.
The aim of the present work was to investigate the
growth kinetics of Fe2
B layers on AISI S1 steel based on
the integral method in the temperature range 1123-1273 K.
This diffusion problem can be solved either analytically
or numerically.An analytic solution for the integral method
has been obtained in order to estimate the boron diffusion
coefficients in Fe2
B.An experimental validation of the integral
method and other used diffusion models was also made for an
upper boron concentration of 9 wt.% in Fe2
B.Furthermore,
the value of activation energy for boron diffusion in AISI
S1 steel was estimated on the basis of the integral method
and compared with that obtained from another diffusion
model 6
. Finally, the estimated value of boron activation
energy from the integral method was compared with the
data available in the literature.
2. The Diffusion Model
The diffusion model deals with the growth kinetics of
Fe2
B layer on a saturated matrix with boron atoms. The
boron concentration- profile along the Fe2
B layer is depicted
in Figure 1.
The f(x,t) function shows the distribution of boron
concentration within the substrate before the formation of
Fe2
B phase tFe B
0
2
(T) represents the boride incubation time
required to form a compact and continuous Fe2
B layer.
Cup
Fe B2
is the upper limit of boron content in Fe2
B (=9 wt.%)
while Clow
Fe B2
represents the lower limit of boron content in
Fe2
B(=8.83wt.%).The variable x(t)=u is the position of (Fe2
B/
substrate) interface. A small homogeneity range of about 1
at. % was observed by Brakman et al.13
for the Fe2
B layer.
The term Cads
B
is the adsorbed boron concentration in the
boride layer during the boriding treatment14
. C0
represents
the boron concentration in the substrate of a very low
solubility (≈0 wt.%)15-17
.
The assumptions taken into account during the formulation
of integral model are given in the reference works 3,4
:
The initial and boundary conditions for the diffusion
problem are given by:
t=0,x>0, with wt..% (1)
Boundary conditions:
for Cads
B
>8.83wt.% (2)
for Cads
B
<8.83wt.% (3)
The Second Fick’s law describing the change in the boron
concentration within the Fe2
B layer is given by Equation (4):
(4)
,C x tFe B2
" % is the distribution of boron element within
Fe2
B layer (wt.%) and DFe B2 represents the diffusion coefficient
of boron in the Fe2
B phase. The boron-concentration profile
along the Fe2
B layer was described by the Goodman’smethod17
as follows:
(5)
The three time-dependent unknowns a(t), b(t) and u(t)
have to meet the boundary conditions given by Equations (2)
and (3). By applying the boundary condition on the surface,
Equation (6) was obtained:
Figure 1. Schematic representation of the boron-concentration
profile through the Fe2
B layer
,C x t t C0 0Fe B 02 .= =Q V" %
,C x t t t t C0Fe B
Fe B
up
Fe B
0 02
2 2
= = = =Q V" %
,C x t t u t t t CFe B low
Fe B
2
2
= = = =Q QV V" %
, ,
D
x
C x t
t
C x t
Fe B
Fe B Fe B
2
2
2
2 2
2
2
2
2
=
" "% %
,
for
C x t C a t u t x
b t u t x x u0
Fe B low
Fe B
2
2
2
# #
= + - +
-Q Q Q
Q Q Q
V V V
V V V" %
3. 3Kinetics of Formation of Fe2
B Layers on AISI S1 Steel
(6)
By integrating Equation (4) between 0 and u(t) and
applying the Leibniz rule, the ordinary differential equation
(ODE) given by Equation (7) was derived:
(7)
The mass balance equation at the (Fe2
B/substrate)
interface can be formulated by Equation (8):
(8)
With W
C C
C C2
up
Fe B
low
Fe B
low
Fe B
0
2 2
2
=
-
+ -Q V# &
At the (Fe2
B/substrate) interface, the boron concentration
remains constant and Equation (8) can be rewritten as follows:
(9)
Substituting Equation (4) into Equation (9) and after
derivation with respect to the diffusion distance x(t), Equation
(10) was deduced:
(10)
Equations (6), (7) and (10) constitute a set of differential
algebraic equations (DAE) in a(t), b(t) and u(t) subjected to
the initial conditions of this diffusion problem. To obtain the
expression of boron diffusion coefficient in the Fe2
B layers,
an analytic solution is possible by setting:
(11)
(12)
and
(13)
where u(t) is the Fe2
B layer thickness and k the corresponding
parabolic growth constant at the (Fe2
B/substrate) interface.
The two unknowns α and β which are positive have to be
searched for solving this diffusion problem.After substitution
of Equations (11), (12) and (13) into the DAE (differential
algebraic equations) system and derivation, the expression
of boron diffusion coefficient was obtained as follows:
(14)
where η is a dimensionless parameter.
with
C C
C C
C C
C C
16
1
1 1 4 12
1
up
Fe B
low
Fe B
up
Fe B
low
Fe B
up
Fe B
low
Fe B
up
Fe B
low
Fe B
2 2
2 2
2 2
2 2
h =
-
+
+ +
+
-
+
S
U
T
T S
X Y
YZ X
R
T
SSSSSSSSSSS
V
X
WWWWWWWWWWW
along with the expressions of a(t) and b(t) given by Equations
(15) and (16):
(15)
(16)
With
C C
C C
C C
2 1 1 4
up
Fe B
low
Fe B
up
Fe B
low
Fe B
up
Fe B
low
Fe B2 2
2 2
2 2
a =
+
- + +
+
-Q
T
V
Y# &
and
C C C C
C C
C C
C C4
2 4
2 1 4
up
Fe B
low
Fe B
up
Fe B
low
Fe B
up
Fe B
low
Fe B
up
Fe B
low
Fe B
up
Fe B
low
Fe B
2 2 2 2
2 2
2 2
2 2
b =
+
+
+
-
-
+
+
-
Q
T
T
V
Y
Y
R
T
SSSSSSSSSSS
V
X
WWWWWWWWWWW
3. Experimental Details
3.1 The material and the boriding treatment
TheAISI S1 steel was used as substrate for the powder-
pack boriding. The chemical composition of AISI S1 steel
is listed (in weight percent) in Table 1.
The samples had a cubic shape with nominal dimensions
of 10 mm×10 mm×10 mm. Before the boriding treatment,
the samples were cut and the cross-sections were polished
u t
dt
da t
a t u t
dt
du t
u t
dt
db t
b t u t
dt
du t
D b t u t
2
3
2 Fe B
2
3
2
2
+ +
+ =
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q
V
V
V
V
V
V
V
V
V
V
V
V
,
W dt
dx
D x
C x tx u
Fe B
Fe B
x u
2
2
2
2
=-=
=
" %
,
,
,
W
x
C x t
t
C x t
D
x
C x t
Fe B
x u
Fe B
x u
Fe B
Fe B
x u2
2
2
2
2
2
2
2
2
2
- =-
=
=
=
J
L
KKKKKKKKK
N
P
OOOOOOOOO
"
"
"
%
%
%
C C b t a tup
Fe B
low
Fe B 22 2
+ =Q Q QV V V
u t k t t TFe B
0
1 22
= -Q QV V! $
a t
u t
a
=Q
Q
V
V
a t
k t t TFe B
0
1 22
a
=
-
Q
Q
V
V! $
b t
k t t TFe B2
0
2
b
=
-
Q
Q
V
V! $
Table 1. The chemical composition of AISI S1 steel (in weight percent).
C Mn Si Cr Mo W
0.40-0.55 0.10-0.40 0.15-1.20 1.00-1.80 0.35-0.50 1.50-3.00
V Ni Cu P S Fe
0.15-0.30 0.3 0.25 0.03 0.03 balance
D kFe B
2
2 h=
a t u t b t u t C Cup
Fe B
low
Fe B2 2 2
+ = -Q Q Q Q QV V V V V
b t
u t 2
b
=Q
Q
V
V
4. Silva et al.4 Materials Research
and 70% SiC. Figure 3 gives an SEM image of the mixture
of powders having an average size of 30 µm.
The container was placed in a conventional furnace
under a pure argon atmosphere in the temperature range
1123-1223 K. Four treatment times (2, 4, 6 and 8 h) were
selected for each temperature. Once the boriding treatment
was finished the container was removed from the furnace
and slowly cooled to room temperature.
3.2 Experimental techniques
The cross-sections of formed boride layers were
examined by SEM (JEOL JSM 6300 LV). The boride layer
thickness was automatically measured by means of MSQ
PLUS software. For the reproducibility of measurements,
seventy tests were performed from a fixed reference on
different sections of borided samples to estimate the Fe2
B
layer thickness; defined as an average value of the long boride
teeth. The presence of the iron boride formed at the surface
of treated sample was verified by use of X-Ray Diffraction
(XRD) equipment (Equinox 2000) with Co-Kα radiation of
wavelength λCo
= 0.179 nm.
4. Results and Discussions
4.1 SEM examinations of Fe2
B layers
Figure 4 shows the cross-sections of borided samples at
a temperature of 1173 K for different treatment times (2, 4, 6
and 8 h). It is seen the formation of a dense and compact Fe2
B
layer with a peculiar morphology. The SEM pictures revealed
the presence of a saw-tooth morphology. Such morphology is
typical for boridedArmco iron and carbon steels where as for
high alloy steels the obtained morphology is very different.
In fact, when increasing the contents of alloying elements
the interface (boride layer/substrate) interface tends to be
flat as observed, for example, in the pack-borided AISI 316
L steel18
. Carbucicchio et al.19
explained the occurrence of a
saw-tooth morphology to the enhanced growth at the tips of
boride needles. Consequently, the iron borides developed a
textured growth along the preferred crystallographic direction
[001] after Palombarini et al.20
.
The Fe2
B layer thickness increased with the treatment
time at 1173 K. The value of Fe2
B layer thickness ranged
from 41.93 ± 8.25 µm for 2 h to 95.48 ± 17.4 µm for 8 h
at 1173 K.
Figure 5 gives the SEM micrographs of the boride layers
formed on theAISI S1 steels at increasing temperatures and for
an exposure time of 4 h. The (boride layer/substrate) interface
exhibited a saw-tooth morphology. The kinetics of formation
of boride layers is a thermally activated phenomenon with a
change in the layer thickness with increasing temperatures.
Figure 2. Schematic view of the stainless steelAISI 304Lcontainer
for the pack-powder boriding treatment (1: lid; 2: powder boriding
medium (B4
C + KBF4
+ SiC); 3: sample; 4: container)
Figure 3. SEM image of boriding agent containing three components
B4
C, KBF4
and SiC
metallographically and then etched by Nital solution to
reveal the microstructure. The powder-pack boriding was
carried out by embedding the samples in a closed-container
containing a mixture of powders as shown in Figure 2. The
used boriding agent was composed of 20% B4
C, 10% KBF4
5. 5Kinetics of Formation of Fe2
B Layers on AISI S1 Steel
Figure 4. SEM micrographs of the cross-sections of boridedAISI S1 steels at 1173
K during different exposure times: (a) 2 h, (b) 4 h, (c) 6 h, and (d) 8 h
Figure 5. SEM micrographs of the cross-sections of AISI S1 steels borided with
exposure time of 4 h, during different boriding temperatures: (a) 1123 K, (b) 1173
K, (c) 1223 K and (d) 1273 K
6. Silva et al.6 Materials Research
Figure 6. XRD patterns obtained at the surface of borided AISI S1 steels for three boriding conditions: (a) 1123 K for 4 h, (b) 1173 K
for 4 h and (c) 1223 K for 4 h
Figure 7. Square of boride layer thickness as a function of boriding
time for increasing temperatures
4.2 XRD analysis
Figure 6 shows the XRD patterns obtained at the surface
of borided AISI S1 steels at 1123, 1173 and 1223 K for 4 h
of treatment. The XRD patterns revealed the presence of
diffracting peaks belonging to the Fe2
B phase. The formation
of Fe2
B layer is related to the quantity of active boron
present in the boriding agent. The observed difference in
the diffracted intensities can be explained by the textured
growth along the easiest crystallographic direction 001 that
minimizes the growth stress20
.
4.3 Estimation of boron activation energy in AISI
S1 steel
The experimental results are needed to evaluate the values
of boron diffusion coefficients in Fe2
B in the temperature
range 1123-1273 K by plotting the variation of the square
of Fe2
B layer thickness as a function of treatment time.
The intercept with the time axis yields the value of boride
Table 2. Experimental values of parabolic growth constants at the
(Fe2
B/substrate) interface along with the corresponding boride
incubation times.
T (K)
Experimental
parabolic growth
constant k (µm∙s-0.5
)
Boride incubation time
tFe B
0
2
(T)(s)
1123 0.3704 2038.8
1173 0.5837 2039.4
1223 0.8861 2040.2
1273 1.3016 2038.4
7. 7Kinetics of Formation of Fe2
B Layers on AISI S1 Steel
incubation time. Figure 7 gives the evolution of the square
of Fe2
B layer thickness as a function of time for increasing
values of boriding temperatures. The growth kinetics of Fe2
B
layers is governed by the parabolic growth law. The slope of
each straight line depicted in the Figure 7 represent the square
of parabolic growth constant at each boriding temperature.
The experimental values of parabolic growth constants at
the (Fe2
B/substrate) interface along with the corresponding
boride incubation times are shown in Table 2.
It is seen that the values of boride incubation times are
nearly constant. The following reason can be provided for
this experimental observation. According to the design of
the thermochemical treatment, the container is always placed
at ambient temperature in a conventional furnace under
a pure argon atmosphere until the boriding temperature
(1123 K ≤ T ≤ 1273 K), the boride incubation time tFe B
0
2
will
not depend on the boriding temperature in this early stage of
the growth. The Fe2
B crystals grow from the contact zones
between the metal surface and mixture of powders composed
Figure 8. The temperature dependence of boron diffusion coefficient
in the Fe2
B layer.
of 20% B4
C, 10% KBF4
and 70% SiC, lengthening upon
the surface of the base metal forming a thin layer during
the nucleation stage. For example, if you want to select
T = 1273 K in the electronic control of the furnace, the
thermochemical treatment will first reach the temperature of
1123 K at the same time as if you had selected the temperature
of 1223 K, for this reason the boride incubation time will be
a constant for each substrate.Figure 8 gives the temperature
dependence of the boron diffusion coefficients in the Fe2
B
layers following the Arrhenius equation.
The value of boron diffusion coefficient in Fe2
B at
each temperature was estimated from Equation (14) based
on the integral method. This value can be easily obtained
from the slope of straight line shown in Figure 8. The
value of 199.16 kJmol-1
indicates the amount of energy
for the boron mobility in the easiest path corresponding to
the crystallographic direction [001] along the Fe2
B layer.
Therefore, the expression describing the evolution of boron
diffusion coefficients in Fe2
B versus temperature is given
by Equation (17) in the temperature range 1123-1273 K:
(17)
where R = 8.314 J mol-1
K-1
and T the absolute temperature
in Kelvin.
Table 3 shows a comparison between the values of
activation energy for boron diffusion in Armco iron and
some ferrous alloys (steels and gray cast iron) and the
estimated value of activation energy for boron diffusion in
AISI S1 steel3,12,21-28
.
It is observed that the obtained values of boron activation
energy by different investigators are dependent on several
factors such as: (the method of calculation, the boriding
method, the nature of boriding agent, the chemical reactions
involved and the chemical composition of the substrate.
For example, Şeşen et al.21
have borided an interstitial
free (IF) steel by using the electrochemical boriding under
Table 3. Comparison of activation energy for boron diffusion in AISI S1 steel with other borided materials.
Material Boriding method Activation energy for boron diffusion (kJ mol-1
) References
XC38 steel Liquid boriding 207.8 (Fe2
B) 12
IF steel Electrochemical boriding
80.70-100.16 (FeB + Fe2
B) depending on the current
density
21
AISI D2 steel Salt-bath 170.0 (FeB + Fe2B) 22
Q235 steel Plasma electrolytic boriding 186.17(FeB + Fe2
B and Ni borides as precipitates) 23
AISI 316 Plasma paste boriding 250.0 (FeB + Fe2B) 24
AISI 1018 Steel Paste 159.3 (Fe2
B) 25
Armco Iron Powder 157.5 ( Fe2B) 26
AISI 9840 steel Powder 193.08 (Fe2
B) 27
EN-JL-250 Gray cast iron Powder 134.21 (FeB + Fe2
B) 28
AISI P20 steel Powder 200 (Fe2
B) 3
AISI S1 steel Powder
199.16 (Fe2
B) by the integral method 199.1 (Fe2
B) by
the masse balance equation
This work
.
.
expD RT
kJmol
3 4 10
199 16
Fe B
3
1
2 #=
--
-
S X
8. Silva et al.8 Materials Research
different current densities. They produced a double boride
layer (FeB and Fe2
B) where FeB was a dominant phase. A
metastable iron boride was also identified by XRD analysis.
The calculated boron activation energies ranged between
80.70 and 100.16 kJ mol-1
, depending on the value of current
density in the range 0.1 -0.4 A cm-2
. It is noticed that these
values are lower than those obtained from other reported
works3,12,21-28
. It should be attributed to the absence of carbon
and nitrogen as interstitial atoms leading to the increase in the
boron mobility within the material substrate. In addition, the
estimated value of activation energy for boron diffusion in
AISI S1 steel is very comparable to the values estimated for
AISI 9840 and AISI P20 steels by using the same chemical
composition of boriding agent3,27
.
4.4 Experimental validation of different diffusion
models
To experimentally validate the diffusion model based
on the integral method and four diffusion models, three
Figure 9. SEM micrographs of the boride layers formed at the surfaces of AISI S1 steel for three extra boriding conditions: (a) 1173 K
for 3.5 h, (b) 1173 K for 6.5 h and (c) 1223 K for 1.5 h
Table 4. Values of boron activation energies estimated from all diffusion models with the expressions used to estimate the Fe2
B layer
thickness.
D0
(m2
s-1
)
Activation
energy Q
(kJmol-1
)
Equations for evaluating the Fe2
B layer thickness References
5.9×10-3
199.15
ln
u t
t
t
C C C
D C C t
2
8
Fe B up
Fe B
low
Fe B
Fe B up
Fe B
low
Fe B
0
02
2 2
2
2 2
=
+ -
-
Q
T Q
QV
Y
V
V
5
5.9×10-3
199.15 u t D t2 Fe B2f=Q V with ε=0.0975 6
5.9×10-3
199.15
.
exp
u t
D t
C C C erf
D
k
C C k D
2
0 5
2
4Fe B
up
Fe B
low
Fe B
Fe B
up
Fe B
low
Fe B
Fe B
0
2 2 2
2
2 2
2
2 2
2
r b
b b
=
+ -
- -
Q
Q
Q
R
U
V
V
V
W
Z" %
with β=0.9517
7
5.9×10-3
199.15 u t
C C C
D C C t
2
2up
Fe B
low
Fe B
Fe B up
Fe B
low
Fe B
0
2 2
2
2 2
=
+ -
-
Q
Q
QV
V
V
8
3.4×10-3
199.16 u t
D t tFe B
Fe B
02
2
h=
-
Q V
! $ with η=13.3175
Present
work
u t
D t t TFe B
Fe B
02
2
h=
-
Q
Q
V
V! $
extra boriding conditions were used for this purpose.
Figure 9 gives the SEM images of the cross-sections of Fe2
B
layers formed at 1173 K for 3.5 h and 6.5 h and at 1223 K
for 1.5 h, respectively.
For such boriding conditions, a compact single phase
layer of Fe2
B was produced with a saw-tooth morphology.
On the basis of integral method, the expression of Fe2
B layer
thickness depending on the boriding parameters (time and
temperature) is given by Equation (18):
(18)
with expD D RT
Q
Fe B 02 = -T Yand η=13.3175
where Q is the activation energy for boron diffusion (kJmol-1
),
D0
represents a pre-exponential constant (m2
s-1
) and T is
the absolute temperature in Kelvin.
9. 9Kinetics of Formation of Fe2
B Layers on AISI S1 Steel
Table 5. Comparison between the experimental values of Fe2
B layers’ thicknesses (obtained for three boriding conditions ) and the
predicted values using different models for an upper boron content in the Fe2
B phase equal to 9 wt.%.
Boriding
conditions
Experimental
value (µm)
Simulated value
(µm)5
Simulated value
(µm)6
Simulated value
(µm)7
Simulated value
(µm)8
Simulated value
(µm) Equation
(18)
1173 K for 3.5 h 59.65±10.43 57.00 61.84 55.37 61.94 60.37
1173 K for 6.5 h 75.14 ±13.76 77.68 84.28 75.45 84.41 85.86
1223 K for 1.5 h 61.54±11.45 56.64 6146 55.02 61.55 51.71
Table 4 provides the expressions of Fe2
B layer thickness
as a function of boriding parameters derived for four diffusion
models with Equation (18) valid for the integral method. It
is seen that the estimated value of boron activation energy
forAISI S1 steel by using the diffusion model6
is very close
to that obtained from the integral method.
Table 5 gives a comparison between the experimental
values of Fe2
B layers’thicknesses (obtained for three boriding
conditions) and the predicted values using four different
models and the integral method for an upper boron content
in the Fe2
B phase equal to 9 wt.%.
It is seen that the experimental values in terms of Fe2
B
layers’ thicknesses coincide in a satisfactory way with the
predicted results.
Equation (18) can be employed as a simple tool to predict
the optimum value of Fe2
B layer thickness as a function of
boriding parameters (the treatment time and the process
temperature) as shown in Figure 10 to match the case depth
that meets requirements for a practical use of AISI S1 steel
in the industry.
Figure 10. Iso-thickness diagram describing the evolution of Fe2
B
layer thickness as a function of boriding parameters
5. Conclusions
In this current work, theAISI S1 steel was treated by the
powder-pack boriding in the temperature range 1123-1273 K
with a variable treatment time (from 2 h to 8 h). The boriding
agent was composed of 20% B4
C, 10% KBF4
and 70% SiC.
The XRD analysis confirmed the presence of Fe2
B phase in
the boride layer for all boriding conditions. For indication,
the XRD patterns for the borided samples at 1123, 1173 and
1223 K for 4 h were only shown as experimental evidence.
The SEM examinations revealed a saw- tooth morphology
for the Fe2
B layers formed on AISI S1 steel. The growth
kinetics of Fe2
B layers on AISI S1 steel was described by
the classical parabolic growth law with the occurrence of
a constant boride incubation time. The value of activation
energy for boron diffusion in AISI S1 steel was estimated
as 199.16 kJmol-1
on the basis of the integral method,and
compared with that obtained from an alternative diffusion
model. Furthermore, this value of boron activation energy
was compared to the values found in the literature. The
present kinetic approach based on the integral method and
four diffusion models were experimentally validated by using
three extra boriding conditions. As a consequence, a good
agreement was noticed between the experimental values
of Fe2
B layers’ thicknesses and the predicted thicknesses.
Finally, an iso-thickness diagram was suggested to be used as
a simple tool for selecting the optimized value of Fe2
B layer
thickness for practical use of AISI S1 steel in the industry.
6. Acknowledgements
The work described in this paper was supported by a
grant of PRDEP and CONACyT México (National Council
of Science and Techonology). Likewise, FCS reconoce los
fondos del Departamento de Física y Matemáticas y de la
División de Investigación de la UIA.The authors wish to
thank to the Laboratorio de Microscopía de la UIA.
7. References
10. Silva et al.10 Materials Research
1. SinhaAK.Boriding(Boronizing)ofSteels.In:ASMHandbook.Volume
4.HeatTreating.MaterialsPark:ASMInternational;1990.p.437-447.
2. KeddamM,ChentoufSM.Adiffusionmodelfordescribingthebilayer
growth (FeB/Fe2B) during the iron powder-pack boriding. Applied
Surface Science. 2005;252(2):393-399.
3. KeddamM,Elias-EspinosaM,Ortiz-DomínguezM,Simón-Marmolejo
I, Zuno-Silva J. Pack-boriding of AISI P20 steel: Estimation of
boron diffusion coefficients in the Fe2B layers and tribological
behaviour. International Journal of Surface Science and
Engineering.2017;11(6):563-585.
4. Keddam M, Ortiz-Dominguez M, Elias-Espinosa M, Arenas-
Flores A, Zuno-Silva J, Zamarripa-Zepeda D, et al.Kinetic
Investigation and Wear Properties of Fe2
B Layers on AISI
12L14 Steel. Metallurgical and Materials Transactions
A.2018;49(5):1895-1907.
5. Ortiz-Domínguez M, Flores-Rentería MA, Keddam M, Elias-
Espinosa M, Damián-Mejía O, Aldana-González JI, et al.
Simulation of growth kinetics of Fe2
B layers formed on gray
cast iron during the powder-pack boriding. Materials and
Technology. 2014;48(6):905-916.
6. Elias-Espinosa M, Ortiz-Domínguez M, Keddam M, Gómez-
Vargas OA, Arenas-Flores A, Barrientos-Hernández FR, et al.
Boriding kinetics and mechanical behaviour of AISI O1 steel.
Surface Engineering. 2015;31(8):588-597.
7. Nait Abdellah Z, Keddam M, Chegroune R, Bouarour B,
Haddour L, Elias A. Simulation of the boriding kinetics of
Fe2
B layers on iron substrate by two approaches. Matériaux
et Techniques. 2012;100(6-7):581-588.
8. Flores-Rentería MA, Ortiz-Domínguez M, Keddam M,
Damián-Mejía O, Elias-Espinosa M, Flores-González MA,
et al. A Simple Kinetic Model for the Growth of Fe2
B Layers
on AISI 1026 Steel During the Powder-pack Boriding. High
Temperature Materials and Processes. 2015;34(1):1-11.
9. Kouba R, Keddam M,Kulka M. Modelling of paste boriding
process. Surface Engineering. 2015;31(8):563-569.
10. Ramdan RD, Takaki T, Tomita Y. Free Energy Problem for the
Simulations of the Growth of Fe2
B Phase Using Phase-Field
Method. Materials Transactions.2008;49(11):2625-2631.
11. Campos I, Oseguera J,Figueroa U, Garcia JA, BautistaO,
Kelemenis G. Kinetic study of boron diffusion in the paste-
boriding process. MaterialsScience and Engineering: A.
2003;352(1-2):261-265.
12. Mebarek B, Benguelloula A, Zanoun A. Effect of Boride
Incubation Time During the Formation of Fe2
B Phase.
Materials Research. 2018;21(1):e20170647.DOI: http://
dx.doi.org/10.1590/1980-5373-mr-2017-0647
13. Brakman CM, Gommers AWJ,Mittemeijer EJ. Boriding of
Fe and Fe-C, Fe-Cr, and Fe-Ni alloys; Boride-layer growth
kinetics. Journal of Materials Research. 1989;4(6):1354-
1370.
14. Yu LG, Chen XJ, Khor KA, Sundararajan G. FeB/Fe2
B
phase transformation during SPS pack-boriding: boride layer
growth kinetics. Acta Materialia.2005;53(8):2361-2368.
15. Okamoto H. B-Fe (boron-Iron). Journal of Phase Equilibria
and Diffusion. 2004;25(3):297-298.
16. Krukovich MG, Prusakov BA, Sizov IG. The Components
and Phases of Systems 'Boron-Iron' and 'Boron-Carbon-
Iron'.In: Krukovich MG, Prusakov BA, Sizov IG. Plasticity
of Boronized Layers. Volume 237 of the Springer Series in
Materials Science. Cham: Springer; 2016. P. 13-21.
17. Goodman TR. Application of Integral Methods to Transient
Nonlinear HeatTransfer.Advances in Heat Transfer.1964;1:51-122.
18. Reséndiz-Calderon CD, Rodríguez-Castro GA, Meneses-Amador
A, Campos-Silva IE,Andraca-Adame J, Palomar-Pardavé ME, et
al. Micro-Abrasion Wear Resistance of Borided 316LStainless
Steel and AISI 1018 Steel. Journal of Materials Engineering
and Performance. 2017;26(11):5599-5609.
19. Carbucicchio M, Badani L,Sambogna G. On the early stages
of high purity iron boriding with crystalline boron powder.
Journal of Materials Science. 1980;15(6):1483-1490.
20. Palombarini G, Carbucicchio M. Growth of boride coatings on
iron. Journal of Materials Science Letters. 1987;6(4):415-416.
21. Sesen FE, ÖzgenÖS, Sesen MK. A Study on Boronizing
Kinetics of an Interstitial-Free Steel. Materials Performance
and Characterization. 2017;6(4):492-509.
22. Sen S, Sen U,Bindal C.An approach to kinetic study of borided
steels. Surface and CoatingsTechnology. 2005;191(2-3):274-
285.
23. Jiang YF, BaoYF, Wang M. Kinetic Analysis of Additive on
Plasma Electrolytic Boriding. Coatings. 2017;7(5):61.
24. Chegroune R, Keddam M, NaitAbdellah Z, Ulker S, Taktak S,
Gunes I. Characterization and kineticsof plasma-paste-borided
AISI 316 steel. Materials and Technology. 2016;50(2):263-268.
25. Campos-Silva I, Ortiz-Dominguez M. Modelling the growth
of Fe2
B layers obtained by the paste boriding process in AISI
1018 steel irons. International Journal of Microstructure and
Materials Properties. 2010;5(1):26-38.
26. Elias-Espinosa M, Ortiz-Domínguez M, Keddam M, Flores-
Rentería MA, Damián-Mejía O, Zuno-Silva J, et al. Growth
Kinetics of the Fe2
B Layers and Adhesion on Armco Iron
Substrate. Journal of Materials Engineering and Performance.
2014;23(8):2943-2952.
27. Ortiz-Domínguez M, Gómez-Vargas OA, Keddam M,Arenas-
Flores A, García-Serrano J. Kinetics of boron diffusion and
characterization of Fe2
B layers onAISI 9840 Steel. Protection
of Metals and Physical Chemistry of Surfaces. 2017;53(3):534-
547.
28. Azouani O, Keddam M,Allaoui O, SehissehA. Kinetics of the
Formation of Boride Layers on EN-GJL-250 Gray Cast Iron.
Materials Performance and Characterization. 2017;6(4):501-
522.