Definitions, Major Causes of Corrosion,Other Causes of Corrosion, Forms Of Corrosion, How Does corrosion Happen ?,The Process of Corrosion (Five facts)
Measurement of Corrosion.
Corrosion Rate.
Comparison between Different metals.
Corrosion Prevention.
Corrosion monitoring.
Side effects of Prevention Methods.
Conclusion.
A brief introduction to corrosion and types of corrosion, such as pitting corrosion.
Cavitations corrosion
Galvanic corrosion.
Fretting corrosion.
Crevice corrosion.
Intergranular and transgranular corrosion,
Stress corrosion
Corrosion is a natural process, which converts a refined metal to a more chemically-stable form, such as its oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and stopping corrosion.
An introductory presentation on corrosion and its prevention. Importance of corrosion, cost of corrosion, various forms of corrosion, and preventive methods are given.
A brief introduction to corrosion and types of corrosion, such as pitting corrosion.
Cavitations corrosion
Galvanic corrosion.
Fretting corrosion.
Crevice corrosion.
Intergranular and transgranular corrosion,
Stress corrosion
Corrosion is a natural process, which converts a refined metal to a more chemically-stable form, such as its oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and stopping corrosion.
An introductory presentation on corrosion and its prevention. Importance of corrosion, cost of corrosion, various forms of corrosion, and preventive methods are given.
Corrosion of material - Engineering MetallurgyMechXplain
The PPT is on Corrosion and Degradation of Material specifically Metal and Reason Behind it. As well as the preventive measures to be taken to prevent it.
When you design your product, you put a lot of money, energy and consideration into achieving the best possible function, good appearance and high reliability. Corrosion, wear and fatigue resistance may not be the first factors you consider.
However, material selection is crucial to obtain a long service life and to avoid damage such as operation failure – for instance due to inadequate mechanical strength - or unacceptable appearance due to corrosion products.
If you choose the correct materials for your product from the beginning, you can prevent damage deriving from corrosion, wear and mechanical impact. In many cases, you may completely avoid corrosion by choosing a resistant material for its actual application environment.
A presentation giving the basic principles of corrosion. Electrochemical nature of corrosion, anodic and cathodic reactions, electrode potentials, mixed potential theory and kinetics of corrosion, thermodynamics of corrosion and Pourbaix diagrams, and passivization behavior of metals are outlined.
It includes mechanism of corrosion of steel reinforcement in concrete. It includes concepts like passivation, chloride ingress and chloride binding. It deals with the durablity aspects of a concrete structure.
Video lecture is available on YouTube on the link:https://youtu.be/xrBnxxN-RUw
For UG students of All Engineering Branches, Chemistry, Food Science, Polymer Science, Chemical Engg. etc.
Corrosion represents one of the most serious noticed in the industrial world especially in petrochemical, petroleum, power plants, etc.
Billions of Dollars are lost yearly due to the affect of corrosion in the world.
General Corrosion
Galvanic Corrosion
Concentration-Cell Corrosion
Intergranular Corrosion
Stress Corrosion Cracking
Pitting
Corrosion of material - Engineering MetallurgyMechXplain
The PPT is on Corrosion and Degradation of Material specifically Metal and Reason Behind it. As well as the preventive measures to be taken to prevent it.
When you design your product, you put a lot of money, energy and consideration into achieving the best possible function, good appearance and high reliability. Corrosion, wear and fatigue resistance may not be the first factors you consider.
However, material selection is crucial to obtain a long service life and to avoid damage such as operation failure – for instance due to inadequate mechanical strength - or unacceptable appearance due to corrosion products.
If you choose the correct materials for your product from the beginning, you can prevent damage deriving from corrosion, wear and mechanical impact. In many cases, you may completely avoid corrosion by choosing a resistant material for its actual application environment.
A presentation giving the basic principles of corrosion. Electrochemical nature of corrosion, anodic and cathodic reactions, electrode potentials, mixed potential theory and kinetics of corrosion, thermodynamics of corrosion and Pourbaix diagrams, and passivization behavior of metals are outlined.
It includes mechanism of corrosion of steel reinforcement in concrete. It includes concepts like passivation, chloride ingress and chloride binding. It deals with the durablity aspects of a concrete structure.
Video lecture is available on YouTube on the link:https://youtu.be/xrBnxxN-RUw
For UG students of All Engineering Branches, Chemistry, Food Science, Polymer Science, Chemical Engg. etc.
Corrosion represents one of the most serious noticed in the industrial world especially in petrochemical, petroleum, power plants, etc.
Billions of Dollars are lost yearly due to the affect of corrosion in the world.
General Corrosion
Galvanic Corrosion
Concentration-Cell Corrosion
Intergranular Corrosion
Stress Corrosion Cracking
Pitting
this slide comprises of definition.rate, and types of corrosion which are found in materials in our daily life.
its contents are:
what is corrosion
what are its basic types and
what is the rate of corrosion in materials
14 Types of Corrosion explained in an awesome manner
Update 26 June 2019: I have enabled the Download option and now everyone can download the "Types of corrosions" PPT and reuse the slides :) I wish I have done this earlier.
Follow my blogs at https://www.geekdashboard.com/
Corrosion is a natural process that deteriorates materials, commonly metals, due to chemical or electrochemical reactions with their environment. It's a significant concern across various industries, including infrastructure, manufacturing, and transportation. The effects of corrosion can range from minor aesthetic damage to catastrophic structural failure, leading to enormous economic costs and safety hazards.
Several factors influence corrosion, including environmental conditions such as moisture, temperature, pH levels, and the presence of corrosive agents like oxygen, sulfur compounds, and salts. Additionally, the material's composition and microstructure play crucial roles in its susceptibility to corrosion.
To mitigate corrosion and prolong the lifespan of materials, various protection methods are employed:
Barrier Protection: This involves applying coatings or barriers to physically isolate the material from its environment. Common barrier materials include paints, polymer coatings, and enamels. These coatings create a protective layer that prevents corrosive agents from reaching the underlying material.
Cathodic Protection: This method involves making the metal to be protected the cathode of an electrochemical cell, thus reducing its corrosion rate. Cathodic protection can be achieved through sacrificial anodes, where a more reactive metal (such as zinc or magnesium) is connected to the metal to be protected, sacrificing itself to protect the base metal.
Anodic Protection: Conversely, anodic protection works by polarizing the metal to be protected to make it the anode in an electrochemical cell. This method is suitable for metals that exhibit passivity, such as stainless steel. By maintaining the metal in its passive state, its corrosion rate is significantly reduced.
Inhibitors: Corrosion inhibitors are chemicals that are added to the environment surrounding the metal to reduce its corrosion rate. Inhibitors work by adsorbing onto the metal surface, forming a protective layer that blocks corrosive agents from reaching the metal. Common inhibitors include organic compounds, chromates, and phosphates.
Alloying: Alloying involves mixing the base metal with other elements to improve its corrosion resistance. For example, stainless steel contains chromium, which forms a passive oxide layer on the surface, protecting the underlying metal from corrosion.
Design Modification: Sometimes, corrosion can be mitigated through design modifications that minimize exposure to corrosive environments or improve drainage to prevent the accumulation of moisture.
Each protection method has its advantages and limitations, and the choice of method depends on factors such as the material, the environment, cost considerations, and the required durability. In many cases, a combination of protection methods may be employed to provide optimal corrosion resistance.
a natural process that converts a refined metal into a more chemically stable form such as oxide, hydroxide, carbonate or sulfide. It is the gradual destruction of materials (usually a metal) by chemical and/or electrochemical reaction with their environment.
This topic describes two main categories of corrosion. It also explains the electrochemical corrosion phenomena and the differences between the types of corrosion. This topic also states the corrosion preventive steps.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
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About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
2. Table of Content
1. Definitions.
2. Major Causes of Corrosion.
3. Other Causes of Corrosion.
4. Forms Of Corrosion.
5. How Does It Happen ?
6. The Process of Corrosion (Five facts).
7. Measurement of Corrosion.
8. Corrosion Rate.
9. Comparison between Different metals.
10. Corrosion Prevention.
11. Corrosion monitoring.
12. Side effects of Prevention Methods.
13. Conclusion.
Page 1 of 33
3. 1. Definitions
What is Steel ?
Steel is an alloy of iron and other elements, primarily carbon, that is
widely used in construction and other applications because of its
high tensile strength and low cost.
What is Corrosion?
Corrosion is defined as the destruction or deterioration of a material
because of its reaction with environment. When metals revert to their
combined state, they corrode. Corrosion may affect one or more
properties of the metal, which need to be preserved.
Page 2 of 33
4. Figure 1. Minaus River Bridge collapse 1983, USA , the incident killed 3 people
and the repairs totaled $20 million USD (flickr.com)
Page 3 of 33
5. 2. Major Causes of Corrosion
• Nature of the metal or alloy.
• Presence of inclusions or other foreign matter at the
surface.
• Homogeneity of the metallic structure.
• Nature of the corrosive environment.
• Incidental environmental factors such as variations in
the presence of dissolved oxygen, of temperature,
and in the velocity of movement either of the
environment or of the system itself.
Page 4 of 33
6. 3. Other Causes of Corrosion
• Other factors such as stress (residual or applied, steady or
cyclic).
• Presence of deposits on surfaces.
• Fayed surfaces and the possibility of corrosion crevices.
• Incidental presence of stray electrical currents from
external sources.
Page 5 of 33
7. 4. Forms Of Corrosion
Corrosion may be classified in
different ways:
• Wet / Aqueous corrosion & Dry
Corrosion
• Room Temperature/ High
Temperature Corrosion
CORROSION
WET
CORROSION
DRY
CORROSION
CORROSION
ROOM
TEMPERATURE
CORROSION
HIGH
TEMPERATURE
CORROSION
Page 6 of 33
8. 4. Forms Of Corrosion (Con..)
• Wet / Aqueous corrosion is the
major form of corrosion which
occurs at or near room temperature
and in the presence of water.
• Dry / gaseous corrosion occurs
when there is no water or
moisture to aid the corrosion,
and the metal oxidises with the
atmosphere alone , and it is
significant mainly at high
temperatures.
Page 7 of 33
Figure 2. Forms of corrosion
(Corrosion.doctors.com).
9. (a) 1. Uniform Corrosion:
Generally occurs due to direct chemical
attacks.
(b) 2. Galvanic Corrosion:
An electrochemical action that occurs
between two dissimilar metals which are
in contact with other.
(c) 3. Crevice Corrosion:
It occurs when metals are in contact with
nonmetals.
(d) 4. Pitting Corrosion:
corrosion of an open metal surface,
confined to a point or small area, which
takes the form of small cavities.
5. Forms Of Corrosion (Con..)
Table 1. Classification of corrosion based on the appearance of the corroded metal (Edward , 2010)
Page 8 of 33
10. (e) 5. Intergranular Corrosion:
It occurs on grain boundaries of a metal
or alloy.
(f) 6. Dealloying Corrosion:
preferential dissolution of an alloying
element due to corrosion (aka parting
corrosion or selective leaching).
(g) 7. Erosion-corrosion:
a conjoint action involving corrosion and
erosion in the presence of a moving
corrosive fluid leading to the accelerated
loss of material.
(h) 8. Environmentally assisted cracking :
EAC is a general term that includes
corrosion fatigue and stress corrosion
cracking (SCC).
Figure 2. a-h shows different types of corrosion (chemistry.tutorvista.com)
5. Forms Of Corrosion (Con..)
Page 9 of 33
11. Table 2. 1970’s Industry Study of Failures (corrosion.doctors.com)
Method % of Failures
Corrosion (all types) 33%
Fatigue 18%
Brittle Fracture 9%
Mechanical Damage 14%
Fab./Welding Defects 16%
Other 10%
5. Forms Of Corrosion (Con…)
Page 10 of 33
12. 6. How Does It Happen ?
• The corrosion product we see most commonly is the rust which forms
on the surface of steel and somehow:
Steel Rust (6.1)
• Two reaction : for this to happen the major component of steel, iron
(Fe) at the surface undergoes a number of reactions :
Firstly, the iron atom can lose some electrons and become a
positively charged ion.
Fe 𝑭𝒆 𝒏+
+ n electrons (6.2)
Anodic reaction (corrosion)
Secondly, the other half of the reaction must involve water (H2O) and
oxygen (O2) something like this :
𝐎 𝟐+ 𝟐𝐇 𝟐 𝐎+ 4e- 4OH- (6.3)
Page 11 of 33
13. 6. How Does It Happen ? (Con..)
• This makes sense as we have a negatively charged material
that can combine with the iron and electrons, which are
produced in the first reaction are used up. We can, for clarity,
ignore the electrons and write :
2Fe + 𝐎 𝟐 + 𝟐𝐇 𝟐 𝐎 → 2Fe(OH)2 (6.4)
Iron + Water with oxygen dissolved in it → Iron Hydroxide
Page 12 of 33
14. 6. How Does It Happen ? (Con..)
• The Next Step, Oxygen dissolves quite readily in water and because
there is usually an excess of it, reacts with the iron hydroxide.
4Fe(OH)2 + 𝐎 𝟐 → 𝟐𝐇 𝟐 𝐎 + 2Fe2O3. 𝐇 𝟐 𝐎 (6.5)
Iron hydroxide + oxygen → water + Hydrated iron oxide
(brown rust)
Page 13 of 33
15. 6. How Does It Happen ? (Con..)
Figure 3. Rust, the Result of Corrosion of Metallic Iron
Page 14 of 33
16. 7. The Process of Corrosion (Five facts)
This series of steps tells us a lot about the corrosion process:
1) Ions are involved and need a medium to move in (usually water)
2) Oxygen is involved and needs to be supplied.
3) The metal has to be willing to give up electrons to start the process
4) A new material is formed and this may react again or could be
protective of the original metal.
5) A series of simple steps are involved and a driving force is needed
to achieve them.
The most important fact is that interfering with the steps allows the
corrosion reaction to be stopped or slowed to a manageable rate.
Page 15 of 33
17. 8. Measurement of Corrosion
During the process of corrosion, weight of material decreases and depth
of corrosion layer/pits increases. Further, the mechanical properties
such as yield (YS) and tensile strength (UTS) are decreased.
Corrosion effect Unit
Weight change g /m2 /year
Increase in corrosion depth µm /year; mpy (mil per year)
Corrosion current mA /cm2
Decrease in Y.S, UTS % / year
Table 3. The effects and measurement units of corrosion(unknown).
Page 16 of 33
18. 9. Corrosion Rate
Status ipy mm/y
Completely Satisfactory <0.01 0.25
Use with caution <0.03 0.75
Use only for short exposure <0.06 0.15
Completely unsatisfactory >0.06 0.15
Table 4: Acceptable corrosion rate (Ukoba, O.Kingsley et. Al, 2013)
𝒄𝒐𝒓𝒓𝒐𝒔𝒊𝒐𝒏 𝒓𝒂𝒕𝒆 =
𝑾
𝑻𝑺𝑨 𝑿
𝑻
𝟑𝟔𝟓
Where: W = weight loss (gram)
TSA = total surface area (mm2)
T = time of exposure (days)
Page 17 of 33
19. 10. Comparison between Different metals.
MASS LOSS g/m2
Corrosiveness categoryCarbon
Steel
Zinc Copper Aluminum
≤10 ≤0.7 ≤ 0.9 Negligible Very low C1
10–200 0.7–5 0.9–5 ≤0.6 Low C2
200–400 5–15 5–12 0.6–2 Medium C3
400–650 15–30 12–25 2–5 High C4
650–1,500 30–60 25–50 5–10 Very high C5
Table 5. Mass loss (g/m2 ) for one year field test exposure in the five corrosivity
classes C1–C5, the order being from the least to the most corrosive. (R.Landolfo,
2010)
Page 18 of 33
20. 11. Corrosion Prevention
1) Conditioning the Metal: This can be sub-divided into two
main groups:
A. Coating the metal, in order to interpose a corrosion
resistant coating between metal and environment. The
coating may consist of (a) another metal, e.g. zinc (b) a
protective coating derived from the metal itself, e.g.
aluminium oxide (C ) organic coatings, such as resins,
plastics, paints.
B. Alloying the metal to produce a more corrosion resistant
alloy, e.g. stainless steel (alloyed with chromium and nickel)
Page 19 of 33
21. 11. Corrosion Prevention (Con..)
2) Conditioning the Corrosive Environment :
A. Removal of Oxygn: By the removal of oxygen from water
systems in the pH range 6.5-8.5 one of the components
required for corrosion would be absent.
B. Corrosion Inhibitors: A corrosion inhibitor is a chemical
additive, which, when added to a corrosive aqueous
environment, reduces the rate of metal wastage. Such as
(a) Anodic inhibitors are chemical substances that form a
protective layer of oxide film on the surface of metal.
(B) Cathodic inhibitors slow the reaction at the cathode or
precipitate cathodic areas in order to increase the resistance
on the surface
Page 20 of 33
22. 11. Corrosion Prevention (Con..)
3) Electrochemical Control:
A. Cathodic protection (CP) is a technique used to control the
corrosion of a metal surface by making it the cathode of an
electrochemical cell. A simple method of protection connects the
metal to be protected to a more easily corroded "sacrificial metal" to
act as the anode.
B. Anodic protection (AP) is a technique to control the corrosion of a
metal surface by making it the anode of an electrochemical cell and
controlling the electrode potential in a zone where the metal is
passive.
Page 22 of 33
23. 11. Corrosion Prevention (Con..)
Steel Tank
Cathod
Mg Rod
Anode
Hot Water
Current
Figure 4. sacrificial anodic protection method (nptel Lectures)
Page 23 of 33
24. 11. Corrosion Prevention (Con..)
Power
Supply
BA
C
Figure 5. Anodic protection of inner surface of a steel acid storage tank (nptel Lectures)
A. Auxiliary cathode
B. B. Reference electrode
C. C. Anode connection to the tank
Page 24 of 33
25. 11. Corrosion Prevention (Con..)
Table 6. Comparison of Anodic and Cathodic protection (corrosiondoctor.com)
Anodic Cathodic
Applicability Active-passive
matals/alloys
All metals/alloys
Nature of corrosive
medium
Weak to aggressive Weak to medium
Cost: Installation
Maintenance
High
Very low
Low
Medium to high
Operating
conditions
Can be accurately
determine
Determined by
empirical testing
Significance of
applied current
Direct measure of
protected corrosion
rate
Complex to indicate
corrosion rate
Page 25 of 33
26. 12. Corrosion monitoring
Corrosion monitoring may be defined as the systematic
measurement of corrosion rate of equipment with the object of
diagnosis and controlling corrosion.
• It can also be used for monitoring efficiency of implementation of
corrosion control system.
• For reliable operation it is important to identify the location, rate,
and underlying causes of corrosion.
Page 26 of 33
27. 12.1 Corrosion Monitoring Activities
An effective corrosion monitoring program includes a wide
range of activities:
• Identification of component alloy composition.
• Measurement of the location and extent of corrosion.
• Prediction of remaining life.
• Identification of failure mechanisms.
• Determination of fitness for service condition.
• Inspection scheduling.
• Development of recommendations for treatment and
correction of problems.
• Development of corrosion prevention strategies.
Page 27 of 33
28. 12.2 Corrosion Monitoring Methods
Corrosion Monitoring uses a wide range of measurement techniques.
non-destructive testing (NDT) methods are the most effective and
broadly applied testing methods. Suitable NDT methods for the
monitoring of corrosion include:
• Ultrasonic testing
• Radiographic testing
• Guided wave testing
• Electromagnetic testing
The selection of the suitable method as well as the inspection and
monitoring of corrosion requires knowledgeable and experienced
personnel.
Page 28 of 33
29. 13. Common methods of corrosion prevention and its
impacts on human and environmental health.
1) Painting:
Even though painting the metalic substance is a great method of
corrosion prevention, it also has negative impacts. When paints dry
up, they release VOC (Volatile Organic Compounds). The fumes of
VOC are very toxic and can cause problems when inhaled and may
play a role in pollution.
2) Galvanizing:
Galvanizing is more effective than painting the surfaces as it lasts
longer and doesn't have any harmful impacts on the environment
and human beings.
Page 29 of 33
30. 13. Common methods of corrosion prevention and its impacts
on human and environmental health (Con..)
3) Cathodic protection:
A side effect of the cathodic protection was to increase marine growth.
Copper, when corroding, releases copper ions which have an anti-
fouling effect.
Figure 6. presents marine growth on offshore structure (offshorewind.biz)
Page 30 of 33
31. 14. Conclusion
• Corrosion is defined as the destruction or
deterioration of a material because of its reaction
with environment.
• There are many Causes of Corrosion such as
Nature of the metal or alloy, and corrosive
environment.
• Corrosion may be classified in different ways for
example wet and dry corrosion.
Page 31 of 33
32. 14. Conclusion
• The metal can be produced by many methods.
• For reliable operation it is important to identify the
location, rate, and underlying causes of corrosion.
• Non-destructive testing (NDT) methods are the
most effective and broadly applied testing methods
for corrosion monitroring.
Page 32 of 33
33. References
1) McCafferty, Edward. Introduction to corrosion science. Springer Science
& Business Media, 2010.
2) Ahmad, Zaki. Principles of corrosion engineering and corrosion control.
Butterworth-Heinemann, 2006.
3) Vandelinder, L. S. "Corrosion Basics-An Introduction." L. S. Vandelinder,
Ed. 364 pages, 8. 5 x 11 in.(22 x 28 cm), hard cloth. NACE, Houston,
Texas, 1984. Item 51020 (1984).
4) Olusunle, S. O. O., B. Ebiwonjumi, and R. O. Medupin. "Mathematical
Modeling: A Tool for Material Corrosion Prediction." (2011).
5) https://www.nrc.gov/docs/ML1122/ML11229A059.pdf
6) http://www.corrosion-doctors.org/
7) https://en.wikipedia.org/wiki/Corrosion_monitoring.