These processes are sometimes referred to as post-processing. They play a very important role in the appearance, function and life of the product. Broadly, these are processes that affect either a thin layer on the surface of the part itself, or add a thin layer on top of the surface of the part. There are different coating and surface treatments processes, with different applications, uses, etc. The important uses include:
• Improving the hardness
• Improving the wear resistance
• Controlling friction, Reduction of adhesion, improving the lubrication, etc.
• Improving corrosion resistance
• Improving aesthetics
9.1. Mechanical hardening of the surface
These methods apply mechanical impulses (e.g. light hammering) on the surface of a metallic part. This hammering action causes tiny amount of plastic flow on the surface, resulting in the work-hardening of the surface layer due to the introduction of compressive residual stresses. Examples of these processes include Shot peening (uses tiny balls of metal or ceramic), Water-jet peening (uses a jet of water at high pressures, e.g. 400 MPa), or Laser peening (surface is hit by tiny impulses from a laser) – an expensive process used to improve fatigue strength of jet fan blades and turbine impellers.
Another method is explosive hardening, where a layer of explosive coated on the surface is blasted – the resulting impact results in tremendous increase in the surface hardness. This method is used to harden the surface of train rails.
9.2. Case hardening
This is a very common process that is used to harden the outer surface of parts such as gear teeth, cams, shafts, bearings, fasteners, pins, tools, molds, dies etc. In most of these types of components, the use involves dynamic forces, occasional impacts, and constant friction. Therefore the surface needs to be hard to prevent wear, but the bulk of the part should be tough (not brittle); this is achieved best by case hardening. There are several types of case hardening: in most cases, the chemical structure of the metal is changed by diffusing atoms of an alternate element which results in alterations to the micro-structure on the crystals on the surface.
A brief knowledge about surface treatment, which is a process applied to the surface of a material to make it better in some way, for example by making it more resistant to corrosion or wear. Shot peening is a surface treatment in which small hard pellets are shot against the surface of a metal to make it more resistant to fatigue.
The presentation covers various aspects of coating and deposition process in detail. The topics that are mainly covered in this PPT are
1) Type of Coating
2) Advantages and limitation for various coating process
3) Figures of various coating process
A brief knowledge about surface treatment, which is a process applied to the surface of a material to make it better in some way, for example by making it more resistant to corrosion or wear. Shot peening is a surface treatment in which small hard pellets are shot against the surface of a metal to make it more resistant to fatigue.
The presentation covers various aspects of coating and deposition process in detail. The topics that are mainly covered in this PPT are
1) Type of Coating
2) Advantages and limitation for various coating process
3) Figures of various coating process
Corrosion: Definition and significance of corrosion, mechanism of chemical (dry) and
electrochemical (wet) corrosion, galvanic corrosion, concentration corrosion and pitting
corrosion. Protection from corrosion; protective coatings-galvanization and tinning, cathodic
protection, sacrificial anode modifications in design.
Definition of coating,advantages of coating, types of coating,brief explanation of each type of coating giving process aaplication advatanges about organic coating, inorganic coating,metallic coating,conversion coating, precoated metals coating hot dipping, electroplating
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.
For construction professionals and sales personnel.
The material will take you through the basics of raw materials and coatings as well as describes how to use them in different applications. After studying the material you will:
* Know the basics of raw materials and coatings
* Know the newest products in coatings
* Get introduced to how different coatings and steel grades are used in construction applications
* Know some technical performance of the coatings
* Get a deeper overview of the two newest coating options
* Get some important tips maintenance-wise
Read more about steel coatings:
ruukki.com/colourcoatedsteels
ruukki.com/metalcoatedsteels
Corrosion: Definition and significance of corrosion, mechanism of chemical (dry) and
electrochemical (wet) corrosion, galvanic corrosion, concentration corrosion and pitting
corrosion. Protection from corrosion; protective coatings-galvanization and tinning, cathodic
protection, sacrificial anode modifications in design.
Definition of coating,advantages of coating, types of coating,brief explanation of each type of coating giving process aaplication advatanges about organic coating, inorganic coating,metallic coating,conversion coating, precoated metals coating hot dipping, electroplating
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.
For construction professionals and sales personnel.
The material will take you through the basics of raw materials and coatings as well as describes how to use them in different applications. After studying the material you will:
* Know the basics of raw materials and coatings
* Know the newest products in coatings
* Get introduced to how different coatings and steel grades are used in construction applications
* Know some technical performance of the coatings
* Get a deeper overview of the two newest coating options
* Get some important tips maintenance-wise
Read more about steel coatings:
ruukki.com/colourcoatedsteels
ruukki.com/metalcoatedsteels
The desired to reach higher efficiencies, lower specific fuel consumption and reduced emission in modern engines has becomes the primary focus of engine researches and manufactures over the past three decades. Ceramic coating is a solution to such problem as they provide good thermal barrier properties for designers. In the design of adiabatic engines, reducing in cylinder heat rejection requires very special thermal barrier coatings on the engine combustion chamber. Partial Thermal barrier coatings (TBC) on the top surface of the piston is considered as a solution for reduction of unburned Hydrocarbon (HC) emission produce by incomplete combustion with respect to crevice volume when engines start. The TBC on the top piston surface decreases the thermal conductivity and increases the unburned charged oxidation, so that the metallic substrates will be exposed to lower peak temperature thereby reducing the thermal stress in engines components. Also thermal barrier coatings on other elements of combustion chamber of internal combustion engine offer advantages including fuel efficiency, multi fuel capacity and high power density. Therefore, thermal barrier coating (TBC) technology is successfully applied to the internal combustion engines, in particular to the combustion chamber.
TALAT Lecture 1202: Metallography of Aluminium AlloysCORE-Materials
This lecture aims at providing a survey of the metallographic techniques available for the examination of aluminium and its alloys. The information must be sufficient to be sure that the students and the users are able to choose the most suitable technique to solve their problems in the examination of samples. The lecture should contain a direct understanding of the main problems in the metallography of the different classes of aluminium materials.
Investigation on corrosion behaviour of mild steel using al, zn, ni cr coatin...IJLT EMAS
Mild steel is the base material most commonly and
widely used in ship and pipe building material. The purpose of
this project is to analyse the different coating material like
aluminium, zinc and Nichrome using thermal spray process and
to select the suitable coating material for mild steel which resists
corrosion better. The main aim of this research is to analyse the
corrosion of coated mild steel in its first stages, in order to
determine its corrosion rate and to select the suitable coating
material for corrosion resistance of mild steel.
Surface Processing Operation includes material surface cleaning and surface treating processes which is physically and/or chemically to alter surface texture, Mechanical properties, Physical properties, Chemical Properties etc, to have a better material.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
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
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.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
1. 1
Lecture 9. Surface Treatment, Coating, Cleaning
These processes are sometimes referred to as post-processing. They play a very important role in the
appearance, function and life of the product. Broadly, these are processes that affect either a thin layer on the
surface of the part itself, or add a thin layer on top of the surface of the part. There are different coating and
surface treatments processes, with different applications, uses, etc. The important uses include:
• Improving the hardness
• Improving the wear resistance
• Controlling friction, Reduction of adhesion, improving the lubrication, etc.
• Improving corrosion resistance
• Improving aesthetics
9.1. Mechanical hardening of the surface
These methods apply mechanical impulses (e.g. light hammering) on the surface of a metallic part. This
hammering action causes tiny amount of plastic flow on the surface, resulting in the work-hardening of the
surface layer due to the introduction of compressive residual stresses. Examples of these processes include
Shot peening (uses tiny balls of metal or ceramic), Water-jet peening (uses a jet of water at high pressures,
e.g. 400 MPa), or Laser peening (surface is hit by tiny impulses from a laser) – an expensive process used to
improve fatigue strength of jet fan blades and turbine impellers.
Another method is explosive hardening, where a layer of explosive coated on the surface is blasted – the
resulting impact results in tremendous increase in the surface hardness. This method is used to harden the
surface of train rails.
9.2. Case hardening
This is a very common process that is used to harden the outer surface of parts such as gear teeth, cams,
shafts, bearings, fasteners, pins, tools, molds, dies etc. In most of these types of components, the use involves
dynamic forces, occasional impacts, and constant friction. Therefore the surface needs to be hard to prevent
wear, but the bulk of the part should be tough (not brittle); this is achieved best by case hardening. There are
several types of case hardening: in most cases, the chemical structure of the metal is changed by diffusing
atoms of an alternate element which results in alterations to the micro-structure on the crystals on the surface.
The basic method is fairly simple: the metal parts are put in an oven, and heated with the atmosphere
containing excess of a gaseous/liquid form of the “doping” substance. This causes the dopant to diffuse into
2. 2
the surface. The duration and temperature control the concentration and depth of the doping. Most of these
processes are used to case harden steel and other iron alloys, including low carbon steels, alloy steels, tool
steels etc.
Process Dopant Procedure Notes Applications
Carburizing C Low-carbon steel part in oven
at 870-950°C with excess CO2
0.5 ~ 1.5mm case gets to
65 HRC; poor
dimension control
Gears, cams,
shafts, bearings
CarboNitriding C and N Low-carbon steel part in oven
at 800-900°C with excess CO2
and NH3
0.07~0.5mm case, up to
62 HRC, lower
distortion
Nuts, bolts, gears
Cyaniding C and N Low-carbon steel part in bath of
cyanide salts with 30% NaCN
0.025~0.25mm case, up
to 65 HRC
nuts, bolts, gears,
screws
Nitriding N Low-carbon steel part in oven
at 500-600°C with excess NH3
0.1~0.6mm case, up to
1100 HV
tools, gears, shafts
Boronizing B Part heated in oven with Boron
containing gas
Very hard, wear
resistant case,
0.025~0.075mm
Tool and die steels
9.3. Thermal spraying
Metal is melted in a specially designed spray gun (using oxy-fuel, plasma, or other means to heat the sprayed
metal till it melts). High pressure gas then sprays the liquid metal, depositing a layer on top the part similar to
a painting process.
9.4. Vapor deposition
In these processes, the layer of deposited material is very thin – only a few microns. In the vacuum
evaporation process, the metal to be deposited is heated in an enclosed oven at high temperature and very low
pressure; some of the metal vapor deposits as a thin layer on the part. The surface can be coated not only with
metal, but also with some carbides, nitrides, or ceramics. Typical applications include surface coating of
cutting tools, e.g. drills, reamers, punches, dies etc.
A very important coating process is Sputtering – it is important because of its extensive use in production of
electronic chips. Here, an electric field ionizes an inert gas (e.g. Argon), and the ions are used to bombard the
coating substance. Atoms of the coating material (on the cathode), when hit by the ions, are knocked out of
the lattice, and later get deposited on the surface of the part by condensation. Aluminum sputtering is used to
create most internal connections in VLSI chips in semiconductor manufacturing.
4. 4
Figure 2. Sputtering processes [source: ece.utep.edu]
9.5. Electroplating
This is a process by which a thin layer of metal is deposited on the surface of an electrically conducting part.
The part is used as a cathode, and the depositing material forms the anode. The electrodes are dipped in a
solution of the appropriate salt, such that on application of voltage, the metal from the anode is dissolved into
the solution, and deposited on the cathode. A simple example of this process is copper plating using CuSO4
solution, using Copper anodes.
Figure 3. Copper plating
9.6. Electroless plating
In this case, the plating is achieved by a purely chemical reaction in the solution that causes the metal to be
deposited. This process can be used to plate non-conducting parts with a layer of metal. The most common
use of this process is deposition of Nickel –the reduction of Nickel chloride in solution by Sodium
hypophosphite, which causes Ni metal to be deposited on the part. The deposited metal is not in crystalline
5. 5
form, so this process is followed by heat-treatment and quenching. Ni-coating using this method is used for
making tool coatings that are quite hard (up to 1000 HV).
9.7. Anodizing
This is a very common process – many common Aluminum parts are surface treated by anodizing to give
them a different color (usually black, red, blue, etc). The process uses the metal part as an anode; using
electrolytic process, a layer of hard metal oxide is formed at the anode (i.e. on the surface of the part).
Common examples include aluminum parts, such as picture frames, car-body parts, door-knobs and other
building fixtures, bathroom fixtures and racks, sporting goods, e.g. baseball bats, and so on.
9.8. Painting
Of course, the most common surface treatment is painting. Examples of its functional value include: (i) car
body paints are corrosion resistant; (ii) boats are painted with anti corrosion paint with (toxic) chemicals to
avoid growth of barnacles, seaweed etc. Examples of aesthetic or decorative value are too numerous.
Paints are of three types:
(a) Enamel: oil-based paints that produce a smooth surface and glossy appearance
(b) Lacquers: these are resin based paints that dry to a thin coat after the solvent evaporates out. Common
examples are varnish used in painting wood.
(c) Water-based paints: common examples include several wall paints and home-interior paints.
The most common methods of paint application include:
(i) Dip coating: part is dipped into a container of paint, and pulled out.
(ii) Spray coating: one or more spray guns move along the surface of the part to give a uniform coat of paint;
this is the method most commonly used in painting auto bodies, home appliances, e.g. fridge doors, etc.
(iii) Electrostatic spraying: Here the paint particles are given an electrostatic charge and the spray is achieved
by applying a voltage difference across the paint particles and the part.
(iv) Silk-screening: this is the most common method of painting patterns, text, etc on top of most products.
Tine holes are made in a thin (silk-like) sheet, corresponding to the pattern that needs to be painted. The
screen is kept on top of the part in the correct position, and the paint is poured n top of the screen. A roller (or
squeegee brush) is used to squeeze the paint out through the holes in the silk screen and onto the part. The
screen is removed and the part is sent to dry in an oven. Silk screening has several very important uses:
1. It is used extensively in the textile industry to create colored patterns on textiles (e.g. logos on T-shirts).
6. 6
2. It is used to paint almost all text and patterns on all electronics products – e.g. all numbers, text and symbols on
your mobile phone!
3. It is used to deposit patterns of solder-paste on top of printed circuit boards. Lead-less electronic chips are
placed on top of these patterns, and a process called wave-soldering then solders the chip to the circuit board.
We will see this process in detail later.
Figure 4. Schematic of an Electrostatic Spray Painting process
Figure 5. Automated spray painting of a car body in a BMW plant
Figure 6. Schematic of Silk screening