Water jet peening.. • Relatively new process • A water jet at pressure as high as 400 MPa impinges on the surface of the workpieces. • Inducing compressive residual stresses and surface and subsurface hardening at the same level as in shot peening. • The water jet peening process has been used successfully on steels and aluminium alloys. • The control of process variables (jet pressure, jet velocity, and the design of the nozzle and its distance from the surfaces) is important in order to avoid excessive surface roughness and surfaces damage.
Water jet machining.. • When we put our hand across a jet of water or air, we feel considerable concentrated force acting on it. This force results from the momentum change of the stream. In water jet machining, this force is utilized in cutting and deburring operations. The water jet acts like a saw and cuts a narrow groove in the material. A pressure level of about 400MPa is generally used for efficient operation, although pressures as high as 1400MPa can be generated. Jet-nozzle diameters range between 0.05mm and 1mm.
• A variety of materials can be cut including plastics, fabrics, rubber, wood products, paper, leather, brick and composite materials. Depending on the materials, thicknesses can range up to 25mm and higher. It is an efficient and clean operation compared to other cutting processes. It is also used in the food processing industry for cutting and slicing food products.
Schematic illustration of the physical deposition process. Source: Cutting Tool Engineering.
Sputtering. • an electric field ionizes an inert gas (usually argon). • The positive ions bombard the coating material (cathode) and cause sputtering (ejecting) of its atoms. • These atoms then condense on the workpiece, which is heated to im¬prove bonding (Fig. 4.6).
FIGURE 4.6 Schematic illustration of the sputtering process. Source: ASM International.
In reactive sputtering, • the inert gas is replaced by a reactive gas, such as oxy¬gen, in which case the atoms are oxidized and the oxides are deposited. • Carbides and nitrides are also deposited by reactive sputtering. • Very thin polymer coatings can be deposited on metal and polymeric substrates with a reactive gas, causing polymer-ization of the plasma.
Radio-frequency (RF) sputtering is used for nonconductive materials such as electrical insulators and semiconductor devices.
Ion plating • is a generic term that describes the combined processes of sput¬tering and vacuum evaporation. • An electric field causes a glow discharge, generating plasma (Figure 4.7). The vaporized atoms in this process are only partially ionized.
FIGURE 4.7 Schematic illustration of an ion-plating apparatus. Source: ASM International.
Dual ion-beam assisted deposition • is a recently-developed hybrid coating technique that combines physical vapor deposition with simultaneous ion-beam bombardment. • This technique results in good adhesion on metals, ceramics, and polymers. Ceram¬ic bearings and dental instruments are examples of its applications.
Chemical vapor deposition (CVD) is a thermochemical process (Figure 4.8). In a typical ap¬plication, such as coating cutting tools with titanium nitride (TiN), the tools are placed on a graphite tray and heated to 950°C - 1050°C at atmospheric pressure in an inert atmosphere. Titanium tetrachloride (a vapor), hydrogen, and nitrogen are then in¬troduced into the chamber. The chemical reactions form titanium nitride on the tool sur¬faces. For a coating of titanium carbide, methane is substituted for the gases.
FIGURE 4.8 Schematic illustration of the chemical vapor deposition process.
Deposited coatings are usually thicker than those obtained using PVD. A typical cycle for CVD is long, consisting of (a) three hours of heating, (b) four hours of coating, and (c) six to eight hours of cooling to room temperature.
The thickness of the coating depends on the (a) flow rates of the gases used, (b) the lime, and (c) the temperature.
The types of coatings and workpiece materials allowable are fairly unrestricted in CVD. Almost any material can be coated and any material can serve as a substrate, although bond strength may vary. The CVD process is also used to produce diamond coatings (Sec¬tion 4.13) without using binders, unlike polycrystalline diamond films, which use 1% to 10% binder materials.
A recent development in chemical vapor deposition is medium- temperature CVD (MTCVD). This technique results in a higher resistance to crack propagation than CVD coatings.
4.7 ION IMPLANTATION
Principle: • ions (charged atoms) are introduced into the surface of the workpiece material. • The ions are accelerated in a vacuum to such an extent that they penetrate the sub¬strate to a depth of a few µm. • Ion implantation (not to be confused with ion plating) mod¬ifies surface properties by increasing surface hardness and improving resistance to friction, wear, and corrosion. • This process can be accurately controlled, and the surface can he masked to prevent ion implantation in unwanted locations.
Application: • effective on materials such as aluminum, titanium, stainless steels, tool and die steels, carbides, and chromium coatings. • This process is typi¬cally used on cutting and forming tools, dies and molds, and metal prostheses such as arti¬ficial hips and knees. • When used in specific applications, such as semiconductors (Chapter 5), this process is called doping, meaning alloying with small amounts of various elements.
4.8 DIFFUSION COATING
Diffusion coating is a process in which an alloying element is diffused into the surface of the substrate, thus altering its properties. The alloying elements can be supplied in solid, liq¬uid, or gaseous states. This process has different names, depending on the diffused element (as can be seen in Table 4.2. which describes the diffusion processes of carburizing, nitriding, and boronizing).
State the reasons for surface treatment and coating 2. Describe surface treatments and coatings methods. 3. Distinguish case hardening to hard facing 4. Explain thermal spraying processes and types 5. Describe two major vapour deposition processes 6. Explain the working principle of ion implantation 7. Explain the reason and types of plating 8. Describe anodizing, conversion coating and hot dipping processes 9. Describe porcelain enamelling, ceramic coatings and organic coatings processes
THE SURFACE TREATMENT AND FINISHING OF ALUMINUM AND ITS ALLOYS
The work is in two volumes and covers every conceivable aspect of aluminum treatment. The first volume deals with properties of aluminum, mechanical surface treatment, electrolytic and chemical polishing, cleaning and etching, conversion coatings and decorative and protective anodizing. The second volume covers hard anodizing, coloring and sealing of anodic oxide coatings, properties and tests of anodic oxide coatings, electrodeposition on aluminum, organic finishing, vitreous enamelling and effluents
Even before surface treatment, the appearance and surface quality of extruded aluminium profiles is perfectly satisfactory for many applications. Thanks to good corrosion resistance, surface treatment is rarely necessary simply to provide corrosion protection. However, there are many other reasons for treating the surfaces of profiles. Examples of attributes that can be changed by surface treatment include: – surface structure – colour – corrosion resistance – hardness – wear resistance – reflectivity – electrical insulation Surfaces do not always need treatment after extrusion. Load-bearing structures and machine parts are examples of products where the surface quality is satisfactory without any treatment.
Mechanical surface treatment
Grinding Grinding is one of the methods used for improving surface quality. The process leaves a fine striation in the direction of grinding. The resultant surface can be “very fine”, “medium” or “coarse”. Grinding is most commonly used for furnishing and interior design products. Ground surfaces are often anodised. Grinding before painting can further improve the surface finish.
Polishing Polishing smoothes the surface. Quality and gloss are determined by customer specifications. Polished surfaces normally go on to be anodised. To achieve a high-gloss finish, polishing is followed by bright anodising.
Anodising Anodising, one of the most common surface treatments, is used to (amongst other things): – maintain a product’s “as-new” appearance. – enhance corrosion resistance. – create a dirt repellent surface that satisfies stringent hygiene requirements. – create a decorative surface with durable colour and gloss. – create a “touch-friendly” surface. – create function-specific surfaces, for example, slip surfaces, abrasion-resistant surfaces for use in machine parts, etc. – give surfaces an electrically insulating coating. – provide a base for the application of adhesives or printing inks.
1.State the reasons for surface treatment and coating 2.Describe surface treatments and coatings methods. 3.Distinguish case hardening to hard facing 4.Explain thermal spraying processes and types 5.Describe two major vapour deposition processes 6.Explain the working principle of ion implantation 7.Explain the reason and types of plating 8.Describe anodizing, conversion coating and hot dipping processes 9.Describe porcelain enamelling, ceramic coatings and organic coatings processes
working Principle ion implantation: - ions introduced into the surface of the workpiece material. - The ions are accelerated in a vacuum to such an extent that they penetrate the sub-strate to a depth of a few - Ion implantation modifies surface properties by increasing surface hardness and improving resistance to friction, wear, and corrosion. - This process can be accurately controlled, and the surface can he masked to prevent ion implantation in unwanted locations.
thermal spraying process,coating(various metals and alloys, carbides and ceramics) are applied to metal surfaces by a spray gun with a stream of oxyfuel flame, electric arc or plasma arc.
The type of thermal spraying:
-Thermal wire spraying -thermal metal powder spraying -plasma -detonation gun -high velocity oxyfuel gas spraying -wire arc
few reasons for surface treatment and coating is:-
• Improve resistance to wear, erosion, and indentation (in machine-tool ways, wear sur¬faces of machinery, and shafts, rolls, cams, and gears). • Control friction (on the sliding surfaces of tools, dies, bearings, and machine ways). • Reduce adhesion (electrical contacts). • Improve lubrication (surface modification to retain lubricants). • Improve resistance to corrosion and oxidation (on sheet metals for automobiles, gas turbine components, and medical devices). • Improve fatigue resistance (bearings and shafts with fillets). • Rebuild surfaces on worn components (worn tools, dies, and machine components). • Modify surface texture (appearance, dimensional accuracy, and frictional characteristics). • Impart decorative features (colour).
Anybody have explanation about shahrul ces and aina questions?
One more thing, do not flood the comments with notes and unrelated things..e.g Hafiz Baha's and Syazwan's comments. Please discuss and give your comments properly. Make sure you know what are you discussing.
Electroless plating is done by chemical reaction and without the use of an external source of electricity. The most common application utilizes nickel, although copper is also used.
In electroless nickel plating, 1. nickel chloride (a metallic salt) is reduced, using sodium hypophosphate as the reducing agent, to nickel metal, 2. which is then deposited on the work-piece. 3. The hardness of nickel plating ranges between 425 HV and 575 HV, and can subse¬quently be heat-treated to 1000 HV. 4. The coating has excellent wear and corrosion resistance. 5. Cavities, recesses, and the inner surfaces of tubes can be plated successfully. 6. This process can also be used with nonconductive materials, like plastics and ceramics.
Electroless plating is more expensive than electroplating. However, unlike that of electroplating, the coating thickness of electroless plating is always uniform.
-The properties of diamond that are relevant to manufacturing engineering are described as: •Cutting-tool material, as a single crystal or in poly crystal line form •Abrasive in grinding wheels, for grinding hard materials •Dressing of grinding wheels (i.e., sharpening of the abrasive grains); •Dies for drawing wire less than 0.06 mm in diameter; and •Coatings for cutting tools and dies
-Important advances have been made in the diamond coating of metals, glass, ceramics, and plastics, using various techniques, such as chemical vapor deposition (CVD), plasma-assisted vapor deposition, and ion-beam-enhanced deposition.
-The examples of diamond-coated products are: •Scratchproof windows (such as those used in aircraft and missile sensors for protection against sandstorms), •Sunglasses, •Sutting tools (such as inserts, drills, and end mills), •Wear faces of micrometers and callipers, surgical knives, razors, electronic and infrared heat seekers and sensors, light-emitting diodes, •Dia¬mond-coated speakers for stereo systems, •Turbine blades, and •Fuel-injection nozzles.
PORCELAIN ENAMELING, CERAMIC COATING, AND ORGANIC COATINGS
Reason coating with a variety of glassy (vitreous) coatings: •To provide corrosion and electrical resistance, •To provide protection at elevated temperatures.
• is an oxidation process (anodic oxidation) in which the workpiece surfaces are converted to a hard and porous oxide layer that provides corrosion resistance and a decorative fin¬ish. • The workpiece is the anode in an electrolytic cell immersed in an acid bath, which results in chemical adsorption of oxygen from the bath. • Organic dyes of various colors (typically black, red, bronze, gold, or gray) can be used to produce stable, durable surface films.
Typical applications for anodizing are aluminum furniture and utensils, architectural shapes, automobile trim, picture frames, keys, and sporting goods. Anodized surfaces also serve as a good base for painting, especially on aluminum, which otherwise is difficult to paint.
4.11 CONVERSION COATING
• also called chemical reaction priming • is the process of producing a coat¬ing that forms on metal surfaces as a result of chemical or electrochemical reactions. • Vari¬ous metals, particularly steel, aluminum, and zinc, can he conversion-coated. • Oxides that naturally form on their surfaces area form of conversion coating.
Material used for coating: • Phosphates, • chromates, and • oxalates. Purposes • corrosion protection, • prepainting and • decorative finish. Application • to serve as lubricant carriers in cold forming operations.
The two common methods of coating are • immersion and • spraying.
The equipment required depends on the method of application, the type of product, and quality considerations.
As the name implies, coloring involves processes that alter the color of metals, alloys, and ceramics. It is caused by the conversion of surfaces (by chemical, electrochemical, or thermal processes) into chemical compounds such as oxides, chromates, and phosphates. An example is blackening of iron and steels, a process that utilizes solutions of hot caustic soda and results in chemical reactions that produce a lustrous, black oxide film on surfaces.
4.12 HOT DIPPING
• workpiece (usually steel or iron) is dipped into a bath of molten metal, • molten metal can be o zinc (for galvanized-steel sheet and plumbing supplies), o tin (for tinplate and tin cans for food containers), o aluminum (aluminizing) and o terne (lead alloyed with 10% to 20% tin). • Hot-dipped coatings on discrete parts provide long-term corrosion resistance to galva¬nized pipe, plumbing supplies, and many other products.
A typical continuous hot-dipped galvanizing line for steel sheet is shown in Figure 4.11. • The rolled sheet is first cleaned electrolytically and scrubbed by brushing. • The sheet is then annealed in a continuous furnace with controlled atmosphere and temperature and dipped in molten zinc at about 450 °C. • The thickness of the zinc coating is controlled by a wip¬ing action from a stream of air or steam, called an air knife (similar to air-drying in car washes). • Proper draining, for the removal of excess coating materials, is important.
The coating thickness is usually given in terms of coating weight per unit surface area of the sheet, typically 150 to 900 g/m2. Service life depends on the thick¬ness of the zinc coating and the environment to which it is exposed. Various precoated sheet steels are used extensively in automobile bodies.
FIGURE 4.11 Flowline for continuous hot-dip galvanizing of sheet steel. The welder (upper left) is used lo weld the ends of coils to maintain continuous material flow. Source: American Iron and Steel Institute.
Physical Vapor Deposition (PVD) Coatings: -PVD coatings involve atom-by-atom, molecule-by-molecule, or ion deposition of various materials on solid substrates in vacuum systems.
# Thermal evaporation uses the atomic cloud formed by the evaporation of the coating metal in a vacuum environment to coat all the surfaces in the line of sight between the substrate and the target(source). It is often used in producing thin, .5 µm (20 µin), decorative shiny coatings on plastic parts. The thin coating, however, is fragile and not good for wear applications. The thermal evaporation process can also coat a very thick, 1 mm (.040 in), layer of heat-resistant materials, such as MCrAlY — a metal, chromium, aluminum, and yttrium alloys, on jet engine parts.
# Sputtering -applies high-technology coatings such as ceramics, metal alloys, organic and inorganic compounds by connecting the workpiece and the substance to a high-voltage DC power supply in an argon vacuum system (10-2 - 10-3 mmHg). The plasma is established between the substrate (workpiece) and the target (donor) and transposes the sputtered off target atoms to the surface of the substrate. When the substrate is non-conductive, e.g., polymer, a radio-frequency (RF) sputtering is used instead. Sputtering can produce thin, less than 3 µm (120 µin), hard thin-film coatings, e.g., titanium nitride (TiN) which is harder than hardest metal. Sputtering is now widely applied on cutting tools, forming tools, injection molding tools, and common tools such as punches and dies, to increase wear resistance and service life.
Chemical Vapor Decomposition (CVD) Coatings:
-CVD is capable of producing thick, dense, ductile, and good adhesive coatings on metals and non-metals such as glass and plastic. Contrasting to the PVD coating in the "line of sight", the CVD can coat all surfaces of the substrate.
# Conventional CVD Coating process requires a metal compound that will volatilize at a fairly low temperature and decompose to a metal when it contact with the substrate at higher temperature. The most well known example of CVD is the nickel carbonyl (NiCO4) coating as thick as 2.5 mm (.1 in) on glass windows and containers to make them explosion or shatter resistant.
# Diamond CVD Coating process is introduced to increase the surface hardness of cutting tools. However, the process is done at the temperatures higher than 700 ºC (1300 ºF) which will soften most tool steel. Thus, the application of diamond CVD is limited to materials which will not soften at this temperature such as cemented carbides.
# Plasma-Assisted CVD Coating process can be performed at lower temperature than diamond CVD coatings. This CVD process is used to apply diamond coatings or silicon carbide barrier coatings on plastic films and semiconductors, including the state of the art .25 µm semiconductors.
function of nozzle in waterjet.... -The control of process variables (jet pressure, jet velocity, and the design of the nozzle and its distance from the surface) is important in order to avoid excessive surface roughness and surface damage.
I can try solve ,question aina about distinguish between technique layer creation and additive process..Have seven process related with additive process..
1)Stereolithography ; liquid layer curing 2)solid-base curing ; liquid layer curing & milling 3)FDM ; Extrusion of melted polymer 4)BPM ; Droplet deposition 5)T-DP ; layer of powder & binder droplet deposition 6)SLS ; Layer of powder 7)LOM : Deposition of sheet material
Based on supply phase for the each process. For the each process have three category.. - LIQUID (SLY, SBC, FDM & BPM process) - POWDER ( TDP & SLS process) - SOLID ( LOM process only)
The answer is typical applications include aircraft engine com¬ponents (such as in rebuilding worn parts), structures, storage tanks, tank cars, rocket motor nozzles, and components which require resistance to wear and corrosion.
working Principle ion implantation: ~ ions introduced into the surface of the workpiece material. ~ The ions are accelerated in a vacuum to such an extent that they penetrate the sub-strate to a depth of a few ~ Ion implantation modifies surface properties by increasing surface hardness and improving resistance to friction, wear, and corrosion. ~ This process can be accurately controlled, and the surface can he masked to prevent ion implantation in unwanted locations.
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This comment has been removed by the author.
ReplyDeletewhat is the purpose to surface treatment and coating..?can somebody tell me that question above..
ReplyDeletewhat the reason to use mechanical surfaces treatment and coating at components or workpieces?
ReplyDeleteAnswers : is to improve the surface properties of finished components or workpieces.
improve corrosion resistance
ReplyDeletewhat means by High Energy Treatments?
ReplyDeletecan somebody tell me what different between water jet peening and water jet machining....
ReplyDeletezam....you can read the note that given(advance manufacturing note)
ReplyDeleteplease pay attantion in cls AZZAM...
ReplyDeletedont play2...
for azzam :
ReplyDeleteWater jet peening..
• Relatively new process
• A water jet at pressure as high as 400
MPa impinges on the surface of the
workpieces.
• Inducing compressive residual stresses and surface and subsurface hardening at the same level as in shot peening.
• The water jet peening process has been used successfully on steels and aluminium alloys.
• The control of process variables (jet pressure, jet velocity, and the design of the nozzle and its distance from the surfaces) is important in order to avoid excessive surface roughness and surfaces damage.
Water jet machining..
• When we put our hand across a jet of water or air, we feel considerable concentrated force acting on it. This force results from the momentum change of the stream. In water jet machining, this force is utilized in cutting and deburring operations. The water jet acts like a saw and cuts a narrow groove in the material. A pressure level of about 400MPa is generally used for efficient operation, although pressures as high as 1400MPa can be generated. Jet-nozzle diameters range between 0.05mm and 1mm.
• A variety of materials can be cut including plastics, fabrics, rubber, wood products, paper, leather, brick and composite materials. Depending on the materials, thicknesses can range up to 25mm and higher. It is an efficient and clean operation compared to other cutting processes. It is also used in the food processing industry for cutting and slicing food products.
could some body state the reason of doing case hardening & hard facing..??
ReplyDeletecan somebody tell me what roller burnishing
ReplyDeletefor YOUNGSTER90:
ReplyDeletemay be to improve frictional and wear properties and resistance to indentation, erosion, abrasion, and corrosion.
Is there any defect on workpiece surface when we used thermal spraying.?
ReplyDeletewhat is layer creation technique??how to differentiation with additive process.not understand question
ReplyDeletestudyhard advanced manu
ReplyDeleteSchematic illustration of the physical deposition process. Source: Cutting Tool Engineering.
Sputtering.
• an electric field ionizes an inert gas (usually argon).
• The positive ions bombard the coating material (cathode) and cause sputtering (ejecting) of its atoms.
• These atoms then condense on the workpiece, which is heated to im¬prove bonding (Fig. 4.6).
FIGURE 4.6 Schematic illustration of the sputtering process. Source: ASM International.
In reactive sputtering,
• the inert gas is replaced by a reactive gas, such as oxy¬gen, in which case the atoms are oxidized and the oxides are deposited.
• Carbides and nitrides are also deposited by reactive sputtering.
• Very thin polymer coatings can be deposited on metal and polymeric substrates with a reactive gas, causing polymer-ization of the plasma.
Radio-frequency (RF) sputtering is used for nonconductive materials such as electrical insulators and semiconductor devices.
Ion plating
• is a generic term that describes the combined processes of sput¬tering and vacuum evaporation.
• An electric field causes a glow discharge, generating plasma (Figure 4.7). The vaporized atoms in this process are only partially ionized.
FIGURE 4.7 Schematic illustration of an ion-plating apparatus. Source: ASM International.
Dual ion-beam assisted deposition
• is a recently-developed hybrid coating technique that combines physical vapor deposition with simultaneous ion-beam bombardment.
• This technique results in good adhesion on metals, ceramics, and polymers. Ceram¬ic bearings and dental instruments are examples of its applications.
4.6.2 CHEMICAL VAPOR DEPOSITION
ReplyDeleteChemical vapor deposition (CVD) is a thermochemical process (Figure 4.8). In a typical ap¬plication, such as coating cutting tools with titanium nitride (TiN), the tools are placed on a graphite tray and heated to 950°C - 1050°C at atmospheric pressure in an inert atmosphere. Titanium tetrachloride (a vapor), hydrogen, and nitrogen are then in¬troduced into the chamber. The chemical reactions form titanium nitride on the tool sur¬faces. For a coating of titanium carbide, methane is substituted for the gases.
FIGURE 4.8 Schematic illustration of the chemical vapor deposition process.
Deposited coatings are usually thicker than those obtained using PVD. A typical cycle for CVD is long, consisting of
(a) three hours of heating,
(b) four hours of coating, and
(c) six to eight hours of cooling to room temperature.
The thickness of the coating depends on the
(a) flow rates of the gases used,
(b) the lime, and
(c) the temperature.
The types of coatings and workpiece materials allowable are fairly unrestricted in CVD. Almost any material can be coated and any material can serve as a substrate, although bond strength may vary. The CVD process is also used to produce diamond coatings (Sec¬tion 4.13) without using binders, unlike polycrystalline diamond films, which use 1% to 10% binder materials.
A recent development in chemical vapor deposition is medium- temperature CVD (MTCVD). This technique results in a higher resistance to crack propagation than CVD coatings.
4.7 ION IMPLANTATION
Principle:
• ions (charged atoms) are introduced into the surface of the workpiece material.
• The ions are accelerated in a vacuum to such an extent that they penetrate the sub¬strate to a depth of a few µm.
• Ion implantation (not to be confused with ion plating) mod¬ifies surface properties by increasing surface hardness and improving resistance to friction, wear, and corrosion.
• This process can be accurately controlled, and the surface can he masked to prevent ion implantation in unwanted locations.
Application:
• effective on materials such as aluminum, titanium, stainless steels, tool and die steels, carbides, and chromium coatings.
• This process is typi¬cally used on cutting and forming tools, dies and molds, and metal prostheses such as arti¬ficial hips and knees.
• When used in specific applications, such as semiconductors (Chapter 5), this process is called doping, meaning alloying with small amounts of various elements.
4.8 DIFFUSION COATING
Diffusion coating is a process in which an alloying element is diffused into the surface of the substrate, thus altering its properties. The alloying elements can be supplied in solid, liq¬uid, or gaseous states. This process has different names, depending on the diffused element (as can be seen in Table 4.2. which describes the diffusion processes of carburizing, nitriding, and boronizing).
State the reasons for surface treatment and coating
ReplyDelete2. Describe surface treatments and coatings methods.
3. Distinguish case hardening to hard facing
4. Explain thermal spraying processes and types
5. Describe two major vapour deposition processes
6. Explain the working principle of ion implantation
7. Explain the reason and types of plating
8. Describe anodizing, conversion coating and hot dipping processes
9. Describe porcelain enamelling, ceramic coatings and organic coatings processes
THE SURFACE TREATMENT AND FINISHING OF ALUMINUM AND ITS ALLOYS
ReplyDeleteThe work is in two volumes and covers every conceivable aspect of aluminum treatment. The first volume deals with properties of aluminum, mechanical surface treatment, electrolytic and chemical polishing, cleaning and etching, conversion coatings and decorative and protective anodizing. The second volume covers hard anodizing, coloring and sealing of anodic oxide coatings, properties and tests of anodic oxide coatings, electrodeposition on aluminum, organic finishing, vitreous enamelling and effluents
Aluminium Surface Treatment
ReplyDeleteEven before surface treatment, the appearance and surface quality of extruded aluminium profiles is perfectly satisfactory for many applications. Thanks to good corrosion resistance, surface treatment is rarely necessary simply to provide corrosion protection. However, there are many other reasons for treating the surfaces of profiles. Examples of attributes that can be changed by surface treatment include:
– surface structure
– colour
– corrosion resistance
– hardness
– wear resistance
– reflectivity
– electrical insulation
Surfaces do not always need treatment after extrusion. Load-bearing structures and machine parts are examples of products where the surface quality is satisfactory without any treatment.
Mechanical surface treatment
Grinding
Grinding is one of the methods used for improving surface quality. The process leaves a fine striation in the direction of grinding. The resultant surface can be “very fine”, “medium” or “coarse”. Grinding is most commonly used for furnishing and interior design products. Ground surfaces are often anodised. Grinding before painting can further improve the surface finish.
Polishing
Polishing smoothes the surface. Quality and gloss are determined by customer specifications. Polished surfaces normally go on to be anodised. To achieve a high-gloss finish, polishing is followed by bright anodising.
Anodising
Anodising, one of the most common surface treatments, is used to (amongst other things):
– maintain a product’s “as-new” appearance.
– enhance corrosion resistance.
– create a dirt repellent surface that satisfies stringent hygiene requirements.
– create a decorative surface with durable colour and gloss.
– create a “touch-friendly” surface.
– create function-specific surfaces, for example, slip surfaces, abrasion-resistant surfaces for use in machine parts, etc.
– give surfaces an electrically insulating coating.
– provide a base for the application of adhesives or printing inks.
Coating processes
Chemical vapor deposition
* Metalorganic vapour phase epitaxy
* Electrostatic spray assisted vapour
deposition (ESAVD)
Physical vapor deposition
* Cathodic arc deposition
* Electron beam physical vapor deposition
(EBPVD)
* Ion plating
* Ion beam assisted deposition (IBAD)
* Magnetron sputtering
* Pulsed laser deposition
* Sputter deposition
* Vacuum deposition
* Vacuum evaporation, evaporation
(deposition)
please answer all my question:
ReplyDelete1.State the reasons for surface treatment and coating
2.Describe surface treatments and coatings methods.
3.Distinguish case hardening to hard facing
4.Explain thermal spraying processes and types
5.Describe two major vapour deposition processes
6.Explain the working principle of ion implantation
7.Explain the reason and types of plating
8.Describe anodizing, conversion coating and hot dipping processes
9.Describe porcelain enamelling, ceramic coatings and organic coatings processes
omar : i want answer your quetion
ReplyDeleteQuestion no 6
ReplyDeleteION IMPLANTATION
working Principle ion implantation:
- ions introduced into the surface of the workpiece material.
- The ions are accelerated in a vacuum to such an extent that they penetrate the sub-strate to a depth of a few
- Ion implantation modifies surface properties by increasing surface hardness and improving resistance to friction, wear, and corrosion.
- This process can be accurately controlled, and the surface can he masked to prevent ion implantation in unwanted locations.
that all..
omar: i want to answer your question no 4
ReplyDeletethermal spraying process,coating(various metals and alloys, carbides and ceramics) are applied to metal surfaces by a spray gun with a stream of oxyfuel flame, electric arc or plasma arc.
ReplyDeleteThe type of thermal spraying:
-Thermal wire spraying
-thermal metal powder spraying
-plasma
-detonation gun
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omar i want to aswer your question no 1
ReplyDeletefew reasons for surface treatment and coating is:-
• Improve resistance to wear, erosion, and indentation (in machine-tool ways, wear sur¬faces of machinery, and shafts, rolls, cams, and gears).
• Control friction (on the sliding surfaces of tools, dies, bearings, and machine ways).
• Reduce adhesion (electrical contacts).
• Improve lubrication (surface modification to retain lubricants).
• Improve resistance to corrosion and oxidation (on sheet metals for automobiles, gas turbine components, and medical devices).
• Improve fatigue resistance (bearings and shafts with fillets).
• Rebuild surfaces on worn components (worn tools, dies, and machine components).
• Modify surface texture (appearance, dimensional accuracy, and frictional characteristics).
• Impart decorative features (colour).
Anybody have explanation about shahrul ces and aina questions?
ReplyDeleteOne more thing, do not flood the comments with notes and unrelated things..e.g Hafiz Baha's and Syazwan's comments. Please discuss and give your comments properly. Make sure you know what are you discussing.
Thank you.
what function of nozzle in waterjet?
ReplyDeleteWhat is electroless plating and how it is done?
ReplyDeleteFOR MUHAMMAD ASRAF:
ReplyDeleteElectroless plating is done by chemical reaction and without the use of an external source of electricity. The most common application utilizes nickel, although copper is also used.
In electroless nickel plating,
1. nickel chloride (a metallic salt) is reduced, using sodium hypophosphate as the reducing agent, to nickel metal,
2. which is then deposited on the work-piece.
3. The hardness of nickel plating ranges between 425 HV and 575 HV, and can subse¬quently be heat-treated to 1000 HV.
4. The coating has excellent wear and corrosion resistance.
5. Cavities, recesses, and the inner surfaces of tubes can be plated successfully.
6. This process can also be used with nonconductive materials, like plastics and ceramics.
Electroless plating is more expensive than electroplating. However, unlike that of electroplating, the coating thickness of electroless plating is always uniform.
DIAMOND COATING
ReplyDelete-The properties of diamond that are relevant to manufacturing engineering are described as:
•Cutting-tool material, as a single crystal or in poly crystal line form
•Abrasive in grinding wheels, for grinding hard materials
•Dressing of grinding wheels (i.e., sharpening of the abrasive grains);
•Dies for drawing wire less than 0.06 mm in diameter; and
•Coatings for cutting tools and dies
-Important advances have been made in the diamond coating of metals, glass, ceramics, and plastics, using various techniques, such as chemical vapor deposition (CVD), plasma-assisted vapor deposition, and ion-beam-enhanced deposition.
-The examples of diamond-coated products are:
•Scratchproof windows (such as those used in aircraft and missile sensors for protection against sandstorms),
•Sunglasses,
•Sutting tools (such as inserts, drills, and end mills),
•Wear faces of micrometers and callipers, surgical knives, razors, electronic and infrared heat seekers and sensors, light-emitting diodes,
•Dia¬mond-coated speakers for stereo systems,
•Turbine blades, and
•Fuel-injection nozzles.
That all from me...tq
dibawah tajuk:
ReplyDeletePORCELAIN ENAMELING, CERAMIC COATING, AND ORGANIC COATINGS
Reason coating with a variety of glassy (vitreous) coatings:
•To provide corrosion and electrical resistance,
•To provide protection at elevated temperatures.
This comment has been removed by the author.
ReplyDeletecan somebody tell me a reason mechanical surface treatment and coating..? from zulkefli yusoff
ReplyDeletei want to answer omar shariffudin question
ReplyDeleteno 8 :-
4.10 ANODIZING
• is an oxidation process (anodic oxidation) in which the workpiece surfaces are converted to a hard and porous oxide layer that provides corrosion resistance and a decorative fin¬ish.
• The workpiece is the anode in an electrolytic cell immersed in an acid bath, which results in chemical adsorption of oxygen from the bath.
• Organic dyes of various colors (typically black, red, bronze, gold, or gray) can be used to produce stable, durable surface films.
Typical applications for anodizing are aluminum furniture and utensils, architectural shapes, automobile trim, picture frames, keys, and sporting goods. Anodized surfaces also serve as a good base for painting, especially on aluminum, which otherwise is difficult to paint.
4.11 CONVERSION COATING
• also called chemical reaction priming
• is the process of producing a coat¬ing that forms on metal surfaces as a result of chemical or electrochemical reactions.
• Vari¬ous metals, particularly steel, aluminum, and zinc, can he conversion-coated.
• Oxides that naturally form on their surfaces area form of conversion coating.
Material used for coating:
• Phosphates,
• chromates, and
• oxalates.
Purposes
• corrosion protection,
• prepainting and
• decorative finish.
Application
• to serve as lubricant carriers in cold forming operations.
The two common methods of coating are
• immersion and
• spraying.
The equipment required depends on the method of application, the type of product, and quality considerations.
As the name implies, coloring involves processes that alter the color of metals, alloys, and ceramics. It is caused by the conversion of surfaces (by chemical, electrochemical, or thermal processes) into chemical compounds such as oxides, chromates, and phosphates. An example is blackening of iron and steels, a process that utilizes solutions of hot caustic soda and results in chemical reactions that produce a lustrous, black oxide film on surfaces.
4.12 HOT DIPPING
• workpiece (usually steel or iron) is dipped into a bath of molten metal,
• molten metal can be
o zinc (for galvanized-steel sheet and plumbing supplies),
o tin (for tinplate and tin cans for food containers),
o aluminum (aluminizing) and
o terne (lead alloyed with 10% to 20% tin).
• Hot-dipped coatings on discrete parts provide long-term corrosion resistance to galva¬nized pipe, plumbing supplies, and many other products.
A typical continuous hot-dipped galvanizing line for steel sheet is shown in Figure 4.11.
• The rolled sheet is first cleaned electrolytically and scrubbed by brushing.
• The sheet is then annealed in a continuous furnace with controlled atmosphere and temperature and dipped in molten zinc at about 450 °C.
• The thickness of the zinc coating is controlled by a wip¬ing action from a stream of air or steam, called an air knife (similar to air-drying in car washes).
• Proper draining, for the removal of excess coating materials, is important.
The coating thickness is usually given in terms of coating weight per unit surface area of the sheet, typically 150 to 900 g/m2. Service life depends on the thick¬ness of the zinc coating and the environment to which it is exposed. Various precoated sheet steels are used extensively in automobile bodies.
FIGURE 4.11 Flowline for continuous hot-dip galvanizing of sheet steel. The welder (upper left) is used lo weld the ends of coils to maintain continuous material flow. Source: American Iron and Steel Institute.
I only have several question about chapter 4, please answer my following question
ReplyDelete1.Explain electroplating process
2.List common applications of thermal spraying
some information about PVD and CVD:
ReplyDeletePhysical Vapor Deposition (PVD) Coatings:
-PVD coatings involve atom-by-atom, molecule-by-molecule, or ion deposition of various materials on solid substrates in vacuum systems.
# Thermal evaporation uses the atomic cloud formed by the evaporation of the coating metal in a vacuum environment to coat all the surfaces in the line of sight between the substrate and the target(source). It is often used in producing thin, .5 µm (20 µin), decorative shiny coatings on plastic parts. The thin coating, however, is fragile and not good for wear applications. The thermal evaporation process can also coat a very thick, 1 mm (.040 in), layer of heat-resistant materials, such as MCrAlY — a metal, chromium, aluminum, and yttrium alloys, on jet engine parts.
# Sputtering
-applies high-technology coatings such as ceramics, metal alloys, organic and inorganic compounds by connecting the workpiece and the substance to a high-voltage DC power supply in an argon vacuum system (10-2 - 10-3 mmHg). The plasma is established between the substrate (workpiece) and the target (donor) and transposes the sputtered off target atoms to the surface of the substrate. When the substrate is non-conductive, e.g., polymer, a radio-frequency (RF) sputtering is used instead. Sputtering can produce thin, less than 3 µm (120 µin), hard thin-film coatings, e.g., titanium nitride (TiN) which is harder than hardest metal. Sputtering is now widely applied on cutting tools, forming tools, injection molding tools, and common tools such as punches and dies, to increase wear resistance and service life.
Chemical Vapor Decomposition (CVD) Coatings:
-CVD is capable of producing thick, dense, ductile, and good adhesive coatings on metals and non-metals such as glass and plastic. Contrasting to the PVD coating in the "line of sight", the CVD can coat all surfaces of the substrate.
# Conventional CVD Coating process requires a metal compound that will volatilize at a fairly low temperature and decompose to a metal when it contact with the substrate at higher temperature. The most well known example of CVD is the nickel carbonyl (NiCO4) coating as thick as 2.5 mm (.1 in) on glass windows and containers to make them explosion or shatter resistant.
# Diamond CVD Coating process is introduced to increase the surface hardness of cutting tools. However, the process is done at the temperatures higher than 700 ºC (1300 ºF) which will soften most tool steel. Thus, the application of diamond CVD is limited to materials which will not soften at this temperature such as cemented carbides.
# Plasma-Assisted CVD Coating process can be performed at lower temperature than diamond CVD coatings. This CVD process is used to apply diamond coatings or silicon carbide barrier coatings on plastic films and semiconductors, including the state of the art .25 µm semiconductors.
thanks to arip,ayie and ali for answer my question....
ReplyDelete1.Explain the working principle of ion implantation
ReplyDelete2.Explain the reason and types of plating
3.Explain thermal spraying processes and types
give the another name for mechanical plating?
ReplyDeletefunction of nozzle in waterjet....
ReplyDelete-The control of process variables (jet pressure, jet velocity, and
the design of the nozzle and its distance from the surface) is
important in order to avoid excessive surface roughness and
surface damage.
I can try solve ,question aina about distinguish between technique layer creation and additive process..Have seven process related with additive process..
ReplyDelete1)Stereolithography ; liquid layer curing
2)solid-base curing ; liquid layer curing &
milling
3)FDM ; Extrusion of melted polymer
4)BPM ; Droplet deposition
5)T-DP ; layer of powder & binder droplet
deposition
6)SLS ; Layer of powder
7)LOM : Deposition of sheet material
Based on supply phase for the each process.
For the each process have three category..
- LIQUID (SLY, SBC, FDM & BPM process)
- POWDER ( TDP & SLS process)
- SOLID ( LOM process only)
Please,List common applications of thermal spraying..bc0z i'm stil confuse this question..
ReplyDeleteThe answer is typical applications include aircraft engine com¬ponents (such as in rebuilding worn parts), structures, storage tanks, tank cars, rocket motor nozzles, and components which require resistance to wear and corrosion.
ReplyDeletewho can help me 2 answer question 15 for assgment?
ReplyDeleteANSWER FOR OMAR'S QUESTION!~
ReplyDeleteworking Principle ion implantation:
~ ions introduced into the surface of the workpiece material.
~ The ions are accelerated in a vacuum to such an extent that they penetrate the sub-strate to a depth of a few
~ Ion implantation modifies surface properties by increasing surface hardness and improving resistance to friction, wear, and corrosion.
~ This process can be accurately controlled, and the surface can he masked to prevent ion implantation in unwanted locations.
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