SURFACE ENGINEERING (HONORS ELECTIVE) Prof.(Dr) MANOJ KUMAR PRADHAN

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1 SURFACE ENGINEERING (HONORS ELECTIVE) By Prof.(Dr) MANOJ KUMAR PRADHAN B.E, (University College of Engineering, Burla, Odisha) M.Tech, (National Institute of Technology, Rourkela) Ph.D, UCE, Sambalpur University, Odisha Professor and Head Department of Mechanical Engineering Gandhi Institute for Technological Advancement (GITA) Bhubaneswar, Odisha

2 B.Tech (Mechanical Engineering) detail Syllabus for Admission Batch th Semester SURFACE ENGINEERING (HONORS ELECTIVE) MODULE I (14 HOURS) Mechanisms of Wear and Metal Cleaning: Basic Mechanisms of wear-abrasive, adhesive wear, contact fatigue, Fretting corrosion, Testing of wear resistance, practical diagnosis of wear, general cleaning process for ferrous and non ferrous metals and alloys selection of cleaning processes, alkaline cleaning, emulsion cleaning, ultrasonic cleaning, pickling salt bath descaling, abrasive bath cleaning, polishing and buffing shot peening. MODULE II (16 HOURS) Thermal Spraying Processes and Electrodeposited Coatings: Thermal spraying materials, characteristics of thermal spray processes, Design for thermally sprayed coatings coating production, spray fused coatings, Principles of electroplating, Technology and control electroplating systems, Properties and applications of electrodeposits, Non aqueous and electro less deposition, plasma coating. Hot Dip Coating and Diffusion Coating: Principles, Surface preparation, Batch coating and continuous coating process, Coating properties and application, Principles of cementation, Cladding-vacuum deposition, Sprayed metal coating, Structure of diffusion coatings, Chemical vapour deposition (CVD), Physical vapour deposition (PVD). MODULE III (14 HOURS) Non-Metallic Coating Oxide and Conversion Coatings: Plating coating, lacquers, rubbers and elastomers, viterous enamels, anodizing Chromating, application to aluminium, magnesium, tin, zinc, cadmium copper and silver, phosphating primers. Quality Assurance, Testing and Selection af Coatings: The quality plan, design, testing and inspection, thickness and porosity measurement, selection of coatings, industrial applications of engineering coatings. TEXT BOOKS : 1. Engineering Coatings-design and application- S. Grainger, Jaico Publishing House. 2. Principles of Metals surface treatment and protection- D. R. Gabe, Pergamon. REFERENCE BOOKS: 1. Electroplating Handbooks- N.V.Parathasarathy, Prentice Hall. 2. Advances in surface treatment- Niku-Lavi, Pergamon.

3 MODULE-I Mechanisms of Wear Basic Mechanisms of Wear- Abrasive Wear Hardness and wear

17 MODULE-II THERMAL SPRAYING PROCESSES

18 Thermal spraying materials

33 MODULE-III QUALITY ASSURANCE The Quality Plan

35 Potential Criteria for Engineering Coatings- Typical tests applicable to coatings-

37 Lacquer A liquid made of shellac dissolved in alcohol, or of synthetic substances, that dries to form a hard protective coating for wood, metal, etc. In modern techniques, lacquer means a range of clear or coloured wood finishes that dry by solvent evaporation or a curing process that produces a hard, durable finish. The finish can be of any sheen level from ultra matte to high gloss, and it can be further polished as required. Lacquer painting is a form of painting with lacquer which was practised in China and Japan for decoration on lacquerware. Making a lacquer painting may take several months depending on the technique used and the number of layers of lacquer. In Vietnam's sơn mài lacquer painting first a black board is prepared. Then outlines in chalk are picked out in white with eggshell and clear varnish, then polished. Then the first layer of coloured lacquer is applied, usually followed by silver leaf and another layer of clear lacquer. Then several more layers of different coloured lacquers are painted by brush, with clear lacquer layers between them. In Vietnam an artist may apply up to ten layers or more of coloured and clear lacquer. In Ming China processes included up to a hundred layers. Each layer requires drying and polishing. When all layers are applied the artist polishes different parts of the painting until the preferred colours show. Fine sandpaper and a mix of charcoal powder and human hair is used to carefully reach the correct layer of each specific colour. Consequently, "lacquer painting" is in part a misnomer, since the bringing out of the colours is not done in the preparatory painting but in the burnishing of the lacquer layers to reveal the desired image beneath. Elastomers A natural or synthetic polymer having elastic properties, e.g. rubber. An elastomer is a polymer with viscoelasticity (having both viscosity and elasticity) and very weak inter-molecular forces, generally having low Young's modulus and high failure strain compared with other materials. The main characteristic of elastomer materials is the high elongation and flexibility or elasticity of these materials, against its breaking or cracking. Depending on the distribution and degree of the chemical bonds of the polymers, elastomeric materials can have properties or characteristics similar to thermosets or thermoplastics, so elastomeric materials can be classified into: Thermoset Elastomers - are those elastomer materials which do not melt when heated. Thermoplastic Elastomers - are those elastomers which melt when heated.

38 Properties of elastomer materials: Can not melt, before melting they pass into a gaseous state Swell in the presence of certain solvents Are generally insoluble. Are flexible and elastic. Lower creep resistance than the thermoplastic materials Examples and applications of elastomer plastic materials: Natural rubber - material used in the manufacture of gaskets, shoe heels... Polyurethanes - Polyurethanes are used in the textile industry for the manufacture of elastic clothing such as lycra, also used as foam, wheels, etc... Polybutadiene - elastomer material used on the wheels or tires of vehicles, given the extraordinary wear resistance. Neoprene - Material used primarily in the manufacture of wetsuits is also used as wire insulation, industrial belts, etc... Silicone - Material used in a wide range of materials and areas due their excellent thermal and chemical resistance, silicones are used in the manufacture of pacifiers, medical prostheses, lubricants, mold, etc... Examples of elastomers adhesives: Polyurethane adhesive 2 components. Polyurethane adhesive by curing 1 component moisture. Adhesives based on silicones Adhesives based on modified silane Now that you know the elastomers, did you know that all the tires of any vehicle are made with elastomer materials? Vitreous enamel Vitreous enamel, also called porcelain enamel, is a material made by fusing powdered glass to a substrate by firing, usually between 750 and 850 C (1,380 and 1,560 F). The powder melts, flows, and then hardens to a smooth, durable vitreous coating on metal, or on glass or ceramics. So in technical terms fired enamelware is an integrated layered composite of glass and metal. Enamelling is an old and widely adopted technology, for most of its history mainly used in jewelry and decorative art. Vitreous enamel can be applied to most metals. Most modern industrial enamel is applied to steel in which the carbon content is controlled to prevent unwanted reactions at the firing temperatures. Enamel can also be applied to gold, silver, copper, aluminium, stainless steel, and cast iron.

39 Vitreous enamel has many useful properties: it is smooth, hard, chemically resistant, durable, scratch resistant (5-6 on the Mohs scale), has long-lasting colour fastness, is easy to clean, and cannot burn. Enamel is glass, not paint, so it does not fade under ultraviolet light.

46 ANODIZING Anodising is an electrochemical process for producing thick oxide coatings, usually on aluminium and its alloys. The oxide layer is typically 5 to 30µm in thickness and is used to give improved surface resistance to wear and corrosion, or as a decorative layer. Anodizing formed coating of aluminum oxide and it is totally non-conductive. Anodizing is hard and clear. You cannot scratch anodizing with your fingernail. Anodizing converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish. Aluminum is ideally suited to anodizing, although other nonferrous metals, such as magnesium and titanium, also can be anodized. Anodization subjects the surface of aluminum pots and pans to a process that builds up the metal's natural coating of oxide. This should yield a hard, nonreactive substance that forms a tough coating. As a result, an anodized aluminum cooking surface is non-stick, scratch-resistant and easy to clean. CHROMATING Chrome plating a component typically includes these stages: Degreasing to remove heavy soiling Manual cleaning to remove all residual traces of dirt and surface impurities Various pretreatments depending on the substrate Placement into the chrome plating vat, where it is allowed to warm to solution temperature Application of plating current for the required time to attain the desired thickness Chromating is an immersion process which affords some corrosion protection but less than anodizing. It is a type of conversion coating used to passivate steel, aluminum, zinc, cadmium, copper, silver, magnesium, and tin alloys. It is primarily used as a corrosion inhibitor, primer, decorative finish, or to retain electrical conductivity. The process is named after the chromate found in chromic acid, also known as hexavalent chromium, the chemical most widely used in the immersion bath process whereby the coating is applied. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness. Chromate is yellow or clear, the clear being better conductivity. Chromate will scratch with your fingernail. Hard chrome plating is an electroplating process in which chromium is deposited from a chromic acid solution. Thickness of hard chrome plating ranges from 2 to 250µm. Various types of hard chrome include micro-cracked chromium, micro-porous chromium, porous chromium and crack free chromium.

Surface Finishes. For woods metals and plastics

Surface Finishes. For woods metals and plastics Surface Finishes For woods metals and plastics Reasons for Surface Finishes Some kind of surface finish is always necessary for the following reasons Resistance to decay (Stopping the material from rotting