pls i want in big answer.. U0.02.2018 Due Date: 18.02.2018 Date of submission:-

Question

pls i want in big answer..

U0.02.2018 Due Date: 18.02.2018 Date of submission:- Questions: SURFACE TREATMENT AND FINISHING PROCESS Briefly explain the Electroplating process with a neat diagram? (maximum 1 page write up) Briefly explain the Electroless plating process? (maximum 1 page write up) 1. 2. 3. Briefly explain the Anodizing process? (maximum half page write up) Write notes on painting process? (maximum half a page write up) Proper references for the above all with the proper format. 4. Actinn taken for the Late Submission of the assignment: For every three days late

Explanation / Answer

Electroplating is a process that uses electric current to reduce dissolved metal cations so that they form a thin coherent metal coating on an electrode. The term is also used for electrical oxidation of anions on to a solid substrate, as in the formation of silver chloride on silver wire to make silver/silver-chloride electrodes. Electroplating is primarily used to change the surface properties of an object (such as abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities), but may also be used to build up thickness on undersized parts or to form objects by electroforming.

Anodizing (spelled anodising, outside USA) is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts.

The process is called anodizing because the part to be treated forms the anode electrode of an electrical circuit. Anodizing increases resistance to corrosion and wear, and provides better adhesion for paint primers and glues than bare metal does. Anodic films can also be used for a number of cosmetic effects, either with thick porous coatings that can absorb dyes or with thin transparent coatings that add interference effects to reflected light.

Anodizing is also used to prevent galling of threaded components and to make dielectric films for electrolytic capacitors. Anodic films are most commonly applied to protect aluminium alloys, although processes also exist for titanium, zinc, magnesium, niobium, zirconium, hafnium, and tantalum. Iron or carbon steel metal exfoliates when oxidized under neutral or alkaline microelectrolytic conditions; i.e., the iron oxide (actually ferric hydroxide or hydrated iron oxide, also known as rust) forms by anoxic anodic pits and large cathodic surface, these pits concentrate anions such as sulfate and chloride accelerating the underlying metal to corrosion. Carbon flakes or nodules in iron or steel with high carbon content (high-carbon steel, cast iron) may cause an electrolytic potential and interfere with coating or plating. Ferrous metals are commonly anodized electrolytically in nitric acid or by treatment with red fuming nitric acid to form hard black ferric oxide.

The process used in electroplating is called electrodeposition

Electroless plating, nonelectrical plating of metals and plastics to achieve uniform coatings by a process of controlled autocatalytic (self-continuing) reduction. Discovered in 1944 by A. Brenner and G.E. Riddell, electroless plating involves the deposition of such metals as copper, nickel, silver, gold, or palladium on the surface of a variety of materials by means of a reducing chemical bath. It is also used in mirroring, in which a clean surface of glass is dipped into an ammoniacal silver solution mixed with Rochelle salt or with a nitric acid–cane-sugar alcohol solution. Nonmetallic surfaces, such as plastics, must be chemically treated prior to electroless plating. The major expansion of electroless plating has come in the area of plastics, as in the plating of printed electronic circuits. A large number of consumer goods are coated by this method to create durable and attractive surfaces

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