Date Published:May. 10. 2016
||Principles and features
||Soak the material into the plating bath as an negative electrode to perform electrolytic deposition of metal film on the material surface by direct current.
||The materials are metal and plastic (electroplating by conducting with electroless plating on the surface).
||For decoration, 1μm or below, for protection and industrial use, 1 - dozens μm or above. IN many cases, pin holes are left.
||Soak the material into dissolved metal and then pull it up for consolidation and coating of the dissolved metal.
||Primary materials are iron and steel and coating metal includes Al, Zn, Sn and Pb, etc.
||Thick coating is possible. Adhesion and deforming processing property depend on the nature of alloy layer formed between the coating layer and the material.
||Metal elements are diffused and cemented over the material surface layer. As the processing temperature is high (around 1000°C), post heat treatment is required.
||Primary materials include iron and steel, Fe-base and Ni-base heat-resistant alloy, etc. Coating metal includes Al, Cr and Si, etc.
||Alloy layer thickness is tens - hundreds μm.
||Physical evaporation method: Coating by vacuum evaporation, spattering and ion plating, etc. Chemical evaporation method: Coating by decomposition of gas compound.
||Materials include metal, ceramic and plastic. Coating materials are metal and ceramic.
||Generally, the evaporation speed is low for the physical evaporation method. The chemical evaporation method cannot avoid high temperature processing.
||Power or particles of thermal spraying materials heated to the dissolved state are sprayed onto the material surface to form coating. The material temperature during spraying is below 200°C.
||Materials include metal, ceramic and plastic, etc. Thermal spraying materials are metal, ceramic, plastic or their mixture.
||The adhesion strength is relatively low. The film has air holes. The practical film thickness is about 0.6 mm or below.
||Rolled pressure welding method and explosion welding method, etc. Processing objects are simple shapes such as plates and cylinder inner face, etc.
||Materials are metal and mostly iron and steel. Flitch materials are metal and alloy.
||For explosion welding, the flitch material thickness is about 3 mm or below.
||Materials are electrolyzed in electrolysis solution such as sulfuric acid and oxalic acid as an anode to form an oxide film on the material surface.
||Primary materials are Al and Al alloy. Others include Mg, etc.
||An oxide film consists of a dense layer and porous layer. Apply normal sealing processing. Good adhesion. Coloration possible.
|Chemical conversion coating
||Form a phosphate or chromate film on the material surface by soaking or spraying method.
||Materials include iron and steel, Al and Zn, etc.
||Primarily, a phosphate film applies to iron and steel materials and a chromate film to Al.
||Carbon elements are diffused and cemented over the material surface layer. Processing temperature is 850 - 950°C. Apply quenching after the processing.
||The material is steel with C content of 0.2% or below (steels for case hardening).
||The carbonizing is 0.5 - 5mm and the hardness is 700 - 850HV. Pay attention to the material deformation caused by the processing and quenching after the processing.
||Nitride elements are diffused and cemented over the material surface layer. Processing temperature is 475 - 580℃. Heat treatment and machine processing are possible before the processing.
||Materials are nitrided steel for gas nitriding (containing Cr, Mo and Al, etc.). Most steel types for ion nitriding.||The nitriding depth is 0.9mm or below. Hardness is 600 - 1150HV. Material deformation is small.
||Perform nitriding at the same time with carbonizing. Processing temperature is 700 - 900℃. Apply quenching after the processing.
||Materials are the same as those for carbonizing. The same can apply to carbon steel.
||Nitrocarburizing depth is 1mm or below. Hardness is about 800HV.
||Sulfur elements are diffused and cemented over the material surface layer. Processing temperature is 400 - 600℃.
||Any steel material and steel type can be used.
||Friction coefficient decreases from the ferric sulfide film thickness 0.2μm.
||Perform nitriding at the same time with sulfurizing. Processing temperature is 560 - 570℃.
||Materials are the same as those for nitriding.
||The nitrosulphurizing depth is 0.1 - 0.5mm.
||Perform quenching after rapid heating and rapid cooling by high frequency conductive current on the material surface.
||Materials are iron and steel. Especially, medium carbon steel, alloy steel and cast iron, etc.
||Hardened layer thickness is 0.4 - 5mm. Working time is short. Material deformation is small.
||Perform quenching after rapid heating and rapid cooling by oxygen-fuel flame on the material surface.
||The same as above
||Hardened layer thickness is 1 - several mm.
|Other surface quenching
||Perform quenching after rapid heating and rapid cooling by laser beam and electric beam, etc.
||Any materials can be used as long as they have a quenching property.
||The hardened layer is extremely thin. Local hardening is possible.
||Coat the material surface by the sheet lining method, thermal spraying method or application method, etc.
||The coating materials are polyethylene, vinyl chloride, fluorine resin and rubber, etc.
||Thick coating is possible. It may be 1mm or above in some cases.
||Coat the material surface by the evaporation method, thermal spraying method or quenching method, etc.
||Coating material is glassy ceramic (enamel). Various ceramic.
||Less adhesive. Repeated heating and cooling may cause cracks on the film.
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