What is surface engineering?
Surface engineering refers to a wide range of technologies designed to modify the surface properties of metallic and non-metallic components for decorative and/or functional purposes. Examples include improving corrosion and wear resistance to extend component life; making items more visually attractive; and giving special properties such as lubricity enhancement, non-stick surfaces, etc. Surface engineering processes can classified as follows:
- Aqueous electrolytic, normally consisting of electroplating of metal coatings, anodising of aluminium and titanium, as well as the electropolishing of stainless steel.
- Electroless processes for those metals, notably copper, nickel, gold and tin that can be applied by chemical reduction methods and avoid the use of electrolytic energy.
- Aqueous non-electrolytic typically cleaning, pickling, phosphating, passivation, mechanical plating and a variety of other colouring processes, eg "blacking" of steel.
- Organic (liquid) which can be solvent or water based but applies pigmented or metal containing coatings by dipping, dip-spinning, flow coating, conventional spraying, or in the case of water based paints, by electrophoretic or auto-catalytic means.
- Organic (powder), the application of dry powders, usually by the process of electrostatic spraying or by fluidised bed techniques.
- Heat treatment. The use of heat, sometimes with specific gases, to metallurgically alter the structure and mechanical properties of a component. The component may be stress relieved, softened or hardened or even changed in composition especially where unique surface properties are desired.
- Galvanizing. A process where ferrous articles are dipped into molten zinc (or an alloy of zinc) to produce a relatively thick surface layer giving protection against corrosion.
- Tinning. A process where ferrous articles are dipped into molten tin (or an alloy of tin) to produce a relatively thick layer of tin (or tin alloy).
- Metal spraying. A technique for uniquely transferring metals by the use of heat, plasma, or arc to the surfaces of prepared components.
- Vitreous enamelling. The application of metallic glass containing liquids by dipping or spraying techniques on to ferrous components eg kitchen hobs.