metallointi

Metallointi, or metallization, is the process of applying a thin layer of metal to a substrate to improve properties such as electrical conductivity, corrosion resistance, wear resistance, reflectivity, or aesthetics. It can involve electroplating (galvanic deposition) where a metal cation in solution is reduced to a solid metal on a conductive substrate, often nickel, copper, chromium, zinc, or gold. It can also involve electroless plating, which deposits metal chemically without external current, used for non-conductive substrates.

Other approaches include physical vapor deposition (PVD) such as sputtering and evaporation, and chemical vapor deposition (CVD), which coat non-metal surfaces or coated tools. Thermal spraying applies molten or semi-molten metal onto a surface at high velocity. Substrates range from metals to polymers and ceramics, with surface preparation crucial: cleaning, etching, roughening, and adhesion promoters. Coating thickness varies from a few nanometers in decorative coatings to tens of micrometers in wear-resistant or functional layers. Adhesion and residual stress are important considerations.

Applications include automotive and aerospace coatings (corrosion protection), electronics (conductive tracks, reflectors), optics (mirror coatings), medical devices, and decorative finishes. Advantages include low cost for large areas, precise thickness control, and the ability to tailor surface properties. Limitations include environmental concerns for certain baths (cyanide-containing) and potential substrate incompatibilities, limited thickness control at high build rates, and the need for post-treatment finishing.