Metallisation

Metallisation, or metallization, is the deposition of a metallic layer onto a surface to confer properties such as electrical conductivity, corrosion resistance, wear resistance, reflectivity, or catalytic activity. The coating may be applied to metals, polymers, ceramics, or composites, and often requires surface pretreatment to promote adhesion.

Techniques used for metallisation include electroplating (electrochemical deposition from an electrolyte), electroless plating (chemical reduction without external current), physical vapor deposition (PVD) methods such as sputtering and evaporation, chemical vapor deposition (CVD), and thermal spraying. Each method varies in energy input, coating thickness, conformity, and ability to coat complex geometries. For large-area or three-dimensional parts, electroplating and thermal spraying are common; for uniform thin films, PVD and CVD are often preferred.

Materials commonly employed for metallisation include copper, nickel, chromium, aluminium, gold, silver, tin, zinc, and various alloys such as nickel-phosphorus. The choice depends on substrate compatibility, intended service conditions, thickness requirements, and cost. In electronics, metallisation forms conductive tracks on insulating substrates; in optics, thin metal films create mirrors; on steel and other metals, protective coatings like nickel or chromium enhance corrosion and wear resistance.

Practical considerations include adhesion quality, thickness control, coating uniformity, and environmental and safety aspects related to waste management and chemical use in plating processes. Metallisation remains a versatile approach in electronics, optics, packaging, and protective coatings.