Metallizing

Metallizing refers to the process of coating metal onto the surface of objects for decorative, protective, or functional purposes. The technique has historical roots in mirror-making, with Justus von Liebig discovering a method to coat glass with metallic silver in 1835. Metallization on non-metallic objects expanded with the introduction of ABS plastic, though such surfaces require pre-treatment to enable plating due to their poor conductivity. This involves chemical etching, sensitizing with tin(II) chloride, and activating with palladium chloride, followed by electroless copper or nickel coating. The adhesion force achieved is moderate (1-6 kgf/cm² or 10-60 N/cm²), but weaker than metal-to-metal bonding.

Vacuum metallizing involves vaporizing metals in a vacuum chamber using resistance heating, electron beams, or plasma, with the vapor condensing onto the substrate. This method was used to apply aluminum coatings on large telescope mirrors, such as the Hale Telescope. Thermal spray processes, also referred to as metallizing, provide long-lasting corrosion protection for steel, often using zinc and aluminum.

Cold sprayable metal technology allows seamless application of metal composites, typically consisting of metal powder, a water-based binder, and sometimes a hardener, to various surfaces at room temperature. The layer thickness, usually between 80 and 150 μm, depends on the desired effect and required final treatment. These methods highlight the versatility and practical applications of metallizing across different industries.