VTD Vakuumtechnik Dresden GmbH
Niedersedlitzer Straße 75
01257 Dresden

Phone:+49 351 - 2805-0
Fax:+49 351 - 2805-240

Metallisation - technology

The surface metallisation technology comprises several stages which are carefully selected depending on the respective substrate and coating material as well as on the requirement profile. The use of a primer is recommended for many substrate materials so as to improve the coating adhesion.

The parts to be coated are fixed on a rotary cage in the vacuum chamber. They rotate around the evaporator unit once or several times if they are borne by so-called planetary wheels during the deposition process. Partial areas not to be metallised are masked.

After closing the vacuum chamber the plant is evacuated to a pressure of approx. 1 to 5 x 10-4 mbar. Coating is mostly preceded by treating the parts in a glow plasma which is ignited in the fine vacuum range of approx. 2 to 8 x 10-2. The coating material is usually evaporised by resistance-heated sources (helical filament / boat).
Schiffchen und Wendel
Metals such as Al, Cu, CrNi, Sn, Ag, Au, though also compounds such as ZnS, MgF2 and SiOx can be used as material to be evaporated. In addition to resistance-heated sources, magnetron sputter sources are available for the deposition of metals such as Al, Cu and particularly stainless steel and chromium. These sources are mainly employed in short-cycle systems.

The typical film thickness ranges from 50 nanometres (0.00005 mm) to several micrometres as with electro-magnetic shielding coatings (EMC), for example, depending on the application.

The deposited coating can be protected against mechanical damage or oxidation with a HMDS polymer coating by plasma polymerisation. In addition to this vacuum procedure, lacquers are also used as a protective coating in practice.

The different metallisation coatings are employed in the following fields:

Al coating

Mirrors, luminaires, reflectors, louvers, packaging film, jewellery, toys, fittings, sanitary appliances. A subsequent treatment with a colourless or coloured transparent lacquer enhances the usability.

Al coating with a smudge-proof protective layer (HMDS)

Vehicle headlamps, lighting, optical components

Cu and Al coating

EMC coating on electrical, electronic, communication components

Ni-Cr and Sn coating

Protective layer for Cu EMC coating, decorative metal coating (Ni-Cr)

Au and Ag coating

Mirrors for optical applications, protective layer for a Cu coating or decorative coating for fashion and jewellery articles, household items and articles of everyday use, decorative parts, trims in automotive and sanitary engineering

MgF2 coating

Protective layer for aluminium; hydrophilic (SiO) coating (wettability) in automotive or lighting engineering