The parts of a utility and control-cabinet key are coated with different materials depending on what the part is made of.
Chrome electroplating
Zinc alloy parts (see {{widget type=”cms/widget_page_link” template=”cms/widget/link/link_block.phtml” page_id=”3367″}}) do not always need to be coated as they are very resistant to corrosion and have an aesthetically pleasing look straight out of the mould…
…but some manufacturers use zinc alloys that corrode faster than pure zinc and so cover the part in a chromium layer. The process is known as ‘chrome electroplating’. It is called electroplating because electricity is passed through the part which makes the new metal coat stick to it.
First the zinc part is placed in a copper bath. The copper makes the surface of the zinc part the same all over and increases its electrical conductivity (ability for electricity to pass through it).
A couple of coats of nickel are applied to prevent corrosion of the copper…
…and, finally, the part is placed in a chromium bath to receive the final coatings. The chromium protects the nickel from damage and creates a very shiny surface.
Powder coating
Powder coatings are made of plastic and are used on steel parts to protect the surface of the steel from light damage and water, which can result in rusting of the steel.
The powder is sprayed onto the part. It sticks due to static electricity. The powder is heated and forms a hard, thick coat which is less likely to chip than paint.
Varnish
Some plastics have a varnished surface to protect it from knocks and scrapes.
Varnish is a liquid made from a resin and a solvent. It dries into a very hard, transparent layer.
