| 摘要 |
A method of chromium coating a substrate is described, which method comprises: a) depositing, preferably electrodepositing, a metallic layer onto the substrate comprising chromium from a plating bath that includes trivalent chromium and no, or substantially no, hexavalent chromium; b) physical vapor depositing a layer comprising chromium cn the layer deposited from step a). In one embodiment, in step a), the layer is chromium and is electrodeposited from a plating bath that includes trivalent chromium and no, or substantially no, hexavalent chromium. The metallic layer deposited in step a) is preferably a metal or an alloy of two or more metals and may be selected from the group consisting of chromium, copper, nickel, cobalt, zinc, lead iron, palladium and tin and alloys thereof, e.g. copper tin, copper zinc, tin lead, tin nickel, tin cobalt, tin zinc, iron nickel, cobalt nickel, zinc nickel, zinc iron, zinc iron nickel, zinc iron cobalt or palladium nickel. Copper and nickel are especially preferred. The coating formed by the method has a blue sheen that is usually associated with chromium electrodeposited from hexavalent chromium baths without having to use a hexavalent chromium bath, which is highly toxic.
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