| 摘要 |
A metal article or part (e.g. of steel, copper, zinc, aluminium or brass) has bonded to its surface a composite metal coating consisting of alternate layers of nickel each 2.5 to 50 microns thick and of chromium each 0.025 to 2.5 microns thick, there being at least two layers of nickel one of which is the foundation layer, the layers being firmly bonded together and the total thickness of the coatings being at least 6.25 microns. The metals are preferably deposited electrolytically, but chemically deposited nickel coatings such as those described in U.S.A. Specification 2,532,283, coatings produced by high vacuum vaporizing and coatings produced by thermal decomposition of metal carbonyls may be used. |
