| 摘要 |
1384724 Roughening an eutectic alloy and applying a metal or Si coating BBC BROWN BOVERI & CO Ltd 20 March 1972 [22 March 1971] 12921/72 Heading C7B [Also in Division B6] A metal or Si protective coating is applied to an eutectic alloy by first roughening the alloy surface and thereafter applying the coating. The eutectic alloy comprises crystal phases, at least one of which is continuous and coherent. The roughening is by removing one of the crystal phases from the alloy surface but leaving a continuous and coherent phase. The eutectic alloy may comprise Cr and C together with Co, Fe and/or Ni. The roughening may be electrolytic, chemical (with or without heating), or mechanical (if one phase is softer than the others). The coating may be applied by vapour deposition, electrodeposition, spraying or diffusion. In the Examples, the eutectic alloy contains 56À9% Co, 40À7% Cr and 2À4%C. In Example 1, it is roughened by means of gas produced by the combustion of Diesel oil, ultrasonically cleaned, and electrolytically Cr plated. In Example 2, it is electrolytically roughened as cathode in 5% HCl, ultrasonically cleaned, and coated with Si by electro-deposition. Coatings of Cr alloy and of Si. alloy are also mentioned. |
