| 摘要 |
1,148, 433. Chromium-nickel plating. KEWANEE OIL CO. April 1, 1966 [April 26, 1965], No.14658/66. Heading C7B. A two layer laminate having 300-3000 cracks per lineal inch is made by electro-depositing on a metal substrate a layer of Ni or Co or Co and Ni 0À03 - 0À52 mil thick, the deposition taking place from a first bath at a temperature between 60‹F. and 160‹F., the deposited metal having a stress value of at least 30, 000 pounds per square inch measured by the rigid strip method, the electrodepositing over the first layer a layer of Cr from 10 to 50 millionths of an inch thick from a second bath at a temperature from 90 ‹F, to 150‹F., the second bath containing a chromium plating solution optionally containing up to 0À1 gram/litre of sodium selenate or an arsenic, strontium or fluosilicate compound to induce stressing of the chromium layer, and finally, if necessary, heating the laminate for 5 to 120 seconds at 180‹F. - 450‹F, to induce cracking the nickel bath may be a Watts type bath or other sulphate, chloride, sulphamate or fluoborate bath and may contain, as stress producing agents amine boranes, pyridinium compounds, quinolinium compounds or isoquinolinium compounds for example. The chromium plating bath may contain chromic acid, sulphate ion and 0‹002 to 0À01 grams per litre of selenate ion. |
