| 摘要 |
In a process of joining together by resistance welding metal parts such as iron or steel for transistor envelopes or thermionic valves, the parts are first coated in an electroless Ni plating bath comprising an aqueous solution of hypophosphite and Ni ions in a mole per cent ratio of at least 3:1, and a compound forming complexes with Ni ions in a mole per cent ratio to Ni of at least 2:1, the solution having a pH of 4-7 and the coating produced contains at least 12% by weight of phosphorus in at least the outer part of the Ni coating. The complexing agents may be citric acid, hydroxy acetic acid, ethylene diamine, ammonia or amino acetic acid. |
