| 摘要 |
PURPOSE:To smoothly advance plating reaction and to suppress the generation of a non-plated part, by carrying out flash plating with respect to an object to be plated in an electroless plating bath prior to carrying out composite plating. CONSTITUTION:For example, an object to be plated made of steel is degreased by trichlene or an alkali degreasing agent and, after the degreased object to be plated is washed by hot water, washed by water, subjected to weak salt pickling and washed by water, the cleaned object to be plated is subjected to electrolytic degreasing and activated by a weak acid. This pretreated object to be plated is immersed in a usual Ni-P type electroless plating bath at about 80- 95 deg.C for several min to carry out flash plating. In the next step, the object to be plated is taken out from the flash plating bath and directly immersed in a composite plating bath for about 2hr. This plating bath contains about 25g/l NiSO4, about 10g/l NaPH2O, about 10g/l sodium acetate, a reaction promotor and a stabilizer and has ultra-hard fine particles with a particle size of about 0.5-25mum while the pH thereof is about 5.0+ or -0.1 and the bath temp. thereof is about 90-93 deg.C. |
