| 摘要 |
<p>1,214,420. Pretreatment of non metallic substrates prior to Ni coating, KNAPSACK A. G. July 25, 1969 [Aug. 1, 1968], No.37458/69. Heading C7F. Non metallic substrates e.g. plastics, rubber, glass, wood or ceramic prior to electroless Ni plating are pickled in concentrated H 2 SO 4 containing a noble metal salt then the noble metal salt adhering to the substrate is reduced with an aqueous solution of a reducing agent e.g. sodium hypaphosphite, containing polyphosphoric acid. Term "noble metal includes Au, Ag, Hg, Pt, Ru, Rh, Pd, Os, Ir. Both pickling and reduction are effected at 75-90‹ C. The pickling solution may contain HNO 3 , H 2 O 2 , chromic acid or alkali metal persulphate and preferably 0À1-0À5g/l palladium chloride. The reducing agent contains 1-20 g/l of poylphosphonic acid, preferably hydroxyethane- .diphosphonic acid. Treating time is 2-20 minutes in each solution. The electroless Ni plating deposited has a high peel strength and electroplated Ni may be deposited on it.</p> |
