セラミックスへのニッケル無電解メッキ

抄録

The application of electroless nickel plating on the sintered substrate of PbTiO₃-PbZrO₃ was studied as an available means for manufacturing precision electronic parts. An improvement in pretreatment process for such a lead-containing substrate was carried out. By trying an intermediate treatment of thin electroless plating of a noble metal between the conventional pretreatment and the electroless nickel plating, the electroless deposition of nickel was accelerated in its initial stage and uniformity of the deposited nickel film was also obtained. Among various factors affecting the deposition rate, the effect of sodium hypophosphite concentration was found to be greater than that of nickel ion concentration in the plating bath. The optimum plating conditions obtained were as follows: pH: 5.40, temperature: 80°C, and immersion time: 45min. Furthermore, the distributions of nickel and phosphor contents on the cross-section of the deposited film were examined by X-ray microanalysis. The phosphor content was lower in the layer nearer to the substrate in the initial stage of deposition, but it became higher nearer to the surface of deposit with the time of immersion; while, the nickel content was constant over the whole thickness of cross-section.