METHOD FOR PLATING NICKEL-BORON ALLOY

摘要

PURPOSE:To form an Ni-B alloy film having superior heat resistance an solderability by carrying out electroplating at a low temp. with a soln. prepd. by using a borohydride compound as a reducing agent in an electroless Ni plating bath having a prescribed composition. CONSTITUTION:A borohydride compound as a reducing agent is added to a soln. contg. an Ni salt and an org. acid such as citric acid, malonic acid or tartaric acid or a salt thereof as a complexing agent to prepare an electroless Ni plating soln. Electroplating is carried out with the plating soln. kept at such a low temp. as about 50 deg.C at which an electroless plating reaction slightly takes place or does not take place at all. By the electroplating, a metallic Ni film is deposited and simultaneously a very small amount of B is deposited. A metallic film formed by this method has heat resistance and solderability comparable to those of an Ni-B alloy film formed by conventional electroless plating. The plating time is shortened.