Ni-B Amorphous Alloy Film Deposited by Electroless Deposition Method

Abstract

Morphorogy of Ni-B amorphous alloys prepared by a electroless deposition method with NaBH4 and its reproducible preparation conditions were investigated. Electroless deposited Ni consisted of the aggregate of microcrystals, but these microcrystal size decreased as the reducing agent concentration in the plating bath is increased. At the concentration of 400 mg/l or above, the morphorogy of the deposited Ni film was an amorphous state. The increase of the reducing agent concentration increases the concentration of boron in the deposited Ni film. When the boron concentration is lower than 11.4%, the deposited film was crystalline but in the case of the saturated concentration (11.4%), the structure became amorphous. It was revealed, therefore, that a high boron content in the deposited film was necessary to form amorphous films, and that the amorphous alloy could be prepared independent of depositing temperature, substrate materials and deposition time.