Abstract
Many studies have recently been made on alloy systems for the preparation of amorphous alloy films by plating method and on their applications, but few have been conducted to prepare electroplated amorphous alloy films in which boron is codeposited. The authors have previously studied and reported on the plating conditions of electroplated amorphous Ni-B alloy films from an electrolytic bath that includes trimethylamineborane (CH3)3NBH3. This study is intended to consider the effect of heat treatment on the crystal structure and hardness of electroplated amorphous Ni-B alloy films and to compare their crystal structure and hardness with those of electroplated Ni-P alloy films. Electroplated Ni-B alloy films are amorphous at boron contents of approximately 5wt.% or more. Analysis of the amorphous Ni-B alloy film by X-ray diffraction pattern analysis and differential scanning calorimetry (DSC) indicated that Ni-B alloy films with boron contents of 4.22wt.% or less had a different phase transition process from those with a boron content of 5.38wt.%. The effect of heat treatment on hardness was such that the hardness of the Ni-B alloy film was maximum at approximately 300°C, while that of the electroplated Ni-P alloy film was maximized at approximately 380°C; the former was higher than the latter.
