Abstract
This study relates to preparation conditions and physical properties of electroplated amorphous ternary Ni-Co-B alloy films that were prepared by the authors based on their previous studies of electroplated binary Ni-B alloy films. The results can be summarized as follows:
1. Preparation of amorphous Ni-Co-B alloy films by electroplating is possible if trimethylamineborane is used as an additive.
2. Increases in depostied cobalt reduce codeposited boron and produce amorphous films, when the deposited cobalt content is approximately 4wt.% or less, and when boron codeposition is approximately 5wt.%.
3. The maximum hardness of heat treated amorphous Ni-Co-B alloy films was Hv (0.025) 1250 at approximately 400°C, while that of heat treated amorphous Ni-B alloy films was approximately Hv (0.025) 1030 at approximately 300°C.
4. Thermal analyses of various Ni-B and Ni-Co-B alloy films, including amorphous films, by differential scanning calorimetry showed that every alloy has its calorific power, which increased with codeposited boron; the calorific power/deposited boron relation for Ni-B alloy films was linear and that for Ni-Co-B alloy films was inversely parabolic. Every curve showed a discontinuity at a codeposited boron content of approximately 4.5wt.%.
