Abstract
The authors investigated the effects of heat treatments on hardness of Co-Ni and Co-Ni-P plating films chemically deposited from 4 kinds of alloy baths reported in the previous papers.
The following results were obtained.
1) The films as deposited from a hydrazine bath exhibited the hardness of 400-500Hv, and the hardness of Co-Ni alloys was higher than that of each single Co or Ni film. The hardness of these films was secarcely changed when they were heated to a certain temperature up to 400°C in nitrogen atmosphere.
2) The hardness of films deposited from hypophosphite baths was slightly higher than that of the above (deposited from a hydrazine bath) films. However, its value was remarkably increased by the heat treatments up to 500°C, owing to the precipitation of metallic phosphide.
3) The treating temperature for giving the maximum hardness of films was found to be 400°C for Ni-P films and it shifted to the higher temperature side with the increase of cobalt content in the film.
