Abstract
Reducing agents, such as sodium thiosulfate, sodium hypophosphite, hydroxylamine and hydrazine sulfate were added to the W-Co alloy plating bath, and the hydrazine sulfate showed the best result. On addition of the hydrazine sulfate to the W-Co alloy plating bath, though the contents of W in the deposits was decreased slightly, the cathode current efficiency was increased markedly compared with the ordinary bath, and the bright deposits were obtained through a long time operation.
Addition of hydrazine sulfate to the W-Fe alloy plating bath was as effective as in the case of W-Co alloy plating, but in the case of W-Ni alloy plating W content in the deposits was less than those in the cases of W-Co and W-Fe alloy plating.
