“…In addition, as the H + ions increased, i.e., the pH value of solution decreased, and the current efficiency of EP Ni-P also decreased. 16 An explanation for this finding is that the greater the amount of H + ions that exist in the bath, the greater the amount of hydrogen evolution formed at the cathode. This demonstrates that the hydrogen ions act as a barrier at the cathode that PO 3 30, 20, and 15* pH 1.8, 20, and 2.5** *30 g/L, 20 g/L, and 15 g/L of H 3 PO 3 were for high, medium, and low phosphorous contents of Ni-P, respectively.…”