Abstract
Boric acid is generally added to buffer the pH and improve the life expectancy of a nickel plating bath. The plating industry has requested alternatives to boric acid because its use will be restricted in the future. In this study, the hull cell, pH buffer correlation and cathode current efficiency tests were conducted using 21 different substitute buffering agents. From these 21 agents, acetic acid, propionic acid, nickel acetate and citric acid showed the same appearance and buffering ability as boric acid. Physical properties, such as Vickers hardness, tensile strength and internal stress test were measured on nickel samples made using these four buffering agents, as well as boric acid. When using these four organic compounds, the internal stress somewhat higher compared with a standard boric acid bath, but the other physical properties were almost all the same, except in the case of citric acid. It was found that citric acid produced samples with higher Vickers hardness. For all the buffers, as current density increased, Vickers hardness decreased and tensile strength increased. The physical properties of samples made with these buffers show the same trends vs. current density as those made with boric acid bath.
