Abstract:

The Co-Mn alloys were electro-plated from the acid sulfate salt plating solution containing sodium citrate as complexing agent and boric acid as a buffer agent. The cyclic voltammetric experiments showed that the initiative co-deposition potential of the alloy is about -1.282 V (vs. Hg-Hg2SO4 , sat.K2SO4). The effect of the plating conditions on the structure and the magnetic performances of the Co-Mn coating were studied by scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDS), X-ray diffractometry (XRD) and vibrating sample magnetometer (VSM), respectively. As a result, the influence of the plating conditions on the coating’s composition is relatively remarkable. With the increase of the cathodic current density from 10 to 40 mA•cm-2 at the plating bath pH 4.0, the manganese content of the coating increases from 0.3 at% to 6.6 at%, and The coating structure is transform from hcp Co-Mn solid solution into fcc Co-Mn solid solution. With the increase of the manganese content of the film, the saturation magnetization increases, then, it decreases. The maximal saturation magnetization reaches 19262.0 kA•m-1. The value of the film coercive force ranges from 31.6 kA•m-1 to 33.9 kA•m-1.

Key words: Electro-deposition, Co-Mn alloy, Magnetic performance, coating