Electroless deposition of Ni-Co-B alloy films and influence of heat treatment on the structure and the magnetic performances of the film

The Ni-Co-B alloy was electrolessly deposited from the bath using potassium borohydride as a reducing agent and ethylenediamine as a stabilizer. The effects of the plating conditions on the plating rate and the composition of the deposit were studied to improve the stability of the plating bath and to control the composition of the Ni-Co-B deposit. The crystallization behavior of the deposit was investigated by X-ray diffraction. The results show that the structure of the as-plated deposit is amorphous, and the deposit was crystallized into cubic Ni₃B and Ni-Co phases at 350 °C. The effect of heat treatment on the magnetic performances of the deposit was studied by vibrating sample magnetometer. The saturation magnetization and the residual magnetization of the coating go up with the increase of heat treatment temperature from 50 °C to 600 °C. The deposit heat-treated at 600 °C is found to be suitable as soft magnetic materials.