Electroless Plating of Ni-P-W Coatings Containing Scattered Nb₂O₅ on Sintered NdFeB Substrate

Abstract

The ternary Ni-P-W coatings containing scattered Nb₂O₅particles were deposited on the sintered NdFeB substrates by electroless plating. The effect of experimental processing parameters on the deposition rate was investigated during electroless plating. The coatings performance, such as corrosion resistance, interfacial adhesion strength and micro-hardness, was evaluated by experimental testing. The experimental results indicated that the corrosion resistance of Ni-P-W/Nb₂O₅ composite and the interfacial adhesion strength between Ni-P-W/Nb₂O₅coatings and NdFeB substrate have been increased with increasing the Nb₂O₅ concentration up to 15gL^-1. Increasing Nb₂O₅ concentration over 15gL^-1decreases the corrosion resistance of Ni-P-W/Nb₂O₅composite and the interfacial adhesion strength. Testing of micro-hardness showed that the hardness of Ni-P-W coatings containing scattered Nb₂O₅ composite increases with increase in Nb₂O₅ concentration.

Keywords:
electroless plating; Ni-P-W/Nb₂O₅ composite; NdFeB substrate