Preparation and sintering of Ni-coated Si3N4 composite powders

Ni-coated Si3N4 composite powders were prepared successfully via electroless plating by using sodium hypophosphate (NaH2PO2) as reducing agent. The Ni coating layers contained 12 wt.% phosphor and were dominantly amorphous with a thickness of 20–60 nm. The sintering properties of Ni–Si3N4 composite were improved by adding Mo2C into Si3N4 powders, in which Mo2C formed liquid to improve the α–β transformation of Si3N4, and Mo2C converted into MoSi2 after sintering. The composite powders were densified by hot-pressing at 1600 °C. The final crystal phases of the sintered samples were Si3N4, Ni and MoSi2.