Formation Mechanism of Microstructure of Fe2(MoO4)3/Si3N4 Composite Powder by Hydrogen Reduction

The microstructure characterization of Fe2(MoO4)3 and Fe2(MoO4)3/Si3N4 composite powder reduced by hydrogen were investigated, and the formation mechanism of the latter was analyzed. The results show that the microstructure of Fe2(MoO4)3 powder particles reduced by hydrogen was consisted by Mo particles coated with thin layer of Fe with thickness around 20 nm. The microstructure of the other were two kinds of particles with different structure which were consisted by Mo particles coated with nanometer-thin layers of Fe with thickness about 3–5 nm and nano Fe–Mo nitride, Si and Mo as adhesive materials on Si3N4 particles surface. The formation reason of the microstructure of Fe2(MoO4)3/Si3N4 composite powder reduced by hydrogen powder was two reactions during the reduction process. One is the decomposition-reduction reaction of Fe2(MoO4)3, the other is the reaction between the surface of Fe2(MoO4)3 and Si3N4.