Microstructure and mechanical properties of a ZnS–SiO2 composite prepared by ball-milling and spark plasma sintering

Raw ZnS and ZnS–SiO2 powders mixed by a 3-D mixer or by using high energy ball-milling with attritor mixing were successfully densified by spark plasma sintering. The mechanical properties of the sintered part were evaluated in terms of microhardness and fracture toughness and then correlated to the observed microstructure. Because of a finer and more homogeneous microstructure, the mechanical properties of the ZnS–SiO2 composite prepared from the ball-milled powder showed the best properties among those investigated. Due to the effect of dispersion hardening and crack deflection by the second phase of fine SiO2, the hardness and fracture toughness were 3.031 GPa and 1.014 MPa·m0.5, respectively.