Effects of zinc oxide on thermal shock behavior of zinc sulfide– silicon dioxide ceramics

Thermal shock resistances of ZnO and non-ZnO containing ZnS–SiO2 composite ceramics are observed using water quenching method. The residual strengths are measured as function of quenching temperature differences. The thermal shock damage parameters R‴ and R⁗ are evaluated to compare with experimental results. Specimens with low thermal shock damage parameters show acute strength degradation up to 76% at a lower quenching temperature difference of 250 °C. The 1% ZnO containing specimen with medium density and higher thermal shock damage parameter values demonstrates a minimal strength drop of 36% at a higher quenching temperature difference of 300 °C. The evaluated R‴ and R⁗ values correspond well with the residual strength at elevated temperature difference. It implies that the good thermal shock resistance of ZnS–SiO2 system can be achieved by improving fracture toughness with moderate ZnO addition and pores.