MgAl2O4-reinforced c-ZrO2 ceramics prepared by spark plasma sintering

c-zirconia ceramic composites have been synthesized by spark plasma sintering (SPS) technique from commercial m-ZrO2, Y2O3 and waste-derived magnesium aluminate spinel (MA) powders. In this study, effect of MA addition on stabilization and reinforcement of 5 mol% yttria-stabilized zirconia (YSZ) was carefully investigated. Spark plasma sintering of designed powder mixtures at 1400 °C for 30 min and 40 MPa produce fully dense compacts with an average grain size of 0.5–10 μm. The pressure was gradually increased up to 40 MPa using argon gas and was kept until the end of the sintering process. The refined microstructure (0.5–10 μm) obtained in this study has achieved superior compaction resistance values that are ten times more than strength values of conventionally sintered specimens. Such improvement in compaction resistance of the sintered specimens was attributed to particle size refinement and grain boundary enhancement. What’s more, spark-plasma sintered composites containing 10–50 wt% MA revealed higher resistance to low temperature degradation (LTD) than the reference composite that doesn’t contain MA spinel; where about ~ 2.8% of t-ZrO2 was converted into m-ZrO2 in case of the latter composite while aging test didn’t influence at all on the structure of the former composites. The outcomes indicated that MA has a significant effect on m-ZrO2 stabilization into a cubic phase structure that concurrently owned an enhanced and comparable compression resistance to Yttrium-doped t-ZrO2 (Y-TZP). In this respect, the ternary oxide ceramic composite systems prepared in this study present huge potential for development c-ZrO2-based industrial ceramics with a wide spectrum of mechanical characteristics for high-tech engineering applications of harsh-stress and humid environments.