Fabrication and thermal shock behaviour of BaZrO3–MgO composites

Abstract

This study introduces BaZrO3 with a perovskite structure as a second phase combined with MgO to prepare composites and apply these magnesium matrix composites in high-temperature fields. The prepared composites have good dimensional stability (linear change rate <1%) and better cold compression strength (50–110 MPa) compared to fused magnesite. Sintered samples containing 5 wt % BaZrO3 possessed a better elastic modulus and flexural strength at 1600 °C compared to fused magnesite. BaZrO3 formed a glass phase with CaO and SiO2 in the fused magnesite sand at high temperatures, which was distributed between the particles of MgO. The BaZrO3 inhibited grain growth, promoted the exclusion of pores, and significantly reduced the thermal conductivity of the sintered samples. Scanning electron microscopy images indicated that compared to single-phase MgO, the composite sample produced a glass phase after a thermal shock, filling its pores, resulting in enhanced retention of the sample mechanical properties and better thermal shock stability. This study demonstrates that magnesium matrix composites with BaZrO3 have promising applications in high-temperature materials.