Influence of ZrO₂ content on the performances of BN-ZrO₂-SiC composites for application in the steel industry

BN-ZrO₂-SiC composites were fabricated with different ZrO₂ contents ranging from 0 to 40 vol%. The mechanical properties and corrosion resistance against molten steel increase with increasing ZrO₂ content, while thermal shock resistance decreases gradually. When ZrO₂ content is 40 vol%, the flexural strength is 346 MPa and corrosion depth is 254 μm. The improved corrosion resistance is attributed that the corrosion layer formed by residual ZrO₂ hinders molten steel penetration. Nevertheless, composite with 40 vol% ZrO₂ shows a sharp decline in residual flexural strength when temperature difference is more than 400°C and critical temperature difference is 520°C.