Oxidation behavior of ZrB2/SiC laminates: Effect of composition on microstructure and mechanical strength

SiC-ZrB2 ceramic laminates with different SiC:ZrB2 ratios were prepared by tape casting, binder burnout and pressureless sintering at 2200 °C in view of their application in thermal protection systems. Their oxidation behavior in air was investigated by TGA up to 1600 °C and by long term oxidation tests at 1500 and 1600 °C. Both microstructure and mechanical features of laminates were compared, before and after oxidation. The formation of a passive layer was always observed but the oxidation resistance worsened and the complexity of the oxide layer microstructure increased with the ZrB2 content. Composition also affected the residual strength and modulus after oxidation.