Continuous SiC fibers-ZrB2 composites

ZrB2-continuous SiC fiber composites were prepared by vacuum-bag infiltration and hot pressing, using SiC fabric preforms. Vacuum bag infiltration was effective when unidirectional fiber layers in a 0-90° architecture were infiltrated with an aqueous ZrB2-rich slurry. Sintering was carried out at temperatures between 1450 and 1600 °C to study the effect on densification and microstructural features. With a fiber content of around 50 vol%, the composites had a density of 4 g/cm3 and final porosities lower than 10 vol%. Flexural strength was measured at room and high temperature in air. Irrespective of the processing temperature, strength values were 150-170 MPa up to 1200 °C and 110 MPa at 1500 °C. Short-term oxidation tests were conducted at 1650 °C in a bottom-up furnace.