Influence of preparation temperature on the properties of C/ZrC composites

The preparation temperature for C/ZrC composites was optimized by assessing the effects on their mechanical and, ablation properties. The composites were prepared by precursor infiltration and pyrolysis at 1500 degrees C, 1550 degrees C and 1600 degrees C. With rising preparation temperature, the open porosity of the composites increased, accompanied by formation of a strong interface and aggravated damage to carbon fibers, which were adverse to the mechanical properties. As a result, the flexural strength and fracture toughness decreased from 232 MPa to 11.9 MPa m(1/2) to 103 MPa and 3.4 MPa m(1/2) respectively. Meanwhile, elevating the open porosity provided more passage for oxygen into C/ZrC composites, which weakened the ablation resistance. The linear recession rate increased from 21.0 mu m/s to 32.0 mu m/s and then to 35.7 mu m/s. Taking mechanical and ablation properties into consideration simultaneously, the optimum preparation temperature was 1500 degrees C. (C) 2016 Elsevier B.V. All rights reserved.