Monolithic nanocrystalline SiC ceramics

Abstract

Additive-free beta-SiC nanopowders were densified by using high-pressure anvil-type with hollows apparatus at the pressure of 4 GPa in the range of 1500-1900 degrees C. The starting powder with average particle size of 10 nm was synthesized by a sol-gel process. Crystallite size and lattice parameters of the samples have been studied at room temperature by X-ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the size of the crystallites gradually increases from 16 to 51 nm with increasing sintering temperature (1500 to 1900 degrees C). Fully densified sample ( GT 99%) was obtained at a sintering temperature of 1900 degrees C for 60 s. This sample exhibits nano-hardness and Youngs modulus of elasticity of 35 GPa and 450 GPa, respectively. Modified vibratory cavitation test method was used for laboratory testing of the cavitation resistance. A very low erosion level with mass loss 0.1% after 10 h was exhibited during the cavitation test. (C) 2015 Elsevier Ltd. All rights reserved.