Effect of Al addition on SiC-B4C cermet prepared by pressureless sintering and spark plasma sintering methods

摘要

SiC-B4C-Al cermets containing 5,10 and 20 wt% of Al were fabricated by high-energy planetary milling followed by conventional sintering and spark plasma sintering (SPS) techniques separately. The average particle size reduced to similar to 3 pm from an initial size of 45 mu m after 10 h of milling. The as-milled powders were conventionally sintered at 1950 degrees C for 30 min under argon atmosphere and SPS was carried out at 1300 degrees C for 5 min under 50 MPa applied pressure. The formation of Al8B4C7 and AlB12 phases during conventional sintering and SPS were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. The formation of Al8B4C7 at 700 degrees C and AlB12 at 1000 degrees C was well supported by XRD and differential scanning calorimetry (DSC). The maximum relative density, microhardness and indentation fracture resistance of SiC-B4C-10Al consolidated by SPS are 97%, 23.80 GPa and 3.28 MPa center dot m(1/2), respectively. (C) 2016 Elsevier Ltd. All rights reserved.