Development of ZrB2-B4C-Mo Ceramic Matrix Composite for High Temperature Applications

Abstract

The present study deals with development of ceramic matrix composite containing the nominal compositions of three powders ZrB2 (40 wt. %), B4C (40 wt. %) and Mo (20 wt. %) were synthesized by ball milling and followed by conventional sintering in a furnace at 1500°C and 1600°C for 3 hours in presence of Ar gas and also spark plasma sintering at 1800ºC for 1 min. During ball milling the crystallite size of the powder gradually decreases with increase in milling time from 0h to 60h and crystallite size of the final product reaches in submicron or nano-metric level. The influence of the processing parameters on the phase evolution and chemical composition during ball milling, conventional sintering and spark plasma sintering for sub-micrometer or nano-metric (60h milling) of the composites were investigated in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM) and EDS analysis. The maximum densification of ZrB2-B4C-Mo ceramic matrix composite was achieved at 1800°C. The composites prepared by spark plasma sintering at 1800°C records extraordinary level of improvement of the hardness (27.34GPa) which is 3-4 times of higher hardness value than that of the composites sintered at conventional techniques. Similarly, the ball on disc wear resistant property of ZrB2-B4C-Mo ceramic matrix composite exhibits higher in the samples prepared by spark plasma sintering at 1800°C