Reactive spark plasma sintering of B4C composite at low temperature using mechanically milled B4C–Ti–B mixtures

Abstract

Sintering of pure B4C requires extremely high temperatures of more than 1800 °C, even with techniques such as spark plasma sintering (SPS). In this study, sintering of B4C was achieved at low temperature using reactive Ti–B mixture as a sintering additive. Ti and B powders (1:2 atom ratio) were milled for 8 h and added to B4C powder in proportions of 5, 10, and 20 wt% and milled for 4 h to achieve good dispersion. Dense B4C composite compacts were obtained using SPS at 1400 °C. A pore free microstructure consisting of B4C grains surrounded with fine grains of (Ti0·9W0.1)B2 and W2B5 was obtained due to WC contamination. The activation energy for sintering reduced from 234 to 155 kJ/mol with the increase in the amount of Ti–B mixture from 5 to 20 wt%. The B4C composite with 5 wt% Ti–B mixture had the maximum hardness of 3225 ± 218 H V.