Effect of 10B enrichment on the thermal expansion of boron carbide

Abstract

The effect of 10B enrichment on the lattice and bulk thermal expansion behaviour of boron carbide (B4C) has been investigated. The coefficients of lattice thermal expansion (LTE) of hot-pressed polycrystalline boron carbide (B4C) with natural 10B isotopic composition (N-B4C) as well as 50% and 90% 10B enriched B4C (50E-B4C, 90E-B4C) are measured in the temperature range of 298–1273 K using X-ray diffraction (XRD) method. The coefficients of bulk thermal expansion (BTE) was measured for the same specimens using dilatometry and compared with the measured LTE. A reasonable increase in both LTE and BTE of B4C has been observed with increase in 10B enrichment. The measured BTE is found to have higher values in comparison with the LTE, irrespective of 10B enrichment which is attributed to the intrinsic distorted structure of B4C as well as the presence of defects in the as-synthesized specimens.