Abstract
The h-BN/feldspar composite was sintered under ambient pressure at low temperatures in air. We studied the effect of the feldspar ratio on the composite strength. The h-BN powder contained 40 mass% B2O3. The feldspar was pre-melted and then milled before sintering. The melting point of the as-received feldspar was nearly 1500 K. The powder mixture of h-BN and the melt and milled feldspar was sintered at 1473 K. The bending strength of the composite improved with increasing the feldspar content above 30 vol%. The highest bending strength of 52 MPa was obtained for the 40 vol% feldspar contained composite. Therefore, the feldspar ratio needs more than 30 vol% for protecting h-BN from air during sintering.
