High thermal stability of diamond–cBN–B₄C–Si composites

Abstract

Improving the thermal stability of diamond and other superhard materials has great significance in various applications. Here, we report the synthesis and characterization of bulk diamond-cBN-B 4 C-Si composites sintered at high pressure and high temperature (HPHT, 5.2 GPa, 1620-1680 K for 3-5 min). The results show that the diamond, cBN, B 4 C, B x SiC, SiO 2 and amorphous carbon or a little surplus Si are present in the sintered samples. The onset oxidation temperature of 1673 K in the as-synthesized sample is much higher than that of diamond, cBN, and B 4 C. The high thermal stability is ascribed to the covalent bonds of B-C, C-N, and the solid-solution of B x SiC formed during the sintering process. The results obtained in this work may be useful in preparing superhard materials with high thermal stability.

High-Pressure Synthesis of Superconducting Sn3S4 Using a Diamond Anvil Cell with a Boron-Doped Diamond Heater

“…Here, there is no Raman peak of cubic boron nitride in the analyzed region. 40 97(6) GPa and 545(5) Å 3 , respectively. The unit cell volume tends to be smaller than the theoretical prediction [15] due to an overestimation feature in the used calculation method.…”

“…The decomposition feature is consistent with the result of the XRD analysis. Here, there is no Raman peak of cubic boron nitride in the analyzed region . The pressure profiles of XRD patterns and Raman spectra of the starting material are presented in Figure S2.…”

Polycrystalline cubic boron nitride prepared with cubic-hexagonal boron nitride under high pressure and high temperature

“…Due to its high hardness, high chemical stability, extreme wear, and high thermal conductivity, polycrystalline cubic boron nitride (PcBN) is widely used in various industrial machining fields. [1][2][3] Traditionally, commercial cBN compacts are produced by sintering cBN powder with the addition of various binders (e.g., Co, Ti), [4,5] , which reduces the experimental pressure and temperature requirements, whereas the additives affect the mechanical properties of the sintered PcBN composite, [6] and downgrade the mechanical properties. Therefore, the best way to obtain PcBN with excellent mechanical properties is free from additives, and the perfect additive is the material itself.…”