纳米B6O—B4C超硬复合材料的高温高压烧结与表征

B6O是近几年来在国际上引起广泛关注的一种新型超硬材料。它具有低密度、高导热性、耐磨性、高硬度和较好的化学稳定性。在高温高压（3～5GPa，1500～1900K）下通过“一步法”合成了高性能纳米结构B6O超硬复合材料，并分析了合成压力、合成温度、初始材料等条件，对合成样品的物理化学性能、微观结构、相组成的影响。合成样品中B6O微粒在几十到几百纳米之间，属纳米级别。试验在较低的压力下（～3GPa）合成烧结良好的圆柱形样品，用维氏硬度计测量其硬度在32GPa，跟立方氮化硼复合片（PcBN）硬度相当，并且具有较好的断裂韧性。最初的切削实验表明以烧结良好的B6O复合材料制成的工具样品可以高速、干式切削各种陶瓷、金属材料。

Sintering at high pressure and high temperature and characterization of nanometer B6O-B4C superhard composite

Boron sub-oxide has generated considerable interest as a novel superhard material recently. It combines extreme hardness, higher chemical stability, lower density, high thermal conductivity, and excellent wear resistance. We report high pressure and high temperature synthesis of nanostructure B6O superhard composites with high comprehensive performance by using ＂one step method＂. Effects of starting materials, pressure and temperature conditions on the microstructure, phase composition, chemical and mechanical properties of synthesized samples are investigated. The samples are well-sintered under a lower pressure（～3GPa） and have high hardness （32GPa）, which is comparable to that of polycrystalline cubic boron nitride （PcBN）, also have better fracture toughness. The initial cutting test results show that the nanostructure B6O superhard composites can be applied for high-speed dry-cutting of various ceramic and metallic materials.