复合超硬材料的高压合成与研究

摘要

Materials having Vickers hardness (HV) higher than 40 GPa are considered to be superhard. Superhard material is exclusively covalent and displays superior hardness, incompressibility, and wear resistance, which make this kind of material essential for a wide range of industrial applications, such as turning, cutting, boring, drilling, and grinding. Most of superhard materials are prepared under extreme pressure and temperature conditions, not only for scientific investigations, but also for practical applications. With the development of high pressure science and technology, the field of superhard composites is more active and more efficient, energy saving and environmental protection. Ultrahigh pressure and ultrahigh temperature method plays an important role in the scientific research and industrial production of superhard materials. It provides the driving forces for the light elements forming novel superhard phases and the way of sintering high-density nanosuperhard materials. In this paper, the recent achievements and progress in high-pressure synthesis and research of superhard materials are introduced mainly in the nanopolycrystalline diamond, nanopolycrys-talline cubic boron nitride (cBN), ultrahard nanotwinned cubic boron nitride, submicron polycrystalline cubic boron nitride, cBN-Si composites material, cubic-Si3N4-diamond nanocomposites and diamond-cubic boron nitride superhard alloy (composite) material prepared under ultrahigh pressure and high temperature, by using multi-anvil apparatus based on the hinged-type cubic press. These superhard composite materials are successfully synthesized by high tem-perature and high pressure, and a variety of performance tests show that their hardness values and thermal stability properties exceed those of the traditional superhard materials. At the same time, some new ideas, approaches to the study of superhard composite materials in recent years have been introduced, such as nanostructuring approaches and special treatments of the starting material for high-performance superhard materials, using the formation of alloys or solid solution to fill the performance gap between different materials for enhancing comprehensive performance (i.e., hardness, fracture toughness, and thermal stability), or changing and optimizing the assembly method to improve the uniformity of performance. Finally, the prospect of superhard composite material is also discussed. In the research field of superhard materials, on the one hand, the relationship between macrohardness and microstructure of superhard materials is studied continuously to establish hardness models with atomic parameters, which can be used to guide the design or prediction of novel superhard crystals. On the other hand, highly comprehensive performance and larger size of super-hard composite materials are synthesized for practical application.%复合超硬材料作为一种性能优异的结构材料,被越来越广泛地应用于切削加工、油气钻探等领域.目前大部分复合超硬材料是通过高温高压方法制备.本文主要介绍了近年来复合超硬材料的高压合成与研究取得的成果和进展,重点包括纳米、亚微米、微米聚晶金刚石与立方氮化硼、立方相氮化硅-金刚石超硬复合材料以及金刚石-立方氮化硼超硬合金(复合)材料等,这些新型的复合超硬材料已经被成功合成,各种性能检测表明这些复合超硬材料的硬度、热稳定性等主要性能已明显超越传统超硬材料,可成为有广阔应用前景的新一代复合超硬材料.文中还介绍了近些年研究复合超硬材料出现的а些新的思路、方法与途径,并对复合超硬材料的进一步研究做出了展望.