Under the conditions of synthesis temperature of 1 400℃～1 500℃,pressure of 5～5.5 GPa and sintering time of 20～25 min,polycrystalline cubic boron nitride(PcBN)compacts with high cBN content are formed by changing the shield cup materials(zirconium,molybdenum and niobium).After surface grinding and cylindrical grinding,the effects of different shielding cup materials on the defects and impact toughness of PcBN compacts are compared.The experimental results show that molybdenum and nio-bium with higher melting point should be selected as shielding materials for the synthesis of PcBN composites with high cBN content,which not only can avoid overburning on the edge of composites at high temperature,broaden the synthesis temperature area,improve the synthesis stability and impact toughness,but also reduce the cracking phenomenon of polycrystalline layer during the cutting process,and significantly improve the product yield and customer satisfaction.
维普
万方数据