Effects of the ratio of binder and the ratio of cBN particle size on the microstructure and properties of PcBN composites

Abstract

Polycrystalline cubic boron nitride composites were prepared under high-temperature and high-pressure conditions. The effects of bonding agent ratio and cBN particle size on the composition, microstructure, microhardness, and abrasive ratios of the PcBN composites were investigated using X-ray diffraction (XRD), field scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The experimental results showed that the PcBN composites performed better under sintering conditions of 5.5 GPa, 1400 ℃, and a 10-minute holding time, achieving a hardness of up to 22.7 GPa and an abrasion ratio of 149.2 at V(TiN0.3)∶V(AlN)=70∶30. Moreover, when the particle size combination of cBN in PcBN composites is (0.5～1) μm:(2～5) μm:(5～10) μm = 3:5:2, the packing density between particles reaches its peak, resulting in optimal performance.

Keywords

• pcbn composite
• high pressure and high temperature (hpht)
• binder
• particle size