Interaction of Al and cBN under High Temperature and High Pressure

Polycrystalline cubic boron nitride(PcBN)samples were obtained by sintering cBN and aluminum micro-powders in volume ratio of 7:3 at high temperature(1300-1500℃)and high pres- sure(5.5GPa).The identification and the morphology of phases,and the distribution of elements in PcBN samples were studied by using X-ray diffraction(XRD),transmission electron microscope(TEM), selected-area electron diffraction(SAED),and energy dispersive X-ray spectrometry(EDS).Results show that Al does not react with cBN at 1300℃.When the temperature is increased to 1400℃,Al can react with cBN to form A1N and AlB_2,and the temperature is increased to 1500℃,the amount of products increases.TEM and EDS analyzing results indicate that Al atoms diffuse into surface layer of cBN particle,and B atoms diffuse into Al zone,forming new phases A1N and AlB_2.