Al与cBN在高温高压下的相互作用

将立方氮化硼(cBN)微粉和铝(Al)微粉按照体积比7:3的比例进行混配, 在高温(1300～1500℃)、高压(5.5GPa)条件下进行烧结. 利用X射线衍射分析(XRD)、透射电子显微镜(TEM)以及X射线色散能谱(EDS)对烧结体的物相构成、显微结构以及各组分元素的分布进行了分析. 实验结果表明, 1300℃, Al尚未与cBN反应; 当温度升至1400℃时, Al与cBN反应生成AlN和AlB₂; 温度进一步升高至1500℃, 反应产物增多, 产物种类不变. TEM和EDS分析表明, 在反应过程中Al扩散进入cBN的表层, B扩散进入富Al的区域, 生成新相AlN和AlB₂.

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 pressure (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 AlN and AlB₂, 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 AlN and AlB₂.