Sintering of polycrystalline boron nitride composites for in-situ synchrotron high pressure research

Abstract

Polycrystalline cubic boron nitride (PcBN) composites were sintered around 6GPa/1200°C in a cubic multi anvil press: aluminium in the starting mixture reacts with cubic boron nitride (cBN) and forms aluminium boride (AlB2) and nitride (AlN) bonding among cBN grains during high pressure high temperature (HPHT) sintering. X-ray diffraction (XRD), Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy were utilized to analyse different phases, micro-structure, morphology, and compositions of the composites material. The dense structure of superhard cBN grains bonded together with light AlB2/AlN offers superior hardness, high strength, and X-ray transparency; PcBN anvils (12mm height×12mm diameter×5mm culet) were built for rotational anvil cell for in-situ synchrotron high pressure experiments on Zirconium, and these PcBN anvils survived up to 32GPa after initial tests.