Morphology of cubic boron nitride crystals synthesized using (Fe, Co, Ni)-(Cr, Mo)-Al alloy solvents under pressure

The growth region of the cubic boron nitride (cBN) using (Fe, Ni)-Cr-Al and Co-(Cr, Mo)-Al solvents were presented in the pressure range of about 4-6 GPa and the temperature range between 1200 and 1700 °C. The minimum pressure for cBN formation was confirmed at about 4-4.1 GPa for both (Fe, Ni)-Cr-Al and Co-(Cr, Mo)-Al solvents. Based upon this pressure-temperature condition of the cBN growth region, the morphology of cubic boron nitride crystals was examined under various compositions of the solvents. The morphology of cBN crystals was affected by not only the reaction pressure and but also the composition of the solvents. It was found that the variation of alloy composition provides various morphologies and grain sizes of cBN crystals.