Conversion of W₂C to WC phase during mechano-chemical synthesis of nano-size WC-Al₂O₃ powder using WO₃-2Al-(1 + x)C mixtures

Due to the weak properties of W₂C phase, its formation during the process of WC synthesis should be prevented. The aim of the present study has been the mechano-chemical synthesis of a WC-Al₂O₃ composite powder free from undesirable W₂C phase through the addition of excess carbon to the WO₃-2Al-C initial mixture. Based on the thermodynamic calculations and results of the supplementary experiments in W-yC and W₂C-C systems, the possibility of the conversion of W ₂C to WC phase through the addition of excess carbon has been investigated. It has been shown that production of a WC-Al₂O ₃ composite powder by 360 min mechano-chemical treatment of an initial mixture of WO₃-2Al-1.8C is possible. TEM observations and Williamson-Hall calculation revealed that the obtained WC-Al₂O ₃ powder contains macro-size agglomerates in which each agglomerate consists of nano-size phases.