METHOD OF PRODUCING ALUMINIUM NITRIDE-BASED POWDER Russian patent published in 1998 - IPC

FIELD: abrasive materials. SUBSTANCE: wet powder waste originated from grinding aluminium nitride-based objects containing aluminium compounds with sintering-activation additives (1-15% AlN, 0.5-5% Y₂O₃, and Al(OH)₃, the balance) is dried in drying box at 150 C for 3 h and calcined in heating furnace at 750 C for 1 h. 700 g of calcined grinding waste, containing 1-15% AlN, 0.5-5% Y₂O₃, and γ-Al₂O₃, the balance, is mixed with 300 g of carbon black on vibration stand. Mixture is disintegrated on planetary mill to dispersity with predominant particle size below 1 mcm. Powder is then nitrided in periodical furnace at 1700 C with curing at maximum temperature for 1 h, involving profound purification of nitrogen with dew point Ц80 C. Non-reacted carbon is removed from thus synthesized powder by calcining powder in heating furnace for 3 h. Method enables: preparing AlN-based powder with sintering-activation additives and nitrogen content 33%; adjusting content of sintering-activation additives in powder (and, respectively, correcting properties of sintered objects manufactured from this powder); using grinding waste instead of aluminium oxide; reducing power consumption because of lowered synthesis temperature and absence of necessity in multi- step process; partially using industrial-grade nitrogen in nitriding process. EFFECT: reduced cost of aluminium nitride powder production and facilitated variation of its characteristics. 1 tbl