Effects of Atmosphere on Sintering and Properties of Aluminum Oxynitride

Sintering of aluminium oxynitride (AlON) is executed at temperatures where a liquid phase is formed. in a furnace with carbon heating elements decomposition occurs due to a low oxygen pressure. Properties of samples sintered in these furnaces are compared. A furnace with tungsten heating elements yields a significantly higher oxygen pressure, which prevents the decomposition. Densification in this furnace is comparable to that in a furnace with carbon heating elements. A model for the decomposition reaction in a furnace with carbon elements is presented. It follows that to prevent the decomposition of y-AlON, carbon should be eliminated in the sintering environment.