ABSTRACT: Sinterabilities of mullite (3Al2O32SiO2–zirconia (ZrO2)composite powders prepared by ultrasonic spray pyrolysis techniques (USPTs) were examined. Starting mullite powders containing 18.5 mol% (15.0 vol%) of zirconia (ZrO2) were prepared by single-nozzle (SN) and double-nozzle (DN) USPT. In SN-USPT, the composite powder was prepared by spray pyrolysis of a water–ethanol solution in an Al(NO3)3–Si(OC2H5)4–ZrOCl2–YCl3 system at 900C, using one ultrasonic vibrator. In DN-USPT, the composite powder was prepared by simultaneous spray pyrolyses of a water–ethanol solution in an Al(NO3)3–Si(OC2H5)4 system and one in a ZrOCl2–YCl3 system at 900C, using two ultrasonic vibrators. When these composite compacts were fired at a temperature between 1400 and 1700C for 5 h, the relative densities attained maxima, i.e., 87.2% (SN-USPT) and 95.5% (DN-USPT), at the firing temperature of 1500C. Densification of the DN-USPT-derived powder compact proceeded more markedly than that of the SN-USPT-derived powder compact.
Journal of Materials Synthesis and Processing 01/1998; 6(3):221-225.