Fabrication of porous spinel (MgAl_2O_4)-zirconia composite ceramics from the powder prepared by ultrasonic spray pyrolysis

摘要

Seven kinds of the spinel (MgAl_2O_4)-zirconia(ZrO_2) composite powders were prepared by an ultrasonic spraypyrolysis. The aqueous solutions (100 cm~3) containing0.100~0.200 mol.dm~-3 Mg(NO_3)_2, 0.200~0.400 mol.dm~-3Al(NO_3)_3, 0.0108~0.0970 mol.dm~-3 ZrOCl_2 and6.67X10~-4~6.00 X 10~-3 mol.dm~-3 Ycl_3 were spray-pyrolysed at 9000C. The molar ratio of MgO to Al_2O_3 was1.00 and that of Y_2O_3 to (ZrO_2+Y_2O_3) was 0.03. Thepowders calcined at 900beg C for 10 mm contained spinel andtetragonal zirconia polycrystals (TZP). The spinel compacts withvarious TZP contents were fired at 1700beg C for 10 h. Therelative density of the spinel compact was reduced down to51.1percent with TZP content up to 48.51 molpercent. Thesintered spinel compact with TZP of 48.51 molpercent wascomposed of the grains with an average size of 4.6 #mu#m andpores with an average size of 7.4 #mu#m. The open and closedporosities of this sintered compact were 22.8percent and26.1percent, respectively.