Abstract
Solid solutions of La2(SO4)3 and Al2(SO4)3 were prepared by rapidly drying mixed aqueous solutions using micro-wave heating. The La3+ion is soluble into the anhydrous aluminum sulfate crystal lattice up to about 6mol%. On heating the thermal decomposition starts at 830°C for the pure Al2(SO4)3, while at 760°C for 6mol% La2(SO4)3 contained Al2(SO4)3. The anhydrous aluminum sulfate solid solution thermally decomposes into the η-Al2O3 without any other crystalline phases. The LaAl11O18 is formed after heating the desulfurized product at 1300°C without forming LaAlO3 when the content of La2O3 is less than 6mol%.The La3+ doping increases the stability of η-Al2O3 at high temperatures. The phase transformation of alumina takes place above 1350°C when the amount of La2O3 is 5mol%.
