Abstract:
The lanthanum aluminate precursor was prepared by the low temperature solid state reaction method using aluminum nitrate nonahydrate and lanthanum nitrate hexahydrate as raw materials and citric acid as complexant. The composition and thermal decomposition process of the precursor were analyzed. Then the lanthanum aluminate precursor was calcined at different temperatures to obtain the lanthanum aluminate powder. The synthesis temperature and the calcination temperature effect on the morphology, grain size and specific surface area of the lanthanum aluminate powder were all studied. The results show that the complex compound containing La-O-Al bond was formed in the lanthanum aluminate, and when the calcination temperature reached 700℃, the lanthanum aluminate grains began to form. With the increase of the calcination temperature, the lattice distortion of the lanthanum aluminate grain decreased and the grain size gradually increased, while the crystallinity of the powder increased and the powder particle size decreased gradually. At the calcination temperature of 1 000℃, the obtained lanthanum aluminate powder had the minimal particle size of 0.310
μm and the maximal specific surface area of 16.58 m
2·g
-1.