低温燃烧合成铬酸镧纳米粉体的结构特性

用低温燃烧合成法合成了铬酸镧纳米粉体.X射线衍射和扫描电镜分析的结果表明:粉体由La1-xCaxCrO3和少量的LaCrO4,La2CrO6和有机物组成.合成过程形成的中间相LaCrO4是凝胶分解反应不完全的结果,La2CrO6的形成与阳离子未完全络合有关.燃烧后的产物呈薄膜状,厚度约80 nm;高温煅烧时薄膜状产物中的有机物挥发和LaCrO4,La2CrO6分解导致薄膜发生破碎,并形成粒径约80 nm的粉体.煅烧后粉体尺寸均匀,但部分颗粒间存在硬团聚.

STRUCTURE CHARACTERISTIC OF LANTHANUM CHROMITES NANO-POWDER BY LOW-TEMPERATURE COMBUSTION SYNTHESIS

Nano-powder of lanthanum chromites were synthesized by low-temperature combustion method. The powders were composed of La1-xCaxCrO3, a little of LaCrO4, La2CrO6 and organic compounds measured by X-ray diffraction and scanning electron microscopy analysis. The phase of LaCrO4, as an inter-phase, was resulted from incomplete decomposition of the gel, and the formation of La2CrO6 was related to incomplete complexation of cations. The products synthesized are as a film-like material with thickness about 80 nm. During the film calcined at high temperature, volatilization of organic compounds and the decomposition of LaCrO4 and La2CrO6 lead to the film broken into the nano powders with average particle size about 80 nm, The powders synthesized are uniform in size, but there are partially hard particle agglomerates in the powders.