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材料工程  2010 

沉淀剂对La2Zr2O7制备过程的影响

Keywords: La2Zr2O7,化学共沉淀法,氨水,草酸铵

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Abstract:

分别采用氨水和草酸铵作沉淀剂,通过化学共沉淀法制备了单相La2Zr2O7粉末.利用DSC-TGA和XRD等方法对LZ前驱体的煅烧分解过程、产物物相进行了分析和表征.结果表明氢氧化物前驱体在400~750℃分解得到无定型的复合氧化物,800℃保温2.5h即完成相转变形成单相组分的La2Zr2O7;而草酸盐前驱体在400~650℃草酸盐发生分解得到无定型氧化镧、氧化锆的混合物;700℃以后,La(OH)3的分解、无定型氧化物晶化得到六方结构氧化镧与单斜相氧化锆、Zr4+扩散到La2O3晶界生成La2Zr2O7等三个反应同时进行.获得单相组分La2Zr2O7的煅烧条件至少要1450℃,保温2.5h.草酸盐前驱体中镧和锆两种成分局部的分布不均匀是造成其处理温度比氨水法要高的直接原因.

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