【摘要】 以硝酸镧、硝酸铜、硝酸锶为原料,采用溶胶-凝胶法制备LaSrCuO4粉体,重点考察了柠檬酸(CA)与乙二胺四乙酸(EDTA)的摩尔比、溶液pH值、烧结温度等工艺参数对LaSrCuO4粉体形貌及相结构的影响。利用X射线衍射(XRD)、扫描电镜(SEM)及能谱仪(EDS)对粉体进行了相应的表征。结果表明:当n(CA):n(EDTA)=1.5:1、pH=9、烧结温度为800℃时得到了较高纯度、呈介孔结构的LaSrCuO4粉体;而当烧结温度为1000℃、EDTA添加量为零时得到的粉体呈片层状结构,添加EDTA时形成介孔结构粉体。介孔结构的形成机理是在表面活性剂EDTA分子与各种无机盐离子之间靠协同模板作用形成液晶相,然后进一步缩聚形成介孔结构。更多还原

【Abstract】 LaSrCuO₄ powder was prepared by a sol-gel method using lanthanum nitrate, cupric nitrate and strontium nitrate as raw materials. The effects of process parameters such as the molar ratio of citric acid（CA） to ethylene diamine tetra-acetic acid（EDTA）, solution p H and sintering temperature on the morphology and phase structure of the LaSrCuO₄ were researched. Surface morphology and phase structure were characterized by scanning electron microscope（SEM/EDS） and X-ray photoelectron diffraction（XRD）, respectively. The results show that higher purity La Sr Cu O4 powder with mesoporous structure can be obtained at the condition of sintering temperature 800 °C, precursor solution p H=9 and n（CA）:n（EDTA）=1.5:1. The lamellar structural LaSrCuO₄ can be obtained at sintering temperature 1000 °C and n（CA）:n（EDTA）=1.5:0, but further increase in the content of EDTA promotes the formation of mesoporous structural powders. The formation mechanism of the mesoporous structure is that the liquid-crystal phases are formed between the molecules of surfactant EDTA and the ions of various inorganic salts by synergy effect and then mesoporous structure appears by polycondensation.更多还原