低温固相反应法合成片状六铝酸镧

Synthesis of Platelet-like Lanthanum Hexa-aluminate Powder by Low-temperature Solid State Reaction Method

以九水合硝酸铝、六水合硝酸镧为原料,柠檬酸为络合剂,采用低温固相反应法制备出六铝酸镧前驱体,再通过煅烧的方式合成了六铝酸镧粉体。利用FTIR和TG-DSC分析了前驱体的组成和热分解过程,采用XRD、SEM和TEM分析了合成粉体的物相组成和形貌。结果表明:经1300℃煅烧后,六铝酸镧开始形成;随着煅烧温度的升高,六铝酸镧晶体形貌逐渐发育成规则的六方片状;经1500℃煅烧后可获得纯相的六铝酸镧粉体;在1600℃时合成的六铝酸镧粉体粒径呈双峰分布,平均粒径为7.25μm。

The lanthanum hexa-aluminate precursor was synthesized by low-temperature solid state reaction using aluminum nitrate nonahydrate and lanthanum nitrate hexahydrate as starting materials,and the citric acid as complex former.Lanthanum hexa-aluminate powders were formed by calcining the precursor.The composition and the thermo-decomposing process of the precursor were investigated by FTIR and TG-DSC.The phase constitution and morphology of as-synthesized powders were characterized by XRD,SEM and TEM.The results show that lanthanum hexa-aluminate crystal begin to form at 1300℃.With the increase of calcination temperature,the morphology of lanthanum hexa-aluminate gra-dually develops into hexagonal platelet structure.Pure lanthanum hexa-aluminate powders can be synthesized at 1500℃.At 1600℃,the ave-rage grain size of as-synthesized lanthanum hexa-aluminate powders are about 7.25μm,which display a bimodal distribution.