层状晶体结构铌酸盐KNb3O8粉体的凝胶–燃烧法合成与表征

Synthesis of KNb3O8 Powders with Layered Structure by a Gel-Combustion Method

本文以水合氧化铌(Nb2O5?nH2O)为铌源,硝酸钾(KNO3)为钾源,采用柠檬酸凝胶–燃烧法合成了层状结构铌酸盐KNb3O8粉体。采用同步热分析仪(TG/DSC)分析了前驱体粉末的热分解过程。借助X射线衍射(XRD)和扫描电镜(SEM)对合成样品的物相组成及微观形貌进行了表征。结果表明,在600℃时KNb3O8开始结晶,粉体呈规则的条状。随着煅烧温度的升高,KNb3O8粉体的结晶度提高,形貌由条状逐渐过渡为类片状。

The niobate (KNb3O8) powders with layered structure were successfully synthesized via the citric acid gel-combustion process using KNO3 and Nb2O5?H2O as the raw materials. Thermal behavior of the precursor was determined by TG-DSC techniques. The phase composition and morphology of the synthesized samples were characterized by using the X-ray diffraction and scanning transmission electron microscope. It was found that KNb3O8 phase was crystallized directly from the amorphous precursor at about 600?C. The SEM images of the samples showed that the particles were bar-like under calcination temperature of 600?C. However, the morphology of the particles transformed into flakes gradually as the calcination temperature increasing.