特殊形貌磷酸锆钠粉体的制备与表征

采用水热法、以八水合氧氯化锆和多聚磷酸钠为原料、水为介质, 一步制备出了单相Na₂Zr(PO₄)₂粉体。利用XRD、SEM、TG-DSC等检测方法, 系统地考察了水热条件和煅烧温度对磷酸锆钠粉体微观结构的影响。结果表明, 原料摩尔配比为n(ZrOCl₂?8H₂O) : n(Na₅P₃O₁₀)=1:2、无需调变pH值的中性条件下, 于140℃水热14 h, 即可制得分散性较好、尺寸较均一、由片组装而成的类线团形貌的Na₂Zr(PO₄)₂粉体; 适当延长水热时间和提高水热温度均有利于粉体的形成, 且温度越高, 形成该粉体所需水热时间越短。高温煅烧会使Na₂Zr(PO₄)₂粉体发生热分解, 其形貌也被破坏。利用生长基元模型解释了水热法生成该磷酸锆钠粉体的机理。

Preparation and Characterization of Sodium Zirconium Phosphate Powder with Peculiar Morphology

Single-phase Na₂Zr(PO₄)₂ powders were directly synthesized by hydrothermal method using ZrOCl₂?8H₂O and sodium polyphosphate as raw materials, water as solvent. The effects of hydrothermal conditions and calcination temperature on the microstructure of sodium zirconium phosphate powders were investigated systemically by SEM, XRD and TG-DSC, etc. It is found that, when the molar ratio of raw materials is 1:2 (n(ZrOCl₂?8H₂O): n(Na₅P₃O₁₀)) without adjusting pH value, slices being assembled coil-like Na₂Zr(PO₄)₂ powders with good dispersion and uniform size can be obtained after 14 h hydrothermal treatment at 140℃. Appropriate extension of time and increase of temperature are beneficial to the powder formation. The higher the temperature, the shorter time the desired powders form. After calcination, Na₂Zr(PO₄)₂ powders decompose and their morphology are destroyed. The growth mechanism of the sodium zirconium phosphate powders being prepared by hydrothermal method is explained by a basic growth unit model.