溶胶-凝胶法制备LaP-5O-14粉体

PREPARATION OF LaP_5O_(14) POWDER BY SOL-GEL METHOD

以La2O3,HNO3和H3PO4为原料,采用溶胶-凝胶法制备了LaP5O14粉体。用热重-差示扫描量热仪,X射线衍射和扫描电子显微镜研究了原料的组成以及热处理工艺等因素对煅烧后粉体的组成、微观形貌和性能的影响,探讨了LaP5O14粉体的合成机理。结果表明:当La2O3与H3PO4摩尔比为1:5时制备的凝胶,在800℃煅烧5h后,制得主晶相为柱状结构的LaP5O14粉体,该粉体的粒径约10μm。LaP5O14粉体以LaPO4为前驱体在煅烧过程中通过P2O5的蒸发凝聚机理形成。该粉体能够在850℃分解并均匀释放出P2O5,LaP5O14的质量损失与时间近似于线性关系,可用于制备硅晶片掺杂用磷扩散源片。

LaP5O14 powder was prepared by sol-gel method using La2O3,HNO3 and H3PO4 as raw materials. The effects of the ratio of raw materials,heat treatment parameters and other factors on the composition,microstructure and properties of calcined LaP5O14 powder were investigated by thermogravimetric-differential scanning calorimeter,X-ray diffraction and scanning electron microscopy. The synthetic mechanism of the LaP5O14 powder was interpreted. The results show that when the mole ratio of La2O3 to H3PO4 is 1：5,the LaP5O14 powder with columnar structure can be obtained by calcining the gel at 800 ℃ f or 5 h,and the particle size of the LaP5O14 powder is about 10 μm. The synthetic mechanism of the LaP5O14 powder is based on LaPO4 precursor and formed by evaporation and condensation of P2O5 during the calcinating process. The LaP5O14 powder can decompose at 850 ℃ and release P2O5 uniformly. The mass loss of the LaP5O14 powder has a good linear relationship with heating time,so it is possible to use LaP5O14 powders for preparing phosphorus-doped silicon wafer diffusion source.