摘要
以TiCl4 为钛源 ,首先制备TiO2 ·nH2 O凝胶 ,然后在 80℃的水热条件下制备了SrTiO3粉。利用X射线衍射 (XRD)、透射电子显微镜 (TEM )和红外光谱 (FTIR)研究了TiO2 ·nH2 O凝胶水洗方式、阴离子 (Cl- 和NO3- )以及TiO2 ·nH2 O热处理对SrTiO3粉性能的影响。结果表明 ,水洗和热处理都能使TiO2 ·nH2 O凝胶产生晶化 ;TiO2 ·nH2 O的晶化程度对产物SrTiO3颗粒的粒度和粒度分布有很大影响 ,以非晶质TiO2·nH2 O为钛源制备的SrTiO3颗粒粒度大且粒度分布宽。以结晶TiO2 ·nH2 O为钛源制备的SrTiO3颗粒粒度小且粒度分布窄 ,而且可以得到纳米颗粒。水热反应液相中存在Cl- 或NO3- 能使产物SrTiO3颗粒粒度稍有增大。综合以上结果 ,TiO2 ·nH2 O凝胶水洗对产物颗粒的影响主要是由于使凝胶产生了晶化 ,而由阴离子脱除产生的影响很小。因此 ,在不考虑阴离子对其它工程化影响 (如设备腐蚀等 )的前提下 。
The SrTiO 3 powders were synthesized from TiO 2 ·n H 2O gel under moderate hydrothermal condition. TiO 2 ·n H 2O gel was prepared by diluting TiCl 4 with cold distilled water. The influence of pre-processing of TiO 2 ·n H 2O gel and anions (Cl -and NO 3 -) on the properties of SrTiO 3 powders was studied in details by X-ray diffraction (XRD), transition electron microscopy (TEM) and Fourier transform infrared spectrometry (FTIR). The results showed that TiO 2 ·n H 2O could be crystallized during the washing and thermal processing. The crystallization of TiO 2 ·n H 2O had an important influence on the product particle size and particle size distribution. The SrTiO 3 powders prepared from amorphous TiO 2 ·n H 2O are with big particle size and wide particle size distribution, and those from crystallized TiO 2 ·n H 2O are with small particle size and narrow particle size distribution. To get nanometer SrTiO 3 powders, the suitable crystallization of TiO 2 ·n H 2O gel is essential. The chloride and nitrate ions can accelerate the formation of large-grained particles of SrTiO 3, but such effect is very small. In a word, the main reason for the effect of washing of TiO 2 ·n H 2O on properties of SrTiO 3 powders is the crystallization of TiO 2 ·n H 2O gel during the washing, and the washing process can be substituted by thermal processing neglecting the effect of anions.
