纳米二氧化钛粉体粒径表征研究

INFLUENCE OF ANALYSIS METHOD ON THE SIZE CHARACTERIZATION OFNANO-TITANIA POWDER

采用水解沉淀法制备了纳米二氧化钛粉体,对其XRD衍射谱用Voigt函数拟合精修,得到精确的(101)和(200)面晶粒度,将结果与SEM和TEM测定的粒径进行比较,结果表明:3种方法所测值差异较大,3种粒径相比,XRD测定的粒径值小但变化较大,其平均值与TEM测定值比较接近;SEM测定的粒径大但相对比较稳定,平均增加约53%;TEM测定的粒径比较稳定。产生上述结果的主要原因:一方面是分析测试手段如XRD的精修参数和计算模式选择不同所致,另一方面与粉体样品的制备过程,以及纳米颗粒的结构特征有关。

The nano-titania powder was prepared by the hydrolysis-precipitate process. The grain size based on(101) and (200) crystal plane was figured out by fitting of Voigt function of XRD spectrum. Comparing the results measured by SEM and TEM, it shows that there are much differences in the measured values by 3 different methods. The particle size estimated from XRD data is the smallest but with the largest deviation. The average size measured by TEM is close to that of XRD but with less variability. The size obtained from SEM is the largest, with an average increment of about 53% to that estimated from XRD data, and its variance is smaller. This deviation is attributed to many factors, such as the special structure of nano-particles, the sample pretreating process, and the limitation of individual analysis approach itself, especially the mode and parameter selecting while estimated form XRD data.