Study on affecting factors on the crystallite size of titanium dioxide prepared by sol-gel using the Taguchi method

In this work, TiO(2) sol was prepared by a previously applied and validated method; hydrolysis ofTitanium tetra-n butyl orthotitanat. In order to obtain precise results, the effect of pH after peptizing,aging time, peptizing temperature and sol concentration on the crystallite size of final precipitatewere investigated in a narrow range. The preparation conditions applied in the production step ofnanocrystalline TiO(2) affected on the desired phase. Experiments were set based on the statisticaldesign of experiments (Taguchi method). Furthermore the calcination and phase transformation ofthe precipitate was investigated using X-ray diffractometry (XRD) and simultaneous thermalanalysis (STA) techniques. To evaluate the results, the obtained data were statistically analyzed.Considering the statistical analysis of experiments, the peptizing temperature is the major parameteraffecting crystallite size. In contrast, pH after peptizing has the smallest effect on the crystallite size.In addition, Transmission electron microscopy (TEM) of the samples revealed that the particle sizeof the powders was well distributed in the nano-size range. Taguchi prediction on the crystallite sizewas 4.855±0.102 nm (with confidence interval of 90%) which confirmed by a verificationexperiment (5.433nm).

Keywords:

TiO(2) , aging time , peptizing , experimental design , Taguchi