Use of emanation thermal analysis in the characterization of microstructure changes during heating of hydrous titania gel layers deposited by sol-gel technique on silica glass

Thermal behavior of sol-gel prepared hydrous titania gel layers was studied by thermogravimetry (TG), differential thermal analysis (DTA), and emanation thermal analysis, (ETA). It was found that the dehydration takes place in the temperature range 30-250 degreesC followed by the thermal decomposition of organic molecules remaining in the sample from Ti-iso-propoxide. Annealing of porosity and surface irregularities of dehydrated titania layers deposited on silica glass was indicated by ETA under in situ conditions of sample heating in the. temperature range 255-440 degreesC. The results of ETA as a less-common technique are discussed in comparison with the results of TG and DTA, X-ray diffraction and scanning electron microscopy. The temperature of 500 degreesC was recommended for the preparation of consolidated polycrystalline anatase layers. (C) 2001 Elsevier Science B.V. All rights reserved.