Multivariate optimization of the synthesis of titania biomorphic ceramics and development of a FT-IR method for quantification synthesis yield

Titania biomorphic ceramics were manufactured from wood preforms by a two steps process, i.e. infiltration and then pyrolysis in an inert atmosphere to produce porous TiC ceramics, followed by infiltration and pyrolysis in an air atmosphere where TiC was oxidized to TiO₂. This technology provides a cost effective and eco-friendly route to advanced ceramic materials. The properties of biomorphic ceramics depend decisively on the synthesis parameters, that were optimized using a multivariate methodology for the design of experiments. Four variables (infiltration time, titanium isopropoxide and acetic acid proportion, and number of infiltrations before and after pyrolysis) were considered as factors in the synthesis optimization process. Interactions between these factors and their optimal levels were investigated using a two level factorial design. For evaluating the yields, a new method by Fourier transform infrared spectrometry (FTIR) has been developed for the direct determination of TiO₂ by absorbance measurements in KBr pellets. The procedure is based on the use of the ratio between the absorbance of the characteristic band of titania and those of a nitrate internal standard added to samples. A multivariate calibration strategy based on inverse least squares approach was employed for quantification.