The preparation of ceramic materials from soluble educts, e. g. by coprecipitation or sol-gel processing, leads to an improved mixing and reactivity of the components in the ceramic precursor powder. Therefore, the calcination and sintering temperatures can be lowered compared to the mixed oxide process. Simultaneous TG-IR measurements allow a detailed analysis of the decomposition of organic and inorganic groups during the calcination of ceramic precursors.

The calibration factors for the quantitative analysis of the IR data are determined from TG-IR runs with reference substances which release only one volatile compound (CuSO₄*5 H₂O for water, PbCO₃ for CO₂ ...).

As an example, we present TG-IR runs of the calcination of  La_1-xSr_xMnO_3+d samples which were prepared by coprecipitation. The measurements reflect the different degree of homogeneity and impurity level caused by variations in the coprecipitation process. Differences between the weight loss measured by TG and determined by quantitative analysis of the IR spectra indicate a change in the oxidation number of Mn which is accompanied by O₂ release or uptake. 

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