Production and characterization of single-phase diopside sol–gel powder

In this work, diopside powder was synthesized through the sol–gel method aiming at obtaining single-phase fine particles. Tetraethyl orthosilicate, calcium nitrate tetrahydrate and magnesium chloride hexahydrate were used as sources of cations, in ratios specific to diopside. Wet gel was synthesized by hydrolyzing a homogeneous solution consisting of precursors dissolved in ethanol. Ground gel powder was investigated by differential thermal analysis and thermogravimetry (DTA-TGA) to define details of the subsequent heat treatments. Samples calcined at 600, 650, 700, 800 and 1100 °C for 3 h underwent characterization through Fourier-transform infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy. Diopside was found as the single crystalline phase in the interval 600–1100 °C.