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Zinc phosphate (Zn3(PO4)2·4H2O) was prepared by a simple route using ZnO and H3PO4 in aqueous and acetone media at ambient temperature. Zn3(PO4)2·4H2O decomposes to Zn3(PO4)2 by three dehydration reactions, as revealed by thermal analytical (TG/DTG/DTA) and differential scanning calorimetry (DSC) techniques. The synthesized Zn3(PO4)2·4H2O and its dehydration product Zn3(PO4)2 were characterized by powder X-ray diffraction, Fourier transfer infrared, and scanning electron microscopy. Kinetic triplet parameters (activation energy, E; preexponential, A; Avrami exponent, n) and thermodynamic functions (ΔH*, ΔG*, and ΔS*) of three dehydration reactions are calculated by DSC experiments. Evaluation and control of the specific characteristics of three dehydration processes of Zn3(PO4)2·4H2O are essentially important in the variously oriented studies, which were discussed from the viewpoints of thermal stability based on kinetics and thermodynamics.

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The CuFe1-xSnxO2 (x = 0.03, 0.05) delafossite samples have been synthesized by a solid-state reaction to investigate electrical and optical properties of the transparent conducting oxide materials. Crystal structure was characterized by XRD. The electrical conductivity and Seebeck coefficient were measured in the high temperature range of 300 to 960 K, while the Hall coefficient, XPS, and UV-VIS-NIR spectra were analyzed at room temperature. The XRD peaks of the samples indicate the delafossite structure phase, and the XPS spectra reveal the stable Sn2+-doping state. The Seebeck and Hall coefficient display a positive sign indicating the p-type conducting oxide. The optical allowed direct gap is 3.45 eV as a visible-transparent material. The activation energies for polaron hopping between Sn2+ sites and Fe3+ sites of 36 and 32 meV are obtained from the samples having x = 0.03 and 0.05, respectively. The CuFe1-xSnxO2 delafossite oxide compounds, of which the Fe3+ sites in the CuFeO2 are substituted by the Sn2+ ions, are p-type transparent conducting oxide materials. The activation energy is found to decrease with an increased in Sn content.

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