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A fluorine-free route has been developed to fabricate V/Pr co-doped zircon (ZrSiO 4) ceramic pigments with Na 3 VO 4 and Pr(NO 3) 3 ·6H 2 O as colourants. The as-prepared pigments were characterized by XRD, Raman, XPS, UV–vis, FE-SEM, TEM and automatic colourimeters. The results show that Na 3 VO 4 can not only act as colourant to produce blue hue, but as mineralizer to accelerate the formation of V/Pr co-doped ZrSiO 4 pigment. A colour tuning between blue, green and yellow can be achieved by increasing the mole ratio of Pr/V, and the most intense yellow hue (L* = 74.55, a* = −0.38, b* = 46.82) is obtained at a mole ratio of Pr/V = 0.5. Both Pr4+ and Pr3+ cations are co-existed in the pigments, where Pr4+ contributes to the generation of yellow hue while Pr3+ undermines the yellow hue. The good chromatic ability in glaze at high temperature suggest its potential application in ceramic decoration. [ABSTRACT FROM AUTHOR]

A fluorine-free and low temperature synthetic route derived from in-situ formed mineralizer has been developed to fabricate V–ZrSiO 4 turquoise ceramic pigment. When the calcination temperature is 750 °C and mole ratio of Na 3 VO 4 to ZrOCl 2 ·8H 2 O (NV/Zr) is 0.3, the as-prepared pigment exhibits a cluster-like structure and deep blue hue (L* = 69.28, a* = −12.15, b* = −20.04). The solid state reaction taking place during the mechanical grinding process lead to the in-situ formation of mineralizer NaCl and certain Si–O–Zr bond. The XRD refinement results and hyperfine structure in EPR spectra indicate that vanadium is located at the zircon interstitial site 16g with an isolated V4+ cluster state. The enameled samples exhibit excellent coloring ability, high chemical and thermal stability, suggesting its potential application in ceramic decoration. [ABSTRACT FROM AUTHOR]

Ba 0.7 Sr 0.3 TiO 3 ceramics have excellent electrical performance and wide applications in sensors, capacitors, dynamic random access memory, and so on. High-quality Ba 0.7 Sr 0.3 TiO 3 powders preparation is the premise and basis for obtaining Ba 0.7 Sr 0.3 TiO 3 ceramics with excellent properties. Monodispersed Ba 0.7 Sr 0.3 TiO 3 powders were synthesized using a novel ultrasonic-driven polycondensation nonaqueous precipitation method with tetrabutyl titanate, anhydrous barium acetate, and anhydrous strontium acetate as precursor materials and glycol as the solvent. Ultrasonic irradiation promotes the polycondensation of raw materials; Ba–O–Ti and Sr–O–Ti bonds form in the precipitate, facilitating low-temperature synthesis of Ba 0.7 Sr 0.3 TiO 3 at 550 °C. Ultrasonic irradiation also assists in the monodispersing of precipitates and BST powders and low-temperature sintering, and considerable properties of Ba 0.7 Sr 0.3 TiO 3 ceramics. The Ba 0.7 Sr 0.3 TiO 3 powder and ceramic particle sizes are approximately 30–50 nm and 100–150 nm, respectively. The proposed ultrasonic-driven polycondensation nonaqueous precipitation method is expected to be widely used for preparation of ceramic powders. [ABSTRACT FROM AUTHOR]