Chemical synthesis of environment-friendly nanosized yellow titanate pigments

As yellow pigments, nanosized rutile structured Ni0.1W0.1Ti0.8O2 and priderite structured BaNiTi7O16 have been prepared through pyrolysis of precursor solution containing nickel nitrate, dimethyl tungstate, titanium oxalate, triethanolamine (TEA) for the former composition and barium nitrate, nickel nitrate, titanium oxalate, TEA for the later composition, respectively. In the reaction, TEA acts to minimize the agglomeration in the products through formation of a highly branched polymeric framework, which anchors the metal ions for producing nanocrystalline powders. The rutile and priderite structured titanates obtained on heat-treatment of the precursor powders at 800 °C and 850 °C, respectively, have been characterized by XRD, TGA–DTA, BET surface area measurement, UV–vis spectroscopy, CIE L*a*b* colour parameter measurements, TEM and HRTEM. XRD reveals the purity of the resulting rutile and priderite phases. Their crystallite sizes, average particle sizes and specific surface areas determined from XRD, TEM, and BET surface area measurement are found to be in the range between 25 nm and 30 nm, 25–45 nm and 100–120 m2/g, respectively, for both compositions.