Synthesis of novel phosphate pigments in imitation of Turquoise

摘要

As novel blue pigment, various copper aluminum phosphate hydroxides imitated with Turquoise, CuAl_6(PO_4)_4(OH)_8•4H_2O, were synthesised by heating the mixture of copper oxide, aluminum hydroxide, andphosphoric acid. Furthermore, the similar chemical compositions with Turquoise were also studied. Theobtained powders were estimated with X-ray diffraction (XRD), Infrared (IR) spectra, ultraviolet–visible(UV–Vis.) reflectance spectra, and L*a*b* color space. The heating temperature and time, volume ofwater were studied in this process. Further, the other related compositions were also investigated. Theobtained materials had the XRD peaks of CuAl_6(PO_4)_4(OH)_8•4H_2O and CuO. The sample synthesised at700°C (3 h, 10 mL) indicated higher lightness than those prepared at other temperatures.