Synthesis of novel green phosphate pigments with phosphophyllite composition

Abstract

A new green pigment with the composition of phosphophyllite was synthesized using zinc oxide, iron oxalate, and phosphoric acid in a hydrothermal process. The effects of hydrothermal treatment temperature and time were investigated. In order to obtain pigments with a variety of colors, compounds with related compositions were also prepared. Further, samples were prepared with nitrogen bubbling to suppress the oxidation of iron. The composition of the fabricated samples was evaluated by X‐ray diffraction and infrared spectra. The color of the samples was evaluated by ultraviolet‐visible reflectance spectra and L*a*b* color space. The samples prepared in this study were a mixture of Zn2Fe(PO4)2•2H2O, the target compound, and iron oxalate, the raw material. The obtained samples were yellow to green in color. The condition that yielded the best green pigment was hydrothermal treatment at 180°C for 20 h with nitrogen bubbling.

Synthesis of Cobalt-Substituted Manganese Phosphate Purple Pigments

“…In addition, samples in which aluminum hydroxide was replaced by lanthanum oxide, La 2 O 3 , or cerium carbonate, Ce 2 (CO 3 ) 3 •8H 2 O, were also prepared. Samples with lanthanum oxide were also prepared by heating for 20 h. In previous studies, an extension of the heating time to 20 h resulted in an increase in the vividness of the samples [18]. Therefore, for conditions that showed relatively good results, samples were prepared even at 20 h.…”