青色無機顔料コバルトブルーの色調におよぼすコバルト原料化合物の影響

The color tone of pigments is affected by various factors such as crystal structure and particle size. These characteristics should be determined by synthesis condition. In this study, the influence of cobalt source on the color tone of cobalt blue pigment was investigated. Cobalt blue (CoAl₂O₄) was synthesized by solid-state reaction method. Co₃O₄ and Co(OH)₂ with two different particle sizes were used as the cobalt source, and γ-Al₂O₃ was used as the aluminum source. The products were characterized by spectrophotometry, XRD, SEM, and TG/DTA. It was revealed that the chroma of the synthesized cobalt blue depends on the cobalt source. The cobalt blue synthesized using smaller size Co(OH)₂ showed most vivid color. It was suggested that the number of the contact points between the starting materials increased with decreasing the particle size, leading to the progress of the reaction.