آنالیز رنگی برخی رنگدانه های آبی بر پایه کبالت

Colour analysis of some cobalt-based blue pigments

آنالیز رنگی برخی رنگدانه های آبی بر پایه کبالت

ABSTRACT

The coloring efficiency in different ceramic glazes of the classical Co olivine blue pigment (Co2SiO4) was compared with those obtained with a Co-doped willemite (Co0.05Zn1.95SiO4), and with a magnesium-doped Co-Al spinel (Mg0.2Co0.8Al2O4). The fired pigments and enameled samples were characterized by XRD, UV-VIS-NIR spectroscopy, CIE-L*a*b* color-measurements, and by SEM/EDX. The Co-olivine and Co-willemite pigments dissolved to a higher extent in the molten glazes than the Co–Al spinel. The darker blue color of the Co-olivine probed to be mostly due to Co2+ ions incorporated in the glassy matrix. The Co-willemite composition (which only contained a 1.3 Co wt.%) developed the bluest color hue of all pigments in both double and single firing glazes, while the magnesium-doped Co–Al spinel was found the most appropriate blue pigment in the bulk coloration of fast-fired porcelainized stoneware.