Chromium-doped calcium zirconate - A potential red shade pigment: Preparation, characterization and testing

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• 作者：Robert Iano艧 ; ^{robert_ianos@yahoo.com" class="auth_mail} ; Radu Laz膬u
• 关键词：Calcium zirconate ; Chromium ; Solid solution ; Ceramic pigment ; Red ; Testing
• 刊名：Dyes and Pigments
• 出版年：June, 2014
• 年：2014
• 卷：105
• 期：Complete
• 页码：152-156
• 全文大小：1750 K

文摘

Chromium doping of calcium zirconate, CaZr_1鈭?em>xCr_xO₃ (x聽=聽0-0.07), leads to red shade pigments. XRD analysis confirmed that CaZr_1鈭?em>xCr_xO₃ solid solution is the only crystalline phase present in the samples annealed at 1400聽掳C. The substitution of Zr⁴⁺ by Cr⁴⁺ causes a progressive decrease of the unit cell volume, because Zr⁴⁺ has an ionic radius larger than Cr⁴⁺. The CaZr_1鈭?em>xCr_xO₃ crystallite size decreases as the substitution degree increases, from 64聽nm (x聽=聽0) to 46聽nm (x聽=聽0.07). The diffuse reflectance spectra of CaZr_1鈭?em>xCr_xO₃ pigments show a broad absorption band between 400 and 650聽nm. CaZr_1鈭?em>xCr_xO₃ pigments are located in the red-yellow area of the CIEL*a*b* color space. The proportion of red ranges between 16.7 and 19.0, whilst the proportion of yellow varies between 6.4 and 8.2. The brightness of the pigments decreases as the chromium proportion increases. Testing the CaZr_0.93Cr_0.07O₃ pigment in coloring a semi-transparent enamel showed that the pigment is dissolved by the molten glass. At the same time, Cr⁴⁺ is reduced to Cr³⁺, which is responsible for the green color of the enamel.