Combustion synthesis of pink chromium-doped alumina with excellent near-infrared reflective properties

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• 作者：Robert Ianoș^a ; ^{robert_ianos@yahoo.com} ; Eliza Muntean^a ; Roxana Băbuță^a ; ^{babuta.roxana@yahoo.com} ; Radu Lazău^a ; Cornelia Păcurariu^a ; Cornelia Bandas^b
• 关键词：A. Powders ; chemical preparation ; C. Optical properties ; D. Al2O3 ; E. Thermal applications
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：1 February 2017
• 年：2017
• 卷：43
• 期：2
• 页码：2568-2572
• 全文大小：593 K
• 卷排序：43

文摘

Pink chromium-doped alumina, Al1.95Cr0.05O3, was prepared by microwave assisted combustion synthesis, starting from a stoichiometric mixture of Al(NO3)3·9H2O, Cr(NO3)3·9H2O and urea. No additional annealing was required, as the X-ray diffraction pattern of the sample indicated that Al1.95Cr0.05O3 was the single crystalline phase, having an average crystallite size of 63 nm. The resulted powder had a pink colour (L*=83.1, a*=4.2, b*=−2.9) and a total solar reflectance of 69.2%. The pigment had a BET surface area of 1.8 m2/g, which corresponds to an equivalent particle size of 838 nm. NIR reflective properties of Al1.95Cr0.05O3 were tested by painting an aluminium sheet with a water-based acrylic coating containing 20% mass pigment. The dry film had a thickness of 150 µm and a total solar reflectance of 61.7%. The surface temperature during irradiation with a 250 W IR lamp indicated a very similar behaviour to that of a white TiO2-based coating. All these features highly recommend pink Al1.95Cr0.05O3 as an effective NIR-reflective (cool) pigment.