中文摘要：

采用柠檬酸溶胶一凝胶法制备了纳米高近红外反射颜料，研究了Fe／Cr摩尔比、水解温度、溶液金属离子浓度、pH值、煅烧温度等因素对凝胶时间及试样性能的影响。结果表明，在Fe／Cr摩尔比为0．50，水解温度70℃，溶液金属离子浓度为2．5～3．5mol／L，pH=3—4，煅烧温度为900℃保温60min的条件下，制备颜料的主晶相为Cr1.3Fe0.7O3，近红外波段范围内（700～2500nm）其平均反射率可达到77．58％，晶粒尺寸在50～200nm之间。

英文摘要：

High near-infrared （NIR） reflective nano pigments were prepared by the citric acid sol-gel method. The effects of molar ratio of Fe and Cr, hydrolysis temperature, pH value, concentration of metal ions and calcination temperature on gel time and reflective performance were investigated. The results showed that with Fe/Cr molar ratio of 0.50, hydrolysis temperature of 70℃, pH value of 3-4, metal ion concentration of 2.5-3.5 mol/L and calcination temperature of 900 ℃, the main crystalline phase of the as-prepared pigments is Cr1.3Fe0.7O3 whose average reflectance is 77.58% in the wavelength ranging from 700 nm to 2500 nm, and grain size is between 50 nm to 200 nm.