尖晶石型NiCr_2O_4的燃烧法合成及表征(英文)

Combustion Synthesis and Characterization of Spinel NiCr_2O_4

通过溶胶-凝胶燃烧法制备了具有立方相的尖晶石型NiCr2O4颜料,并采用TG/DSC、XRD、FTIR和SEM等手段对其进行表征和研究。结果表明:将燃烧后的粉末于900℃下煅烧2 h可以得到单一相的NiCr2O4,温度达不到900℃时所得粉末(包括燃烧后粉末和500和700℃煅烧得到的粉末)为NiO和Cr2O3组成的混合物。利用紫外/可见/近红外分光光度计仔细研究了燃烧后粉末和煅烧后粉末的颜色参数。尽管具有相同的成分,500和700℃下煅烧得到的粉末与燃烧后粉末却具有明显不同的颜色,这可从一氧化镍为非整比化合物的角度加以解释。此外,900和1 000℃下煅烧得到的NiCr2O4粉末呈现出随温度变化的绿色。

Cubic spinel NiCr2O4,as a pigment,was synthesized via a sol-gel combustion method and characterized using TG/DSC,XRD,FTIR and SEM techniques.The results reveal that a single-phase NiCr2O4 with the cubic structure is obtained after heat treatment of the as-burnt powder at 900 ℃ for 2 h.The powders obtained below 900 ℃ appear as a mixture of NiO and Cr2O3.The color parameters for the as-burnt powder and the powder calcined at various temperatures were studied using PerkinElmer Lambda 950 UV-Vis-NIR spectrometer.Although having the same compositions,the 500 and 700 ℃ calcined powders show a different color（black） from the as-burnt powder（black green）.This phenomenon may be interpreted in terms of non-stoichiometry in NiO crystals.Moreover,the as-prepared spinel NiCr2O4 powders calcined at 900 and 1 000 ℃ show green color which changes with the calcination temperature.