二氧化硅/二氧化锆核壳复合材料的制备及性能

Preparation and property of SiO_2/ZrO_2 core-shell composite materials

合成了一种新型的二氧化硅/二氧化锆(SiO2/ZrO2)核壳型复合材料。利用异丙醇锆的水解缩合在SiO2微球表面沉积ZrO2层,得到二氧化锆包覆的SiO2/ZrO2核壳型复合氧化物。采用SEM、EDX、XRD等对复合材料的形貌及性质进行表征。利用IR-1红外发射率测量仪测定复合粒子在8～14μm波段的红外发射率。结果显示:该复合物具有明显的核壳结构。随着沉积次数的增加,ZrO2在SiO2表面的含量增加。ZrO2层经高温热处理可分别形成四方和单斜两种晶型。ZrO2层沉积在SiO2表面后,得到的SiO2/ZrO2核壳复合粒子的红外发射率较基底SiO2的有所降低。ZrO2的晶型也影响着复合材料的红外发射性能。ZrO2层为单斜晶的SiO2/ZrO2核壳复合物在8～14μm波段的红外发射率值比ZrO2层为四方晶时的更小。ZrO2层和SiO2球之间的界面作用解释了该复合材料红外发射率降低的原因。

Silica/zirconia（SiO2/ZrO2）core-shell composite microspheres were synthesized by depositing ZrO2 on silica microspheres through the hydrolysis of zirconium precursor.The composites were characterized by scanning electronic microscope（SEM）,energy dispersive spectroscope（EDX） and X-ray diffraction（XRD）.The infrared emissivity values of the particles in 8—14 μm wave band were measured by IR-1 infrared radiometer.Experimental results indicated that the composites represent obvious core-shell structure,and the zirconia content on the surface of silica particles is increased with the increase in deposition cycles.The ZrO2 layer could form monoclinic and tetragonal crystals after thermal treatment.The SiO2/ZrO2 composite particles showed lower infrared emissivity value than pure SiO2.In addition,the infrared emissivity properties of the composites were affected by the crystalline form of ZrO2.ZrO2 coating with monoclinic crystalline structure showed lower infrared emissivity value than that with tetragonal crystalline structure.The remarkable decrease in infrared emissivity value of the composites was attributed to the interfacial interactions between the ZrO2 layer and the SiO2 spheres.