高反射和高红外辐射性能的粉体分别可以提高涂料的反射和红外辐射能力，进而提高涂料的隔热性能。同时具备高反射、高辐射复合粉体的研发和应用对于改善涂料的隔热性能，推动节能环保事业具有重大的意义。在众多反射材料中，二氧化钛（TiO2）以其高白度、高折射系数和强稳定性等优点被广泛应用于涂料、塑料、造纸、化妆品等行业。二氧化锆(ZrO2)具有高红外辐射、耐磨、耐腐蚀、耐高温等特点，被用于陶瓷涂层、高温发射体等领域。然而TiO2红外波段的红外辐射能力不如ZrO2，ZrO2可见及近红外光波段的反射能力不如TiO2。我们知道，物体起反射的作用主要是表层部分，那么将两者进行复合——在ZrO2表面包覆TiO2，会不会带来复合粉体反射和辐射性能的同步提高呢？如果是，这将有助于提高材料的利用率，增强粉体单位体积的隔热能力。然而，目前将高反射材料和高辐射材料的研究鲜见报导。本文对ZrO2表面包覆TiO2的工艺及二者复合后的性能变化进行了研究，并主要从以下两个方面开展了工作：一、以四方氧化锆为基体、四氯化钛为钛源，利用水解沉淀法，制备了四方氧化锆基的复合粉体；二、以立方氧化锆为基体、钛酸丁酯为钛源，通过溶胶凝胶法，制备了立方氧化锆基的复合粉体。对复合粉体进行X射线衍射分析、热重分析及扫描电镜分析等手段系统研究了复合粉体的形成机理，利用紫外-可见-近红外分光光度计、傅里叶红外光谱仪等对复合粉体的反射性能和红外辐射性能进行了分析。结果发现：经水解沉淀法制备的复合粉体，表面含有部分含钛的钠盐，在可见光波段反射能力下降，在红外波段辐射能力也没有明显改善；而经溶胶凝胶法制备的复合粉体在可见-近红外波段反射率比包覆前提高了近10%，在中红外波段红外辐射率有所下降，而在其中对辐射致冷效果最明显的大气窗口波段（8~13µm）红外辐射率只有略微下降。溶胶凝胶法制备的立方氧化锆基复合粉体同时具备了高的反射和红外辐射能力。本论文在高反射材料和高红外辐射材料的复合对二者性能改变的研究上有一定的指导意义，同时为工业上更好地制备优质颜填料材料提供了较好的参考。
Powders with high reflectance and emissivity can have a great improvement on the coatings’ reflectance and infrared radiation, respectively, further improving the coatings’ thermal insulation properties. Researching and developing both high reflectance and emissivity composite powders is highly beneficial to the improvement of the coatings’ thermal insulation properties, energy conservation and environmental protection. As one kind of reflective materials, titania is widely used in industries such as coatings, plastics, paper, cosmetic, et al. for its high refraction index, whiteness, stability and so on. With high emissivity, wear resistance, corrosion resistance, temperature tolerance and others, zirconia is used in the fields of ceramic coatings and high temperature emitter. The emissivity of titania in the infrared wavelength is not quite good as zirconia. However, its reflectance is higher than zirconia in the visible-near infrared wavelength. As we know, light is reflected by the object’s surface, then what about coating zirconia with titania? Would it bring the improvement of both reflectance and emissivity? If so, material utilization would be improved and the powders’ insulation capacity per unit volume would be enhanced. However, researches in this filed are rarely reported.In this paper, the preparation process and performance of ZrO2/TiO2 were both studied. And they were carried out mainly from the following two aspects: tetragonal zirconia was coated through hydrolysis precipitation by TiCl4, cubic zirconia was coated through sol-gel method by TNBT. The formation mechanism of the composite powders was studied by X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) and so on. The powders’ reflectance and emissivity were analyzed with a UV-VIS-NIR spectrophotometer and a Fourier Transform infrared spectrometer. The results show that sodium salt containing with titanium is formed on the surface of powders prepared by hydrolysis precipitation, the powders’ reflectance is decreased in visible wavelength, and their emissivity has no significant improvement in the infrared wavelength. Composite powders prepared by sol-gel method show a 10% increase of reflectance in the Vis-NIR after coated, the emissivity decreased slightly in the atmospheric window 8-13μm, which is concerned with radiative cooling. Cubic zirconia-based composite powders have both high reflectance and emssivity. In conclusion, this work not only brings some useful information for the compound of high reflectance materials and infrared radiation materials, but also gives some suggestions to the preparation of high performance powders in industry.
