Synthesis Of Nano-yttrium Oxide And Study On The Near Infrared Reflectance Properties Of Its Composite Materials

In this thesis, we used the ammonia precipitation method and the urea homogeneous precipitation method successfully synthesized nano-yttria with different appearance, different size, different dispersion and different heat-reflective properties. On this basis,we have been further got Y2O3-SiO2, Y2O3-ZnO composite materials. At the same time X-ray diffraction (XRD), UV-visible-Near infrared spectrophotometer (UV-Vis-NIR spectrophotometer), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), field emission scanning electron microscopy (FSEM) was used for testing and characterizing the materials, respectively. Meanwhile, the results are given a reasonable explanation, and make some meaningful discussions. Details as follows:Yttrium oxide with about 80 nm diameter was synthesized through optimized a variety of the experimental conditions with two different methods. After testing, the highest UV-visible-Near infrared reflectance properties of the obtained nano-yttria could achieve 88.6% and 92.5%. By analyzing the morphology of the samples, we found that the obtained yttrium oxide by urea homogeneous precipitation method was close approximation of intensive sheet structure, but the ammonia precipitation method was to be erected sheets stacked flower-like structure, so the optical properties differences have a reasonable explanation.Based on the above, we modified the synthesized yttrium oxide by urea homogeneous precipitation method with surface modification. The purpose is to further improve the dispersion properties of powder samples, so that in organic solvents could be better distributed and then laid a solid foundation for obtaining uniform and stable coating. In the modification process, the selected two different types of dispersant: surface-active agent class - stearic acid, silane-KH560 and KH570. The best experimental conditions were obtained through the dispersion results and the properties of modified powder coating were examined. Experimental results showed that: compared with silane coupling agent KH-560 and KH-570, through the stearic acid modified, the best performance heat-reflective coating was obtained. Throughout the UV-visible-Near infrared spectrum, we founded that its heat-reflective rate varied little, basically 80% to 93% range. Obviously, the coating's performance which was modified with the KH-560 and KH-570 significantly better than the stearic acid-modified coating and the highest reflectivity was less than 90%.In order to further expand the application value of the yttrium oxide, we synthesized two different yttrium oxide composite materials. The results showed that, compared the single-phase Y2O3, Y2O3-SiO2 composite materials have better heat-reflective performance. But the Y2O3-ZnO composite materials were not only in heat-reflective performance have been more substantial improvements, but also had a strong UV absorption. Therefore the application space of nano-yttria was further expanded. Overall, compared with the existing bead insulation coating, the obtained coating in this subject can reduce temperature much better, which was a highly efficient thermal insulation composite nano-thin film coating. It can be widely used in exterior walls insulated roofs and surface coatings, industrial containers and pipelines, military equipment, warehouse, thermal insulation, etc., which have a more broad market prospect.