Micro-, Nano-y <sub> 2 </ Sub> O <sub> 3 </ Sub> Synthesis And Complex Oxides The Performance Of The Near-infrared Reflectance Study

In this paper, we synthesize yttria nanoparticles(nanorods nanoflakes and nanospheres) via solvothermal method and homogeneous precipitation method, in which Y(NO3)3·6H2O was used as the yttrium source, sodium hydroxide (NaOH) and urea [CO(NH2)2] as the precipitator. X-ray diffraction (XRD), transmission electron microscopy (TEM) have been employed to characterize the as-prepared Yttria nanostructures. A Cary 500 UV-vis-NIR spectrophotometer along with a diffuse reflectance accessory (DRA, also called an integrating sphere) was used to measure the reflectance properties of the samples. The factors on the morphology was studied. The growth mechanism were reseached. The main contents are as follows:1. Nanorods and nanoflakes Y(OH)3 and Y2O3 were synthesized by solvent-thermal method, without any catalysts, templates, or substrates. Through the experimental results and theoretical analysis, the best synthetical conditions of Y(OH)3 and Y2O3 nanorods and nanoflakes were made certain. Its growth mechanism were reseached.2. Three different diameter nanoyttria (about 40nm, 100nm, 180nm) were synthesized by homogeneous precipitation method. The factors such as the different yttrium salt, the concentration of Yttrium nitrate Y(NO3)3, the type and concentration of polyethylene glycol (PEG), hydrolysis time, were researched.3. Near-infrared reflectance spectra of the as-prepared Yttria were studied.The reasults show that the reflectivity of samples have relationship with their morphologies and diameters. Compare to the yttria nanorods and nanoflakes, the spherical possess the highest performance near-infrared reflectance. Among the three different diameters of spherical yttrium oxide (40nm, 100nm, 180nm), 180nm spherical yttria have the highest near-infrared reflectance properties in the near-infrared range (λ=750～2500nm), the reflectance is of 86～93 %.4. The film near-infrared reflectance were researched, which by coating with 180nm spherical yttrium oxide and oil-based acrylic resin. The results show that the near infrared properties of the coating have relationship with the coating thickness, powder percentage. With the coating thickness and powder percentage increase, the near infrared reflectance of the coating increase, too. By adding an appropriate amount of titanium dioxide in yttrium oxide powder, the UV absorption properties of the powder can be improved.5. The thermal insulation experiment of the coating show that the thermal insulation performance of yttrium oxide- titanium dioxide composite coating were distinguished, the results as follows: When the coating thickness was 0.18mm, the thermal insulation performance of the composite coating was more 4-5.5°C than a blank glass, more 3-4.5°C than conventional calcium carbonate coatings.