Research On Nano-Ti_O2 Films Coated Hollow Glass Microspheres And Their Thermal Insulation Property

With high demand for comfort of the living environment, The application of air conditioner equipment gets more and more popular. Energy-saving of building draw many people’s attention. Improving the heat insulation properties of buliding is an Important measures of energy conservation. As a type of new constructional material, heat insulation coating can applicat to beautify ande strew people’s life, and has excellent heat insulation properties. It is an effective measure to reduce energy consumption of air conditioning and to improve the comfort of living environment. Important Function of heat insulation coating Made up of reflective powder. Hollow glass microspheres(HGM) have the following characteristics: small particle size, hollow structures, light mass and little heat conductivity. Ti O2 has characteristics of high refractive index. If coating Ti O2 films on the surface of HGM, Material with properties of good heat insulation and high refractive index can be obtain. However, Some problems still exist on preparation of Ti O2-HGM, such as hard to get high cladding rate, easy to Appear free Ti O2. That’s bad for heat insulation and wastes Ti O2. Surface properties of HGM contribute to this. To study the influence of sample preparation method to HGM and adopt new method of preparation has important implications.In this paper the films were coated by sol-gel process and heterogeneous deposition process. The influences of the follow reactive conditions were studyed : titanium concentration, standing time, p H values, calcining temperature. The effect of pretreatment methods to the composition and structure of HGM, and to the coat effect of Ti O2 were studied in this paper. Then the mechanism of heterogeneous deposition process was discussed briefly,Finaly heat preservation performance of Ti O2-HGM studied in this paper.The results shows as follows:(1) As the retention time of sol increase, coating rate improved, depositing uniformity decreased, the suitable retention time are 8~12 hour. titanium concentration must have an effect on continuity of Ti O2 film, The optimal molar ratio of Ti4+ to Ethanol was 1:15 ~1:20. p H have serious influence on stability of the sols and coating rate. p H need to be controlled between 2~4. Anatase titanium dioxide transferred at temperature of 600℃.(2) Ti O2 coated on the surface of HGM which Pretreated by HF, Na OH, Ca(OH)2. All of the three preprocess methods can improve the coating rate effectively. Glasses dissolved and The substrate roughness increase when HGM pretreatment by HF and Na OH. Uniformity of thin films gets better when HGM pretreated with CBTA and SDBS. CSH appears on the surface of HGM pretreated by Ca(OH)2 at 90℃. The new product layer can prevent cracking of Ti O2 film. The sample of highest coating rate, crack-free of Ti O2 film and best heat preservation effect can be obtained.under the condition of HGM pretreated with Ca(OH)2 at 90℃.(3)The zeta potential and surfactants of HGM changed after pretreated by HF、Na OH、Ca(OH)2. Both of zeta potential and surfactants function to Ti O2 growing on the surface of HGM. At the initial stage, Island particles growth on the surface of HGM. Nano particles grow and agglomeration with time, then film formatted. Step growth models were clearly shown.(4) The experimental results show heat preservation properties of Ti O2-HGM is better than Ti O2 and HGM physical blend into coating. The coating rate of Ti O2-HGM prepare by sol-gel is 8.2%, and the temperature difference is 11.8℃. The coating rate of Ti O2-HGM prepare by heterogeneous deposition method is up to 28.6%, and the temperature difference is 27.6℃.