Synthesis Of Zirconia Sol By Hydrothermal Method

Zirconia sol is a kind of transparent aqueous liquid with the characteristics of high transmittance and high refractive index.At the same time,due to the very high fluidity,zirconia sol is widely used in coatings,adhesives and catalysts.In this dissertation,we have prepared yttria stabilized zirconia sol by hydrothermal method.The effects of stabilizer content,reaction temperature,reaction time,filling degree,pH value and concentration on the synthesis of zirconia sol have been studied.XRD,SEM,UV,laser Raman and Fourier transform infrared spectroscopy have been used to characterize the synthesized zirconia sol.The effect of pH value on zirconia sol is studied.When the pH value is 7.6,7.9,8.2 and8.5,zirconia sol is synthesized,and when the pH value is 9.0,zirconia gel is synthesized,both of which are cubic phase with a small amount of monoclinic phase.When the pH value is 6.0,zirconia gel is synthesized,which is totally monoclinic phase.When the pH value is4.5,9.5 and 12.5,the synthesized zirconia is all precipitation.Therefore,the most suitable pH value for the synthesis of cubic zirconia sol is between 7.6 and 8.5.The effect of molar ratio of stabilizing agent yttrium to zirconium on zirconia sol is studied.When the content of Y?NO₃?₃ is 0 and 3mol%,the zirconia sol is synthesized with no precipitation,and the former is monoclinic phase,the latter is a cubic phase with a small amount of monoclinic phase.When the content of Y?NO3?3 is from 5mol%to 10mol%,zirconia sol is synthesized with a small amount of precipitation,which mainly is consisted of a cubic phase with a small amount of monoclinic phase.The effect of reaction temperature,reaction time and filling volume on zirconia sol synthesis is studied.When the reaction temperature is 145^oC and 150^oC,zirconia sol is synthesized with a small amount of precipitation,which mainly is consisted of a cubic phase with a small amount of monoclinic phase.When the reaction temperature is 155^oC,a part of zirconia is zirconia gel and another part is amorphous zirconia.Therefore,the most suitable reaction temperature for the synthesis of cubic zirconia sol is 145^oC to 150^oC.When the reaction time is 4h,8h and 12h,zirconia sol is synthesized with a small amount of precipitation,which mainly is consisted of a cubic phase with a small amount of monoclinic phase.When the reaction time is 3h,zirconia gel is synthesized.When the filling volume is40%,60%and 80%,zirconia sol is synthesized with a small amount of precipitation,which mainly is consisted of a cubic phase with a small amount of monoclinic phase.The effect of the molar ratio of oxalic acid to zirconium,the precursor concentration and the concentration of TMAOH aqueous solution on zirconia sol synthesis is studied.When the molar ratio of oxalic acid to zirconium is changed to 1:1,1.5:1 and 2:1,the precursor concentration is changed to 0.15mol/L,0.225mol/L and 0.3mol/L,and the concentration of TMAOH aqueous solution is changed to 25%,12.5%and 8.3%,zirconia sol is synthesized with a small amount of precipitation,which mainly is consisted of a cubic phase with a small amount of monoclinic phase.When molar ratio of stabilizing agent,yttrium to zirconium is 0mol%to 3mol%,reaction temperature is 145^oC to 150^oC,reaction time is above 4h,the molar ratio of oxalic acid to zirconium is 1:1,the precursor concentration is 0.3mol/L and the concentration of TMAOH aqueous solution is 12.5%,transparent,stable,pure and yttria stabilized cubic zirconia sol can be synthesized successfully.