Study On The Preparation Of Yttria Stabilized Zirconia Nanoparticles And Its Oxygen Sensing Properties

Zirconia (ZrO2) is a kind of sensitive materials used to produce oxygen sensor, with the improvement of oxygen sensor technology and its performance, zirconia with the excellent performance is needed. The thesis is based on the background of the development needs of the oxygen sensor. Yttria stabilized zirconia nanoparticles were synthesized by hydrothermal and sol-gel method with raw materials of ZrO(NO3)2·2H2O and Y(NO3)3·6H2O. The microstructure of the products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. Then the effect of the yttria-stabilized zirconia on the oxygen sensing properties was studied. The results lay the foundation of the new oxygen sensor sensitive materials research and their industrialized production.Yttria stabilized zirconia nanoparticles were synthesized by hydrothermal method with the raw materials of ZrO(NO3)2-2H2O and Y(NO3)3·6H2O. The effects of pH value, hydrothermal temperature, the hydrothermal time, drying manner, surface activator, alcohol additive and mineralizer on the yttria stabilized zirconia nanoparticles were studied respectively. The morphology, crystal phase and the partical size were analyzed to optimize the synthesis process of Yttria stabilized zirconia powder. Comparied with the common drying methods, agglomeration of product can be decrease with the microwave drying and addition of surface activator. The crystal phase and crystallinity can be influence by pH value, the crystallinity increases with pH value increase. At the different hydrothermal temperature crystal phases of product is almost the same. Through comparing cubic crystal phsase of Yttria stabilized zirconia powders that were obtained at different time, it can be find that the crystal gradually developed completely with increasing hydrothermal time. Organic additives change the crystallinity of product, and, especially, glycerin has a most obvious effect, additionally, morphology of product is influlenced by addition of glycerin. Addition of mineralizer improve crystallinity of the product and also has an effect on crystalline morphology, so the optimal condition of the yttria stabilized zirconia nanoparticles were decided:temperature is 200℃, time is 12h, pH is 9, using microwave drying and the addition of surfactant. Then the yttria-stabilized zirconia powders, which is cubic phase, spherical morphology and the paticle size is less than 10nm, can be obtained. Using the citric acid as complexing agent the yittria-stabilized zirconia were synthesized by sol-gel method. The results show that the crystal phases of the powder after calcined were monoclinic and tetragonal. When the precursors were calcined at 600℃and 700℃, the produced yttria-stabilized zirconia powder with about 1μm in columnar crystal. The structure of yttria-stabilized zirconia nanoparticles is cubic phase when it prapered by sol-gel method with pectin as gelling agent and sucrose as stabilizing agent, and the mount of agglomeration increases with the concentration of the solution.The oxygen sensor was prepared with the yttrium stabilized zirconia powder by th hydrothermal method, and the properties was discussed. The results show that the oxygen sensor obtained had a good stability, a higher accuracy, and the response time was less than 10 seconds.