Study On The Preparation And Properties Of Zirconia-based Ceramic Fiber And Fiber Board

In this paper, by the reaction with zirconium oxycarbonate and acetic acid, the yttria is used as the precursor to stable zirconium acetate and the sol-gel method is used to prepare poly zirconium precursor sol and zirconia gel precursor fibers. By studying the added ratio of H+/Zr4+, it is found that when the ratio is 1.8-1.9, a better stability and spinnability sol can be obtained, and the optimum spun viscosity is 20-30Pa-S by viscosity measurement; with the help of Differential Thermal Analy -sis (TG-DTA) and Fourier Transform Infrared spectroscopy (FT-IR), the existence of chain structure is infered in the poly zirconium precursor gel fibers, and a reasonable heat treatment system is worked out on this basis. Using X-ray diffraction, scanning electron microscope and other testing methods to test the diameter of the fiber, the grain size and the strength of Y-TZP ceramic fiber and Al2O3-3Y-TZP ceramic fiber withlOwt% doped Al2O3 under different calcinations temperature, it is found that the fiber diameter is about 10～12μm and the grain size is about 80～300μm, and the additive of alumina can restrain the grain growing of ZrO2, which can increase the fiber tensile strength and the maximum can reach 1.2GPa.Zirconia-based fiberboards are prepared by wet molding methord, using vacuum filter press Gaga leveling process method, then adding forming agent in the short ceramics fibers cut by continuous Al2O3-3Y-TZP fibers. Different densities of Zirconia-based fiberboards with flat surfaces and uniform thickness are successfully prepared by vacuum filtering molding process and applying different pressures. Studying on the hot shrink of ceramic fiberboards, the permanent linear shrinkage is larger in the thickness direction, it’s about 10%-12%; while they are smaller in length and width directions (about 2%-4%); the flexural strength and compressive strength of the ceramic fiberboards will improve with the increase of density, when the density is 0.55g/cm3, the flexural strength can reach 2.386MPa and the compressive strength can reach 0.353MPa. By testing the thermal conductivity of different densities ceramic fiberboards under 1000℃, it is found when the fiberboard with larger porosity and low density, the heat convection will dominate, then the thermal conductivity will increase with the porosity increasing; when the density increases and porosity reduces, the heat conduction will dominate, then the thermal conductivity will increase with increasing density; the optimum density range is 0.4～0.8 g/cm3.At this time, the thermal conductivity of ceramic fiberboard will be the lowest under 1000℃,which is about 0.20～0.25 W/m-K.Adding different ratio Al2O3-3Y-TZP short zirconia ceramic fibers into the ceramic foams, it is found the higher content of the fibers, the higher flexural strength of ceramic foam; when the adding content of short fibers is 30wt%, the flexural strength is 37.95 MPa.