Investigation On Preparation And Properties Of Zirconia Fibers And Zirconia Fibers Board

In this paper, high-strength polycrystalline c-ZrO2 fibers with good flexibility were successfully prepared by sol-gel method using polyoxozirconium acetate precursor spinning solution synthed by Zirconium oxycarbonate, acetic acid, and de-ionized water as raw materials and the yttrium nitrate as stabilizer, and using centrifugal spinning followed by heat-treatment in air atmosphere. The molecular structure of polyoxozirconium acetate was deduced from the characterizations of FT-IR and DSC-TG. XRD, SEM and TEM were used to study the microstructure of the ZrO2 fibers and the factors influencing the strength of the fibers. The results shows that the c-ZrO2 grain has grown up to about 6nm when the precursor fibers with 10mol%Y2O3 doped heat-treated to 400℃. T-ZrO2 fibers with 3mol%Y2O3 doped and c-ZrO2 fibers with 8mol% and 10mol%Y2O3 doped had no phase change after calcined 1600℃for 2h.The ZrO2 fibers board with even and controllable density was successfully prepared by vacuum filtering molding process and pressure to level technique. Wet fibers board was fabricated using c-ZrO2 fibers as base materials and poly-zirconium spinning solution diluted with water as the binder. After drying and calcining, the c-ZrO2 fibers board was obtained. The permanent heating conductivity of length, width and thickness directions of the c-ZrO2 fibers board prepared by ZrO2 fibers pre-heated at 1600℃were only 1.15%,1.03% and 1.90%, when the fibers board sintered at 1600℃forl8h after the boad had heat-treated at 1600℃for 6h. The thermal conductivity was only 0.08W/m·k for c-ZrO2 fibers board with a density of 0.40×10-3g/mm3. The compressive strength was up to 1.75MPa, when the c-ZrO2 fibers board with a density of 1.16×10-3g/mm3 was compressed 10% for thickness direction.The ZrO2 continuous fibers were prepared by synthesis of inorganic polyzirconium spinning solution using zirconium oxychloride and hydrogen peroxide as raw materials and the yttrium chloride as stabilizer, and using centrifugal spinning and gas compression dry spinning techniques. The obtained precursor fibers up to dozens of meters in length were heat-treated in steam atmosphere. FT-IR, DSC-TG, XRD and SEM were used to study the characteristics of precursor fibers and ZrO2 fibers. Based on the test results, the molecular structure of inorganic polyzirconium was inferred, and a suitable process of heat treatment and atmosphere were developed. The fibers heat-treated under steam atmosphere had uniform structure, high strength and good flexibility, while the fibers heat-treated in air atmosphere had poor microstructure and low strength.