The Preparation And Properties Of Zirconia Fiber/Zirconia Foam Ceramics Composite

In this paper,the ZrO2 fiber was prepared by the sol-gel method with the inorganic zirconium system.The ZrO2 fiber was prepared as raw materials by direct foaming method and adding pore forming agent to prepare ZrO2 fiber composite ZrO2 foam ceramics.The comprehensive performance of the prepared ZrO2 foam ceramics was analyzed by optical microscope,XRD,thermal conductivity tester,universal testing machine and so on.The experiment content of this paper is divided into three parts:(1)Using the inorganic poly zirconium system,with zirconium oxychloride and hydrogen peroxide as raw materials,three yttrium chloride phase stabilizer,The ZrO2 precursor fiber with Tens of centimeters of centimeters was successfully prepared by sel-gel method combined with centrifugal spinning process,Then the precursor fibers were sintered at high temperature to get ZrO2 fibers under the atmosphere of water vapor.The results show that the inorganic zirconium spinning glue has good stability and spinnability,when the molar ratio of H2O2/ZrOCl2 to 4?5,reaction temperature of 15?25?,the reaction liquid timegoing 3-5d.The ZrO2 fibers have good continuity,the diameter is 6?10?m,smooth surface without pores,and the internal grain distribution is dense.(2)Using direct foaming method,with cubic ZrO2 powder and ZrO2 short fiber as raw material,polyvinyl alcohol as binder,wet foams obtained by reaction of zirconium oxychloride and hydrogen peroxide,Putting wet foam at room temperature for several days after curing and drying,ZrO2 foam ceramic with excellent performance was obtained through heat treatment.The results show that when the mass ratio of ZrO2 powder to ZrO2 fiber is 1:0.31?0.55,the mass ratio of ZrO2 powder to ZrOCl2 is 1:0.04,the mass ratio of ZrO2 powder to H2O2 is 1:0.15?0.2,the mass ratio of ZrO2 powder to PVA is 1:0.002?0.003,reaction temperature is 10?20?,stirring rate is 80?100r/min,the prepared ZrO2 foam ceramic has better performance.Bulk density of 1.5g/cm-3,High porosity(Porosity of up to 80%,the air hole rate is up to 48%),the lowest coefficient of thermal conductivity is 0.18W/(m·K);heating permanent linear shrinkage is less than 0.42%;the maximum compressive strength of up to 4.7MPa.The crystalline phase of ZrO2 foam ceramics fired at different sintering temperatures is a fully stable cubic ZrO2.(3)The ZrO2 foam ceramics were successfully prepared by adding pore forming agents,using cubic ZrO2 powder and ZrO2 fiber as raw materials,PVB and amidon as pore forming agent,PVA as the binder,by semi-dry press molding,place at room temperature for several days.The ZrO2 ceramic foam was successfully prepared by heat treatment.The results show that the properties of the prepared ZrO2 foam ceramics are good when the pore forming agent is 17-22wt%and the pressing pressure is 60-70MPa.High porosity(up to 64%),the pore structure of a circular aperture,generally less than 150 ?m;compressive strength is up to 2.7MPa;the minimum thermal conductivity can reach 0.28W/(m·K).The crystalline phase of the prepared ZrO2 foam ceramics is a fully stable cubic ZrO2.