Study On Preparation Of Alumina/zirconia Composite Fibers

In this study,alumina/zirconia spinning solution was prepared by sol-gel method with aluminum powder,hydrochloric acid,acetic acid,and zirconium oxychloride as the raw material,using polyvinyl alcohol(PVA)as spinning additives.The impact of the ratio of raw materials,concentration temperature,moisture content,PVA added amount and type of PVA to the stability,rheology and spinning of alumina/zirconia spinning solution was studied.The impact of fiber-forming crafts on fiber morphology and the diameter of the fibers were described.Some research on heat treatments is done at the same time.The experient show that:(1)Zirconia and alumina were uniformly mixed according to the ratio of 40%～50%.And after distillated at 75 ℃,the most stable alumina/zirconia spinning solution was obtained;When the moisture content of alumina/zirconia spinning solution was from 35%to 45%,and the internal temperature of system were in the range of 35-45 ℃,alumina/zirconia spinning solution had the best rheology.According to m(zirconium oxychloride):m(zirconium acetate)=(0.5 to 0.9): 1,zirconium oxychloride and zirconium acetate were configured as zirconium solution.And adding 1788 type PVA(accounting for the sum of the quality of alumina and zirconia)with the mass fraction of 7%,aged for about3-6d between 25 ℃ and 45 ℃,The alumina/zirconia spinning solution had the best spinnability.(2)When the temperature of ompressed air at about 50 ℃,the speed of compressed air between 12m/s and 16m/s,the temperature of cotton collection system between 40 ℃ and50 ℃ and relative humidity of about 20%,the rotation speed of spinning disk between20 Hz and 25 Hz,the precursor fibers with uniform diameter,fewer defects,low content of slag balls were obtained.The average diameter of fibers increased with the increase of the speed of compressed air.When selecting the speed of compressed gas from 15m/s-17m/s,the diameter distribution of fiber was more concentrated and the average diameter was fit.(3)Special heat treatment was required from room temperature to 500 ℃,and the heating rate was 5 ℃/min from room temperature to 500 ℃;The optimum calcination temperature of alumina/zirconia precursor composite fibers was 1300 ℃;The holding time was not more than 90 min at 1300 ℃,80 min as the best heat preservation period.(4)Alumina/zirconia composite fibers prepared in this experiment were soft with the diameter between 4um and 6um.And the content of slag balls was less than 2%.The vibration grinding rate was about 5%.It can be used at 1300 ℃ for a long time.