纤维长径比对纤维多孔材料性能的影响

Effect of fiber aspect ratio on the properties of fiber porous materials

以氧化铝短切纤维为基体,分别经20目、40目、60目筛超洗,以聚丙烯酰胺为分散剂、硅溶胶为粘结剂、叔丁醇/水二元混合溶液为料浆液相溶剂,采用冷冻浇注工艺制备氧化铝纤维多孔陶瓷。在1500℃对样品进行烧结,测试烧结后样品的压缩强度;用扫描电镜观察样品表面形貌,研究纤维长径比对材料力学性能和隔热性能的影响。结果表明,随过筛目数增大,氧化铝多孔纤维材料密度减小,孔隙率增加,抗压强度下降。纤维过40目筛样品抗压强度略低于过20目筛样品,过60目筛样品的抗压强度最差。在隔热性能测试中,纤维过40目筛样品冷面温度略低于过60目筛样品,过20目筛样品的隔热性能最差。过40目筛纤维长径比为20~35,其所制备样品的隔热性能和力学性能俱佳。

Alumina fiber porous ceramics are prepared by freezing casting process,with alumina chopped fiber as the matrix,sifted by 20/40/60 mesh sieves respectively,polyacrylamide as the dispersant,silica sol as the binder,and TertButyl alcohol/water binary mixed solution as the slurry liquid phase solvent.Sinter the samples at 1500℃and test the compressive strength.The surface morphology of the samples is observed with scanning electron microscope,and the effect of fiber aspect ratio on thermal insulation and mechanical properties is studied.The results show that as the mesh number increases,the density of alumina porous fiber material decreases,the porosity increases,and the compressive strength decreases.The compressive strength of the sample sieved with 40 mesh is slightly lower than that of the sample sieved with 20 mesh,while the compressive strength of the sample sieved with 60 mesh is the worst.In the insulation performance test,the cold surface temperature of the sample sieved with 40 mesh is slightly lower than that of the sample sieved with 60 mesh,while the insulation performance of the sample sieved with 20 mesh is the worst.The aspect ratio of fiber sifted by 40 mesh sieve is 20~35,and the samples prepared have excellent thermal insulation and mechanical properties.