莫来石/碳化硅复相泡沫陶瓷的制备及抗压强度研究

Preparation and Compressive Strengths of Mullite/SiC Composite Ceramic Foams

以碳化硅微粉作为原料,并选用Al2O3、高岭土和Mg O作为烧结助剂,同时选用羧甲基纤维素钠(CMC)、聚丙烯酰胺(PAM)和可溶性淀粉作为添加剂,通过有机泡沫浸渍法制备出莫来石/碳化硅复相泡沫陶瓷材料。研究了不同原料组成、不同烧结温度等工艺参数对所制备的莫来石/碳化硅复相泡沫陶瓷物相组成、微观结构的影响,同时对莫来石/碳化硅复相泡沫陶瓷的孔隙率、力学性能进行了测试。研究结果表明:莫来石/碳化硅复相泡沫陶瓷的微观结构控制主要受碳化硅含量的影响,随着碳化硅含量的增加,莫来石/碳化硅复相泡沫陶瓷的孔隙率有明显的降低,但抗压强度随之提高;随着烧结温度的提高,孔棱的致密度增加,抗压强度亦显著提高;莫来石/碳化硅复相泡沫陶瓷的最佳烧结温度为1600℃,陶瓷粉料中最佳的Si C含量为35%。在1600℃烧结温度下,碳化硅的含量为35%时,获得了孔隙率为76.19%和抗压强度为4.63 MPa的莫来石/碳化硅复相泡沫陶瓷。

Mullite/SiC composite ceramic foams were prepared by polymer replica method. A12 03, kaolin and MgO were selected as sintering additives. Meanwhile, sodium carboxy methyl cellulose （CMC）, polyacrylamide （PAM） and soluble starch were selected as additives. The effects of compositions of powder mixtures and sintering temperature on the phase and microstructure of ceramic foams were analyzed. The porosity and mechanical properties of ceramic foams were characterized. The results showed that the porosity of mullite/SiC composite ceramic foams definitely diminished via increasing the content of SiC in the powder mixtures, while the compres- sive strength was enhanced. The strut density and compressive strength were apparently improved when the sintering temperature in- creased. The best sintering temperature was 1600 ~C, and the best content of SiC in mullite/SiC composite ceramic foams was 35%. Under this condition, the porosity and compressive strength of mullite/SiC composite ceramic foams were 76.19% and 4.63MPa, re- spectively.