不同含铝微粉对原位莫来石结合SiC多孔陶瓷膜支撑体性能的影响

Effects of different alumina-containing micropowders on properties of in-situ mullite-bonded SiC porous ceramic membrane support

为降低陶瓷膜支撑体的制作成本,以SiC颗粒为骨料,分别以α-Al_2O_3微粉、ρ-Al_2O_3微粉以及Al(OH)3粉作为莫来石相的铝源,利用烧结过程中Si C微粉表面氧化产生的SiO2作为硅源,以木炭粉为造孔剂,碱式碳酸镁作为助烧结剂,于1 350℃保温3 h在空气气氛下无压烧结制备原位莫来石结合SiC多孔陶瓷膜支撑体试样,并研究了三种不同含铝微粉对试样性能的影响。结果表明:经1 350℃烧后,采用活性ρ-Al_2O_3微粉结合的试样抗折强度达到19. 9 MPa,分别高于采用α-Al_2O_3和Al(OH)3结合试样的51. 1%和33. 5%。SEM及XRD分析表明,添加活性ρ-Al_2O_3微粉的试样内部颗粒之间的颈部结合程度最好,原位生成的莫来石相最多。

This work aims at reducing the production cost of ceramic membrane support. In-situ mullitebonded silicon carbide porous ceramic membrane support specimens were fabricated using SiC particles as aggregates,α-Al2O3 micropowder, ρ-Al2O3 micropowder and Al （OH）3 powder as the aluminum resource,SiO2 generated from the surface oxidation of SiC micropowder during sintering as the silicon source,charcoal powder as the pore forming agent, basic magnesium carbonate as the sintering aid,and pressureless sintering at 1 350 ℃ for 3 h in air. Effects of different alumina-containing micropowders on properties of the specimens were investigated. The results show that the flexural strength of the specimen with ρ-Al2O3 micropowder reaches 19.9 MPa,51.1% and 33.5% higher than those of the specimens with α-Al2O3 and Al（OH）3,respectively. The SEM and XRD analysis shows that the neck bonding between the particles in the specimen with active ρ-Al2O3 as the aluminum source is the best, in-situ forming the most mullite phase.