莫来石晶须前驱体原位增强海胆状莫来石材料的性能研究

Properties of Mullite Whisker Precursor In-Situ Reinforced Urchin-Like Mullite Materials

为了提高粉煤灰的高附加值利用,分别以氢氧化铝和粉煤灰漂珠作为海胆状莫来石前驱体的铝源和硅源,氢氧化铝和粉煤灰为莫来石晶须前驱体增强剂的铝源和硅源,AlF_(3)和V_(2)O_(5)为晶须促进剂和烧结助剂,采用固相法原位制备了莫来石陶瓷材料。主要研究了增强剂与海胆状莫来石前驱体的配比(质量比分别为3∶7、4∶6、5∶5、6∶4、7∶3)对制备的莫来石陶瓷材料性能、物相组成和显微结构的影响。结果表明,随着增强剂与海胆状莫来石前驱体的配比从3∶7增大至7∶3,试样中形成的晶相全为莫来石,材料内部更加致密,体积密度和抗压强度逐渐增大,总气孔率逐渐减小,增强剂的引入提高了材料的线变化率和抗热震性能,但降低了材料的重烧线变化率,材料的残余抗压强度及残余强度比先增加后减小。当增强剂与海胆状莫来石前驱体的质量比为6∶4时综合性能较佳。

In order to improve the high value-added utilization of fly ash,mullite whisker precursor reinforced urchin-like mullite ceramic materials were in-situ prepared by the solid-phase method by using aluminum hydroxide and fly ash hollow sphere as aluminum and silicon source of urchin-like mullite precursor,aluminum hydroxide and fly ash as the aluminum and silicon source of mullite whisker precursor reinforcing agent,AlF_(3) and V_(2)O_(5) as the whisker accelerator and sintering aid severally.The effects of the ratio of reinforcing agent to the urchin-like mullite precursor(the mass ratio were 3∶7,4∶6,5∶5,6∶4,and 7∶3 respectively)on the properties,phase composition,and microstructure of the prepared mullite ceramic materials were studied.The results show that when the ratio of reinforcing agent to the urchin-like mullite precursor change from 3∶7 to 7∶3,the crystal phase formed in the sample is mullite,and the interior of the material is denser,the bulk density and compressive strength gradually increase,total porosity gradually decrease.The introduction of the reinforcing agent improves the linear change rate and thermal shock resistance,but reduces the reheating linear change rate of materials,and the residual compressive strength and residual strength ratio first increase and then decrease.The prepared mullite materials with better comprehensive properties can be obtained when the mass ratio of the reinforcing agent to urchin-like mullite precursor is 6∶4.