莫来石纤维增强堇青石质陶瓷材料性能研究

Study on the Property of Mullite Fiber Reinforced Cordierite Ceramics

以堇青石粉为原料,碳粉为造孔剂,甲基纤维素(MC)为粘结剂,甘油、乙醇为润滑剂,通过挤压成型和固态粒子烧成法制备具有高开孔率,高强度的陶瓷。通过烧结温度和保温时间的正交实验确定堇青石基体材料的烧结制度。通过考察烧结温度和莫来石纤维(PMF)添加量对纤维陶瓷性能的影响,确定使纤维与基体材料结合程度最佳的烧结制度和莫来石添加量。采用SEM、XRD表征样品的断面形貌和晶相种类,以分析基体材料和莫来石纤维的相互作用对陶瓷性能的影响。结果表明:1300℃下保温2 h的堇青石陶瓷综合性能较佳;含纤维陶瓷的烧结温度越高,莫来石纤维与堇青石基体的结合越紧密,莫来石纤维的增强作用越明显,但高于1300℃时,复合陶瓷的抗压强度会由于堇青石基体材料强度下降而下降;莫来石纤维添加量为20%时,陶瓷开孔率为49. 25%,抗压强度为15. 69 MPa,比无纤维的陶瓷增加了153%。

The ceramic with high open porosity and high strength were prepared by extrusion molding and solid state sintering, using cordierite powder as raw material, carbon powder as pore former, glycerin and ethanol as lubricants and methyl cellulose (MC) as binder. The sintering system of cordierite matrix material was determined by orthogonal experiment of sintering temperature and holding time. By investigating the influence of sintering temperature and mullite fiber(PMF) addition on the properties of fiber ceramics, the sintering system with the best degree of fiber to substrate bonding was determined. The cross-sectional morphology and crystal phase of the sample were characterized by SEM and XRD, the effect of the interaction between the matrix material and mullite fiber on the properties of the ceramic were analyzed. The results show that the performance of cordierite ceramics sintered at 1300 ℃ for 2 h is better;the higher the sintering temperature of fiber-containing ceramics, the closer the combination of mullite fibers and cordierite matrix, and the reinforcing effect of mullite fibers is stronger, however, when the temperature is higher than 1300 ℃, the compressive strength of the composite ceramics will decrease due to the significant decrease of the strength of the cordierite substrate. When the mullite fiber addition is 20%, the opening pore ratio of the ceramics is 49.25%, and the compressive strength is 15.69 MPa. It is 153% stronger than fiber-free ceramics.