烧成温度和保温时间对堇青石相的合成及其力学性能的影响

Effect of Firing Temperature and Holding Time on Synthesis of Cordierite Phase and Mechanical Properties

实验以高岭土、烧结镁砂和硅灰为主要原料,以稀土金属氧化物氧化镧为添加剂,采用半干压成型法将试样成型为直径30 mm的生坯,采用一次烧成法制备堇青石多孔陶瓷。主要研究氧化镧的引入量为1.5%时,烧成温度和保温时间对堇青石多孔陶瓷性能及显微结构的影响。结果表明:当试样的烧成温度为1300℃,保温时间为2 h时,试样的基本性能较优,即试样的线收缩率为4.43%,吸水率为20.35%,显气孔率为34.39%,体积密度为1.69 g/cm^(3),耐压强度为35.96 MPa;且从试样的XRD和SEM分析结果可知,在一定烧成温度下,适当提高保温时间有利于堇青石相的合成,为拓宽堇青石陶瓷的应用领域奠定了重要的理论基础。

In this experiment,kaolin,sintered magnesia and silica were used as the main raw materials,and lanthanum oxide of rare earth metal was used as the additive.The samples were formed into green billet with diameter of 30 mm by semi-dry pressing method,and porous cordierite ceramics were prepared by single firing method.The effects of firing temperature and holding time on the properties and microstructure of cordierite porous ceramics were studied when the amount of lanthanum oxide was 1.5%.The experimental results showed that:when the firing temperature was 1300℃,and the holding time was 2 h,the basic properties of the sample was better,that is,the linear shrinkage rate of the sample was 4.43%,the water absorption rate was 20.35%,the apparent porosity was 34.39%,the bulk density was 1.69 g/cm^(3),and the compressive strength was 35.96 MPa.The results of XRD and SEM analysis showed that at a certain sintering temperature,increasing the holding time is beneficial to the synthesis of cordierite phase,which lays an important theoretical foundation for expanding the application field of cordierite.