Effects of ZrO2 on the properties and dry-pressing preparation of mullite based crossing network structure

Mullite based crossing network structure were dry-pressing prepared by using waste gangue and calmogastrin as the main raw material. Effects of ZrO2 on the properties of the samples were studied. The samples were characterized by X-ray diffraction, scanning electron microscopy and the corresponding energy dispersive analysis. The experiment results showed that when ZrO2 content was 20%, the sample reached 123.21 MPa of bending strength, 123.75% of bending strength retention rate and the coefficient of thermal expansion of 5.023x10(6)/degrees C-1. It could be attributed to the crossing network structure of the mullite, which produced a lot of pore porosity to accommodate a certain expansion deformation and thus alleviate the heat stress. Moreover, micro cracks around the porosity can be formed in the main crack tip region, which decreases local elastic strain energy and restrains the crack propagation and thus enhances the materials properties.