Abstract:In the raw material of diopside-pyrophyllite-clay system, the content variation of diopside, pyrophyllite, clay gives rise to the variation of crystal phases and of ceramics properties, such as the water absorption, the shrinking percentage of green bodies, flexural strength, and the coefficient of thermal expansion. The crystal phases and morphology of the ceramics were analyzed by XRD and SEM. Based on thermal expansion curves, the coefficients of thermal expansion were calculated through Excel software. It is clarified that decreasing of diopside, and at the same time increasing of quarts in the formulation diminish enstatite and enhance the quarts and mullite in the product, which results in higher mechanical strength, but lower thermal expansion. An appropriate proportion of diopside and pyrophyllite in the formulation can result in more feldspar in the product, which induces a satisfying thermal expansion.