(1) Lower firing temperature: The traditional ceramic raw material is mainly kaolin, which belongs to the silicon-aluminum system. It is fired at high temperature (1250 ~ 1350 ℃), and the generated crystal phase is mainly mullite. Wollastonite is introduced to form a silicon-aluminum-calcium eutectic system, and the main crystal phase is anorthite. The temperature at which wollastonite and kaolinite should form feldspar is 900-1000 ° C, and the reaction temperature for higher mullite to mullite is much lower.
(2) Shorten the firing cycle: Because the wollastonite powder particles are needle-shaped, the wollastonite needle-like crystals become a channel for moisture to escape during the drying and firing of the green body, so the drying and firing are fast, thus Shorten the firing cycle and improve work efficiency.
(3) Improve the strength of the green body and the product: the wollastonite needle crystals are interwoven in the green body, the linear expansion coefficient of the wollastonite is small, the volume shrinkage during firing is small, and the interwoven structure of the residual wollastonite improves the blank The mechanical strength of the body and products, which is useful for making high-strength ceramics.
(4) Reduce the hygroscopic expansion: Alkali metal compound flux can be added to the wollastonite-containing ceramic with or without added. The calcined product has low alkali content, so the product has low moisture absorption rate and can improve the durability of the product.
(5) Production of low-dielectric insulating ceramics: Wollastonite itself has good insulation, low dielectric loss, needle-like crystals, and low moisture absorption of fired ceramics, making it an ideal material for making high-strength electrical insulating porcelain.
(6) Reduce the blank and glaze defects: Wollastonite itself does not contain volatile gas, so that the blank body has fewer defects, so that the glaze does not produce pinholes and pits. The low-expansion and fusibility of wollastonite is beneficial to the production of low-expansion low-temperature glaze.
(7) Making high-temperature and high-strength ceramic molds: gypsum molds have low strength and low use temperature, which can no longer satisfy large-scale high-yield. The bulk density of the powder trial-produced in this project is less than 1 and the porosity of the stacking can reach more than 60%. It is an ideal material for the development of high-temperature high-strength ceramic molds.
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