| The glass-ceramics used as dental materials in the system SiO2-Al2O3-K2O- Na2O are studied in this thesis. The crystallization, chemical durability and mechanical properties of different compositions and heat treating regime of samples were mainly measured.Leucite was crystallized as the main crystal phase of glass-ceramics in the system SiO2-Al2O3-K2O-Na2O after heat treatment. The leucite which was crystallized can prevent the expansion of internal micro crack and enhance the mechanical property and the chemical durability of the glass ceramics. The best heat treatment is as follows:nucleation temperature 760℃, soaking time 1 hour; crystallizing temperature 1010℃, soaking time 2 hour. The samples after heat treatments have good mechanical properties, chemical durability and resistance of thermal vibration. The bending strength of a sample reached 100.9 MPa and the microhardness reached 6.72 GPa. The color and luster are close to the natural teeth's. So some samples in this system fit for the requirements of ceramic enamel for dental materials.
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