| The all-ceramic dental materials have good bio-compatibility , mechanical properties and chemical stability. So they fit for complicated physiological environment. Besides, they look like real teeth and have glabrous surface so that bacteria can not attach. However, the intrinsic brittleness of ceramic and its low strength limit the application of all-ceramic restoration for dental use. How to increase strength and toughness of ceramic is the most important mission of material researchers.The La glass-infiltrated (Y, Ce)-ZrO2/Al2O3 porous ceramic composite is studied in this paper, and physical properties, phase composition & microstructure are investigated . Besides, influences on preparation of material and their properties are also discussed.(Y, Ce)-ZrO2/Al2O3 porous ceramic is prepared by way of reaction between solid phases sintering. The optimal directions for producing chemicals for (Y, Ce)-ZrO2/Al2O3 porous ceramic is (Y, Ce)-ZrO2 60 vol%, (Mg)-Al2O3 40 vol%. The sample is heated in 1200℃,1h and test its physical properties. The results of total sintering linear shrinkage quotiety is 1.5%, porous quotiety is 38.62%, bending strength is 80.14MPa, micro-hardness is 710.88HV, and the mean value of thermal expansion coefficient is 2.27×0-6/℃(200℃-500℃). The analysis of substances is investigated by XRD, and the main phases are t-ZrO2, (X-Al2O3 and m -ZrO2. Microstructure of crack of porous ceramic is discussed by SEM, and the results indicate that the size of crystals are evenly, and there are amount of pores to air, the size of the pore is almost 15μm, which is benefit for glass infiltration.La2O3-Al2O3-SiO2-B2O3 glass is prepared by melting way and the optimal chemical content, melting temperature is 1320℃, 1h and test its physical properties. The first fuse temperature is 820℃, and all fuse temperature is 1040℃.The wetting angle is almost 0 to porous ceramic basement, and the mean value of thermal expansion coefficient is 2.16×10-6/℃(200℃-500℃), and bending strength and micro-hardness are 116.78MPa and 386.86HV, respectively.The La glass-infiltrated (Y, Ce)-ZrO2/Al2O3 porous ceramic composite is prepared by infiltration. La2O3-Al2O3-SiO2-B2O3 glass and (Y, Ce)-ZrO2/(Mg)-Al2O3 porous ceramic are compounded in furnace, melting temperature is 1120℃, melting time is 4h, and depth of infiltration is 1.04mm. The physical properties are tested. The results of porous quotiety is 4.09%, bending strength is 193.62MPa, micro-hardness is 900.24HV. Besides, its loss of erosion is 327μg/cm2, and its chemical stability is good. The results of microstructure of crack of the composite and chemical substances are investigated by SEM & EDS, they indicate that glass phase and crystals are compounded together constantly, the glass fill in the pores of the ceramic basement and they combine tightly. The all-ceramic dental material meets the demands of clinic implication.
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