Title: Crystallization and mechanical properties of high strength α-cordierite glass-ceramics
Abstract: Suitable thermal expansion coefficient and high strength are prerequisite of glass-ceramics for sealing with metal.The influences of heat treatment and nucleator on crystallization process and mechanical property for MgO-Al2O3-SiO2 system were studied by DTA,XRD,SEM techniques.The study results show that,thermal analysis method can be used to accurately determine the optimal nucleation temperature.Different content of TiO2 nucleator leads to different primal crystal phases,but at last,the major crystal phases are all α-cordierite phases.Adding 12% mass fraction of TiO2 decreases the crystallization activation energy of the system about 60kJ/mol comparing with that of adding 8% mass fraction of TiO2,which makes the process of crystallization more easily,and reduces the crystallization temperature of α-cordierite.However,addition of excessive nucleator e.g.12% TiO2 could make the crystallization too fast and the crystallite too large,and thereby the mechanical properties of the glass-ceramics to be worse.Finally the glass-ceramics,which has major tiny,uniform α-cordierite crystal,good mechanical properties(316 MPa),suitable thermal expansion coefficient(51.6×10-7 ℃-1) and seals 4J29 alloy very well,was prepared by adding 8%(mass fraction) TiO2 as nucleator and heat treated at 790 ℃ for 2 h,then at 1 150 ℃ for 1.5 h
Publication Year: 2007
Publication Date: 2007-01-01
Language: en
Type: article
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