Research of Structure and Properties on SrO-Al_2O_3-SiO_2 System Glass-ceramics

Abstract: In this paper, the research background, classification, faBaication technology and application of glass-ceramics (mainly about SrO-Al_2O_3-SiO_2 system glass-ceramics) were systematically reviewed. The influence of heat treatment and composition on structure and properties of the SrO-Al_2O_3-SiO_2 system glass-ceramics were investigated by DTA, XRD and SEM. And relationships among composition, heat treatment, crystallization and properties were studied to attain some results about reasonable composition and heat treatments and high-performance glass-ceramic substrate.Firstly, the influence of SrO content on crystallization and properties of the glass-ceramics was investigated. The results showed that there was only the monocelsian phase existed in the glass-ceramics, with various SrO contents. And the flexure strength of the glass-ceramics increased firstly and then decreased, with the increasing of SrO content. thus, the higher strength and lower thermal expansion coefficient were obtained when the SrO content was 20%. At the same time, lower nucleation temperature and higher crystallization temperature in favor of the crystallization degree and mechanical and thermal properties of the glass-ceramics.Secondly, the influence of Al_2O_3 content on crystallization and properties of the glass-ceramics was studied. The results indicated formation of the monocelsian and the hexcelsian phase and transformation from the hexcelsian phase to the monocelsian phase in the glass-ceramics when the Al_2O_3 content was high. And when the Al_2O_3 + SrO content was 20% +20%, the micro-structure of glass-ceramics was compact and the thermal expansion coefficient was lower. Then when the content was 26%+20%,the glass-ceramics show higher flexure strength for its higher degree of crystallization.And then, the influence of heat treatment system on the flexure strength and the thermal expansion coefficient of SrO-Al_2O_3-SiO_2 system glass-ceramics was investigated. The better heat treatment system was obtained by the analysis of cross experiment to each factor of the heat treatment, containing the nucleation temperature 925℃, nucleation time 180 min;crystal temperature 1180℃, crystal time120 min. The important order of relevant factors is: nucleation temperature> nucleationtime>crystal temperaturOcrystal time. However, the influence of heat treatment system on the thermal expansion coefficient was slight.Finally, according to the above experiment, the proper composition of base glass was selected. When TiO2+ZrO2 content was constant, the influence of changing the content of TiO2 and/or ZrO2 based on the proper composition and various heat treatment temperatures on crystallization behavior and properties of the glass-ceramics was investigated. And the results demonstrated that the micro-structure of glass-ceramics would prone to compact and the thermal expansion coefficient lowered, used ZrCh for single nucleation agent;there were slight crystal and large mount of glass existed in the glass-ceramics, with higher thermal expansion coefficient, used TiO2 as single nucleation;the glass-ceramics with higher flexure strength and lower thermal expansion coefficient could be faBaicated by using ZrO2 +TiC>2 as complex nucleation agents and contents was 2 % +2 %…
Key words: Glass-ceramics; SrO-Al_2O_3-SiO_2; heat treatment; flexure strength; thermal expansion coefficient

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