| Recently, there have been many researches on architectural decorated glass-ceramic at home and abroad, and the main crystalline phase of that is -wollastonite. With the development of CAS glass-ceramic industry, there are some intractable problems in the industry process, such as transmogrification or burst. The emergence of these problems can deeply reduce the rate of finished products, thus affect the economic benefit of enterprises and the development of industrial technique. Otherwise, it brings the unsafe factors to the customers. Regarding to the causation, it's due to the structure stress and thermal stress existing in the glass-ceramic which is deserved to research. At present the domestic and foreign researches on this topic are not deep enough.Internal stresses have been studied more deeply in metal materials and its theory has developed relatively mature, while in inorganic non-metal materials it is comparatively laggardly. Furthermore, how to control and relax the internal stresses in order to reduce the destruction are necessary to study deeply in theory. Therefore, it is particularly important to test the stresses in glass-ceramics. Now the main means on testing stresses are polariscope, X ray diffraction stresses testing instrument , neutron diffraction stresses testing instrument ultrasonic stresses testing instrument and so on .In this paper, the structure and properties of the glass-ceramics were tested with X ray diffraction testing instrument, correlative software, and other modern testing means. Then we studied deeply and analyzed the effect of annealing heat-treatment on internal stresses in CaO-Al2O3-SiO2 glass-ceramics, explored the relative basic theory, and combined these results with practical production to guide the research, exploitation and application in congeneric materials.X-ray diffraction method on testing the internal stresses in CaO-Al2O3-SiO2 glass-ceramics was adopted in this paper. The means utilized the X radial incidence produced from cathode radial tube, and took the space between crystals as measurement of strain. When the stresses produced, the space between crystals changed and the diffraction peak moved during Bragg.diffraction. The magnitude of movement is related to the stresses. Thus we calculated the value of A20/Asin2after testing the 20,and got the according to the formula : ax=KA26/Asin2\j/(MPa). Where K was constant ,and equal to 0, 3, 6and 9. The test was carried out on the X-ray diffraction testing instrument named D/Max-IIIA produced from Rigaku Company of Japan.The results of testing show that internal stresses in glass-ceramics could be tested by X-ray diffraction. There were different magnitude of stresses in glass-ceramics after annealing at different temperature, and the stresses changed from compressive stress to tensile stress with the decrease of annealing temperature. Especially, there were both the tensile stress and compressive stress in glass-ceramics when the annealing temperature was at 850 C. Thus, we could suitably control the annealing heat-treatment to shorten the glass-ceramics producing period without changing the property of the glass-ceramics. For example, we could rapidly cool the glass-ceramics at the temperature above 850 C after crystallization.The author would like to thanks for the financial support by Nation Natural Science Foundation(50272043)... |
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