【作者】 郑勇；

【导师】 程金树；

【作者基本信息】 武汉理工大学 ， 材料学， 2006， 硕士

【摘要】 本课题以Li₂O-Al₂O₃-SiO₂系统微晶玻璃为研究对象,根据Li₂O-Al₂O₃-SiO₂系统三元相图设计了一组玻璃组成配方,并在基础组分不变的前提下,选择了La₂O₃等5种稀土氧化物采取外加法进行掺杂,利用熔融法制备出微晶玻璃。本文研究了稀土氧化物对Li₂O-Al₂O₃-SiO₂系统玻璃粘度和熔制温度的影响;以及掺杂La₂O₃对Li₂O-Al₂O₃-SiO₂系统微晶玻璃析晶、结构和性能的影响;并优化了掺杂La₂O₃后Li₂O-Al₂O₃-SiO₂系统微晶玻璃的热处理制度。 本实验应用高温粘度测试分析了玻璃液的高温粘度;应用差热分析（DTA）、X射线衍射分析（XRD）、扫描电镜分析（SEM）、红外光谱（IR）等测试手段分析了微晶玻璃的内部结构和形貌;应用热膨胀测试、抗折强度测试和可见光透过率测试分析了微晶玻璃的性能。 结果表明:La₂O₃等5种稀土氧化物都具有降低玻璃液粘度的作用,其中以La₂O₃的作用最大。少量La₂O₃的掺入对微晶玻璃的结构没有太大影响,La₂O₃并未进入玻璃网络成为网络形成体,而只是作为网络修饰体,使Si-O键长和Si-O-Si键角发生轻度的改变,从而降低玻璃液的粘度及熔制温度（1610℃）;同时,La₂O₃能够促进析晶,但对微晶玻璃的主晶相没有影响,仍为β—石英固熔体,随着La₂O₃的增加,微晶玻璃中的晶粒尺寸逐渐长大,微晶玻璃试样的热膨胀系数变大,抗折强度降低。通过重复实验,考虑到试样的综合性能,确定向LAS系统玻璃中外加入0.5mol%La₂O₃,并采用正交设计实验,确定了适合此组分微晶玻璃的热处理制度为590℃/1h→790℃/2h。更多还原

【Abstract】 In this thesis, the research object is Li₂O-Al₂O₃-SiO₂ system glass-ceramics. According Li₂O-Al₂O₃-SiO₂ system glass phase diagram, a set of compositions are designed, and without the change of compositions La₂O₃ and other 4 rare earth are doped in the compositions for extra ingredient, then the glass-ceramics is produced by fusion. The influence of doping with rare earth on the viscosity and the melting temperature is studied and the influence of doping with La₂O₃ on the crystallization、 the structure and the performance is studied;the heat treatment was optimized.In the experiment, the viscosity is studied by means of High Temperature Viscometer, the structure and the appearance are studied by means of DTA、 XRD、 SEM and IR and so on. The performances are studied by means of heat expansion testing、 intension testing and visible light transmission testing and so on.The results indicate that with La₂O₃ and other 4 rare earth addition, the viscosity decreases, especially doping with La₂O₃. With a small amount of La₂O₃ addition, the structure of the LAS system glass-ceramics doesn’t show obvious transformation. La₂O₃ doesn’t enter the network of glass, but to be the modifier of the network which changes the bond length of Si-0 and the bond angle of Si-O-Si slightly. Because of this, the viscosity、 the glass melting temperature（1610℃） decrease, also La₂O₃ can accelerate the crystallization, but there is no influence on the main crystal phase which is β-quartz, and with adding La₂O₃ the dimension of the crystal and heat expansion coefficient increase, intension performance becomes lower. By repetitive experiment, in order to achieve the integrated performance with 0.5mol% La₂O₃ addition is suitable, and the best heat treatment is 590℃/1h→790℃/2h.更多还原