注浆成形法制备熔融石英陶瓷的研究

发布时间：2018-03-06 16:24

本文选题：石英陶瓷　切入点：注浆成形　出处：《华南理工大学》2010年硕士论文　论文类型：学位论文

【摘要】： 太阳能作为开发前景最好的绿色能源被世界各国重视和大力推广,导致用于太阳能转换的多晶硅的用量急剧增加。石英陶瓷由于不会与硅发生化学反应,且具备低热膨胀系数、低热导率和优异的热稳定性而被应用于生产多晶硅的坩埚,为了适应多晶硅片的规格不断增大的需求,石英陶瓷坩埚的尺寸必须随之增大,从而对石英陶瓷的制造技术提出了更高的要求。注浆成形是石英陶瓷坩埚常用的成形方法之一,具有低成本和低污染等优点。但是生坯强度低制约了大尺寸石英陶瓷坩埚的发展。本文研究了球磨、pH值、分散剂和固相含量对石英陶瓷浆体的影响,通过优化工艺参数,制备出适合注浆成形的高固含量和低粘度的稳定石英浆体。并且通过二次加料球磨,调整浆料的颗粒级配提高石英陶瓷生坯强度。研究表明,采用乳酸为分散剂,其加入量为0.1-0.5 wt%,熔融石英固含量为63 vol%时,以一定颗粒级配的玛瑙球为研磨介质球磨5 h后,再搅拌24 h,制备的石英浆体粘度为114mPa.S,符合注浆成形的要求。通过调整浆体的颗粒级配,使颗粒之间能够形成有效紧密堆积,是非常有效提高坯体强度的方法。本课题通过混合两种不同粒径的石英颗粒来调整颗粒分布,粗细颗粒中位径比为8.3,当粗细颗粒混合比为80:20时,体系达到最紧密堆积,生坯强度提高1倍,解决了注浆成形生坯强度低的问题。同时研究也发现Funk-Dinger理想颗粒函数能够很好地反映颗粒间的堆积紧密程度。此外,本研究发现搅拌有利于降低浆体粘度,这与搅拌能够促进颗粒表面电位的生成有关。并且同时提出了乳酸稳定石英浆体的机理,红外光谱分析表明二氧化硅颗粒表面存在一定量的羟基,石英浆体对乳酸的吸附是由于氢键的作用,颗粒表面的羟基与乳酸分子中羧基中的氢离子形成氢键,从而吸附乳酸分子在二氧化硅颗粒表面周围,乳酸的另一端分子链之间产生的空间位阻作用使石英浆体稳定。
[Abstract]:Solar energy, as the most promising green energy, has been paid more attention to and popularized all over the world, resulting in a sharp increase in the amount of polysilicon used for solar energy conversion. Quartz ceramics have low thermal expansion coefficient because they do not react with silicon. Low thermal conductivity and excellent thermal stability are used to produce polysilicon crucible. In order to meet the increasing size of polysilicon wafer, the size of quartz ceramic crucible must be increased. Therefore, a higher requirement is put forward for the manufacture technology of quartz ceramics. Slurry forming is one of the common forming methods for quartz ceramic crucible, which has the advantages of low cost and low pollution. However, low green strength restricts the development of large size quartz ceramic crucible. The effect of dispersant and solid content on quartz ceramic slurry was studied. Stable quartz slurry with high solid content and low viscosity was prepared by optimizing process parameters. Adjust the particle gradation of slurry to improve the strength of quartz ceramic blank. The results showed that when lactic acid was used as dispersant, the amount of lactic acid was 0.1-0.5 wt and the content of fused quartz was 63 volg%, agate ball with certain particle size was used as grinding medium for 5 h. After stirring for 24 h, the viscosity of the prepared quartz paste is 114 MPA. The viscosity of the slurry meets the requirements of grouting forming. By adjusting the particle gradation of the slurry, it is possible to form an effective tight packing between the particles. It is a very effective method to improve the strength of the billet. In this paper, the particle distribution is adjusted by mixing two kinds of quartz particles of different sizes. The median diameter ratio of the coarse and fine particles is 8.3, and when the mixing ratio of the coarse and fine particles is 80: 20, the system achieves the closest stacking. The strength of green billet is increased by 1 times, which solves the problem of low strength of blank formed by grouting. It is also found that the ideal particle function of Funk-Dinger can well reflect the compactness between particles. In addition, it is found that stirring can reduce the viscosity of slurry, which is related to the formation of potential on the surface of particles, and the mechanism of stabilizing quartz paste with lactic acid is also proposed. Infrared spectrum analysis shows that there is a certain amount of hydroxyl groups on the surface of silica particles. The adsorption of lactic acid by quartz paste is due to the action of hydrogen bonds. The hydroxyl groups on the surface of silica particles form hydrogen bonds with hydrogen ions in the carboxyl groups of lactic acid molecules. Thus the adsorption of lactic acid molecules around the surface of silica particles, the other end of the molecular chain of lactic acid between the formation of steric blocking action to stabilize the quartz slurry.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TQ174

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