刚玉与其他添加剂对氧化硅陶瓷型芯的影响

发布时间：2018-03-09 01:33

  本文选题：氧化硅基陶瓷型芯　切入点：刚玉　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：陶瓷型芯的研究对高温空心叶片生产具有重要的参考价值。陶芯的综合性能包括强度、高温挠度、开气孔率、收缩率等,缺一不可,本课题针对目前实际生产中大型复杂硅基陶瓷型芯高温强度难以满足要求等问题进行研究。本文通过总结以往研究和应用成果,通过大量实验确定了型芯基本成分;同时通过对型芯抗弯强度、高温挠度、收缩率、开气孔率等性能的测量,通过微观组织观察和烧结相组成分析,研究了刚玉矿化剂,方石英和Na OH等添加剂对硅基陶瓷型芯综合性能的影响,最终得出较合理的陶瓷型芯成分和制造工艺参数。刚玉微粉的加入使陶芯室温抗弯强度有很大的提高,添加5%200目刚玉微粉的陶芯抗弯强度达18.614 MPa,强度提高约7.4 MPa,收缩率为1.364%,1550℃条件下高挠度值为1.833mm,综合性能良好。添加刚玉微粉的粒度配比需结合总体粉料的颗粒分布进行考虑,当添加刚玉微粉的含量为15%时,200目:400目:600目配比5:3:2的陶芯综合性能优于未配比的陶芯。相较于1200℃,终烧温度为1180℃陶芯性能较佳。方石英的加入对陶芯综合性能的有一定的改善作用。预加一定量的方石英有利于改善陶芯收缩率和高温性能,但加入量要合理控制。预加5%方石英用刚玉微粉陶芯的高温性能良好,挠度值降低为0.816mm(1550℃持温30min),收缩率降低0.306%,抗弯强度为14.162MPa。少量Na OH的加入对陶芯收缩性能影响明显,添加0.5%Na OH的陶芯,由于Na+破坏Si-O和Al-O,添加刚玉微粉中得到的Al3+变为玻璃网络变性离子,促进方石英的析出,使陶芯的收缩率减至0.45%,陶芯的尺寸精度良好,开气孔率升为0.356,脱芯更容易,1550℃条件下高温挠度值为1.25mm(1550℃持温30min),但Na+的引入量要严格控制,以保证良好的综合性能。
[Abstract]:The study of ceramic core has important reference value for the production of high temperature hollow blade. The comprehensive properties of ceramic core include strength, high temperature deflection, open porosity, shrinkage, etc. In this paper, the current production of large and complex silicon-based ceramic core is difficult to meet the requirements of high temperature strength. This paper summarizes the previous research and application results, through a large number of experiments to determine the basic components of the core; At the same time, corundum mineralizers were studied by measuring the bending strength, deflection at high temperature, shrinkage and porosity of the core, observing the microstructure and analyzing the phase composition of sintered corundum. The effects of additives such as cristobalite and NaOH on the comprehensive properties of silicon-based ceramic cores were obtained, and the reasonable composition of ceramic cores and manufacturing process parameters were obtained. The flexural strength of ceramic cores at room temperature was greatly improved by the addition of corundum micropowder. The flexural strength of ceramic core added 50 mesh corundum micro-powder is 18.614 MPa, the strength is increased about 7.4 MPA, the shrinkage ratio is 1.36440 鈩，

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