【作者】 黄川；

【导师】 龚树萍；

【作者基本信息】 华中科技大学 ， 微电子学与固体电子学， 2006， 硕士

【摘要】 注凝成型是陶瓷成型方法中的一种,它是将传统的陶瓷工艺与聚合物化学结合起来的一种新型的湿法成型技术。它是一种较为新颖的近净尺寸原位凝固成型技术,可制作高质量、形状复杂的部件。论文围绕制备多层片式PTCR元件这条主线,从生坯的成型到样品的烧成再进行叠层。通过运用注凝成型和液体干燥剂法来进行电极玻璃釉粘结法的多层片式PTCR的前期单片制备,并从多层片式PTCR的前景进行分析,提出了有关共烧法的一些建议。围绕这些建议,也进行了一定的实验和论述。论文详细介绍了注凝成型BaTiO3基PTCR陶瓷生坯的工艺流程,包括浆料的制备、注凝成型、脱模后干燥和样品的烧成等。重点强调了使用液体干燥剂法干燥湿坯的优点,并选用聚乙二醇作为湿坯的液体干燥剂,具体研究了浆料的固相含量、干燥剂的浓度以及湿坯的尺寸和形状与干燥速率之间的关系,并与传统的干燥法进行比较,得出了有用的结论。初步探讨了PTCR的片式叠层技术,并成功地运用电极玻璃釉粘结法制备出了室温电阻为4.34 ?,居里温度为69.2℃,温度系数α为9.76 %/℃,升阻比β为1.419×105的三片叠层体,其尺寸为9.52 mm×7.56 mm×1.90 mm。尝试性地从另一条工艺路线出发,利用水热法制备出了掺杂BaTiO3超细粉体,晶粒粒径可达28.9 nm。并讨论了Ba/Ti摩尔比、反应温度、反应时间以及矿化剂KOH的量与合成的BaTiO3超细粉体性能之间的关系。更多还原

【Abstract】 Gelcasting has been a novel colloidal forming method for integrating polymer chemistry into conventional ceramic technology. The forming method of ceramics is the most prospective method in making the near net shape and complicated ceramics.This paper introduced the process of producing the multilayer PTCR, including the forming of green body, sintering of sample and the lamination process of ceramic chip. Analyzing the foreground of multilayer PTCR, we put forward some advice about co-fire processing. In allusion to the advice, we carried out certain experiment and discussion.This paper mainly introduced the fundamental principle and technological process of gelcasting PTCR based on BaTiO3, including the preparation of slurry, the forming of green body, drying method and the sintering of sample. The advantage of using liquid desiccant was emphasized. We chose poly glycol as liquid desiccant, and investigated affect factors which influenced the drying rate, such as loading level of ceramic slurry, concentration of liquid desiccant and geometry of green body. We studied on modeling of liquid desiccant drying method for gelcasting ceramic green bodies, and compared with conventional drying methods.We discussed on forming technology of multilayer PTCR, and succeeded in fabricating multilayer thermistor based on BaTiO3 with high properties. The characteristic parameters are as follows: the number of layers: 3, size: 9.52 mm×7.56 mm×1.90 mm, room resistance: R25=4.34 ?, resistance rising rate:β=1.419E+5, temperature coefficient:α=9.76 %/℃.We attempted to prepare doped BaTiO3 ultra fine powders by hydrothermal method, in order to fabricate multilayer PTCR using Doctor Blade Method(DBM). The grain size can be 28.9 nm. We discussed on the affect factors which affected properties of BaTiO3 powder, such as Ba/Ti mol ratio, reaction temperature, reaction time and the amount of mineralizer KOH.更多还原