文档介绍：华中科技大学
硕士学位论文
多层片式PTC元件用细晶陶瓷的研究
姓名:张航航
申请学位级别:硕士
专业:微电子学与固体电子学
指导教师:龚树萍
20090526
华中科技大学硕士学位论文
摘要
随着科学技术的迅速发展,电子元元件的小型化、片式化已经成为趋势。 PTCR
热敏电阻也必须朝着多层、片式化的方向发展。要制备高性能的多层片式 PTC 元件,
首先需要制备得到晶粒尺寸 1-2µm 同时具有良好 PTC 性能的细晶陶瓷。本文主要围
绕着减小 PTC 陶瓷的晶粒尺寸同时尽可能降低瓷体电阻率开展研究工作。
本研究以水热法粉体和固相法粉体为原料,研究施受主掺杂、预烧温度、烧结温
度等因素与陶瓷晶粒尺寸的关系。通过调整施受主掺杂浓度,提高预烧温度,降低烧
结温度,添加玻璃相等方法减小陶瓷的晶粒尺寸。流延法是一种陶瓷成型方法,它具
有可连续操作、生产效率高、适合大规模生产的优点。为了更贴近多层片式 PTC 元件
制备的实际需要,在压制成型材料组分研究的基础上,本文对流延法成型制备 PTC 细
晶陶瓷进行了研究。
采用水热法粉体作为原料制备的陶瓷半导化良好,升阻比在 104 以上。其平均晶
粒尺寸为 2-5µ。由于水热法粉体存在钡钛比失衡,杂质较多的缺点。实验结果表明进
一步减小其晶粒尺寸具有很大的难度。
固相法工艺成熟,应用广泛,很适合大规模的工业化生产。用固相法粉体作为原
料,通过调整施受主掺杂、烧成温度等方法在 1300℃烧结得到平均晶粒尺寸 2µm 的
样品,其室温电阻率为 ·cm,升阻比为。以固相法 BaTiO3 粉体为原料,
采用流延法制备了生坯。生坯在 1300℃烧成,陶瓷平均晶粒尺寸 1-2µm,电阻率为
·cm,升阻比为。
关键词:PTC 细晶固相法水热法有机流延
I
华中科技大学硕士学位论文
ABSTRACT
PTCR thermistor must develop towards multilayer and chip type, low room
temperature resistance to meet miniaturization, chip type, low loss of electronic device. To
prepare high-performance multilayer PTCR, there is one key points: preparing fine-grained
ceramic to ensure strong PTC effect and the decrease of grain size. This paper mainly
studied on preparing of fine-grained ceramic powder and forming of chip PTCR ceramic.
This research use ceramic powder prepared by solid phase method and hydrothermal
method as raw material. The influence of content of donor element, content of acceptor
element, presintering temperature and sintering temperature on grain size were studied. The
grain size was decreased by increase the content of donor, heighten the presintering
temperature and lower the sintering temperature.
PTCR ceramic with raw materials synthesized by hydrothermal method which was
sintered at 1300℃ has a low room temperature resistivity and the average grain size is 2-
5µm. The grain size couldn’t decrease more by any method because the raw materials
synthesized by hydrothermal method contain many Impurities.
Solid