(华中科技大学 电子科学与技术系， 武汉 430074)
摘 要: 研究了用注凝成型工艺制备片式PTCR热敏陶瓷。 采用PMAA-NH4为分散剂， 丙三醇为增塑剂， 并加入适量的有机单体AM制备了高固相含量、 低粘度的BaTiO3半导瓷浆料， 研究了浆料粘度及坯体的性能与浆料固相体积分数、 有机单体含量及增塑剂含量之间的关系。 研究表明： 浆料固相体积分数对坯体的干燥及烧结行为有较大影响， 当浆料固相体积分数在45%以上时， 可有效避免制品干燥和烧结过程中收缩过大而产生的变形开裂缺陷； 当有机单体的质量分数为2％~4%， 丙三醇的体积分数为3％~6%时， 可获得有一定强度和柔韧性的生坯； 研究了注凝成型PTCR陶瓷的微观结构及陶瓷元件的PTCR性能， 成功地制备了层数为5、 室温电阻为0.8 Ω、 电阻温度系数为13.40%/℃、 升阻比大于105的多层片式PTCR元件。
关键字: 片式PTCR； 叠层结构； 注凝成型； 固相体积分数； 粘度
（ Department of Electronic Science and Technology,
Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract: Gelcasting was used for the fabrication of chip PTCR thermistors. BaTiO3-based ceramic slurries with high solid loading and low viscosity were prepared by using ammonium salt of poly (methacrylic acid) (PMAA-NH4) as a dispersant, glycerol as plasticizer and adding some monomers. The influence of solids loading, content of monomers and plasticizer on the viscosity of slurry and the physical characterization of green sheets was investigated. The results show that increasing the solids loading of slurry up to 45% allows minimizing deformation of green sheets during drying and sintering process effectively. When the content of monomers in shurry is 2%-4%(mass fraction), and the content of plasticizer in shurry is 3%-6%(mass fraction), green sheets with good strength and flexibility are obtained. The microstructures and the electric characteristics of PTCR chip thermistors were investigated. A five-layer chip PTCR thermistor with room resistance of 0.8 Ω, temperature coefficient of resistance of 13.40%/℃, and ratio of maximum to minimum of resistance larger than 105 is successfully fabricated.
Key words: PTCR chip thermistors; multilayered structure; gelcasting; solids loading; viscosity
