Two screen printing inks were developed for the low-temperature fabrication of printed and flexible thick film negative temperature coefficient thermistors able to operate at room temperature. The first of the two screen printing inks developed utilised cobalt ferrite (CoFe ₂ O ₄ ) as the temperature sensing material with the second ink incorporating manganese ferrite (MnFe ₂ O ₄ ). These were then screen printed onto lithographically printed silver interdigitated electrodes with a 200 µm track and gap using a synthetic paper (Teslin) as the substrate. The inks required a 10 min curing step at 80°C. Pre-annealing of the ferrite powders before ink formulation enabled the avoidance of high-temperature processing post-fabrication typically required in industrial thermistor production. The printed thermistors were tested at a controlled constant humidity between 15 and 50°C. Both materials demonstrated typical natural logarithmic responses with high linearity and sensitivity.

中文翻译：

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铁氧体基室温负温度系数印刷热敏电阻

开发了两种丝网印刷油墨，用于低温制造能够在室温下运行的印刷和柔性厚膜负温度系数热敏电阻。开发的两种丝网印刷油墨中的第一种使用钴铁氧体（CoFe ₂ O ₄ ）作为感温材料，而第二种油墨采用锰铁氧体（MnFe ₂ O _4） ）。然后使用合成纸（Teslin）作为基材，丝网印刷到具有200 µm轨迹和间隙的平版印刷银指状电极上。油墨需要在80°C下固化10分钟。在油墨配制之前对铁氧体粉末进行预退火可以避免工业热敏电阻生产中通常需要的高温加工后加工。印刷热敏电阻在15至50°C的恒定湿度下进行测试。两种材料均显示出典型的自然对数响应，具有很高的线性和灵敏度。