News Release

Flexible temperature sensor with high sensitivity ranging from liquid nitrogen temperature to 1200℃

Peer-Reviewed Publication

International Journal of Extreme Manufacturing

Comparison of the temperature measurement range of different kinds of flexible thermocouple sensors. In this work, the prepared sensor has two temperature measurement ranges. Range-1 (-30℃~700℃): Achieve long-term temperature monitoring; Range-2 (-196℃~1200℃): Achieve short-time temperature detection.

image: The prepared flexible thermocouple temperature sensor aerogel blanket substrate has a good temperature measurement range, capable of long-term stable operation in the temperature range of -30℃~700℃ and instantaneous measurement in the temperature range of -196℃~1200℃. The prepared flexible temperature sensor has absolute temperature measurement advantages compared with other flexible temperature sensors of the same type. The flexible thermocouple temperature sensor not only inherits the advantages of the flexible sensor such as being attachable, conformable and easy to attach, but also overcomes the defects of the flexible sensor which is difficult to withstand high temperature. view more 

Credit: By Zhaojun Liu, Bian Tian, Zhuangde Jiang, Shuimin Li, Jiaming Lei, Zhongkai Zhang, Jiangjiang Liu, Peng Shi and Qijing Lin.

As an important physical parameter that characterizes the state and properties of an object, temperature plays a very important role in our production life. Flexible thin-film temperature sensors, with their advantages of being able to deform, easy to attach, thin and light, have received a lot of attention and research, and systematic research has been carried out in the areas of human body temperature measurement and daily temperature measurement. 

However, the existing flexible thin film temperature sensors are limited by the flexible substrate, temperature-sensitive materials and other restrictions, therefore, it is difficult to achieve the temperature measurement in the high-temperature field. Existing high-temperature temperature measurement means are limited by the large size of the device, the need to destroy the structure, destroy the airflow field, subject to environmental interference, etc., it is difficult to achieve nondestructive real-time temperature monitoring of the temperature field. Therefore, how to ensure the advantages of flexible thin-film sensors based on their application in high-temperature environments is worth our attention.

Recently, Professor Bian Tian, Zhuangde Jiang and his collaborative team from the Institute of Precision Engineering, School of Mechanical Engineering, Xi'an Jiaotong University have proposed a design concept of the flexible thermocouple temperature sensor based on aerogel felt substrate, using screen printing technology to prepare temperature sensors with indium oxide and indium tin oxide as temperature sensitive layers. Since aerogel mats with a wide temperature range are chosen as the flexible substrate for the temperature sensor, it is difficult to realize thin film deposition and functionalization by the conventional coating process due to its uneven surface and roughness. Therefore, in the fabrication of this flexible temperature sensor, a screen-printing technique was used to prepare a thick film to overcome the above difficulties. 

In practice, the organic binder is mixed with functional powder to complete the slurry configuration, and then the excess organic matter is removed from the film by using high-temperature heat treatment. At the same time, for different application surfaces, the curved surface of the film is prepared based on the advantages of deformable and conformable flexible materials. The prepared flexible temperature sensors can be attached to different curved surfaces, such as blades. It also has the advantages of being ultra-thin and ultra-light.

The team has conducted various laboratory and practical tests on the prepared flexible temperature sensors. These include real-time measurement of the temperature of the tail jet flame of a small turbine engine, transient monitoring of water vapor temperature during a physical explosion, real-time monitoring of the metal melting process in a crucible, etc. The sensors show great potential for applications in aerospace, steel metallurgy and other fields. The team also expects that the prepared flexible sensor can be further optimized to achieve temperature measurement on the surface of turbine blades, human skin and other large areas.

Professor Bian Tian, one of the lead researchers, commented: "It is surprising and gratifying to optimize the existing flexible temperature sensor and greatly increase the temperature range. But this work has just begun, and there are still many improvements and optimizations to be made in the stability and accuracy of temperature measurement."

Dr Zhaojun Liu is the first to transfer the existing preparation process method applied to conventional flexible temperature sensors to high-temperature flexible temperature sensors. For the actual flexible substrate and application environment, he optimized and improved the preparation process. He successfully realized the temperature detection of flexible temperature sensor under high-temperature load such as muffle furnace and high-power laser. This novel flexible temperature sensor makes a breakthrough from the traditional flexible sensor applications and opens the door to high-temperature field application scenarios.

Dr Jiangjiang Liu said: "This is a landmark achievement and it is just the beginning. On the basis of the successful design and preparation of flexible high-temperature sensor, it will provide a good reference for other kinds of flexible sensors, such as flexible pressure sensor and flexible thermal flow sensor, and hope to achieve the highly integrated design and preparation of high-temperature flexible sensor in the future."

About IJEM:

International Journal of Extreme Manufacturing (IF: 10.036) is a new multidisciplinary, double-anonymous peer-reviewed and fully open-access journal uniquely covering the areas related to extreme manufacturing. The journal is devoted to publishing original articles and reviews of the highest quality and impact in the areas related to extreme manufacturing, ranging from fundamentals to process, measurement and systems, as well as materials, structures and devices with extreme functionalities.

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