Thin Film Thermocouples Research Articles

The Feasibility and Performance of Thin-Film Thermocouples in Measuring Insulated Gate Bipolar Transistor Temperatures in New Energy Electric Drives

In the new energy electric drive system, the thermal stability of IGBT, a core power device, significantly impacts the system’s overall performance. Accurate IGBT temperature measurement is crucial, but traditional methods face limitations in IGBT’s compact working space. Thin-film thermocouples, with their thin and light features, offer a new solution. In this study, Ni 90% Cr 10% and Ni 97% Si 3% thin-film thermocouples were prepared on polyimide substrates via magnetron sputtering. After calibration, the Seebeck coefficient of the thin-film thermocouple temperature sensors reached 40.23 μV/°C, and the repeatability error stabilized at about 0.3% as the temperature rose, showing good stability. Researchers studied factors affecting IGBT temperature. Thin-film thermocouples can accurately monitor IGBT module surface temperature under different conditions. Compared to K-type wire thermocouples, they measure slightly higher temperatures. As the control signal’s switching frequency increases, IGBT temperature first rises then falls; as the duty cycle increases, the temperature keeps rising. This is consistent with RAC’s junction temperature prediction theory, validating the feasibility of thin-film thermocouples for IGBT chip temperature measurement. Thin-film thermocouples have great application potential in power device temperature measurement and may be a key research direction, supporting the optimization and upgrading of new energy electric drive systems.

Experimental research on mechanical performance of the lightweight composite slabs

Abstract The minimization of measurement errors holds paramount importance in bridging the gap between the measured values and the actual values of the data. Conventional sensor technologies have been constrained by their incapability to precisely capture real transient temperature variations with satisfactory precision. In the present study, the viability of multimodal sensors for enhancing measurement accuracy was investigated through static calibration experiments conducted on E-, K-, S-, and B-type thin film thermocouples. The findings reveal that the E-type film thermocouple exhibits the highest Seebeck coefficient, reaching up to 56.92 μV/°C, whereas the S-type film thermocouple demonstrates the lowest Seebeck coefficient, merely 10.0 μV/°C. Moreover, the E-type film thermocouple is associated with the largest repeatability error of 2.61%, while the K-type film thermocouple presents the smallest repeatability error of 1.26%. It can thus be inferred that multimodal sensors are characterized by a reduced measurement repeatability error, which is conducive to the improvement of measurement accuracy.

Research on NiCr/NiSi thin film thermocouple sensor for measuring the surface temperature of automobile engine

Research on NiCr/NiSi thin film thermocouple sensor for measuring the surface temperature of automobile engine

Accurate temperature measurement of new energy vehicle engine by using NiCr-NiSi thin film thermocouple

Accurate temperature measurement of new energy vehicle engine by using NiCr-NiSi thin film thermocouple

A Micro-Nodal Tungsten-Rhenium Thin-Film Thermocouple Based on Electrohydrodynamic Printing.

High-temperature thin-film thermocouples (TFTCs) have gained significant attention in the aerospace and energy industries due to their compact size and millisecond response time. Although previous studies have reduced the size of TFTCs to the millimeter scale, the heat flow field has continued to limit temperature measurement accuracy. To address this issue, this study used an electrohydrodynamic printing process to fabricate tungsten-rhenium TFTCs with a thickness at the micrometer scale. In the static test, the tungsten-rhenium TFTCs showed good performance with a measurement accuracy better than 1.2%, repeatability better than 0.99%, and a drift rate of 0.72%/h. In dynamic tests, the response time was 1.2 ms. Additionally, during flame gun heating tests, the response time and temperature measurement accuracy exceeded those of the standard thermocouple.

Research on Precise Temperature Monitoring and Thermal Management Optimization of Automobile Engines Based on High-Precision Thin-Film Thermocouple Technology.

Thin-film thermocouple is widely used in temperature measurement because of its high temperature measurement accuracy and small size. In order to calibrate the temperature accurately with thin-film thermocouple, NiCr/NiSi thin-film thermocouple was prepared by magnetron sputtering according to the Seebeck effect. Through static calibration experiments, the Seebeck coefficient of K-wire thermocouple was found to be 39.23 μV/°C, while that of the NiCr/NiSi thin-film thermocouple was 38.89 μV/°C. Further experiments showed a Seebeck coefficient of 39.092 μV/°C for the NiCr/NiSi thin-film thermocouple, which verifies that the prepared thin-film thermocouple has good consistency and repeatability. Through the temperature measurement experiment of automobile engines, the highest stable working temperature of the engine is 107.9 °C, which further verifies that the prepared NiCr/NiSi thin-film thermocouple can have a sensitive dynamic response to temperature and high temperature measurement accuracy. Finally, the causes of experimental errors, the application prospect and existing problems of thin-film thermocouples are analyzed.

High temperature resistant thin film thermocouple prepared based on inkjet printing

High temperature resistant thin film thermocouple prepared based on inkjet printing

A New Type of CuNi/TiB2 Thin-Film Thermocouple Fabricated by Magnetron Sputtering

A new CuNi/TiB2 thin-film thermocouple was fabricated using magnetron sputtering. A 400 nm thick CuNi interior layer was deposited on a dielectric substrate initiatory, and then covered by an 800 nm thick TiB2 layer. The tests revealed that the TiB2 layer had a dense and columnar cross-section. The measured hardness and elastic modulus of the TiB2 layer were ~20.5 and 315.9 GPa, respectively. No cracking or delamination occurred at the CuNi/TiB2 interface. The work functions of the TiB2 and the CuNi layers were calculated to be 4.406 and 4.726 eV, respectively. The difference in work functions between the TiB2 and the CuNi was ~0.3 eV. The CuNi/TiB2 thin-film sensor exhibited a high Seebeck coefficient of 38.07 μV/°C with excellent linearity. The maximum service temperature of the thin-film sensor was evaluated to be ~400 °C. A further increase in temperature degraded the Seebeck coefficient due to oxidation of the TiB2 layer.

Microsecond Dynamic Response Calibration of ITO Thin-Film Thermocouples under Laser and Detonation Conditions

Microsecond Dynamic Response Calibration of ITO Thin-Film Thermocouples under Laser and Detonation Conditions

Evaluating Thin-Film Thermocouple Performance on Additively Manufactured Turbine Airfoils

Abstract As gas turbine engine designs continue to target higher turbine entry temperatures for increased thermal efficiency, gas turbine manufacturers and operators require additional feedback from life-limited engine components. Moreover, additively manufactured (AM) hardware is becoming more prevalent in the engine development cycle to reduce component lead times and associated costs. Although additive manufacturing unlocks unique capabilities for sensor integration, the inherent roughness from additive surfaces poses unique challenges to the direct-write sensor installation processes. The current study addresses these realities by demonstrating sensor operation on additively manufactured vane hardware in a turbine research facility operating at scaled conditions. Thin-film thermocouples were deposited on fully-cooled AM turbine vanes and tested over a range of operating conditions in a one stage research turbine at Penn State University. The low-profile surface-mounted sensors were compared with traditional small-diameter embedded thermocouples in terms of calibration accuracy and durability. A comparison between traditional masked thermal spray and direct-write installation was also evaluated as part of the sensor integration strategy for the AM vanes. Ultimately, this study shows thin-film thermocouples on additively manufactured airfoils can operate reliably over an extended test campaign in rig-scaled conditions. Furthermore, the measurement accuracy of thin-film thermocouples demonstrated through this study is equivalent to traditional mineral-insulated thermocouple sensors showing the utility of these technologies for future turbine research and development applications.

A Study on the Effect of Cutting Temperature on CFRP Hole Wall Damage in Continuous Drilling Process

In the assembly process of aerospace parts, drilling is essential for carbon fiber-reinforced materials. However, due to the extreme thermal sensitivity of these composites, continuous drilling often leads to irreparable defects such as hole wall burns and exit delamination caused by concentrated cutting heat, resulting in the scrapping of parts. To address this issue, this paper explores the impact of temperature characteristics on drilling quality, providing guidance for optimizing the composite drilling process. A simulation model for single and continuous drilling was established to analyze the temperature distribution on the tool surface during drilling. A drilling temperature measurement system based on thin-film thermocouple technology was developed, enabling real-time online temperature monitoring. Continuous drilling experiments were conducted, analyzing the correlation between maximum drilling temperature and hole quality. Results show that temperatures from −25.75 °C to −9.75 °C and from 182 °C to 200.75 °C cause significant exit damage, while optimal hole quality is achieved between −1.25 °C and 168 °C.

Intelligent temperature measuring thermal spray multilayer thermal barrier coatings based on embedded thin film thermocouples

Intelligent temperature measuring thermal spray multilayer thermal barrier coatings based on embedded thin film thermocouples

Polynomial fitting calibration method for K-type thermo-couples based on the least squares method

Abstract Thin-film thermocouples, a crucial technology for accurate temperature measurement, have attracted considerable attention in energy utilization, environmental monitoring, and advanced manufacturing. This paper provides an overview of the evolution of thin-film thermocouples, with a focus on the calibration methods and experimental performance of K-type thermocouples. Utilizing a five-layer film structure that includes a polyimide substrate, aluminum oxide insulation layer, nickel-chromium and nickel-silicon metal films, and a silicon oxide protective layer, we have designed and implemented a new thin-film thermocouple temperature measurement system, which has been experimentally validated for stability and repeatability under high-temperature conditions. The results indicate that the system demonstrates excellent thermoelectric potential output and good repeatability in temperature measurement within the range of 50°C to 250°C. Although the long-term stability in extremely high-temperature environments requires further study, this research provides theoretical and experimental support for the future development of thin-film thermocouple technology.

Measurement and Analysis of Surface Temperature Gradients on Magnetron Sputtered Thin Film Growth Studied Using NiCr/NiSi Thin Film Thermocouples.

In the general analysis of thin-film growth processes, it is often assumed that the temperature of the film growth surface is the same as the temperature of the film growth substrate. However, a temperature gradient exists between the film growth surface and film growth substrate. Using the growth surface of TiO2 thin films as an example, the temperature gradient of the film growth surface is tested and analyzed. A NiCr/NiSi thin-film thermocouple is fabricated using the direct-current pulse magnetron sputtering method. A three-layer NiCr/NiSi thin-film thermocouple temperature measurement system is established to measure the temperature gradient of the film growth surface. The growth surface temperature and substrate temperature of the TiO2 thin films are measured. For a sputtering power density of 0.83W cm- 2, the temperature difference between the first and second layers is 104.79°C, while the temperature difference between the second and third layers is 39.92°C. A standard K-type thermocouple is used to measure the substrate temperature, which is recorded to be 132.05°C, consistent with common measurements of substrate temperature. The heat conduction on the film growth surface in the vacuum chamber is examined and a model for the temperature measurement device during film growth is constructed.

Design and fabrication of metal spherical conformal thin film multisensor for high-temperature environment

Design and fabrication of metal spherical conformal thin film multisensor for high-temperature environment

Sandwich probe temperature sensor based on In2O3-IZO thin film for ultra-high temperatures

High-temperature thin-film thermocouples (TFTCs) have attracted significant attention in the aerospace and steel metallurgy industry. However, previous studies on TFTCs have primarily focused on the two-dimensional planar-type, whose thermal sensitive area has to be perpendicular to the test environment, and therefore affects the thermal fluids pattern or loses accuracy. In order to address this problem, recent studies have developed three-dimensional probe-type TFTCs, which can be set parallel to the test environment. Nevertheless, the probe-type TFTCs are limited by their measurement threshold and poor stability at high temperatures. To address these issues, in this study, we propose a novel probe-type TFTC with a sandwich structure. The sensitive layer is compounded with indium oxide doped zinc oxide and fabricated using screen-printing technology. With the protection of sandwich structure on electrode film, the sensor demonstrates robust high-temperature stability, enabling continuous working at 1200 °C above 5 h with a low drift rate of 2.3 °C·h−1. This sensor exhibits a high repeatability of 99.3% when measuring a wide range of temperatures, which is beyond the most existing probe-type TFTCs reported in the literature. With its excellent high-temperature performance, this temperature sensor holds immense potentials for enhancing equipment safety in the aerospace engineering and ensuring product quality in the steel metallurgy industry.

Utilizing screen printing technology to fabricate tungsten-rhenium thick film thermocouples with a maximum temperature limit of 1600 °C

Utilizing screen printing technology to fabricate tungsten-rhenium thick film thermocouples with a maximum temperature limit of 1600 °C

3D-Printed Conformal Thin Film Thermocouple Arrays for Distributed High-Temperature Measurements

Conformal thin film sensing represents a cutting-edge technology capable of precisely measuring complex surface temperature fields under extreme conditions. However, fabricating high-temperature-resistant conformal thin film thermocouple arrays remains challenging. This study reports a method for manufacturing conformal thin film thermocouple arrays on metal spherical surfaces using a printable paste composed of silicates and Ag. Specifically, the use of silicate glass phases enhances the high-temperature performance of the silver printable paste, enabling the silver ink coatings to withstand temperatures up to 947 °C and survive over 25 h at 900 °C. The thermocouples, connected to Pt thin films, exhibited a Seebeck coefficient of approximately 17 μV/°C. As a proof of concept, an array of six Ag/Pt thin film thermocouples was successfully fabricated on a metal spherical surface. Compared to traditional wire-type thermocouples, the conformal thin film thermocouple arrays more accurately reflect temperature variations at different points on a spherical surface. The Ag/Pt conformal thin film thermocouple arrays hold promise for monitoring temperature fields in harsh environments, such as aerospace and nuclear energy applications.

High-temperature protection performance of Mg-doped Al2O3 protective layers on the thin film thermocouples

High-temperature protection performance of Mg-doped Al2O3 protective layers on the thin film thermocouples

Research on the improvement of the adhesion strength of the Cu films deposited on the Al2O3 films

Due to the significant discrepancy in the coefficient of linear thermal expansion between Cu and ceramic in T-type thin film thermocouples, the Cu thin films often exhibit a low adhesion strength with the ceramic layers (Al2O3). In order to improve the adhesion strength of the Cu with the Al2O3 films, several methods during preparation were studied. First, different thicknesses of the Cu thin films deposited at different deposition temperatures on the Al2O3 thin films prepared by the magnetron sputtering were studied. Second, the Ti/Ni buffer layer between the Cu and the Al2O3 thin films was prepared. Finally, the average roughness of Al2O3 was studied. The adhesion strength of the Cu with the Al2O3 thin films, the microstructure of the surface and the cross section of the Cu and the Al2O3 thin films, and the grain size and the roughness of the films are characterized by nanoscratch testing, scanning electron microscopy, and atomic force microscopy. The adhesion strength of the Cu films with the Al2O3 films increases with an increase in the thickness of the Cu thin films and the roughness of the Al2O3 thin films and the addition of the Ti/Ni buffer layers.