Thin film thermocouples (TFTCs) are known for their wide temperature measurement range and high precision, showing significant potential in aerospace and steel metallurgy applications. The lack of effective manufacturing techniques has been a major barrier to their mass production. Inkjet printing, a high-quality thin film additive manufacturing process operating outside vacuum environments, offers a viable solution for large-scale practical applications of TFTCs. We successfully fabricated ITO/In2O3 high-temperature thin film thermocouples on ceramic substrates using inkjet printing technology. We developed a printable ink with excellent fluid characteristics, suitable for constructing the sensitive layer of the thermocouples. The fabricated sensors exhibited outstanding high-temperature stability and reliability, with a maximum measurement temperature exceeding 800 degrees C, surpassing the upper limits reported in other inkjet-printed temperature sensors. Continuous operation at 800 degrees C for 8 h resulted in a low drift rate of 1.53 degrees C/h. The sensors demonstrated 98.55 % high repeatability and 98.7%FS high accuracy across a wide temperature range, with a maximum Seebeck coefficient reaching 111 mu V/ degrees C, superior to most other high-temperature thin film sensors reported in literature. These findings show great potential in enhancing the safety of aerospace engineering equipment and ensuring the quality of products in the steel metallurgy industry.

Traditional thermocouples face challenges in meeting the temperature measurement requirements of crucial aero-engine components, such as low interference, high temperature resistance, quick response, and in-situ measurement. The temperature measurement requirements mentioned above can be satisfied by thin film thermocouples, thanks to advancements in thin-film preparation technology. In this study, the indium oxide (In2O3) was calculated using first principle calculation both before and after doping. It was found that doping Aluminium oxide (Al2O3) can increase the Seebeck coefficient of In2O3. Solid-phase sintering was used to create aluminum oxide-doped In2O3 nanopowders, and thin film thermocouples were fabricated using screen printing. The thermoelectric characteristics of thin film thermocouples were studied to analyze the effects of different annealing procedures and doping concentrations. The optimal annealing process was determined to be at 1300 °C for 1 hour, and the ideal doping ratio was found to be Al0.1In2O3.15. The indium oxide film doped with aluminum oxide exhibits a Seebeck coefficient that is 45.9% higher than that of the undoped indium oxide film. The thin film thermocouples underwent tests for impact and vibration resistance, laser pulse response, surface and cross-section morphology, X-ray diffraction, and thermoelectric output. It has been confirmed that doping indium oxide with aluminum oxide can increase a material's Seebeck coefficient. Additionally, a thin-film temperature sensor that has been prepared can be used in challenging conditions to meet the temperature measurement requirements of an aero engine.

Thin-film thermocouples (TFTC) have been extensively studied for their wide range of applications in various environments. However, TFTC faces challenges in electromagnetic environments as they can generate AC interference voltage. In this study, we introduce a thermocouple temperature sensor shielded by silver (Ag) thin film on both sides of aluminum oxide (Al2O3) substrate. The high conductivity of Ag film (11.48 m Omega/square) helps reduce interference caused by alternating current, resulting in a superior electromagnetic shielding effectiveness of 43.68 dB. The temperature sensitivity coefficient of this sensor is 20.87 mu V/degrees C at a hot end temperature of 318.44 degree celsius. These shielded TFTC temperature sensors show great potential for applications in aerospace, iron and steel metallurgy, and other industries.

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 degrees C above 5 h with a low drift rate of 2.3 degrees Ch(-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.

With the growing demand for thermal management of electronic devices, cooling of high-precision instruments, and biological cryopreservation, heat flux measurement of complex surfaces and at ultralow temperatures has become highly imperative. However, current heat flux sensors (HFSs) are commonly used in high-temperature scenarios and have problems when applied in low-temperature conditions, such as low sensitivity and embrittlement. In this study, we developed a flexible and highly sensitive HFS that can operate at ultralow to high temperatures, ranging from −196 °C to 273 °C. The sensitivities of HFSs with thicknesses of 0.2 mm and 0.3 mm, which are efficiently manufactured by the screen-printing method, reach 11.21 μV/(W/m 2 ) and 13.43 μV/(W/m 2 ), respectively. The experimental results show that there is a less than 3% resistance change from bending to stretching. Additionally, the HFS can measure heat flux in both exothermic and absorptive cases and can measure heat flux up to 25 kW/m 2 . Additionally, we demonstrate the application of the HFS to the measurement of minuscule heat flux, such as heat dissipation of human skin and cold water. This technology is expected to be used in heat flux measurements at ultralow temperatures or on complex surfaces, which has great importance in the superconductor and cryobiology field.

Flexible temperature sensors have been extensively investigated due to their prospect of wide application in various flexible electronic products. However, most of the current flexible temperature sensors only work well in a narrow temperature range, with their application at high or low temperatures still being a big challenge. This work proposes a flexible thermocouple temperature sensor based on aerogel blanket substrate, the temperature-sensitive layer of which uses the screen-printing technology to prepare indium oxide and indium tin oxide. It has good temperature sensitivity, with the test sensitivity reaching 226.7 μ V °C ^−1 . Most importantly, it can work in a wide temperature range, from extremely low temperatures down to liquid nitrogen temperature to high temperatures up to 1200 °C, which is difficult to be achieved by other existing flexible temperature sensors. This temperature sensor has huge application potential in biomedicine, aerospace and other fields.

For the large amount of waste heat wasted in daily life and industrial production, we propose a new type of flexible thermoelectric generators (F-TEGs) which can be used as a large area bionic skin to achieve energy harvesting of thermal energy. With reference to biological structures such as pinecone, succulent, and feathers, we have designed and fabricated a biomimetic flexible TEG that can be applied in a wide temperature range which has the highest temperature energy harvesting capability currently. The laminated free structure of the bionic F-TEG dramatically increases the efficiency and density of energy harvesting. The F-TEGs (single TEG only 101.2 mg in weight), without an additional heat sink, demonstrates the highest output voltage density of 286.1 mV/cm 2 and the maximum power density is 66.5 mW/m 2 at a temperature difference of nearly 1000 °C. The flexible characteristics of F-TEGs make it possible to collect the diffused thermal energy by flexible attachment to the outer walls of high-temperature pipes and vessels of different diameters and shapes. This work shows a new design and application concept for flexible thermal energy collectors, which fills the gap of flexible energy harvesting in high-temperature environment.

The application environment and scenarios of flexible sensors are limited by the low temperature tolerance of the flexible substrate and the lack of protection of the sensitive layer surface. A flexible alumina-silicon oxide composite nanofiber mat (Al2SiO5) with high-temperature resistance is obtained based on electrospinning technique. The maximum tensile strength of the nanofiber mat reach 3.09 MPa and the maximum withstanding temperature exceeds 973 ?through parameter optimization. The patterned functional thin films are successfully prepared on the flexible Al2SiO5 nanofiber mat by using magnetron sputtering technology, vacuum vapor deposition technology and ink jet printing technology and other coating processes. Meanwhile, the process characteristics of the nanofiber mat prepared by electrospinning technique are fully utilized to realize flexible packaging of the high-temperature flexible sensors. Multifunctional nanofiber mats prepared based on electrospinning have great prospects for future applications in the field of flexible sensors.

In order to avoid the instability flutter of aero-engine blade and prevent the failure of thin film thermocouple caused by the blade in complex environment, the structural strength of the thermocouple on the actual blade surface was studied in this paper. Firstly, based on the 3D scanning of the real blade, the blade model is established after the point cloud graphics. The surface thermocouple model of the blade is established in Solidworks for simulation, and the modal and harmonic response analysis of the blade is simulated. Secondly, the vibration of the curved thin film thermocouple and the stress distribution of the blade under the acceleration shock were studied in Comsol, and the failure weakness was analyzed to avoid the failure of the thin film thermocouple caused by the bending, fracture or shedding of the thin film thermocouple on the blade due to vibration and shock, providing the most suitable thermocouple selection for the engine blade.

In this study, thin-film thermocouples (TFTCs) were combined with a smart bolt to design a smart bolt that can directly test high temperature in service monitoring and parameter calculation for gas turbine structure design. The first-principles calculation was used to analyze the design of the surface properties of nickel-based alloys and insulating layers, and finite element analysis was used to optimize dimension parameters by controlling the thermal stress matching of insulating layers and sensitive layers. The effect of the glass powder with different particle sizes on the microstructure of the ITO and In2O3 films was studied via SEM. The preferred particle size of the additive glass powder is 400 nm. The XRD pattern shows the (222) peak has the highest intensity. The intensities of the (222) and (622) peaks increase after the heat treatment. The calibration results show that the average Seebeck coefficient of the TFTCs can reach 64.9 μV/°C at 1100 °C with a maximum voltage of 71.4 mV. The repeatability error of the cycles of the sensor after heat treatment is ±1.05%. The repeatability of the sensor is up to 98.95%. The smart bolts were tested for application in small aero engines. It can be seen that under the impact of 1000 °C, the thermal response of the prepared smart bolt is better than that of the K-type armored thermocouple, and the thermal balance is achieved faster. The intelligent bolt sensor proposed in this work has better engineering application prospects owing to its convenience of installation in harsh environments.

The design, fabrication, testing and implementation of a new high-performance tungsten-rhenium thin film thermocouple are introduced. In this paper, tungsten-rhenium TFTCs are taken as the research object, after simulation analysis in COMSOL software and design, it is made by screen-printing technology and magnetron sputtering. This kind of thin film thermocouple primarily utilizes two kinds of electrode materials with varying composition combination, mainly tungsten with 5% rhenium and tungsten with 26% rhenium. Furthermore, high-temperature annealing is performed to maintain the mechanical properties and thus improve thermoelectric performance. The results demonstrate that the performance is reliable in the temperature range of 150-600 C° with a repeatability of 2.02%, providing application value for high-temperature in-situ sensing.

Owing to the low flow field disturbances and fast response, thin-film thermocouples (TFTCs) are used to measure the service temperature of aero-engines. Indium tin oxide (ITO) and In2O3 are widely used in high-temperature measurements. However, ITO undergoes phase transition and consequent thermoelectric failure at above 1300 degrees C. In this study, In1.35ZnO2.11/In2O3 TFTCs were prepared on alumina substrates via screen printing method through introduction of ZnO nanopowder followed by annealing treatment. Results show that prepared TFTCs exhibited good thermoelectric properties at 1500 degrees C. The morphology, structure, and electrical coefficients of TFTCs were investigated. The average Seebeck coefficient was 39.8 mu V/degrees C at 1500 degrees C with a drift rate (DT) of 0.84 degrees C/h, which was significantly improved with respect to that of ITO/In2O3, corresponding to 44.5 mu V/degrees C at 1270 degrees C with a DT of 5.44 degrees C/h and failed at higher temperature. The result of lumped capacity method test show that the response time was 4.8 ms at 100 degrees C. Preliminary engine gas temperature measurements with a heat load of 1000 degrees C at 1 Mach show that these TFTCs are promising candidates for engineering applications. Finally, the structural reliability under high-magnitude vibration and impact tests (10-2000 Hz/20 g and 100 g/(-)(1) ms) was also investigated. As a result of the excellent bonding strengths of 47.36 and 59.83 N between the film and the substrate for both In1. 35ZnO2.11 and In2O3, respectively, destructive cracking and peeling of the film were not observed, and no change in the Seebeck coefficient of the sample occurred after impact and vibration tests. These results provide an important basis for the potential application of In1.35ZnO2.11/In2O3 TFTCs in aero-engine high-temperature measurements of flow channel components.

In this study, a tungsten–rhenium thin-film thermocouples (TFTCs) is fabricated via magnetron sputtering on silicon carbide ceramics. Cuboid TFTCs probe is sealed with stainless steel shell to make the TFTCs probe sensor. This sensor has an average Seebeck coefficient of 27.2 µV °C −1 at 1167 °C (temperature difference). The thermal volatilization characteristics, electromotive force behavior, and response time of this tungsten–rhenium TFTC sensor are investigated. The real engine experimental results show that the TFTCs probe sensor can work normally under the high temperature and high-speed air flow environment of 4 Mach and 900 °C. In addition, the correlation between the response speed, substrate thickness, and film thickness is discussed based on simulations of the response to carbon dioxide laser pulses. As indicated by the dynamic experiment results, the laser response time is from 0.49 to 1.51 ms, which is much shorter than that of traditional armored C-type thermocouples (for tungsten–rhenium thermocouples, the response time is around 1 s). Tungsten–rhenium TFTCs probe sensor is a suitable alternative to conventional thermocouples to meet the requirements of measuring high temperatures with a quick response.

Thin-Film Thermocouples (TFTCs) are characterized by their high spatial resolutions, low cost, high efficiency and low interference on the air flow. However, the thermal stability of TFTCs should be further improved for application since their accuracy is influenced by joule heat and temperature time drift. In this paper, 3D molecular dynamics and finite element analysis are used for structural design. The effects of RF magnetron sputtering power and gas flow rate on conductivity and temperature time drift rate (DT) of high thermal stability tungsten–rhenium (95% W/5% Re vs. 74% W/26% Re) TFTCs were analyzed. According to the experimental results, the average Seebeck coefficient reached 31.1 µV/°C at 900 °C temperature difference (hot junction 1040 °C) with a repeatability error at ±1.37% in 33 h. The conductivity is 17.1 S/m, which is approximately 15.2 times larger than the compared tungsten-rhenium sample we presented, and the DT is 0.92 °C/h (1040 °C for 5 h), which is 9.5% of the old type we presented and 4.5% of compared ITO sample. The lumped capacity method test shows that the response time is 11.5 ms at 300 °C. This indicated an important significance in real-time temperature measurement for narrow spaces, such as the aero-engine combustion chamber.

To meet the need for micro-volume devices for high-precision measurement of temperature, Cu-Constantan (CuNi45) thin films with a novel array structure of thermo-electrodes were designed and fabricated. The thermo-electrodes on the probe-type substrate were deposited by magnetron sputtering technology and the profiling mask was prepared by 3D printing technology. The comprehensive performance of the temperature sensor was improved by systematic optimization of the heat treatment process and accuracy correction algorithm. Results showed that the sensor can measure with an accuracy of up to ±0.19%FS from −60 °C to 200 °C. The three-dimensional probe array temperature sensor shows great advantages in sensitivity, reliability resolution, stability, and measurement accuracy.

Accurate temperature measurements can efficiently solve numerous critical problems and provide key information. Herein, a flexible micro-three-dimensional sensor, with a combination of platinum and indium oxide to form thermocouples, is designed and fabricated by a microfabrication process to achieve in situ real-time temperature measurements. The stability and reliability of the sensor are greatly improved by optimizing the process parameters, structural design, and preparation methods. A novel micro-three-dimensional structure with better malleability is designed, which also takes advantage of the fast response of a two-dimensional thin film. The as-obtained flexible temperature sensor with excellent stability and reliability is expected to greatly contribute to the development of essential components in various emerging research fields, including bio-robot and healthcare systems. The model of the application sensor in a mask is further proposed and designed to realize the collection of health information, reducing the number of deaths caused by the lack of timely detection and treatment of patients.

A tungsten-rhenium (W-Re) thin film thermocouples (TFTCs) temperature sensor for ultra-high temperature detection is proposed to solve the problem of turbine inlet temperature measurement. The TFTCs is composed of silicon carbide (SiC) substrate, aluminium nitride (AlN) transition layer and W-Re3/W-Re25 alloy thermoelectric layer with a stacking structure. The thermoelectric characteristics and thermomechanical stability of the designed multi-layer heterogeneous films are simulated with the finite element simulation software. Combined with magnetron sputtering technology, the designed TFTCs is prepared and tested through the self-built calibration platform. The result shows that the fabricated TFTCs has excellent linearity and repeatability and can meet the requirements of stable, reliable and rapid response high temperature measurement.

In this work, indium tin oxide (ITO)/indium oxide (In2O3) thin film thermocouples (TFTCs) were prepared based on screen printing technology for high temperature measurement. With terpilenol as solvent, epoxy resin and polyether amine as binders and glass powders as additives, the ITO and In2O3 slurries were printed onto the Al2O3 substrate to form thermocouples. The effect on thermoelectric properties of the TFTCs with heat treatment and different contents of additives was investigated through microstructure observation and thermal cycle test. The static calibration experiment shows that the annealed TFTCs with 7.5 wt. % glass powders additives have the maximum Seebeck coefficient. The thermoelectric voltage output of the TFTCs can reach 126.5 mV at 1275 °C while the temperature difference is 1160 °C and the sensitivity of the TFTCs was 109.1 µV/°C. The drift rate of the TFTCs was 8.34 °C/h at a measuring time of 20 min at 1275 °C. The TFTCs prepared via screen printing technology with excellent thermoelectric properties and thermal stability are aimed to be a viable replacement for practical applications.

In the present study, a high-performance n-type temperature sensor was developed by a new and facile synthesis approach, which could apply to ambient temperature applications. As impacted by the low sintering temperature of flexible polyimide substrates, a screen printing technology-based method to prepare thermoelectric materials and a low-temperature heat treatment process applying to polymer substrates were proposed and achieved. By regulating the preparation parameters of the high-performance n-type indium oxide material, the optimal proportioning method and the post-treatment process method were developed. The sensors based on thermoelectric effects exhibited a sensitivity of 162.5 μV/°C, as well as a wide range of temperature measurement from ambient temperature to 223.6 °C. Furthermore, it is expected to conduct temperature monitoring in different scenarios through a sensor prepared in masks and mechanical hands, laying a foundation for the large-scale manufacturing and widespread application of flexible electronic skin and devices.

An eccentric reflective optical fiber micro-electro-mechanical system (MEMS) micro-pressure sensor is proposed in this paper. The core part of the sensor consists of a dual fiber collimator (a fiber collimator with two pigtails) in an eccentric position and a sensitive silicon diaphragm. The sensitive silicon diaphragm adopts the BM (beam-membrane) structure with small structural parameters manufactured by MEMS manufacturing technology. Simulation results show that the BM structure has good sensitivity and high natural frequency. Overall structure of the sensor with the measurement range of 0 similar to 10 kPa is designed. The way of intensity demodulation ensures the performance and stability of the sensor and makes the sensing system easier to process signals. By building a static test platform and conducting experiments, we can conclude that the sensitivity of the sensor is -0.32 dB kPa(-1). Furthermore, the repeatability of the sensor is 1.26%FS (full-scale), the hysteresis of the sensor is 0.95%FS and the zero drift of the sensor is 0.615%FS h(-1). By building a dynamic experimental platform and conducting experiments, it can be seen that the response time of the sensor is 0.47 ms (<1 ms), the sensor has good dynamic response.