Platinum (Pt) resistance temperature detectors (RTDs) are extensively employed as thin film temperature sensors. However, agglomeration of Pt thin films occurs above 800°C due to grain boundary grooving on the free surface, ultimately limiting its application at high temperatures. In this work, a Pt RTD was prepared by depositing multilayer Al ₂ O ₃ protective layer on Pt thin films using electrodynamic jet printing (EJP) technology. The surface morphology and energy dispersive spectroscopy spectrum of Pt thin films indicated that the voids on the surface are reduced, the grains growth are inhibited, the movement and grooving of grain boundaries are limited. The test results indicate that the Pt RTD has not failed after 6 cycles of repeated warming and cooling from 800°C to 1300°C. After repeated cycles, the initial resistance of the Pt RTD with a rate of change of less than 0.5%. In addition, the maximum relative deviation of the resistance in a single cycle is less than 1.6%. The Pt RTD with an 18-layer Al ₂ O ₃ protective layers has undergone 12 cycles without failure, indicating a cycle life exceeding 10 h. Pt RTDs are stable over the range of 25°C to 1400°C with correlation coefficients R ² greater than 0.999, showing good linear correlation. It can withstand temperatures up to 1440°C when printed with 18 protective layers. Compared to a Pt RTD without protective layers, the operating temperature is increased by 40%. This advancement provides a viable solution for the high-temperature monitoring of hot end components in aerospace applications.

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.

Aerospace engines and hypersonic vehicles, among other high-temperature components, often operate in environments characterized by temperatures exceeding 1000 °C and high-speed airflow impacts, resulting in severe thermal erosion conditions. Coaxial thermocouples (CTs), with their unique self-eroding characteristic, are particularly well suited for use in such extreme environments. However, fabricating high-temperature electrical insulation layers for coaxial thermocouples remains challenging. Inspired by the self-healing mechanism of pine trees, we designed a composite electrical insulation layer with a similar self-healing function. This composite layer exhibits excellent high-temperature insulation properties (insulation resistance of 14.5 kΩ at 1200 °C). Applied as the insulation layer in K-type coaxial thermocouples via dip-coating, the thermocouples were tested for temperature and heat flux. Temperature tests showed an accuracy of 1.72% in the range of 200–1200 °C, a drift rate better than 0.474%/h at 1200 °C, and hysteresis better than 0.246%. The temperature response time was 1.08 ms. Heat flux tests demonstrated a measurable range of 0–41.32 MW/m² with an accuracy better than 6.511% and a heat flux response time of 7.6 ms. In simulated extreme environments, the K-type coaxial thermocouple withstood 70 s of 900 °C flame impact and 50 cycles of high-power laser thermal shock.

An all-fiber dual-parameter pressure–temperature sensor with enhanced contrast and sensitivity is proposed, fabricated, and experimentally validated for gas monitoring in high-temperature environments. The sensing structure combines a Fabry–Pérot interferometer (FPI) for pressure detection and a fiber Bragg grating (FBG) for temperature measurement. A collimation-enhancement mechanism, based on the self-focusing effect of the graded-index fiber, is employed to improve signal contrast. The diaphragm-based closed-end FPI cavity is fabricated using precision mechanical cutting and arc discharge techniques. To further enhance the pressure sensitivity, the fiber end-face is treated using mechanical grinding followed by femtosecond laser roughening. The sensor's performance was evaluated at ambient conditions and under extreme conditions of 700 °C and 5 MPa. At 700 °C, the sensor exhibits a temperature sensitivity of 11.61 pm/°C and a pressure sensitivity of 46.96 nm/MPa. The full-temperature drift of the pressure sensitivity is less than 3 nm/MPa, with a maximum full-scale error of 2.95%. Owing to its high mechanical robustness and sensitivity, the proposed sensor is well suited for simultaneous gas temperature and pressure monitoring in harsh, high-temperature environments.

Multi-point array thin-film thermocouples have strong potential for high-precision, wide-range temperature monitoring in applications such as aircraft engine thermal condition assessment and industrial process control. However, conventional single-point thin-film thermocouples cannot satisfy the distributed measurement requirements of large-area temperature fields, and the accuracy of multi-point arrays is often degraded by coupling effects among sensing nodes, which hinders their engineering deployment. In this work, a multi-point array thin-film thermocouple is fabricated via precision welding, and an insulating layer is deposited on the sensor surface using electrospray atomization to establish a multi-point temperature-sensing hardware system. To compensate for coupling-induced deviations, a deep learning–based calibration method is developed: measurements from the array and reference thermocouples are synchronously collected to build the dataset, outliers are removed using the interquartile range (IQR) method, and a three-hidden-layer multilayer perceptron (MLP) is trained for each node independently using the Adam optimizer (learning rate 0.001) with an 8:2 train–test split. Performance is quantified by MAE, MSE, and R², and the results show that the proposed approach markedly reduces measurement errors and improves the accuracy of the array thermocouples, demonstrating reliable performance and practical applicability for precise large-area temperature-field monitoring.

The strain measurement accuracy of aerospace hot end components is severely affected by the change of environmental temperature. How to reduce the apparent strain derived from temperature variation within a wide range still is of a great challenge hitherto. In this work, a self-compensated thin film strain gauge (SC-TFSG) with sensing resistor and suspended compensation resistor is developed. These two resistors are orthogonal to each other and form a half bridge measurement structure, which is used to reduce the apparent strain introduced by temperature changes. Results show that the temperature coefficient of resistance (TCR) of the SC-TFSG is only -136 ppm/°C within a wide temperature range from room temperature to 1200 °C. The thermal output is 89.52% lower than the strain gauges without compensation resistor. Furthermore, the results of the standard strain cyclic loading test at 600 °C, 800 °C, 1000 °C and 1200 °C indicate that the maximum error between the SC-TFSG measured values and the standard loading strain can be controlled within 6%. The work provides an effective method for strain measurement and accuracy compensation of hot end components in a wide temperature range.