Fabrication of High-Temperature Polymer- Derived Ceramic Thin-Film Heat Flux Sensor by 3-D Printing and Laser Pyrolysis

Heat flux density is an important parameter for evaluating the high-temperature performance of turbine blades. Accurate heat flux density data play a significant role in the design and manufacture of turbine blades and their heat-dissipation performance. Current studies have shown that thin-film heat flux sensors (TFHFSs) are suitable for signal monitoring of complex turbine blade surfaces. However, TFHFSs have a multilayer structure, which is difficult to achieve using traditional physical vapor deposition (PVD). In this article, we propose an approach to fabricate high-temperature polymer-derived ceramic (PDC) TFHFSs using 3-D printing and laser pyrolysis. Through direct ink writing (DIW), sensitive, antioxidant, and thermal resistance layers were written directly on an alumina substrate. The sensitive layer was rendered electrically conductive owing to laser-induced graphitization. Thus, the structure of multilayer TFHFS can be quickly achieved using the proposed method. The results showed that the sensor can operate at 800 °C. Its sensitivity was 1.349 mV/(kW/
$\text{m}^{{2}}{)}$
. Thus, it is feasible to prepare TFHFSs by 3-D printing and laser pyrolysis, which provides a new in situ integrated manufacturing method for fabricating heat flux sensors suitable for working in harsh environments such as aviation.