Design, Preparation, and Performance Study of a Miniaturized High-Temperature Thick-Film Heat Flux Sensor

Solving heat transfer problems in high-temperature and temperature-changing environments is critical in a variety of applications, including modern turbines, aerospace, and nuclear power plants. However, most current thin-film-type heat flow sensors operate at approximately 1000 °C. Thus, we fabricated a kind of platinum–platinum/rhodium thick-film thermopile-type heat flux sensor (HFS) which can work stably at 1200 °C based on an alumina ceramic substrate. The entire electrode layer was prepared by screen-printing process. The surface morphology of the Pt electrode and the material in the thermal resistance layer at different stages were investigated using scanning electron microscopy. The steady-state characteristics of the sensor were evaluated using a high-temperature test platform. The experiments show that the peak voltage of the sensor is 1.4126 mV at the temperature of 1200 °C and the heat flow density of 283.3 kW/
$\text{m}^{{2}}$
. Moreover, the repeatability of sensor at 1200 °C and high-temperature holding for 4-h experiments were performed, verifying that the sensor has good consistency and durability. Therefore, we infer that the designed sensor can be applied for a long time under high-temperature and large heat flow conditions, such as aerospace, mechanical metallurgy, and energy construction fields.