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

Conformal thin-film sensors enable precise monitoring of the operating conditions of components in extreme environments. However, the development of these sensors encounters major challenges, especially in uniformly applying multiple film layers on complex metallic surfaces and accurately capturing diverse operational parameters. This work reports a multi-sensor design and multi-layer additive manufacturing process targeting spherical metallic substrates. The proposed high-temperature dip-coating and self-leveling fabrication process achieves high-temperature thin-film coatings with excellent uniformity, high-temperature electrical insulation, and adhesion properties. The fabricated Ag/Pt thin film thermocouple arrays and a heat flux sensor exhibit a maximum temperature resistance of up to 960 °C, with thermoelectric potential outputs and high-temperature resistance closely mirroring those of wire-based Ag/Pt thermocouples. Harsh environmental testing was conducted using high-power lasers and a flame gun. The results show that the array of thin-film conformal thermocouples more accurately reflected temperature changes at different points on a spherical surface. The heat flux sensors achieve responses within 95 ms and withstand environments with heat fluxes over 1.2 MW/m2. The proposed multi-sensor design and fabrication method offers promising monitoring applications in harsh environments, including aerospace and nuclear power.