Direct Write Fabrication of Platinum-Based Thick-Film Resistive Temperature Detectors

This paper investigates the feasibility and performance of platinum thick-film resistance temperature detectors (RTDs) fabricated using extrusion-based direct write (DW). A platinum (Pt) layer of micron-level thickness was directly deposited onto a planar alumina substrate and was physically and electrically characterized. A four-wire electrical configuration was used to eliminate the effects of contact resistance and increase measurement accuracy. The resistance-temperature behavior of printed Pt traces was consistent with that of bulk Pt wire. Durability testing indicated the printed Pt RTD was suitable for temperature measurements from room temperature to at least 350 degrees C, showing no degradation under long-term heating and lower signal noise than was observed in a Nickel-alloy type E thermocouple (TC). At 500 degrees C, the peak temperature variation of the Pt RTD was comparable to that of the type E TCs. To demonstrate the design freedom enabled by DW technology, an additional conformal RTD design was deposited onto a semi-cylinder glass-ceramic substrate and was subsequently characterized. This paper offers an alternative to current thick-film RTD fabrication techniques.