Thermal stability evaluation of sheathed platinum resistance sensor based on nitride nano-coating

The strong wear-resistant application environment requires the temperature sensor to be flexible, durable, high-precision, and good long-term stability. The sheathed platinum thermistor sensor with nitride nano coating prepared by magnetron sputtering is selected. First, in order to improve the effectiveness and accuracy of the thermal stability observation data of platinum resistance sensor, the stability and reliability of the observation equipment are evaluated; through analysis, it is determined that the main factors affecting the uncertainty of platinum resistance temperature sensor are measurement repeatability, the stability and uncertainty of standard thermometer, the resolution of the thermometer to be tested, and the non-uniformity of the calibration bath temperature, etc., and an evaluation model for the reliability of the calibration results of platinum resistance temperature sensor is established. Then, by selecting the resistance value of the sheathed platinum thermal resistance sensor under the water three-phase point as the stability comparison benchmark, a high-precision test evaluation system is designed, which is not greater than 3mK. Finally, the high temperature electrical life test, temperature shock test and natural storage test were carried out for the sheathed platinum resistance sensor, and the long-term thermal stability of the sheathed platinum resistance sensor based on the nitride nano coating was evaluated to reach 8mK, meeting the requirements of international regulations for platinum resistance.