Micro-Sensor for In-Situ Rolling Element Bearing Temperature and/or Pressure Measurement

The overall objectives of the proposed program are to develop non-invasive, wear resistant, light weight sensors and instrumentation for in-situ monitoring of temperature and vapor pressure for space and land based anti-friction rolling element bearings. This will be achieved by depositing thin films of appropriate materials on the raceways of rolling element bearings using RF-sputter coating and patterning the coatings into micro-sensors using photolithography. RF-sputter coating allows deposition of coatings at temperatures less than 180 degrees C. Maintaining low temperatures is essential in assuring that the hardened bearing steel is not tempered. Zirconium and nichrome will be used for development of micro-temperature and pressure sensors respectively. In Phase I micro-temperature and pressure sensors will be fabricated and evaluated in a bearing simulator rig allowing rolling and sliding conditions. Sliding increases surface heating and shear stress and tests the durability of micro-sensors. These micro-sensors can be used with minor modifications to monitor lubricated contacts in aerospace and automotive applications (e.g. gears, journal bearings, seals, etc.). A thermal balance formed using a thermocouple junction both as a sensor and heating block will be used to measure vapor pressure. The vapor pressure and quartz micro-balance sensors will be used to monitor lubricant losses.