Non-contact in situ microwave material measurements for high temperature process monitoring

Non-contact real time microwave measurement and signal analysis techniques to extract high temperature material parameters from the mono-static reflections gathered by a compact air cooled corrugated horn are presented in this work. Non-contact in situ microwave measurements gathered over 20–24 GHz inside a closed furnace were processed to identify the thermodynamic phase change temperature of metal and glass melts. The melting point of aluminum alloy and glass transition of a borosilicate glass matrix extracted from the time gated and processed microwave measurements were in good agreement with differential scanning calorimetry measurements. Thus, the ability to measure high temperature material process parameters using non-contact microwave measurements is demonstrated.