Normal spectral emissivity changes of tungsten at 633 nm in the range from room temperature to melting point under pulse-heating conditions

The classical steady-state technique for the measurement of thermophysical properties at high temperatures suffer from many limitations (for example, chemical reaction, evaporation, loss of mechanical strength, etc. may exist). These problems may be overcome by transient techniques of sub-second durations. Pulse-heating experiments were performed on tungsten strip specimen, taking the specimen from room temperature to the melting point based on rapid resistive self-heating of the specimen. The normal spectral emissivity of the specimen was measured by integrating sphere reflectometry developed at HIT. At the same time, the radiance temperature is measured by high-speed pyrometer from 1200K to the melting point. Details of the measurement technique, measurement apparatus and of the calibration technique are described. Results of the normal spectral emissivity of tungsten at 633nm from room temperature to melting point are presented and discussed.