The temperature dependence of absorptivity is little known for temperatures near and above the melting point, and the data obtained strongly vary up to now. This can be explained among others by the fact that the interaction of laser radiation with matter is not only dependent on temperature but also considerably influenced by surface conditions like oxidation and roughness.

A reflectometry device for the measurement of absorptivity at Nd:YAG-wavelength will be presented. The system is set up in a vacuum chamber, where pressures down to 10−6mbar can be obtained to enable a cleaning of the sample surface from oxides. Results for polished samples of pure iron and low carbon steel up to temperatures above the melting point will be presented. The influence of roughness as well as of oxidation has been investigated up to the melting point and the results will be compared to theoretical considerations.

This content is only available via PDF.
You do not currently have access to this content.