Change in degree of blackness of heat-resistant alloys with heating in air

The article gives the data of an experimental investigation of the integral and spectral normal degrees of blackness of heat-resistant alloys of the systems $\rm Ni - \rm Cr{,}\,\rm Ni - \rm Cr - \rm Fe{,}$ and $\rm Fe - \rm Cr - \rm Al$. The spectral and integral degrees of blackness of the investigated alloys depend on the time and the oxidation temperature. An attempt is made to connect the character of the change in the spectral degree of blackness with the composition and structure of the forming oxide film.