2001 Volume 87 Issue 6 Pages 441-448
The authors have made clear that spectral emissivity ε(λ0, t) of non-oxidized steel at the effective wavelength (λ0=0.65 μm) of optical pyrometer is approximately 0.4 and that the wavelength dependency in visible region is negative. But in case of oxidized surface, above-mentioned ε(λ0, t) is increased to approximately 0.9 and the wavelength dependency is changed from negative to positive.
When the oxidized film thickness is increasing, it is known that ε(λ0, t) does not increase monotonously but increase in vibratory curve.
The above-mentioned process is not still made clear yet.
In this paper, the spectral emissivity ε(λ0, t) and the ratio of emissivity ε(λ1, t)/ε(λ2, t) at the two effective wavelengths (λ1, λ2) of twocolor pyrometer are measured during the steel oxidizing. And the vibratory curve should be considered as the light interference phenomenon.
Consequently, taking account of nonlinearity, the dispersion model of light interference phenomenon is proposed and the experimental results can be explained well by the model.
