Hello Javier.

I think that you should consider first a measurement of the roughness of the surface. Typically a rough surface acts like micro blackbody cavities, enhancing the total emissivity of the surface. As soon you have an idea of the magnitude of the "valleys" and "hills" of the surface, you may be able to correlate it to the wavelengh. I know this will not be simple, but I think it is a good starting point.

Regards,

Renato

Ok but in some manner there should be a typical rough surface profile, that could be considered "diffuse". The question is: by knowing the emissivity of an specular surface, how can it be estimated, the corresponding to that material but in a diffuse configuration? I need something like an equation.

Interesting question, I'm thinking of an experiment with a thermal camera. Place two samples at the same temperature and the same emissivity, the difference is that one of them must have a smooth surface and the other is not. I'm going to play with the emissivity and see what happens. Kind regards

Thank you Enrique

Please keep me informed.

I have found an interesting paper regarding this topic

International Journal of Heat and Mass Transfer 49 (2006) 4279–4289 www.elsevier.com/locate/ijhmt

Modeling the effects of surface roughness on the emissivity of aluminum alloys Chang-Da Wen, Issam Mudawar