Effect of surface conditions on the normal spectral emittance of titanium and zirconium between 1000 and 1800 K

Discontinuity in normal spectral emissivity of solid and liquid copper at the melting point

“…Furthermore, the spectral emissivity of solids is also very sensitive to the surface condition of the sample, i.e., the roughness of the sample surface. [5,6] This effect is considered to be a source of scatter in published data for solid metals.…”

Beyond Fresnel: absorption of fibre laser radiation on rough stainless steel surfaces

“…The experiments of Baria and Bautista [23] validated the effect of the surface roughness on the absorptivity 4 at higher temperatures with the result of a more intense absorption peak at specific temperatures at higher surface roughness. Wieting and DeRosa [24] measured a 30% higher absorptivity of a CO 2 laser beam on ground than on polished surfaces at room temperature, while this difference disappeared at higher temperatures.…”

“…Due to its wide application in industry, metal sheets of AISI 304 (X5CrNi18-10) stainless steel with different surface finishes were used for the determination of the absorptivity behaviour. [13] 0.05-3.26 0.08-4.17 1.053; 0.527 Ang et al [14] 0-5 0.248 Peiponen and Tsuboi [15] 0.1-1.6 0.632; 0.488 Barbarino et al [16] 0.002-0.7 Halogen lamp Endriz and Spicer [17] 0.001-0.027 0-0.4 Beaglehole and Hunderi [18] 0.002-0.005 0.05 0.25; 0.55 Elson and Sung [19] 0.003-0.06 1-5 1; 4; 10 Bergström et al [20] 0.01-2 1.064 Zhang et al [21] 0.05 0.5-1 Wang et al [22] no details about roughness heights 0.445 Baria and Bautista [23] electropolished, mechanically polished, ground K60 0.645…”

“…The probe sheets were cleaned with ethanol before experimentation to remove any existing dirt or grease. The absorptivity of 304 stainless steel is assumed to be temperature-independent for a temperature range up to 700 °C for light with a 1.07 µm wavelength [25], wherefore the temperature dependence, which might have an influence on absorptivity [23,24], may be neglected in our experiments. The analysed surface finishes and the corresponding roughness heights in terms of R rms as well as the correlation length a of the surface roughness are listed in table 2.…”

“…Since for opaque materials like metals the transmission can be neglected, the reflectivity and absorptivity are directly linked through the equation R = 1 − A 4. In article[23] the effect of surface roughness on emissivity is studied. According to Kirchhoff's law of thermal radiation the direct spectral emissivity is equal to the direct spectral absorptivity, wherefore it can be analysed here in terms of direct spectral absorptivity.J.…”