Spectral selectivity of composite enamel coatings on 321 stainless steel

• Published in: Solar energy materials and solar cells Vol. 93; no. 8; pp. 1404 - 1410
• Main Authors: Brown-Shaklee, Harlan J., Carty, William, Edwards, Doreen D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.08.2009; Elsevier
• Subjects: Applied sciences; Enamel coatings; Energy; Exact sciences and technology; Natural energy; Solar absorber; Solar absorptance; Solar collectors; Solar energy; Solar thermal conversion; Spectrally selective coatings; Thermal emittance; Thermal emittance; Solar collectors; Spectrally selective coatings; Enamel coatings; Solar absorptance; Solar absorber; Borosilicates; Solar collector; Glass; Absorption coefficient; Transition metal; Solar absorbers; Spectral reflectance; Thermal stability; Serigraphy; Composite coating; Stainless steel; Selective coating; Pigments; Protective coatings
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2009.03.009

Composite porcelain-enamel coatings consisting of spinel-type transition-metal-oxide pigments embedded in a borosilicate-glass matrix were deposited on 321 stainless steel using screen-printing techniques and characterized using total reflectance over the spectral range of 200 nm to 25 μm. The composite coatings exhibited moderate spectral selectivity and excellent thermal stability at 450 °C. Solar absorptance ( α) ranged from 0.82 to 0.90 and calculated thermal emittance at 500 °C ( ε) ranged from 0.46 to 0.79. Both depended on coating thickness and pigment volume concentrations. As an example, the highest solar selectivity was measured in a 0.9 μm coating with α and ε (500 °C) being 0.82 and 0.46, respectively.