Black Nickel Coating and Color Anodized Layers for Solar Absorber

作者：Bagheri M^*; Ashrafizadeh F; Najafabadi M Hosseini

来源：Transactions of the Indian Institute of Metals, 2014, 67(6): 927-934.

DOI：10.1007/s12666-014-0418-3

• Ni-P coating
• Electroless process
• Anodizing
• Optical properties
• Heat treatment

Solar selective absorbers are considered as an essential part of a thermal solar collector for which the optical properties are dependent upon their structure and surface morphology. In this paper, optical properties of Ni-pigmented anodized are compared with black electroless nickel coatings. The effect of heat treatment on optical properties of the coatings was also investigated. Anodized films were formed in 6 M phosphoric acid followed by a black coloration process. Scanning electron microscope was used to study the morphology, and X-ray diffraction was employed to identify the phases present. Evaluation of optical properties was carried out by spectral reflectance. Evaluation of the optical characteristics showed that Ni-pigmented anodized and black electroless samples, after heat treatment, had the highest absorption coefficient at about 0.98 as well as the lowest emission coefficient. The xi factor reached about 6 in heat treated Ni-pigmented anodized layer and offered optimal properties in this research.

• 出版日期2014-12