Rugometric and Microtopographic Inspection of Cr–Cr2O3Cermet Solar Absorbers

Abstract

The development of new efficient and cost effective solar energy collectors and converters either quantum or thermal attracts great attention and effort in a number of research laboratories all over the world. Cr–Cr2O3cermet PVD coatings can be successfully employed in thermal converters. Their energy conversion efficiency depends on their chemical and physical structural characteristics and related optical properties like reflectance, emittance, solar light absorption, or absorptance and transmittance. Parameters such as roughness and topographic characteristics of the produced coatings will greatly influence their relevant optical properties. A careful evaluation of the coatings' roughness and their microtopographic inspection is fundamental. The Cr–Cr2O3cermet coatings sputter deposited on cooper and aluminium shows similar absorption (92%) but the first ones present a better emittance and higher waviness (over30%) with similar roughness. In comparison with commercially available solar panels with a slightly better absorption but worse emittance our coatings have a much lower waviness (∼150%) and roughly50%higher roughness.