Study of durability of (molybdenum-copper)-black coatings in relation to their use as solar selective absorbers

In this work (Mo-Cu)-black coatings on Ni-plated Cu substrates have been prepared by electrodeposition. Their stability and durability has been investigated. The durability tests were carried out in two forms; accelerated ageing, and weathering. Reflectance measurements were used to evaluate both solar absorptance (α) and thermal emittance (ϵ) of the coatings. The coatings have been characterised before and after durability testing, using spectrophotometry together with other techniques, such as electron microscopy, X-rays, and ion beam. The main degradation modes of these coatings are loss of water, diffusion of metal atoms, and oxidation. (Mo-Cu)-black coatings undergo some changes in α and ϵ during outdoor ageing.