Spectrally selective black nickel coating prepared by a conversion process

Abstract

Black nickel coatings have been prepared on zincated and zinc-electroplated aluminium substrates by a conversion process. The zincating and zinc electroplating parameters have been optimized for preparing zinc-coated aluminium substrates for the deposition of black nickel coatings. The optical properties and the morphology of these coatings have been investigated in respect of the morphology of the zinc surface underneath. It has been observed that the substrate preparation and morphology of the zinc coatings play a vital role in determining the surface morphology and the optical properties of the final solar selective black coatings. Thermal stability and humidity tests of these coatings have been carried out and it has been observed that these coatings do no degrade on thermal annealing up to 200 °C.