METHOD OF FORMING A SOLAR SELECTIVE SURFACE COATING

摘要

A solar selective surface coating (13) that is deposited on a solar collector element (10). The surface coating (13) comprises a three-layer structure having an inner layer (14) in the form of a bright metal infrared reflective coating layer, a solar energy absorptive coating layer (15) deposited on the reflective coating layer, and an anti-reflective surface layer (16). The absorptive coating (15) is deposited as a cermet, typically a tungsten-aluminium nitride cermet, which is formed by sputtering material simultaneously from first and second metal electrodes (23 and 24) in the presence of a gas which is reactive with the metal from which the second electrode (24) is formed and substantially non-reactive with the metal from which the first electrode (23) is formed. That is, the solar energy absorptive coating (15) is formed by co-depositing materials from the first and second electrodes (23 and 24) in the presence of a gas which is reactive with the metal of one only of the electrodes.