CHEMICAL AND OPTICAL CHARACTERIZATION OF NI-P SPECTRALLY SELECTIVE SURFACES COATED BY FLUOROCARBON FILMS

The spectrally selective surfaces (SSS) of nickel-phosphorus films produced by chemical deposition were coated with sputtered films from a target of PTFE in an attempt to obtain an increase of their life time. Optical microscopy, X-ray diffraction, IR and XPS were used to investigate the physical characteristics of the film; the last technique was used also for the interface (film/SSS) chemical analysis. The optical properties of uncoated and coated SSS are compared and the increase observed in the emissivity of the coated surfaces is attributed essentially to a chemical reaction of the gas in the sputtering reactor with the elements present in the selective surface. The behaviour of the coated and uncoated SSS under different environmental conditions, was also investigated. © 1990.