Composite metal technology is used to manufacture intermetallic compound (IC) absorption surfaces and to combine them integrally with a composite metal tube-in-sheet collector plate. Heat treatment process for Al--Ni system was optimized and ..cap alpha.. greater than or equal to 0.95 and epsilon less than or equal to 0.3 were obtained over a broad range of compounding conditions. Studies by SEM show that the Al--Ni IC surface is porous, spongelike and the dimensions of its fine structure are of the same magnitude as the wave length range of solar radiation, explaining at least partially the selectivity. Auger electron spectroscopy indicated that rather continuous aluminum oxide layer covers the fine structure of the Al--Ni. Low carbon steel--copper composite has been shown to be a suitable candidate for the collector plate. Additional work is required to resolve the conflicting requirements of the formation of the IC surface and of the manufacturing of the composite metal tube-in-sheet collector plate.