Method for making a selective absorption film for solar energy

摘要

A method for making a selective absorption film for solar energy which comprises immersing aluminum or its alloy in water which contains at least two members selected from phosphate ions, fluoride ions and triethanolamine, and optionally ions of a metal selected from copper, iron, cobalt, silver and a mixture thereof thereby forming a chemical conversion film which shows a great absorptivity and a small emissivity.