Aluminum.

The Finishing of aluminum edited by G.H. Kissin 1963 The metallurgy of aluminium and aluminium alloys Anderson, Robert John 1925 The practical anodising of aluminium Hubner, Walter W. E. 1960 The technology of aluminium and its alloys Varley, Philip Copley 1970 Welding Alcoa aluminum Aluminum Company of America. [from old catalog] Year not listed