Corrosion of Al-Sn-Bi alloys in alcohol at high temperatures. Part I: Effects of the metallurgical structure of the alloys and the metal salt additions to alcohol

摘要

Corrosion of free machining Al alloys that contain Sn and Bi was investigated at 391-415K in 2-(2-(2-methoxyethoxy)ethoxy)ethanol (MEEE) and 2-(2-(2-butoxyethoxy)ethoxy)ethanol (BEEE) with/without SnCl2, Sn(OC2H5)4, FeCl3, and CuCl2. The Al-Sn-Bi alloy displayed severe pitting corrosion in MEEE as did the Al-Sn alloy in BEEE at 415K, and Sn and Sn/Bi were enriched on the surface of pits. Immersion tests of pure Al in MEEE containing Sn/Cu-salts at 415K also showed severe corrosion and the deposition of metallic Sn and Cu on the surface. The corrosion mechanisms are discussed in terms of the electro-catalytic activity of the Sn enriched on the surface.