CVG 2141 Lecture Notes - Lecture 7: Hygroscopy, Aluminium Oxide, Bauxite
9 Aug 2016
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Most abundant metal on earths crust (exists as oxides) High energy needed for extraction from oxides. Aluminum is added as an alloy for structural applications: pure aluminum cannot be used for construction applications (can be used for smaller products e. g. containers, doors & windows, electrical conductors, consumer goods , etc. ) From bauxite ore (which contains 45 60 % alumina) Pros: lightweight (1/3 density of steel, good thermal and electrical conductor, high strength/weight ration, corrosion resistant. Cons: high initial cost (high energy extraction, lack of performance information. Spruce, pine, firs, cedar: softwood is normally used for construction purposes, b/c hardwood is much more expensive. Rings are larger, less dense, weaker than latewood. Latewood: formed during winter/fall, less produced, dense, stronger than early wood b/c larger volume of wall material/area. Made of: cellulose: forms microfibrils, provides axial strength. Lignin: glue" that binds cell walls, provdes rigidity and compressive strength. Hemicellulose (another binding agent), chemicals, water can be found in wood.
