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Aluminium | |
|---|---|
| Symbol | Al |
| Atomnummer | 13 |
| Gruppe | 13 (III) |
| Periode | 3 |
| Fysiske og kemiske egenskaber | |
| Gennemsnitlig Atomvægt | 26,982 g/mol |
| Stabile Isotoper | 27Al |
| Smeltepunkt | 660,32°C |
| Kogepunkt | 2519°C |
| Densitet | 2,70 g/cm3 (20°C) |
| Oxidationstrin | +3 |
| Diverse | |
| CAS-nummer | 7429-90-5 |
| E-nummer | E 173 |
Aluminium er et grundstof med atomnummer 13 i det periodiske system. Symbol Al. Det er et let hvidt metal.
Aluminium danner Al+++ ioner ved at afgive sine 3 elektroner i den yderste elektronskal.
[redigér] Historie
Aluminium blev isoleret første gang i 1825 af H.C. Ørsted. Tidligere har man traditionelt tildelt æren til den tyske kemiker Friedrich Wöhler, der udvandt aluminium som et gråt pulver i 1827, men Wöhler har i et brev til Ørsted erkendt, at det er Ørsted, der har lavet det grundlæggende arbejde med at isolere metallet.
De første metoder til fremstilling af aluminium var ikke velegnet til storproduktion, og de første mange år var metallet en sjældenhed med priser på niveau med guld og platin. Først da fremstilling ved hjælp af elektrolytiske metoder blev udviklet i midten af 1880'erne kom der gang i en større produktion af aluminium.
[redigér] Kilder
- Niels Lichtenberg: Aluminium "Sølvet af Ler", radioforedrag, Industriraadet 1938
- F.J.Billeskov Jansen, Egill Snorrason, Chr.Lauritz-Jensen: Hans Christian Ørsted, IFV-energi i/s (Isefjordværket), 1987, s. 96-97.
[redigér] Eksterne henvisninger
- 2004-11-25, Sciencedaily: 'Brick Wall' Helps Explain How Corrosion Spreads Through Alloy Citat: "...The fissures seem to follow a random path between grains of the alloy...Corrosion often follows the region between the grains, called grain boundaries, which are more susceptible to attack...The United States Air Force spends almost $1 billion each year fighting corrosion...“The problem is, we don’t know how these probabilities change form plate to plate or alloy to alloy,” he said..."
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