Does Aluminum change color when heated or does it stay the same? closest answer gets best answer?

Is there anyone out there that knows some remedial Chemistry because I have posted this question a hundred times and I still have not got one answer.

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  • 1 decade ago
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    Don't need to know chemistry for this one..

    I welded aluminum... the hardest thing about doing so is that aluminum does not change color, or glow when heated or melted.

    It looked normal then it would just suddenly flow away as a liquid molten metal unlike iron that glows increasingly brighter as it gets hotter.

    Impurities in the aluminum will glow but not PURE AL.

    Source(s): My own experience. if you need more proof: http://www.youtube.com/watch?v=gge5NyqoNIQ
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  • Anonymous
    1 decade ago

    http://books.google.com/books?id=TyBMexKSEI0C&pg=P...

    most things begin to have a red glow when heated to between 480 and about 600 C but

    Mg, Al, Ti, Zr have a white glow instead of red

    The MP of Al is 660 C, just above where a glow would start.

    In a vacuum, or inert atmosphere, reactive metals like Mg, Al, Ti, Zr can be heated without oxidation and you will see colors progress from red to orange to yellow to white as they get near their boiling points (in vacuum). In many cases, heating is rapid so they look bright white where they are being heated and the colors are actually seen in reverse as the lump of metal cools down at a slower rate and without the bright hot-spot.

    In air, most metals oxidize and form oxide coatings which may be colored or colorless but just appear to be colored depending on their thickness. In a vacuum or inert atmosphere, the metals do not change color until heated enough to glow from the heat. But that's just energy being released due to the heat. The metal just looks that color temporarily and will return to normal color on cooling.

    Source(s): In my job I routinely heated Al and Ti in a vacuum to evaporate the metals.
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