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  • Ancient metallurgy

    BBC, News, BBC News, news online, world, uk, international, foreign, british, online, service


    The dagger, made of an alloy of gold and platinum, was found near the village of Dubovo....

    According to officials at the museum, the dagger is 16cm (6in) long and is sharp enough to shave with.
    An alloy of Pt70Au30 becomes quite hard with cold working, but it is incredible that it can keep an edge over thousands of years, as gold does suffer from fluage. This alloy is a crystalliine mixture of two intermetallic compounds with an Alpha1 matrix in Alpha2.
    Brian (the devil incarnate)

  • #2
    are there other references of aincient platinum working? Especially in alloys? I hadnt thaught that it had been worked untill quite reciently.

    Perhaps they were belnded by accident?
    Dont just swallow the blue pill.

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    • #3
      Supposedly 'primitive' metallurgists and science were a lot more advanced than modern man sometimes wants to admit. Look at the Antikythera mechanism, which used differential gears as a astronomic calculator 1600 years before differential gears were supposed to have been developed. Not bad for 80 BC



      Schematic:



      Replica:

      Last edited by Dr Mordrid; 7 August 2006, 15:44.
      Dr. Mordrid
      ----------------------------
      An elephant is a mouse built to government specifications.

      I carry a gun because I can't throw a rock 1,250 fps

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      • #4
        Platinum was able to worked in ancient times, it was just really dangerous to; The metalsmiths of the time had to use mercuric or arsenic catalyzers to get elemental platinum to melt. However, for platinum to be semi-forged (forged well below the eutectic point), it didn't take such drastic (outright suicidal without a modern hood and an oxygen mask) measures. Most Platinum from ancient times was alloyed with gold, because it was discovered along with gold ore/nuggets or mixed-in with Gold during the refining process, either by accident or on purpose.
        Hey, Donny! We got us a German who wants to die for his country... Oblige him. - Lt. Aldo Raine

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        • #5
          And yet all those fools couldn't figure out how to use Aluminum, the most common metal in the Earth's crust!

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          • #6
            Aluminum

            And one of the least reduceable... It wasn't until the late 19th. Century that Aluminum was regarded as anything less than a precious metal. IIRC, the Washington Monument's spire is capped with an Aluminum tip, the amount of which was worth several thousand dollars at the time.

            The Spaniards and Portugese, when panning for Gold on the Amazon River, would throw Platinum nuggets back into the river for it to age more and become gold. At least, that's what they thought...

            At least they didn't discover how to mine and refine such metals as Iridium and Beryllium. A Beryllium sword would have been a most cruel weapon.
            Hey, Donny! We got us a German who wants to die for his country... Oblige him. - Lt. Aldo Raine

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            • #7
              Originally posted by MultimediaMan
              At least they didn't discover how to mine and refine such metals as Iridium and Beryllium. A Beryllium sword would have been a most cruel weapon.
              ..are we talking a +2 longsword of wounding?
              /meow
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              • #8
                Beryllium (atomic #4) and its salts are toxic and carcinogenic, but it's great for making alloys with many of them being hard, springy and temperature resistant. The right Be alloy would be a light and very, very tough edged weapon.
                Dr. Mordrid
                ----------------------------
                An elephant is a mouse built to government specifications.

                I carry a gun because I can't throw a rock 1,250 fps

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                • #9
                  Be also makes a good tweeter. The top in-wall speakers from Sonance have tweeters made from a Be alloy.

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                  • #10
                    Obviously, the ancients had no access to Hg or As. Au/Pt alloys have no defined eutectic point, but Pt dissolves in molten gold to form alpha intermetallic crystals in the gold. The temperature elevation over the melting point of gold, required for alloys up to 70% Pt, is relatively modest, about 200°C and could be obtained with blown charcoal. I agree that melting pure platinum was probably outside the possibilities of ancient man. This alloy could be cast, with difficulty, being somewhat pasty and would go through two phases during cooling. The crux of the metallurgy would be the rate of cooling as that would determine the crystal sizes in the matrix. Subsequent cold-working would harden the alloy by altering the matrix form.

                    Native platinum is found in Armenia, on the borders of the Thracian empire, and it is known to have been mined in ancient times. I suggest that alloys with sufficient Pt to retain an edge would be unlikely to have been an accidental find in nature. Much more likely a deliberate mixture.
                    Brian (the devil incarnate)

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