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I want to embed a rare earth magnet inside some aluminum. Think of it like an aluminum rod that has a thin layer of Al at one end, and underneath is the rare earth magnet.

Al melts at 660C. At what temp does neodymium melt at? Is there a magnetic material that has a higher melting point that I can embed in the Al?

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    Need it be a solid rod of aluminum, rather than one that starts out as 2 pieces? – user24 May 15 '19 at 15:54
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The melting temperature of a magnet is irrelevant because it loses it's magnetation long before melting.

Have a look at this site and you'll see that the maximum working temperature of neodymium magnets is approx. 230°C for the most heat resistant magnets. This site explains why the magnets get permanently demagnetized by heat.

The only way to embed a magnet into aluminum and keep it intact is to prepare a cavity in the aluminum and insert the magnet later (when the metal cooled down to working temperature). If you want to coat the magnet, either use galvanization or a different material.

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  • Great call out! There's also a variety of YouTube videos that demonstrate the loss of magnetism due to the heat). I find them interesting to watch. – user24 May 15 '19 at 15:53
  • With a close fit and degreased parts, epoxy works very well on the (nickel) plating if you glue the magnet into a recess – Chris H May 17 '19 at 8:32
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Neodymium magnets are magnetized post forming and plating, or so claims this magnet manufacturer. If the magnet is permanently demagnetized, you could try to remagnetize it with a coil and high-current capacitor bank. There may be some interference from current induced in the aluminum, which may be addressable by using a longer current pulse.

First I would try heating the magnet in question to the temperature where aluminum melts, perhaps by pressing a ball of aluminum foil around the magnet and heating it in a cast iron pan. The foil will monitor the temperature, and touching/moving the magnet during the process will show you the demagnetization properties.

You are casting the aluminum around the magnet. If the aluminum is thin enough, it may be that the temperature of the magnet never reaches the critical temperature.

Since Aluminum had no grain structure (like wood), it may be best to cut the rod, create a cavity, polish the ends, glue it all together, and then turn and polish the rod on a lathe to remove any discontinuity from the cut. Carefully cut, polished, glued, and finished, the break in the aluminum rod could be nearly invisible.

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