GE samarium cobalt magnet development

Tom's ~1970 student field trip to GE Research with Professor Flemings. Pre-Nd-Fe-B competitor; expensive samarium.

Who was working on it before? General Electric came up with neodymium iron. I went as a student in the early 70s — actually about 1970 — we went on a field trip, Professor Flemings took one of the classes on a field trip to General Electric Research in Schenectady, New York. They weren't working on neodymium iron because General Motors hadn't invented it yet. They were working on samarium-cobalt. The problem with samarium-cobalt was samarium's expensive. The great thing about neodymium iron is there's plenty of neodymium in the world, they just didn't have a lot of it in metallic form to make magnets, but iron was cheap and neodymium could be cheap. Samarium-cobalt was always going to be expensive and still is. It has certain advantages.

1970s GE research on samarium cobalt — Tom studied this as an MIT undergraduate.

Same type of thing with rare earth magnets. The rare earths that are used in lots of electronic things nowadays — the rare earth magnets. Originally there wasn't a big market for them, and in this paper, "Bringing New Materials to Market," I use this as one of the exceptions. General Motors discovered neodymium-iron-boron magnets. [Tom passes a pair of rare-earth magnets around.] That's what these very strong rare-earth magnets are. You can barely pull them apart. Pass it around. Second, they're very brittle — you'll see someone cracked one. They discovered these rare-earth magnets that had tremendous strength. These are not structural materials, but I'll show you some plots of what these things do. Here's the magnetic coercivity of magnet alloys over time. This is the BH product. B is the self magnetic field, H is the applied field, and the strength of a motor goes as the magnetic field squared, or the self field times the applied field. This is what we had with Alnico magnets — those were the strong magnets when I was a kid. Then we came up with samarium cobalt, which we studied when I was an undergraduate here. They were working in the 1970s on samarium cobalt at General Electric research, and then in the 1980s General Motors came up with neodymium-iron-boron, which is about forty times greater than the old magnets we had years ago.