Sony Walkman and neodymium-iron-boron magnets

Nd-Fe-B enabled portable tape players (Walkman); before that, "tape player was the size of a football."

I could put lithium batteries up there, but we've had batteries for a hundred years. Lithium is just a small improvement. To me it's not a groundbreaking new technology. They're just using lithium instead of magnesium or manganese. It's better, but it's not a hundred times better. It's a question of what you want to say is groundbreaking. These were really disruptive technologies. The thing that made Sony Walkmans viable was neodymium-iron-boron magnets. You could make a videotape player or a tape recorder to play music, but you couldn't make it light enough and small enough and have enough battery life unless you had neodymium-iron-boron magnets. That's what Sony came out with, which they got the magnets from Sumitomo. That allows you to miniaturize things. Before that, a tape player was the size of a football. You want to carry a football around in your pocket while you're jogging? No.

GM Research invented NdFeB magnets (~40,000 gauss vs. 10,000 for ceramic, 7,000 for Alnico). The energy-squared scaling let starter motors shrink from football-sized (15–20 lb of copper) to fist-sized.

There are also other magnets. This is a neodymium-iron-boron magnet, invented by General Motors Research. It's much stronger. The strength of a magnet in energy terms goes as the magnetic field squared. If you go from an Alnico magnet — might be seven thousand gauss — to a ceramic magnet, ten thousand gauss, to neodymium-iron-boron, forty thousand gauss. Start squaring forty compared to ten or seven. Lots more energy.

Example of "fitness for latent requirements." The Walkman as product made possible by GM's development of neodymium-iron-boron magnets in the early 1980s.

There's a number of useful things in the very first chapter. It talks about how originally we used to manufacture as fitness to a standard, and then it became fitness to use, and then fitness to cost, and then there was this thing coming out in the 1980s called fitness for latent requirements. The example was something that most of you have never heard of — the Walkman. You ever heard of the Walkman? It was bigger than a deck of cards, but it basically had a cassette, and you could play your music. You didn't have digital music at the time. Sony came out with the Walkman, and no one knew they had to listen to music while they were walking. That was a latent requirement. But Sony made a fortune off these things. They cost about a hundred bucks, and everybody had one.

Early-1980s Walkman with AA batteries lasted ~2 hours; later devices last 16-48 hours due to rare-earth-magnet motor efficiency.

When I was your age I couldn't afford to pay to have my car repaired. Nowadays I pay a mechanic to do it, but back then I had to rebuild the starters on cars. It's sort of a pain, kind of dirty. A starter motor weighed about fifty or sixty pounds, and a starter motor on a car today is about the size of your fist. That's because they're using neodymium-iron-boron magnets. In the old days they used Alnico magnets, which aren't as strong. When the Sony Walkman came out in the early '80s, this was the great music thing, and you put your double-A batteries in there that lasted for about two hours. Now you have batteries in your music devices that play for sixteen, twenty-four, forty-eight hours. It's all because of neodymium-iron-boron magnets. The little motors in there essentially run off very powerful magnets.

Nd-Fe-B invented at GM research lab. GM's threat to vertically integrate into Brazilian neodymium mining triggered third-party suppliers to enter the market. Illustrates "availability" as a constraint distinct from properties or cost.

I told you about the rare earth magnets. Did I tell you about neodymium boron? It was invented at the General Motors research lab. This is for small motors and things like that. When you're talking about the automotive business, General Motors wanted to use these to reduce the size of motors and starters in engines. But they looked at the abundance of neodymium in the world before they came up with this alloy. No one had ever used neodymium metal. It might have been something that someone bought ten grams of in a research laboratory, but that doesn't really make a market.