Something weird happens at 770°C.

Credit: Up and Atom

Wondering what happens when AI is used? Here’s the answer 🙂

Heat disrupts the alignment of magnetic domains, weakening magnetism. If the temperature exceeds the material's Curie temperature, it loses its ferromagnetic properties. Examples off Curie temp: - Iron: 770°C - Nickel: 358°C - Cobalt: 1121°C

Curie temperature. This is why many bladesmiths use a magnet to estimate the correct temperature for quenching (hardening); heat until non-magnetic + a tiny bit more. 820C typical for carbon steels using oil as a quenching medium.

Permanent magnets lose their magnetism when heated

I see the attraction here.

Why this happens: Above the Curie temperature, the magnetic domains in iron (small regions that are normally aligned in the same direction under a magnetic field) lose their alignment. As a result, the iron no longer exhibits strong magnetic properties. Instead, it weakly responds to a magnetic field, like any paramagnetic material. When iron will stick again: Once cooled below 770 °C, the ferromagnetic properties of the iron will be restored. However, if the iron underwent additional changes during heating (e.g., oxidation or structural alterations), its behavior might differ. For instance, the formation of a scale (iron oxides) on the surface could reduce its ability to stick to a magnet.

But we totally have a molten magnetic core 🧑‍🔬

That is called the Curie temperature

That's not weird, that's simple physics. Like centuries old physics.

Curie temperature. Cool demo.