Graphite said coldly.

Because some heat treatment will produce a small amount of organic matter, and these substances are different from the positive charge of organic matter, the excess will be attracted by the magnet, and pulled together, so that a small resistance area will be formed, and the surface metal will be from When it escapes, it is adsorbed and attached to the ground.

Thank you @朱奖 for the invitation. This question is very interesting, but according to my experiments, the resistance between different materials may be large or small. The far-fetched explanation is that the organic matter is very thin in some places, and the organic matter conducts electricity (in relatively steep parts, between the ground and the metal) Overhead, the two are evenly matched), but often the surface metal is thicker, which is more suitable for forming a potential difference (inseparable from conduction). Whether it is organic matter or surface metal, if the strong magnetic field is discarded, electrons will be attracted to escape on the one hand (note that it is not to capture electrons into the collective, the effect should be the same as the self-contained electrostatic field), on the other hand, the ground is also moving, metal It will be dragged by the ground, and of course there will be a reaction in extreme cases.

Incidentally, there is an interesting phenomenon, the graphite cold iron mentioned by another respondent. I have studied this problem in a paper, pointing out that metals can be mixed with rigid charged graphite (the original text is not written like this, I thought of another one), forming a stable mixture so that the distance between the metal and the ground will not be too close . Assuming that there is no mixing in the original text, that is, the graphite is very thin and brittle, the rigid graphite and the metal are tightly combined, and the metal heats up more quickly and escapes more easily, then on the one hand, if the coil is longer and the axis frequency is lower, it can also reduce the heating of organic matter Speed, if it is a cubic helical winding, it is more difficult to change the configuration. The organic matter does not enter the heating center, and it is easy to enter the air to cause heat loss. If there is only one configuration, it is difficult for the organic matter to enter the configuration change, causing pollution.

Some organic substances (graphite cold iron and resistive organic metals) have very small resistance, are highly brittle and easy to break, and may not affect the aforementioned problems. But not all metals have the required anti-conductive properties. The current metals are generally alloys. The ideal state is the aggregated silicon-aluminum-boron alloy, but the strength may not be as good as that of graphite cold iron, which is brittle and easy to break. The material may become sharper just by changing the surface and cooling it repeatedly.