Is there a Vacuum in the Bulb?

"The minority is subject to the majority" and "the principle of the majority" are the principles we have always advocated, but sometimes the truth is in the hands of the minority. The chemist Millan broke the routine and succeeded by sticking to his own ideas.

The tungsten wire in the bulb becomes brittle and has a short life after it is energized, so the General Electric (GE) asked chemist Millan to solve the problem. Millan believes that the reason for the tungsten's brittleness must be found out. Later, Millan discovered that it was caused by gas impurities in the tungsten filament, and he suggested heating filament samples in high vacuum conditions to measure the amount of gas produced in various situations.

The results show that Millan was right. A bulb that has not been heated in a vacuum for long periods of time will produce water vapor slowly on the surface of the glass, which will reacts with the tungsten wire in the bulb to produce hydrogen gas; some materials also release some gas where the bulb joints. It is the chemical action of such gases that makes the tungsten filament brittle and the bulb blackened, thus reducing the service life of the tungsten bulb.

At this point, it was agreed that the problem could only be solved if the vacuum of the bulb was further increased. However, Millan thinks the opposite. "Fill the bulb with different gases and see how the gases and tungsten react," he said. Millan then filled the bulb with oxygen, nitrogen, hydrogen, water vapor, carbon dioxide and other gases one at a time, and tested them under

“Nitrogen does not dissociate at high temperatures, and many of the vaporized tungsten atoms return to the wire after striking the nitrogen molecule.” Millan discovered the "secret" between nitrogen and tungsten wire excitedly, “In other words, nitrogen can protect the tungsten wire and prolong its life.”

After four years of painstaking research, Millan has finally succeeded in making powerful, long-lasting, and efficient inflatable bulbs. Later, he invented a low-power inflatable bulb made from argon instead of nitrogen gas.

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