How can we obtain transparent ceramics? Experts have summarized three necessary conditions for making transparent ceramics: first, the purity of the raw material must be high; second, the structure of the raw material must be a crystal with relatively small optical anisotropy; The third is that the production process must minimize light scattering.

At present, there are mainly two series of transparent ceramics that have been developed. One is the oxide series of transparent ceramics, such as alumina, magnesia, beryllium oxide, yttrium oxide, thorium oxide, yttria-zirconia, lead lanthanum zirconate titanate ceramics and so on. The other is non-oxide series of transparent ceramics, such as gallium arsenide, zinc sulfide, zinc selenide, calcium fluoride, magnesium fluoride ceramics and so on.

Transparent ceramics have a wide range of uses, one of which is to replace glass in high-temperature working environments. Glass is an excellent optical material. The only drawback is that it has a relatively low melting point and tends to soften and deform at high temperatures, so it is no longer transparent.

Transparent ceramics are not only as transparent as glass, but also have a high melting point. At high temperatures, transparent ceramics have better mechanical strength and stability, so they can be used at high temperatures. For example, aluminum oxide transparent ceramics can be used to make high-pressure sodium lamps. The working temperature of this sodium lamp can often be as high as 1,200 degrees Celsius, the luminous efficiency is very high, and the service life can reach 20,000 hours. It is also a high-efficiency energy-saving lamp. Now the annual consumption in the world is as high as 1 million or more.

Transparent ceramics can also be made into nuclear flash blinding goggles for use by workers participating in nuclear tests. In addition, the eye protection used by electric arc welders and steel workers are also made of transparent ceramics. Transparent ceramics can also be used to manufacture bullet-proof car windows, tank observation windows, bomber sights, advanced protective glasses, etc.

Transparent ceramics also have other important uses in the military. For example, it is often used to make an infrared detector for the head of a missile. Generally speaking, if an infrared detector can be installed on the head of the missile, the missile will be able to detect the extremely weak infrared rays radiated from the enemy aircraft as if it had eyes.

But the most important issue is that if the missile is to hit a supersonic aircraft, the speed of the missile must be at least more than twice the speed of the aircraft. In this way, the temperature of the missile head will reach 1,000 degrees Celsius or more due to the strong friction with the air. For optical glasses that can transmit infrared rays, this is simply not compatible, because their use temperature is only 200 degrees Celsius. Therefore, infrared detectors for missile warheads can only be made of transparent ceramics.