Brief Introduction of Piezoelectric Ceramics

Piezoelectric ceramics have piezoelectric effect ceramics, called piezoelectric ceramics. It has a peculiar piezoelectric effect characteristic. That is, when subjected to a small external force, it can turn mechanical energy into electrical energy, and when an alternating voltage is applied, it turns electrical energy into mechanical energy.

Piezoelectric ceramic is usually formed by solid-phase reactions of several oxides or carbonates during the sintering process, and its manufacturing process is similar to ordinary electronic ceramics. The sintered ceramic body is polycrystalline, its spontaneous polarization is disorderly oriented, and the main component is ferroelectric, so it is called ferroelectric ceramics and has no piezoelectric properties. When a strong DC electric field is applied to such a ceramic body for polarization treatment, the spontaneous polarization of the original chaotic orientation is oriented along the electric field direction. After the electric field is removed, the ceramic body still retains a certain overall residual polarization, so that the ceramic body has piezoelectric properties.

Compared with piezoelectric single crystal materials, piezoelectric ceramics are characterized by easy manufacture and can be made into various shapes. The polarization axis direction can be selected arbitrarily. It is easy to change the composition of the ceramic material to obtain a ceramic material with various properties. Piezoelectric ceramics are low cost and suitable for mass production. But because it is a polycrystalline material, the frequency of use is limited. The most commonly used piezoelectric ceramics are barium titanate, lead titanate, lead zirconate titanate, ternary piezoelectric ceramics, transparent ferroelectric ceramics, and niobate ceramics.

Piezoelectric ceramics are extremely versatile due to its piezoelectric effect. For example, piezoelectric ceramics can generate or receive sound waves, infrasound waves, and ultrasonic waves under the action of alternating voltage, so they can be made into underwater radars, fish detectors, etc. Use it to make a small, exquisite, highly sensitive piezoelectric gyroscope, which can control the flight of the missile. As long as the missile is deflected, the torque will be transmitted to the piezoelectric gyroscope, and the piezoelectric gyroscope will output current to make the missile press fly on the right track.

In naval battles, the most difficult thing to deal with is the submarine. It can submerge under the sea for a long time, and unknowingly attack ports and ships, causing the enemy's brains to be troubled. How to find enemy submarines? You can’t rely on your eyes, nor can you use radar, because electromagnetic waves will attenuate sharply in the sea, and you can’t efficiently transmit signals. Sonar—underwater ears—is used to detect submarines. Piezoelectric ceramics is the material used to make sonar. It emits ultrasonic waves and reflects back when it encounters a submarine. After being received and processed, the position and distance of the enemy submarine can be measured.

Because piezoelectric ceramics can convert force energy into electrical energy and discharge, they can be used for high-voltage ignition and detonation. For example, if a small piezoelectric ceramic element is installed on an anti-tank projectile, it will rely on pressure when the projectile hits the tank. The electric ceramics are pressed to ignite, causing explosives to explode and destroy the tank. Electronic lighters use the same method to spark the piezoelectric ceramics in the lighters and ignite combustible gas. In industry, piezoelectric ceramics can be used to make frequency modulation filters, flashlight triggers, piezoelectric transformers, piezoelectric stepping motors, welding transducers, earthquake predictors, etc. In medical treatment, piezoelectric ceramics can also be used to make blind vision aids, artificial heart pacemakers, digital display pulse meters, blood pressure monitors, etc., and can also be used to diagnose certain diseases in the human body.

So what is a good piezoelectric ceramic? It depends on what standard is used to divide. Regarding whether it contains lead as the standard, most of the currently used piezoelectric ceramics contain lead, and the performance indexes of piezoelectric ceramics that do not contain lead can not reach the wide practical use. Regarding performance indicators as the standard, although those piezoelectric ceramics with extremely poor performance are bad ceramics, the piezoelectric ceramics currently on the market or manufactured by the manufacturers of piezoelectric ceramics should be products that they think are qualified. I think they are all qualified. But their performance standards are different, so we can’t say which one is good or which one is bad. In addition, piezoelectric ceramics have many parameters, which can only achieve a balance. Sometimes it is too much to pursue a certain index and sacrifice other indexes. It's not a good thing either. The practice is the criterion for testing truth. I think that it is good for users to apply it, and it is bad if it is not applicable.

Our company often encounters such a situation: the user’s circuit is fixed, and the performance of the piezoelectric ceramics we provide has completely reached the theoretical index of the material. We think it is very good, but the user says no. The reason is that the sensitivity is too high. The saturated state cannot be used, and performance is required to be reduced. It is not easy to reduce the performance of the finished products! There is also this situation: the finished piezoelectric ceramics are not qualified, and a record is placed in the non-conforming product area. Some users The sample is urgently needed. The size is just the same as the unqualified one. Explain the reason. The unqualified piezoelectric ceramic chip is provided to the user for trial. The user actually has a very good use.

So we sum it up as: As long as the piezoelectric ceramics reach a certain performance, there is no difference between good and bad, and the application is good. This requires our manufacturers to carefully record the process, and to truly understand the product performance corresponding to different processes, only in this way can we try to meet the requirements of different users.

Weifang Jude Electronic Co. Ltd is a China famous piezoelectric manufacturers, providing high-quality piezoelectric ceramics for a multitude of electrical functions. If you have any needs, please contact us.