Last Updated on February 7, 2023 by You Ling
Read the article about Curie temperature
Curie temperature of piezoelectric ceramics
1、The temperature problem of high-temperature piezoelectric ceramics
2、what is the Curie temperature of piezoelectric ceramics
3、Customer Questions and Answers
The temperature problem of high-temperature piezoelectric ceramics
Recently, customers often call to inquire about high-temperature piezoelectric ceramics. The operating temperature is required to reach 300-400°C. For such a high temperature, standard piezoelectric ceramic products must not meet the requirements. We provide customers with special customized high-temperature piezoelectric ceramics. ceramics.
What limits the operating temperature of standard piezoelectric ceramic products? In addition to changes in performance, increased electrical losses, and temperature limitations of insulating materials or contact mechanisms, an important factor is the “Curie temperature”.
what is the Curie temperature of piezoelectric ceramics
Today we will introduce what is the Curie temperature of piezoelectric ceramics:
The Curie temperature of piezoelectric ceramics refers to the phase transition temperature of piezoelectric materials from the ferroelectric phase to the paraelectric phase. For all piezoelectric ceramic products, piezoelectric materials have a critical temperature Tc, that is, Curie temperature. Below the critical temperature, the piezoelectric ceramic exhibits a ferroelectric phase. At this time, the piezoelectric ceramic is in a state of polarization and order. When the temperature exceeds the critical temperature Tc, the piezoelectric ceramic changes from a ferroelectric phase to a paraelectric phase. The dipole moment is chaotic and in a state of polarization disorder, which is what we often call a depolarization phenomenon.
When the temperature is lower than 260K, the ferroelectric properties of piezoelectric ceramics will gradually weaken with the decrease of temperature.
The Curie temperature depends on the piezoelectric material, and the piezoelectric materials used in different piezoelectric products are different, so the Curie temperature is different.
Generally, the Curie temperature of low-voltage stacked co-fired piezoelectric ceramics is 150°C, and the Curie temperature of composite structure piezoelectric ceramics is about 350°C. The Curie temperature of specially tailored piezoelectric ceramics can reach 430°C.
Customer Questions and Answers
1、Can piezoelectric ceramics work normally when the temperature exceeds the Curie temperature?
As we have mentioned above, when the temperature of the piezoelectric ceramic exceeds its Curie temperature, the piezoelectric ceramic will depolarize and can no longer work normally.
2、Can piezoelectric ceramics that are depolarized by exceeding the Curie temperature be unusable?
Of course not. Piezoelectric ceramics depolarized due to high temperature can be repolarized by applying voltage, such as 150V driven piezoelectric ceramics hs150/5×5/20. If depolarization occurs due to high temperature, it can be repolarized by loading full amplitude Repolarize the piezo ceramics by holding the value voltage for more than 5 seconds.
3、If the product used does not give the use temperature, how to judge the safe use temperature according to the Curie temperature?
Usually, we recommend using the temperature at about half of the Curie temperature, which can ensure the long-term stability of piezoelectric ceramics. The ferroelectric properties of piezoelectric ceramics and the properties of piezoelectric ceramics will disappear when the piezoelectric ceramic material exceeds the Curie temperature, so it is important to use piezoelectric ceramics below the Curie temperature.
4、Is it possible that two piezoelectric materials with different Curie temperatures have the same other properties?
The Curie temperature is very different, and other characteristics will also be different. It is impossible to only change the Curie temperature of piezoelectric ceramics without changing other properties.
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