QUESTION:

What is the difference between hard and soft PZT?

Which material should I choose for a certain application?

ANSWER:

Hard materials have a low dielectric loss, and a high mechanical Q value. This makes them suitable for applications, where you want to transmit as much power as possible. The sensitivity of such materials is however not very high.
Hard PZT materials in Ferroperms programme are Pz24, Pz26 and Pz28.
Datasheets for each material can be downloaded from our Internet page.

Soft materials have much higher sensitivity, higher displacement, and a lower mechanical Q value. This makes them suitable for sensor applications. The loss is however much higher, and they are therefore not able to transmit very high power without having problems with overheating and depolarisation.
Soft PZT Materials in Ferroperms programme are Pz21, Pz23, Pz27 and Pz29.
Datasheet for each material can be downloaded from our Internet page.

Based on these general remarks it can thus be seen, that the material selection should be initiated by identifying if you need a sensor or a transmitter.

For sensors you often need a soft material with high sensitivity. Pz27 is a good starting point for most applications, but Pz21 and Pz29 can often improve results once it has been established, that there will not be any problems with elevated temperature or high mechanical stress levels.

For transmitters you often need a hard material with low losses in order to avoid risks of overheating or depolarisation. The most common material for high-power transducers is Pz26, so this will most often be a good starting point in new designs. Transducers operated at very high pre-loads sometimes make it necessary to use Pz28 instead of Pz26.

If there are any doubts on what material to select, please do not hesitate to contact us, and we will do whatever we can to assist you further.