What is the condition for poling such piezo material .
1- how can I predict poling temperature ? does the poling temperature related to ( or depend on ) Curie temperature .
2- How can I predict the poling voltage
3- Researcher normally use Silicone oil with poling of Piezoelectric . can I use glycerine or paraffin oil instead
4-does the Poling with ultra High voltage ( or voltage grater than normal temperature of poling ) affect on the result ( d33 , K , and dielectric constant )
5- Now I am working on Bismuth( Sodium , Potassium ) titanate - Barium titanate - Bismuth ferrite . any suggestion on poling these materials ( ceramic ) .
1. Yes, poling temperature SHOULD be more than critical (Curie) temperature. And the sample should be cooled in presence of external electrical field from above Tc to below it.
2. It depends upon dielectric break down voltage of the material and on the thickness of the sample.
3. Because it has higher breakdown voltage and picks less of moisture upon storage.
4. Not. After aligning the dipoles, increase of field will not help.
5. Lots of papers are there
Poling field can be calculated as 2 or 3 times of coercive field.
Poling conditions for samples you asked are
1. Bismuth(sodium, potassium) titanate-poling field is 3-4kV/mm at 80deg. C for 5 min.
2. BaTiO3-poling field is 2.5-3kV/mm at 80deg.C for 5 min
A simple method to polarize ferroelectric materials
1 Do the hysteresis loops to Know Ec
2 Do the Permitivitty versus T to observe when the dielectric begin to increase (Tp)
3 After that , apply 2Ec and the polarization temperature (Tp)
4 Why apply at Tp? In the cooling process, the dielectric constant decreases and the sample maybe arrive to the breakdown, although the poling field is constant.
I agree with some of previous advices. Each composition have peculiar poling conditions. Genrally, it's better to pole at Tp and using cooling under field. Generally, the best is to try with one sample at a given temperature, by progressivly increasing field, and for each field measure either d33 or the resonance curve up to constant values. Thus you will not exceed breakdown field.
The advices that you received are quite well. Any way, you need to take care to do not exceed breakdown field.
What are poling field for sodium potassium niobate - barium titanate samples, and please explain the poling field and coercive field.
I heard some one using the ultra-high voltage (reaching 100000V) to pole the piezoelectric materials in a minimum time of micro second. Did some one know this poling method?
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