High Temperature Shear – Simplified

Ionix shear plates made from high temperature HPZ580 material can enable the creation of devices that can serve a range of demanding environment applications. These shear parts operate beyond the capability other commercially available materials, with both a high piezoelectric activity and high operating temperature. Read on to find out more.

What is shear?

Shear mode occurs where the electric field is applied to the part perpendicular to the poling direction.

Why use shear?

A higher piezoelectric activity means the shear piezoelectric coefficient (d₁₅) is at least 30% higher than the axial coefficient (d₃₃) for PZT. Additionally, sensing is only in one direction without interference from lateral modes. Using a high temperature shear also means that the pyroelectric charge generation is almost zero.

Why use HPZ?

Ionix Advanced Technologies have developed a proprietary piezoelectric material system (HPZ) which operates at higher temperatures than conventional PZT-based piezoelectric ceramics. Also, HPZ580 exhibits a higher piezoelectric activity than other high temperature piezoelectric ceramics, such as lead metaniobate, bismuth titanate and single crystal piezoelectrics, operating continuously up to 550 °C whilst maintaining a piezoelectric activity (d₁₅) higher than 130 pC/N. 

Materials such as bismuth titanate cannot be produced as shear mode plates longer than ~ 5 mm, as the poling field required to produce parts of this size is too high.

Additionally, HPZ580 has a positive thermal expansion coefficient in the poled direction . PZT is negative which can make integration with other materials challenging.

Key Features: 

• Ionix shear parts offer long term operation up to 580 °C. 
• High piezoelectric activity (d₁₅) compared to competitor materials. 

Current Issues with Other Materials

Other commercial piezoelectric materials suffer from either low piezoelectric activity, such as aluminium nitride, low operating temperature, such as lead metaniobate and PZT, or have too high a coercive field for production of shear plates > 5mm, such as bismuth titanate. PZT has a negative thermal expansion coefficient, making integration challenging. With a high piezoelectric activity and high Curie temperature, Ionix HPZ580 material is uniquely placed for shear applications in a range of demanding environments.  

For more information about our piezoceramic capabilities please get in contact with one of our team members: https://ionixadvancedtechnologies.co.uk/contact-us-ionix-advanced-technologies/

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