Piezo Solutions

When it comes to piezoelectric actuators with large displacements there is no way around multilayer technology. Here TDK is offering various solutions for the internal electrode systems: silver palladium alloys (AgPd), the industry standard used by most manufacturers, as well as copper (Cu) is offered by TDK. 

The Cu technology becomes extremely useful in the case of demanding environmental conditions. AgPd systems tend to have issues under humid conditions where so-called silver migration can occur, causing the actuators to fail. 

This advantage becomes obvious if you take a look at our test series where we compared the performance of multilayer stacks under humid conditions. Under 85 °C and 85% relative humidity piezo stacks with 95% Ag content typically failed at around 1 million cycles. Reducing the Ag content showed a positive effect, however, even at 25% Pd content the stacks still failed after around 4 million cycles. Stacks with Cu inner electrodes however showed not a single failure, even after 100 million cycles. 

While increasing the Pd content can be helpful in overcoming issues under humid conditions, the economic consequences are immense: Palladium has become the main driver for the material cost of multilayer piezo components: Only within the last decade, the average cost of Palladium has increased by more than a factor of four, making it now the dominant cost factor in the price of piezoelectric actuators. 

Using copper for the internal electrodes makes you independent of the future Pd price development.

Our rectangular piezo benders are available in a range up to 80 mm in length, up to 44 mm in width and thickness up to 2 mm. Other sizes and constructions are available on request. Piezolelectric plates are available as customized solutions as well.