TDK Corporation announces the third generation of EPCOS piezo actuators with copper internal electrodes, which offer both improved performance and higher cost-effectiveness. These innovative actuators are characterized by outstanding stability and reliability. They can operate a billion switching cycles without failures at 170o C. Silver-palladium actuators already exhibit significant failure rates under these extreme conditions. The new copper piezo actuators set a new standard for operating life. The maximum number of cycles even under harsh operating conditions such as high temperature and humidity is one of the most important criteria for use of piezo actuators in energy-efficient fuel injection systems for automobiles.
The third generation of EPCOS piezo actuators with copper electrodes is designed with a minimum proportion of inactive zones in the multilayer actuator and is thereby able to achieve the highest possible volume efficiency. As a result, actuator performance is 20 percent higher than conventional designs of the same size. The basis for this is a ceramic material newly developed by TDK, whose piezoelectric coupling - conversion of electrical power into mechanical power - is higher than 75 percent. With this innovative material in combination with volume efficient actuator design, the new copper piezo actuators have a significantly higher performance than predecessor models and competing products.
TDK is still the only company to use relatively inexpensive copper for the internal electrodes of its piezo actuators, whereas competitors use silver-palladium allows. When there are very high proportions of silver in the electrode material, silver migration can occur and cause failure of the actuators - especially in high humidity conditions. Besides using copper internal electrodes, TDK has developed a new lead-free high-melting metal bond that exhibits no loss of contacting, even at high temperatures. The new piezo actuators withstand a 2000-hour test at 200o C with no signs of embrittlement.