Piezo and Ferroelectric Materials
Piezoelectric materials respond to pressure by producing an electric charge. Renishaw Advanced Materials exploit the characteristics of matter demonstrating the piezo effect for practical applications, as well as researching other potential uses for piezo materials.
Renishaw Advanced Materials researches and exploits the properties of piezo effect materials in the form of sensors and actuators. PZT (lead –zirconia-titanate) is one of a large family of materials, whose structure change on the application of an electric current or, when strained, generate electricity. These specific piezo or ferroelectric effects as they are known mean that when a current is applied, a volume change occurs in the material. This property is used to produce extremely precise actuator and translation stages capable of operating with resolutions of less than 1.0 nm. If the PZT is constrained on a deformable substrate, a lever arm or actuator can be realised with a much larger movement, traded off against a lower force. Conversely, when the material is strained, it produces electricity, the electric output having a well defined relationship with the strain applied; therefore PZT can be used as a strain sensor. Induced strain, generating small currents, also has potential in the area of energy harvesting.
As with the other materials described, Renishaw Advanced Materials continuously explores ways to improve functional performance and applications of the material types; PZT is no exception. A method has been devised to permit PZTs to be used in hostile environments that would normally cause a significant degradation in performance. Multiple thin-film and interface coatings have been applied to the ceramic PZT, reducing the ingress of moisture into the sintered, porous structure. The coating thickness however, has been arranged so that it doesn't affect the functional performance of, in this case, a PZT actuator.
Renishaw Advanced Materials has already applied piezo technologies for various functions, for example:
• as actuators, working in hostile environments such as high humidity
However, the full potential of piezo technology is still under investigation.
Other applications currently being researched are: