Novel friction material solutions for piezoelectric micro-motors

Purpose and goal

The project, which is a preliminary study, has fulfilled its purpose and goal to provide guidance for the further development of the drive system for PiezoMotor AB´s engines based on piezo ceramic, to promote cooperation between industry and research at Uppsala University and more specifically to increase friction between the driving surfaces in PiezoMotors products. All three of these have been met within the framework of the project. There has also been an exchange of competencies between the parties that were not related to the specific project.

Expected results and effects

The project has shown that it is possible to coat the driving surfaces with materials that provide higher friction coefficients. Due to the limitation in time of the preliminary study, only initial lifetime tests have been carried out. The results are positive, but further optimization of material selection and deposition process is required to further improve the lifetime of the motor. The results of the feasibility study support continued research and development in the area of interest. The decision is to apply for new research grants to proceed after this feasibility study.

Planned approach and implementation

F1: Literature study confirmed that chromium nitride (CrN) is a candidate for preliminary studies. CrN has relatively high friction coefficient and has a known process to deposition. F2: The process of depositing CrN on Aluminum oxide, which is used as the drive rod in the motor, was optimized to produce test objects. F3: Produce a number of drive rods with CrN coating. Material analyzes and lifetime tests that show positive results and support continued research and development. F4: A continuation project has been defined to advance from the preliminary study.