Comparison between AlN and Al₂O₃ ceramics applied to barrier dielectric of plasma actuator

This paper reports the material characterization and performance evaluation of an AlN ceramic based dielectric barrier discharge (DBD) plasma actuator. A conventional Al₂O₃ ceramic is also investigated as a control. The plasma images, thermal characteristics and electrical properties of the two actuators are compared and studied. Then, with the same electrical operating parameters (12-kV applied voltage and 11-kHz power frequency), variations of the surface morphologies, consumed power and induced velocities are recorded and analyzed. The experimental results show that the AlN actuator can produce a more uniform discharge while the discharge of the Al₂O₃ actuator is easier to become filamentary. The later condition leads to higher power consumption and earlier failure due to electrode oxidation. In the plasma process, the power increment of the AlN actuator is higher than that of the Al₂O₃ actuator. The induced velocity is also influenced by this process. Prior to aging, the maximum induced velocity of the AlN actuator is 4.2 m/s, which is about 40% higher than that of the Al₂O₃ actuator. After 120-min plasma aging, the maximum velocity of the aged AlN actuator decreases by 27.8% while the Al₂O₃ actuator registers a decrease of 25%.