Effect of pulse duration on the structure and properties of Ti nano-crystalline films

Abstract:

The microstructure and mechanical properties of nano-crystalline Ti films were studied with different pulse duration,which were deposited by the High Power Pulsed ion plating. The results shows that when the average current kept in low value, the larger peak current can be obtained by adjusting the pulse duration (duty ratio), which has a significant effect on the microstructure of the thin film. The surface morphologies showed gradually appeared apparent porosity of the particles and the growth dimensions of the spherical agglomeration significantly increases with the single pulses duration prolonged. The cross section of the growth showed that the morphology transition from the columnar to the dendritic with the extension of the duration of the pulse, while a large number of pores and defects occurred and the density of the films decreased obviously. The hardness and modulus of the films are showing increased first and the substantially reduced trend with the prolonged of the pulse duration. The value of the hardness and modulus exist the maximum when the single pulse duration reached about 4ms.

Key words:pulse duration; nano-crystalline Ti films; microstructure; mechanical properties