Improvement of plasma uniformity and mechanical properties of Cr films deposited on the inner surface of a tube by an auxiliary anode near the tube tail

Abstract

In order to improve the length of plasma into the whole tube and mechanical properties of Cr films deposited on inner surface of tube, a high-power impulse magnetron sputtering (HiPIMS) coating method with planar cathode target and auxiliary anode was proposed. The auxiliary anode was placed near the tube tail to attract plasma into the inner part of the tube. Cr films was deposited on the inner wall of 20# carbon steel tube with diameter of 40 mm and length of 120 mm. The influence of auxiliary-anode voltage on the discharge characteristics of Cr target, and the structure and mechanical properties of Cr films deposited on the inner surface of tube were explored. With higher auxiliary anode voltage, an increase of substrate current was observed, especially in tube tail. The thickness uniformity, compactness, hardness and H/E ratios of the Cr films deposited on the inner surface of tube increased with the increase of auxiliary anode voltage. The Cr films deposited with auxiliary anode voltage of 60 V exhibited the highest hardness of 9.6 GPa and the lowest friction coefficient of 0.68.

Characteristics of the plasma sheath in helium discharge within dielectric tubes

“…High breakdown voltage is required and to which the operators are exposed [2][3][4][5][6]. Non-thermal atmospheric-pressure plasma jets, rich in reactive chemical species at room temperature, show advanced surface modification, sterilization and decontamination applications [7][8][9][10][11][12][13]. Chen et al developed a transferred atmospheric-pressure plasma inside polytetrafluoroethylene (PTFE) tubes ignited by an argon plasma jet [14].…”

An atmospheric pressure plasma device with multiple ring electrodes for decontamination of flexible tubing with variable scales

“…Discharge plasma for sterilization of narrow tube inner surface, in terms of bactericidal effect, compared with ozone and UV light irradiation, [12] has more application prospects with a self-enhanced plasma discharge effect under certain conditions. [13,14] However, low-pressure plasma sterilization is most likely only suitable for the sterilization of relatively smooth outer surfaces and not for narrow tubes, unless the plasma is ignited inside the tube without a reliable sterilization function. Here, atmospheric pressure plasmas might be more suitable because they are much cheaper to develop for a specific medical device.…”