Zhiwen Xie

Fourth-generation plasma immersion ion implantation and deposition facility for hybrid surface modification layer fabrication

The fourth-generation plasma immersion ion implantation and deposition (PIIID) facility for hybrid and batch treatment was built in our laboratory recently. Comparing with our previous PIIID facilities, several novel designs are utilized. Two multicathode pulsed cathodic arc plasma sources are fixed on the chamber wall symmetrically, which can increase the steady working time from 6 h (the single cathode source in our previous facilities) to about 18 h. Meanwhile, the inner diameter of the pulsed cathodic arc plasma source is increased from the previous 80 to 209 mm, thus, large area metal plasma can be obtained by the source. Instead of the simple sample holder in our previous facility, a complex revolution-rotation sample holder composed of 24 shafts, which can rotate around its axis and adjust its position through revolving around the center axis of the vacuum chamber, is fixed in the center of the vacuum chamber. In addition, one magnetron sputtering source is set on the chamber wall instead of the top cover in the previous facility. Because of the above characteristic, the PIIID hybrid process involving ion implantation, vacuum arc, and magnetron sputtering deposition can be acquired without breaking vacuum. In addition, the PIIID batch treatment of cylinderlike components can be finished by installing these components on the rotating shafts on the sample holder.

Influence of Si content on structure and mechanical properties of TiAlSiN coatings deposited by multi-plasma immersion ion implantation and deposition

TiAlSiN nanocomposite coatings were prepared by multi-plasma immersion ion implantation and deposition (MPIIID). The chemical composition, microstructure and mechanical properties of these coatings were investigated by energy dispersive X-ray (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nano-indentation and scratch tests. XRD patterns reveal that the main reflection in the as-deposited coating corresponds to a strong TiN (200) preferred orientation. XPS results show that AlN, Si3N4, Al2O3 and Ti2O3 are also formed in the coating. Comparing with the TiN coating, when the Si content in the coating is 0.9%, the film shows an increased hardness of 32 GPa, while its fracture toughness and adhesion strength are weak. When the Si content is increased to 6.0%, the coating exhibits a super hardness of 57 GPa as well as excellent fracture toughness and adhesion strength.

Mechanical performance and corrosion behavior of TiAlSiN/WS2 multilayer deposited by multi-plasma immersion ion implantation and deposition and magnetron sputtering

Abstract To reduce the friction coefficient of the superhard TiAlSiN composite coating, TiAlSiN/WS 2 multilayers were synthesized by multiple plasma immersion ion implantation and deposition as well as radio-frequency (RF) magnetron sputtering. X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectrum, nano indentation, tribological and electrochemical tests were employed to characterize the microstructure, mechanical properties and corrosion behavior of the as-deposited multilayers. SEM results reveal that the TiAlSiN/WS 2 multilayers have a good periodicity. Nano indentation results show that the nanohardness of TiAlSiN/WS 2 multilayers is between that of the TiAlSiN and WS 2 coatings. Tribological tests prove that the friction coefficient of the TiAlSiN/WS 2 multilayers is lower and more stable than that of the TiAlSiN coating. In addition, the TiAlSiN/WS 2 multilayers show excellent corrosion resistance and the corrosion current density decreases obviously at a relative small modulation period.

Ion implantation and energy loss effect during high-voltage pulsed glow discharge in a tube

Plasma parameters of high-voltage pulsed glow discharge in a tube were studied using a static probe and optical emission spectrometry. Experiment results show that two kinds of plasma can be obtained in the tube and a virtual anode can be formed at the center of the tube. The potential of the virtual anode is about 20%–30% of the applied bias. The Auger electron spectroscopy depth profile shows that the peak depth of the implanted ions in the tube is about 70%–80% of that outside the tube, owing to the virtual anode.