Plasma Immersion Ion Implantation And Deposition Research Articles

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.

MoS2/Ti multilayer deposited on 2Cr13 substrate by PIIID

Plasma immersion ion implantation and deposition (PIIID) was used to fabricate the MoS2/Ti multilayer on the 2Cr13 substrate. The Ti layer was deposited by a pulse cathodic arc plasma source and the MoS2 layer was obtained by a radio-frequency (RF) magnetron sputtering system. Scanning electron microscope (SEM), ball-on-disk, electrochemical and water vapour spray tests were used to characterize the as-deposited multilayer. The SEM result shows that the MoS2/Ti multilayer has formed a good layered structure. The friction curves of MoS2/Ti multilayers reveal that the wear resistance and friction coefficient of the multilayer can be improved significantly by a proper structure. The anode polarization curves obtained in 0.5% H2SO4 solution show that the corrosion current density of the MoS2/Ti multilayer can be decreased to 68% of that of the MoS2 single layer. In addition, results of the water vapour spray test for 48h show that the surface of the MoS2/Ti multilayer is smooth and no erosion can be found, where the MoS2 single layer is partially peeled off from the substrate.

Duplex diamond-like carbon film fabricated on 2Cr13 martensite stainless steel using inner surface ion implantation and deposition

A duplex plasma immersion ion implantation and deposition (PIIID) process, involving carbon ion implantation and diamond-like carbon (DLC) film deposition, is proposed to treat the inner surface of a tube. Samples of 2Cr13 martensite stainless steel were placed inside the tube to investigate the performance of the films. Carbon ion implantation was finished by biasing the tube with a high voltage, and the DLC film deposition was obtained by biasing the tube with a medium voltage. Raman spectrum, ball-on-disc, indentation and scratch tests were used to investigate the structure, tribological property and adhesion strength of the as-deposited films. The Raman spectrum shows that the sp 3 bonding is formed in the as-synthesized film. Tribological and scratch test results reveal that the duplex DLC coating with the implantation time of 1 h has the largest adhesion strength and the best wear resistance.

Properties of Zr–ZrC–ZrC/DLC gradient films on TiNi alloy by the PIIID technique combined with PECVD

The Zr–ZrC–ZrC/DLC gradient composite films were prepared on TiNi alloy by the techniques combined plasma immersion ion implantation and deposition (PIIID) and plasma enhanced chemical vapor deposition (PECVD). With this method, the Zr–ZrC intermixed layers can be obtained by the ion implantation and deposition before the deposition of the ZrC/DLC composite film. In our study, an optimal gradient composite film has been deposited on the NiTi alloys by optimizing the process parameters for implantation and deposition. The surface topography was observed through AFM and the influence of the deposition voltage on the surface topography of the film was investigated. XPS results indicate that on the outmost layer, the Zr ions are mixed with the DLC film and form ZrC phase, the binding energy of C 1s and the composition concentration of ZrC depend heavily on the bias voltage. With the increase of bias voltage, the content of ZrC and the ratio of sp 3/sp 2 firstly increases, reaching a maximum value at 200 V, and then decreases. The nano-indentation and friction experiments indicate that the gradient composite film at 200 V has a higher hardness and lower friction coefficient compared with that of the bare NiTi alloy. The microscratch curve tests indicate that gradient composite films have an excellent bonding property comparing to undoped DLC film. Based on the electrochemical measurement and ion releasing tests, we have found that the gradient composite films exhibit better corrosion resistance property and higher depression ability for the Ni ion releasing from the NiTi substrate in the Hank's solution at 37°C.

Duplex DLC coatings fabricated on the inner surface of a tube using plasma immersion ion implantation and deposition

A duplex plasma immersion ion implantation and deposition (PIIID) process, involving carbon ion implantation and diamond-like carbon (DLC) deposition, is proposed to modify the inner surface of a tube. In the research, samples of GCr15 bearing steel were placed inside a tube in the vacuum chamber. After the vacuum chamber was evacuated to a base pressure of 6 × 10 − 3 Pa, C 2H 2 gas was introduced into the chamber, and the tube was biased by a negative pulsed bias. Since a pulsed glow discharge (PGD) plasma can be formed by the bias, carbon ion implantation and DLC film deposition process can be obtained by biasing the tube with a high and low bias, respectively. To synthesize different DLC films, single PIIID processes employing a low voltage (several kV) PGD method and duplex PIIID processes combining the high (several tens kV) and low voltage PGD techniques were carried out. The as-synthesized films were characterized by Raman spectrum, nano-indentation, scratch, tribological and electrochemical tests. Raman results show that duplex DLC films were synthesized by this duplex PIIID process. In addition, compared with the single DLC film synthesized by the low voltage PGD process, the duplex DLC films can obtain a high wear and corrosion resistances. Furthermore, using this duplex PIIID method, batch treatment of outer-rings of the bearing was realized.

Small amplitude reciprocating wear performance of diamond-like carbon films: dependence of film composition and counterface material

Small amplitude (50 μm) reciprocating wear of hydrogen-containing diamond-like carbon (DLC) films of different compositions has been examined against silicon nitride and polymethyl-methacrylate (PMMA) counter-surfaces, and compared with the performance of an uncoated steel substrate. Three films were studied: a DLC film of conventional composition, a fluorine-containing DLC film (F-DLC), and silicon-containing DLC film. The films were deposited on steel substrates from plasmas of organic precursor gases using the Plasma Immersion Ion Implantation and Deposition (PIIID) process, which allows for the non-line-of-sight deposition of films with tailored compositions. The amplitude of the resistive frictional force during the reciprocating wear experiments was monitored in situ, and the magnitude of film damage due to wear was evaluated using optical microscopy, optical profilometry, and atomic force microscopy. Wear debris was analyzed using scanning electron microscopy and energy dispersive spectroscopy. In terms of friction, the DLC and silicon-containing DLC films performed exceptionally well, showing friction coefficients less than 0.1 for both PMMA and silicon nitride counter-surfaces. DLC and silicon-containing DLC films also showed significant reductions in transfer of PMMA compared with the uncoated steel. The softer F-DLC film performed similarly well against PMMA, but against silicon nitride, friction displayed nearly periodic variations indicative of cyclic adhesion and release of worn film material during the wear process. The results demonstrate that the PIIID films achieve the well-known advantageous performance of other DLC films, and furthermore that the film performance can be significantly affected by the addition of dopants. In addition to the well-established reduction of friction and wear that DLC films generally provide, we show here that another property, low adhesiveness with PMMA, is another significant benefit in the use of DLC films.

Effect of hydrogen on the behavior of cultured human umbilical vein endothelial cells (HUVEC) on titanium oxide films fabricated by plasma immersion ion implantation and deposition

In this paper, titanium oxide (Ti–O) thin films were fabricated by plasma immersion ion implantation and deposition (PIII-D), and subsequently hydrogen ions were implanted into the film surface by PIII to improve the biocompatibility of blood and vascular contacting biomaterials and prosthesis such as stents, etc. The films were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS), and atomic force microscopy (AFM). The contact angle of Ti–O films with simulated body fluid was measured. The biological behavior of cultured human umbilical vein endothelial cells (HUVECs) on Ti–O film surfaces was evaluated by an in vitro cultured HUVEC experiment. The in vitro investigation of cultured ECs on Ti–O films revealed that the biological behavior of HUVECs, such as adherence, growth and proliferation etc., were better biologically for hydrogen-containing Ti–O films than for untreated Ti–O films. The results of our study support the hypothesis that the surface morphology and biological properties such as wettability and surface tension etc. of the implanted Ti–O films are changed to a more desirable range by the high energy H plasma immersion ion implantation and by H incorporation in the films. As a result, the H-containing Ti–O films possess good biocompatibility.

The Study of Surface Energy, Electrical Properties and Platelet Adhesion Behavior of a-C/a-CN Films Synthesized by PIII-D

Amorphous carbon (a-C) and carbon nitrogen (a-CN) films were synthesized using plasma immersion ion implantation and deposition (PIII-D) under different N2 flow at room temperature (R.T.). Lifshitz-van der Waals/acid-base approach (LW-AB) was introduced in order to study films’ surface energy deeply. The results showed that the capability of the surface of the film on receive electron changed with N2 flow, which effected platelet adhesion of film strongly. Hall effects tests were employed to characterize the electrical properties of the films. The results showed that the as-deposited films exhibited n-type semiconductor characteristic, and carrier concentration of the films decreased with N2 flow increasing. Raman spectra with 514nm laser-source were employed to analyze the structural of the films.

Corrosion behavior of NiTi alloys coated with diamond-like carbon (DLC) fabricated by plasma immersion ion implantation and deposition

A dense and well-adhered diamond-like carbon (DLC) coating was prepared on NiTi alloys by plasma immersion ion implantation and deposition (PIIID). Electrochemical impedance spectroscopy and potentiodynamic polarization tests indicated the corrosion resistance of the NiTi alloys was markedly improved by DLC coating.

DLC films fabricated by plasma immersion ion implantation and deposition on the NiTi alloys for improving their corrosion resistance and biocompatibility

Diamond-like carbon films with different bias voltages were deposited on polished NiTi alloys by plasma immersion ion implantation and deposition (PIIID) using acetylene as precursor. The chemical structure of the DLC films was characterized by Raman scattering spectroscopy. The electrochemical behavior and blood compatibility of the DLC coated and uncoated NiTi alloys were investigated by means of potentiodynamic polarization tests, clotting time measurement, and platelets adhesion. The results show the corrosion resistance and blood compatibility of the NiTi alloys is improved due to the DLC films, and the sp 3/sp 2 ratio and the corrosion resistance of the DLC films on the NiTi alloys first increases and then decreases with the increase of the bias voltage. Thus, it can be inferred that the corrosion resistance of the DLC films is influenced by the sp 3/sp 2 ratio.

Structure and topographies of diamond-like carbon films produced on tungsten pre-implanted stainless steel substrate by plasma immersion ion implantation and deposition

DLC films were deposited by plasma immersion ion implantation and deposition (PIII-D) on steel substrates using different pretreatment procedures. Our results show that DLC films with good quality can be produced on the W pre-implanted steel substrates but it is not so on the untreated substrate or on the steel substrate with a W buffer layer. Moreover, altering the pre-implantation parameters gives rise to different distributions and amounts of W that influence the film growth at the latter stage. The final surface morphologies and structures of the deposited DLC films are also strongly affected by the pretreatment parameters.

Batch treatment of industrial components using plasma immersion ion implantation and deposition

Surface modifications of industrial components, such as the balls, inner and outer rings of bearings, are very difficult to perform for their sophisticated shapes. Plasma immersion ion implantation and deposition (PIIID) offers an effective way for surface treatment of such components. However, implantation doses of these components are not uniform in a conventional PIIID process. To obtain uniform surface modifications, we designed a rotating target holder. Using the target holder and proper process parameters, the PIIID batch treatment of sophisticated-shape components has become easy work. In the PIIID batch treatments of balls, outer and inner surfaces of cylinder-like components, the dose uniformity can be evidently improved by using sample rotation, short width high frequency implantation pulse, and middle-frequency and -voltage glow discharge, respectively. The practical test results reveal that the life of these components can be improved significantly by this novel PIIID batch treatment.

TiN/ZrO 2 multilayers synthesized on GCr15 bearing steel using plasma immersion ion implantation and deposition

TiN/ZrO 2 multilayers with different modulation periods were synthesized on GCr15 bearing steel using plasma immersion ion implantation and deposition (PIIID). The total thickness of the TiN/ZrO 2 multilayers was approximately 2 μm and the modulation period was varied from 8 to 400 nm. The as-deposited films were characterized by scanning electron microscopy (SEM), micro-hardness, friction, scratch and corrosion tests. The SEM result indicates that the structure of the TiN/ZrO 2 multilayers has a good periodicity. Micro-hardness testing results show that the hardness enhancement effect takes place at the specific period of 15 nm, 100 nm and 200 nm. In addition, the friction coefficient declined from 0.8 to 0.1–0.3 and the cut-through number was increased greatly. The critical load in the scratch test exceeds 100 N, which shows a high adhesion strength. Moreover, the corrosion resistance of the TiN/ZrO 2 multilayers was improved significantly at the modulation period of 100 nm and 200 nm.

Raman spectroscopy study of DLC films prepared by RF plasma and filtered cathodic arc

The build-up of intrinsic stress in carbon thin films deposited by vapour deposition can be a major cause of delamination. Arguably, this issue has been one of the main reasons why the industrial exploitation of carbon vapour deposited films has so far been of limited success. In the present study we deposited single and multilayer thin films of carbon and found that under certain deposition conditions, we were able to produce thin films free from delamination. Single and multilayer of films Diamond-like Carbon (DLC) were prepared by Plasma Immersion Ion Implantation and Deposition (PIIID) from two deposition systems: (1) Radio-Frequency (RF) plasma and (2) Filtered Cathodic Vacuum Arc (FCVA). Raman spectroscopy revealed a shift in the peaks previously identified as D and G band in the structures. The sp 2 and sp 3 ratio contents were characterized by Raman spectroscopy.

Effect of bias voltage on the structure and the electrochemical corrosion behavior of hydrogenated amorphous carbon (a-C:H) films on NiTi alloys

Hydrogenated amorphous carbon films with different bias voltages were deposited on polished NiTi alloys by plasma immersion ion implantation and deposition (PIIID) using acetylene as precursor. Film composition and microstructure were characterized by X-ray photoelectron spectroscopy (XPS) and Raman scattering spectroscopy. The electrochemical behaviour of amorphous carbon films was investigated in Hank's solution by means of potentiodynamic polarization tests and atomic absorption spectrometry. The results show the a-C:H films improve the corrosion resistance of NiTi alloys, and the sp 3/sp 2 ratio and corrosion resistance of the a-C:H films on the NiTi alloys first increase and then decrease with the increase of bias voltage. Moreover, the relationship between the corrosion resistance and the structure of the a-C:H films is clarified.

Modification of biomedical NiTi shape memory alloy by TiC/Ti films using PIIID

TiC/Ti coatings were deposited on the surface of Ti–50.6 at.% Ni alloy by plasma immersion ion implantation and deposition (PIIID) technique. The microstructure, mechanical properties and hemocompatibility of the samples were investigated by means of XRD, AFM, nanoindentation, and scratch and platelet adhesion tests. The result of XRD analysis shows that the crystalline TiC coating has a preferential orientation of (111) in the normal direction. The surface presents a very smooth and dense microstructure with 1.517 nm root mean square roughness (RMS). The average hardness and modulus values of the TiC coating are much higher than those of the NiTi substrate. In the initial stage of scratching, some obvious transversal cracks and worm-like cracks spreading into the film from both side of the scratch track were observed. At higher normal loads for the scratching test, the film delaminated from the substrate at the margins of the substrate. Platelet adhesion tests demonstrate that the hemocompatibility of the coated sample is improved.

Formation of TiN films on biomedical NiTi shape memory alloy by PIIID

TiN coatings with the characteristics of excellent corrosion and wear resistance, high hardness and good biocompatibility, have received much attention in biomedical applications. Plasma immersion ion implantation and deposition (PIIID) is a novel method that can not only ensure excellent bonding between the coating and underlying material, but also overcome the line-in-sight shortcoming. The aim of the present study is to deposit TiN coatings on the surface of Ti–50.6 at.% Ni alloy by the advanced PIIID method to improve the wear resistance and hardness of a NiTi alloy surface. Two process parameters, i.e. voltage, and flows of Ar and N 2 were varied in the present experiments. The chemical composition, mechanical and corrosion resistance properties of the samples were investigated using XPS, nanoindentation and electrochemical method. The XPS results showed that the flows of Ar and N 2 had a great influence on the composition of the TiN films. The hardness and elastic modulus of the TiN films increased with an increase of pulse bias voltage and reached a maximum value for films deposited at −20 kV when the flow rate ratio of Ar to N 2 was 2/1. The experimental results revealed that the film preparation parameters directly affected the microstructure of the TiN, and thus influenced the mechanical and corrosion properties of the NiTi alloy, open circuit potential (OCP) values of the specimens increased with the negative pulse bias voltage and reached its maximum value when the flow rate of Ar/N 2 was 2/1. Combined with the results of Tafel and anodic polarization curves, an excellent corrosion resistant TiN coating by PIIID technique could be obtained by varying the process parameters.

Effect of working pressure on the structure and the electrochemical corrosion behavior of diamond-like carbon (DLC) coatings on the NiTi alloys

DLC coatings with different working pressure (2 × 0 − 2 , 6 × 10 − 2 and 8 × 10 − 2 Pa) were deposited on polished NiTi alloys by plasma immersion ion implantation and deposition (PIIID) using graphite as plasma source. The results of Raman spectra and X-ray photoelectron spectroscopy (XPS) indicate the sp 3/sp 2 ratio is decreased with the increase of the working pressure. The cross-section microstructure of the DLC coated NiTi alloys indicates that the DLC coating is dense and compact. The corrosion results show that the corrosion resistance of the NiTi alloys is improved by the DLC coating, and the corrosion resistance of the DLC coatings on the NiTi alloys is decreased with the increase of the working pressure. It can be concluded that the sp 3/sp 2 ratio has obvious effect on the corrosion resistance of the DLC coatings.

Formation of ZrO 2 coating on the NiTi alloys for improving their surface properties

ZrO 2 films were fabricated by plasma immersion ion implantation and deposition (PIIID) on the polished NiTi alloys. The results obtained from X-ray diffraction (XRD) and scanning electronic microscopy (SEM) showed the dense and well adhered ZrO 2 coating were successfully fabricated by PIIID. Pin-on-disc and scratch tests revealed the surface friction coefficient of NiTi alloys was decreased due to the ZrO 2 coating and good adhesion strength between the coating and substrate was obtained, respectively. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies indicated a significantly larger increase of the coated sample in the corrosion resistance compared with the uncoated samples. The mechanism of the improvement in the corrosion resistance of NiTi alloys due to ZrO 2 coating was clarified.

Surface characterization and electrochemical studies of biomedical NiTi alloy coated with TiN by PIIID

TiN coatings were deposited on the surface of Ti–50.6 at.% Ni alloy by the advanced plasma immersion ion implantation and deposition (PIIID) technique to improve the wear and corrosion resistances. The surface characteristics and corrosion property of the samples were investigated by atomic-force microscopy (AFM) and electrochemical measurement. The AFM results showed that negative pulse bias voltage and N 2/Ar flow rate greatly influence the surface roughness of the TiN films. Combined with the results of Tafel curves, anodic polarization curves and electrochemical impedance spectroscopy, we found that an excellent corrosion resistant TiN coating by PIIID technique could be obtained by varying the process parameters. The sample deposited at −20 kV, with 1:2 nitrogen to argon flow ratio, exhibited excellent anti-corrosion property, which had a more positive value of corrosion potential E corr, a higher value of polarization resistance R p and a low corrosion current density I corr. An appropriate equivalent circuit model was proposed to describe the corrosion process of the TiN coated samples in the present study.