Effect of cathode composition on microstructure and tribological properties of TiBN nanocomposite multilayer coating synthesized by plasma immersion ion implantation and deposition

Nanocomposite multilayer TiBN coatings were prepared on Si(100) and 9Cr18Mo substrates using TiBN composite cathode plasma immersion ion implantation and deposition technique(PIIID). Synthesis of TiBN composite cathodes was conducted by powder metallurgy technology and the content of hexagonal boron nitride(h-BN) was changed from 8% to 40%(mass fraction). The as-deposited coatings were characterized by energy dispersive spectrometer(EDS), grazing incidence X-ray diffraction(GIXRD), Fourier Transform Infrared Spectroscopy(FTIR) and high resolution transmission electron microcopy(HRTEM). EDS results show that the B content of the coatings was varied from 3.71% to 13.84%(molar fraction) when the composition of the h-BN in the composited cathodes was changed from 8 % to 40%(mass fraction). GIXRD results reveal that the TiBN coatings with a B content of 8% has the main diffraction peak of TiN(200),(220) and(311), and these peaks disappear when the B content is increased. FTIR analysis of the multilayer coatings showed the presence of h-BN in all coatings. TEM images reveal that all coatings have the characteristics of self-forming nanocomposite multilayers, where the nanocomposites are composed of face-centered cubic Ti N or h-BN nanocrystalline embedded in amorphous matrix. The tribological tests reveal that the Ti BN coatings exhibit a marked decrease of coefficient at room temperature(~0.25). The improved properties were found to be derived from the comprehensiveness of the self-forming multilayers structure and the h-BN solid lubrication effects in the coatings.

Structure and Tribological Property of TiBN Nanocomposite Multilayer Synthesized by Ti-BN Composite Cathode Plasma Immersion Ion Implantation and Deposition

A Ti-BN complex cathode is made from Ti and h-BN powders by the powder metallurgy technology, and TiBN coating is obtained by plasma immersion ion implantation and deposition with this Ti-BN composite cathode. The TiBN coating shows a self-forming multilayered nanocomposite structure while with relative uniform elemental distributions. High resolution transmission electron microscopy images reveal that the multilayered structure is derived from different grain sizes in the nanocomposite. Due to the existence of h-BN phase, the friction coefficient of the coating is about 0.25.

Nitrogen Deposition Via N^+ Implantation:Implications for Primordial Amino Acids Synthesis Revisited

In this paper amino acids synthesis in aqueous solution induced by ion implantation, which was possibly ubiquitous on primitive Earth, is investigated. As a discharge using a graphite rod as the anode under a nitrogen atmosphere was performed against ammonia water, it was found that three kinds of amino acids were produced. They were glycine, serine and alanine. By introducing ion implantation into the carboxylate solution, ammonia and amino acids were also formed via nitrogen deposition/fixation. Another isotopic experiment showed that both OH and H radicals played a crucial role in the arc-discharge-promoted reactions in aqueous solution Therefore, we believe that the impact of ions in the original atmospheric conditions might have functioned as a promoter in the chemical origin and evolution of life.

Low temperature soldering alloy using Sn63 Pb37 implantation of silica ceramics and copper solder assisted by ion and deposition

Copper ion implantation and deposition technique was applied as a pretreatment method for low temperature joining of silica ceramic （ SiO2 ） and copper alloy. The effect of copper ion implantation and deposition parameters on the microstructures and mechanical behavior of the soldering joints was investigated by scanning electron microscope （SEM） , X- ray diffraction （ XRD ） and shearing test. The copper implantation depth was about 90 nm with peak concentration of 70% for the SiO2 sample implanted for 90 rain. If copper film was deposited for 4 rain using magnetron sputtering, copper layer with thickness of 150 nm and peak concentration of 80% was obtained. After pretreatment of ion implantation and deposition, SiO2 and copper were joined successfully at low temperature directly using SnPb solder. The SnPb solder filling ratio along joining seams was up to 100% without defects with smooth soldering toes. With the increase of implantation dose, the shear strength of the Si02/Cu joints increases accordingly. After a special pretreatment on SiO2 （ Cu implantation for 30min, following Cu deposition for 4 rain, then Cu implantation for 60 rain and finally Cu deposition for 120 min） , a maximum soldering strength of 22 MPa was achieved, and the soldering joints fractured at the SiO2 base material.

Diamond-like carbon films synthesized on bearing steel surface by plasma immersion ion implantation and deposition

Diamond-like carbon (DLC) films were synthesized by plasma immersion ion implantation and deposition (PIIID) on 9Cr18 bearing steel surface. Influences of working gas pressure and pulse width of the bias voltage on properties of the thin film were investigated. The chemical compositions of the as-deposited films were characterized by Raman spectroscopy. The micro-hardness, friction and wear behavior, corrosion resistance of the samples were evaluated, respectively. Compared with uncoated substrates, micro-hardness results reveal that the maximum is increased by 88.7%. In addition, the friction coefficient decreases to about 0.1, and the corrosion resistance of treated coupons surface are improved significantly.

Modeling of Inner Surface Modification of a Cylindrical Tube by Plasma-Based Low-Energy Ion Implantation

The inner surface modification process by plasma-based low-energy ion implantation（PBLEII）with an electron cyclotron resonance（ECR）microwave plasma source located at the central axis of a cylindrical tube is modeled to optimize the low-energy ion implantation parameters for industrial applications.In this paper,a magnetized plasma diffusion fluid model has been established to describe the plasma nonuniformity caused by plasma diffusion under an axial magnetic field during the pulse-off time of low pulsed negative bias.Using this plasma density distribution as the initial condition,a sheath collisional fluid model is built up to describe the sheath evolution and ion implantation during the pulse-on time.The plasma nonuniformity at the end of the pulse-off time is more apparent along the radial direction compared with that in the axial direction due to the geometry of the linear plasma source in the center and the difference between perpendicular and parallel plasma diffusion coefficients with respect to the magnetic field.The normalized nitrogen plasma densities on the inner and outer surfaces of the tube are observed to be about 0.39 and 0.24,respectively,of which the value is 1 at the central plasma source.After a 5μs pulse-on time,in the area less than 2 cm from the end of the tube,the nitrogen ion implantation energy decreases from 1.5 keV to 1.3 keV and the ion implantation angle increases from several degrees to more than 40°;both variations reduce the nitrogen ion implantation depth.However,the nitrogen ion implantation dose peaks of about 2×10^（10）-7×10^（10）ions/cm^2 in this area are 2-4 times higher than that of 1.18×10^（10）ions/cm^2 and 1.63×10^（10）ions/cm^2 on the inner and outer surfaces of the tube.The sufficient ion implantation dose ensures an acceptable modification effect near the end of the tube under the low energy and large angle conditions for nitrogen ion implantation,because the modification effect is mainly determined by the ion implantation dose,just as the mass transfer process in PBLEII is dominated by low-energy ion implantation and thermal diffusion.Therefore,a comparatively uniform surface modification by the low-energy nitrogen ion implantation is achieved along the cylindrical tube on both the inner and outer surfaces.

Thin relaxed SiGe layer grown on Ar^+ ion implanted Si substrate by ultra-high vacuum chemical vapor deposition

Thin strain-relaxed Si0.81Ge0.19 films (95 nm) on the Ar+ ion implanted Si substrates with different ener- gies (30 keV,40 keV and 60 keV) at the same implanted dose (3×1015cm-2) were grown by ultra high vacuum chemi- cal vapor deposition (UHVCVD). Rutherford backscattering/ion channeling (RBS/C),Raman spectra as well as atomic force microscopy (AFM) were used to characterize these SiGe films. Investigations by RBS/C demonstrate that these thin Si0.81Ge0.19 films were epitaxially grown on the Ar+ ion implanted Si substrates,although there existed lots of crystal defects. The relaxation extent of Si0.81Ge0.19 films on the Ar+ implanted Si substrates is larger than that in the unimplanted case,which were verified by Raman spectra. Considering the relaxation extent of strain,surface roughness and crystal defects in these SiGe films,the thin relaxed SiGe film on the 30 keV Ar+ implanted Si substrate is optimal.

Deposition of TiN Films by Novel Filter Cathodic Arc Technique

A straight magnetic filtering arc source is used to deposit thin films of titanium nitride. The properties of the films depend strongly on the deposition process. TiN films can be deposited directly onto heated substrates in a nitrogen atmosphere or onto unbiased substrates by condensing the Ti^＋ ion beam in about 300 eV N2^＋ nitrogen ion bombardment. In the latter case, the film stoichiometry is varied from an N：Ti ratio of 0.6-1.1 by controlling the arrival rates of Ti and nitrogen ions. Meanwhile, simple models are used to describe the evolution of compressive stress as function of the arrival ratio and the composition of the ion-assisted TiN films.

Plasma Immersion Ion Implantation of the Pea Seed and Its RBS Spectra

Plasma immersion ion implantation (PI^3), a new technique with certain advantages over biological samples, was developed. Argonion as well as nitrogen ion implantation of the pea seeds has been carried out with the PI^3 implanter and their RBS spectra were also studied. The results show that the mass deposition effect of ion implantation on biological samples can be achieved with the PI^3 implanter. In addition, there is an optimal implantation time for a given treatment condition. It presents new possibilities for the ion implantation into biological samples.

Determination of activation energy of ion-implanted deuterium release from W–Y2O3

The retention and release of deuterium in W–2%Y2O3 composite materials and commercially pure tungsten after they have been implanted by deuterium plasma(flux ~ 3.71 × 1021 D/m2·s, energy ~ 25 eV, and fluence up to 1.3 × 1026D/m2)are studied. The results show that the total amount of deuterium released from W–2%Y2O3 is 5.23 × 1020 D/m2(2.5 K/min),about 2.5 times higher than that from the pure tungsten. Thermal desorption spectra(TDS) at different heating rates(2.5 K/min–20 K/min) reveal that both W and W–2%Y2O3 have two main deuterium trapped sites. For the low temperature trap, the deuterium desorption activation energy is 0.85 eV(grain boundary) in W, while for high temperature trap, the desorption activation energy is 1.57 eV(vacancy) in W and 1.73 eV(vacancy) in W–2%Y2O3.

Hybrid Method for the Formation of Biocomposites on the Surface of Stainless Steel Implants

This study reports a hybrid method which allows the formation of biocomposites on stainless steel implants. The main idea of the method is to create multilayer coatings consisting of titanium primer layer and a microarc calcium-phosphate coating. The titanium layer is deposited from plasma of continuous vacuum-arc discharge, and calcium-phosphate coating is formed by the microarc oxidation technique. The purpose of the hybrid method is to combine the properties of good strength stainless steel with high bioactivity of calcium-phosphate coating. This paper describes the chemical composition, morphology characteristics, adhesion and the ability of the formed biocomposites to stimulate the processes of osteoinduction. It is expedient to use such biocomposites for implants which carry heavy loads and are intended for long-term use, e.g. total knee endoprosthesis.

PLASMA IMMERSION ION IMPLANTER FOR THE MODIFICATION OF INDUSTRIAL AEROSPACE COMPONENTS

A commercial plasma immersion ion implanter has been designed and constructed to enhance the surface properties of parts and components used in aerospace applications. The implanter consists of a vacuum chamber, pumping and gas inlet system, custom sample chuck, four sets of hotfilaments, threefiltered vacuum arc plasma sources, special high voltage modulator, as well as monitoring and control systems. Special attention has been paid to improve the uniformity of plasma in the chamber. The power modulator operates in both the pulse bunching and single pulse modes. The maximum pulse voltage output is 80kV, maximum pulse current is 60A, and repetition frequency is 50～500Hz. The target chuck has been specially designed for uniform implantation into multiple aerospace components with irregular geometries as well as effective sample cooling. An in situ temperature monitoring device comprising dual thermocouples has been developed. The instrument was installed in an aerospace company and has been operating reliably for a year. In addition to reporting some of the hardware innovations, data on the improvement of the lifetime of an aircraft hydraulic pump disk using a dual nitrogen treatment process m-2; 30～45kV are presented. This treatment protocol has been adopted as a standard production procedure in the factory.

Zinc ion implantation-deposition modification of titanium for enhanced adhesion of focal plaques of osteoblast-like cells

Background Surface modification by ion implantation-deposition is well established in materials science and can be an effective way to improve biocompatibility. The aim of this study is to evaluate the chemical composition of a modified titanium （Ti） surface after zinc （Zn） ion implantation and deposition and examine the effect of the modification on the formation of cellular focal adhesion plaques in vitro. Methods cp-Ti discs were modified with Zn ion implantation and deposition via PIIID. The chemical composition of the surface modification was characterized by X-ray photoelectron spectroscopy （XPS）. The formation of focal adhesion plaques on the modified Ti was investigated with human osteoblast-like MG-63 cells that were seeded onto the Ti surfaces and quantified by morphometric analysis under a confocal microscope. Results XPS data revealed that the modified Zn-Ti surface consisted of Ti, oxygen, Zn, and carbon. In addition, Gaussian fitting of the spectra indicated that the modified surface contained titanium dioxide and zinc oxide. After 6 hours of MG-63 cell culture, there were significantly more focal adhesion plaques on the modified surfaces than observed on the nonmodified Ti （P 〈0.05）. Conclusion Zn ion implantation and deposition greatly improved the biocompatibility of Ti for the growth of MG-63 cells.

Electrochemical Corrosion Behavior of the DLC Coated and Uncoated NiTi Alloys

A dense and well-adhered diamond-like carbon （DLC） coating was prepared on the nickel-titanium （NiTi） alloys by plasma immersion ion implantation and deposition （PIIID）. Potentiodynamic polarization tests indicated the corrosion resistance of the NiTi alloys was markedly improved by the DLC coating. The Ni ions release of the NiTi alloys was effectively blocked by the DLC coating.

Effects of Fluorine and Silicon Incorporation on Tribological Performance of Diamond-Like Carbon Films

Diamond-like carbon (DLC) is a metastable amorphous film that exhibits unique properties. However, a number of limitations exist regarding the use of DLC, for instance, its tribological characteristics. In this article, the fluorine and silicon incorporated diamond-like carbon (F-DLC and Si-DLC) films are studied, taking into account the tribological properties of these films compared with pure DLC. The structures of the films were characterized using Auger electron spectroscopy and Raman spectroscopy. The hardness and elastic modulus were evaluated by nanoindentation hardness testing. The friction behavior was assessed using ball-on-disk friction testing and optical microscopy. The results indicated that the deposited DLC films contained 0.6 - 2.1 at.% F and 26.7 - 38.4 at.% Si. A decrease in the hardness and elastic modulus was obtained as F increased in content, which was the opposite of the behavior observed in the Si-DLC films. This was due to the shifting in the G-peak position, which is related to the sp3 bonding fraction in the film. When measured in ambient air, the addition of Si into the DLC film strongly influenced the friction coefficient, whereas doping with F only slightly influenced the films, as evidenced by their wear scars. In addition, only a 26.7 at.% Si-DLC film showed a very low friction coefficient when measured in dry air. This was attributed to the formation of silicon-rich transfer layer on the ball surfaces. Therefore, the addition of Si with 26.7 at.% content to a DLC film can be considered beneficial for improving tribological performance.

Tribological Behavior of Binary B-C Films Deposited by Sputtering-PBII Hybrid System

In this article, the authors report on the use of Radio Frequency (RF) Magnetron Sputtering combined with Plasma-Based Ion Implantation (PBII) technique to synthesize the Boron-Carbon (B-C) films. High purity of boron carbide (99.5%) disk was used as a target with an RF power of 300 W. The mixtures of Argon (Ar)-Methane (CH4) ware used as reactive gas under varying CH4 partial flow pressure at the specified range of 0 - 0.15 Pa and fixed total gas pressure and total gas flow at 0.30 Pa and 30 sccm, respectively. The effect of CH4 flow ratio on the friction coefficient of B-C films was studied. The friction coefficient of the film depended on the concentration of B. When it was 10% or lower, the coefficient decreased to 0.2 or lower. In this concentration range of B, the specific wear rate also decreased to the order of 10-7 mm3/Nm, and excellent wear resistance was displayed.

离子注入诱导成核外延高质量AlN

超宽禁带AlN材料具有禁带宽度大、击穿电场高、热导率高、直接带隙等优势,被广泛应用于光电子器件和电力电子器件等领域.AlN材料的质量影响着AlN基器件的性能,为此研究人员提出了多种方法来提高异质外延AlN晶体的质量,但是这些方法工艺复杂且成本高昂.因此,本文提出了诱导成核的新方法来获得高质量的AlN材料.首先,对纳米图案化的蓝宝石衬底注入不同剂量的N离子进行预处理,随后基于该衬底用金属有机化学气相沉积法外延AlN基板,并在其上生长多量子阱结构,最后基于此多量子阱结构制备紫外发光二极管.研究结果表明,在注入N离子剂量为1×10^(13) cm^(-2)的衬底上外延获得的AlN基板,其表面粗糙度最小且位错密度最低.由此可见,适当剂量的N离子注入促进了AlN异质外延过程中的横向生长与合并过程;这可能是因为N离子的注入,抑制了初期成核过程中形成的扭曲的镶嵌结构,有效地降低了AlN的螺位错以及刃位错密度.此外,基于该基板制备的多量子阱结构,其残余应力最小,光致发光强度提高到无注入样品的152%.此外,紫外发光二极管的光电性能大幅提高,当注入电流为100 mA时,光输出功率和电光转换效率分别提高了63.8%和61.7%.

Deposition and Properties of CrN_x films by High Power Pulsed Unbalanced Magnetron Sputtering

High-power pulsed magnetron sputtering (HPPMS) technology has drawn extensively attention for producing ultra-high dense plasma and high ionization fractions of the sputtered species,depositing dense films with high performance.CrNx films were deposited on the substrates of Si(100) using high-power pulsed unbalanced magnetron sputtering (HPPUMS) technology,and the analyses of XRD and atomic force microscope (AFM) were conducted on the properties of microstructure and surface morphology of CrNx films;the friction coefficient and the adhesion between CrNx film and substrate were measured,respectively.It was found HPPUMS discharge is able to deposit CrNx films with super comprehensive properties:higher adhesive strength between the film and substrate and lower coefficient of friction.Deposition rate of CrNx films,which was tested by interferometry,was about 4.2nm/min at 0.6Pa and the pulse power density up to 6.8kW/cm2 with the pulse repetition frequency of 0.7Hz,which is about 56% of that provided by the mid-frequency magnetron sputtering discharge under the conditions of the same average power output.However,clusters with a dimension of several hundred nanometers were observed on the AFM morphology probably related to high pulse current.

Ion implantation assisted synthesis of graphene on various dielectric substrates

Direct synthesis of high-quality graphene on dielectric substrates is of great importance for the application of graphene-based electronics and optoelectronics. However, high-quality and uniform graphene film growth on dielectric substrates has proven challenging due to limited catalytic ability of dielectric substrates. Here, by employing a Cu ion implantation assisted method, high-quality and uniform graphene can be directly formed on various dielectric substrates including SiO2/Si, quartz glass, and sapphire substrates. The growth rate of graphene on the dielectric substrates was significantly improved due to the catalysis of Cu. Moreover, during the graphene growth process, the Cu atoms gradually evaporated away without involving any metal contamination. Furthermore, an interesting growth behavior of graphene on sapphire substrate was observed, and the results show the graphene domains growth tends to grow along the sapphire flat terraces. The ion implantation assisted approach could open up a new pathway for the direct synthesis of graphene and promote the potential application of graphene in electronics.

氮、氧及金属离子注入铝合金表面改性层摩擦磨损性能研究

在不同温度下对6061铝合金分别进行了氮、氧等离子体浸没离子注入处理,氮与氢混合气体等离子体浸没离子注入处理,以及在氮气氛中的钛或铝等离子体浸没离子注入与沉积处理;采用X射线光电子能谱仪分析了注入改性层的相组成、高温下氧离子注入层的成分及注入离子浓度的深度分布;同时测定了注入改性层的显微硬度及摩擦磨损性能.结果表明:经300℃下氧离子注入处理后铝合金表面形成了较厚的硬质Al2O3层,从而使铝合金表面的耐磨寿命显著延长;经氮/氢混合注入以及氮气氛中金属离子注入和沉积处理后的铝合金表面的抗磨性能显著改善;同单一氮离子注入相比,氮/氢混合注入能更有效地改善铝合金的性能.