Ar/O2 gas pressure dependences of a pulsed zirconium arc and extracted ion characteristics

A pulsed dc zirconium arc discharge is generated in an argon diluted oxygen gas by separating a pin electrode as an anode from the cathode. The arc is transiently generated, and its life time is approximately 3 ms for a series resistance of 1 Ω and a dc output of 33 V. The life is prolonged and the plasma becomes stable with increasing the arc current. A target with a diameter of 100 mm is set at 150 mm from the arc source, and is immersed in the plasma. A pulse voltage is applied to the target to extract ions from the plasma. The ion current is not detected after approximately 8 ms since the plasma initiation. When the plasma is generated in oxygen without argon, the plasma generation time is scattered, and the plasma is unstable. An ion density is estimated from the temporal behavior of the target voltage in the recovery region after the pulse voltage. The ion density at the target is approximately 2.5 × 10¹⁵ m^− 3 at a mixed gas pressure of 1.9 Pa, which corresponds to the plasma density of 1.1 × 10¹⁷ m^− 3 under an assumption of electron temperature of 1 eV.     

Effects of pressure on metal atom transport and plasma properties during arc ion plating of TiAlN

Arc ion plating is used to deposit titanium and aluminum nitrides as wear and corrosion resistant layers on the surface of steel tools. In this study, the deposition efficiency for the evaporated metal atoms in arc ion plating was obtained by a view factor solution for the collisionless transport and a diffusion solution for the continuum transport. In the diffusion solution, the deposition efficiency decreases rapidly with pressure. A global nitrogen plasma model with a set of simplified plasma chemistry was used to investigate the plasma properties at pressures ranging from several mTorr up to 50 mTorr. The results indicate that the electron temperature, the ratio of electric field to gas density, and the nitrogen atom density all decrease with increasing pressure, while the plasma density increases. Based on the combined considerations of deposition efficiency and effective ion bombardment of the films on the substrate, an operating pressure range from 20 to 30 mTorr is recommended for highly efficient (Ti, Al)N coating during film deposition.     

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.     

全方位离子注入与沉积类金刚石碳膜的结构与性能

用等离子体浸没离子注入与沉积(PIIID)复合强化新技术在AISI440C不锈钢表面制备了类金刚石(DLC)碳膜。膜层表面的原子力显微镜(AFM)形貌显示出DLC膜结构致密均匀。Raman光谱分析结果表明,制备的DLC主要是由金刚石键(sp3)和石墨键(sp2)组成的混合无定形碳膜,且sp3键含量大于10%。以纯石墨棒做阴极,C2H2为工作气体条件下合成的DLC薄膜中,sp3键含量总体上较单纯用石墨作阴极而无工作气体条件下合成的DLC薄膜中sp3键含量高。与基体相比,薄膜试样的显微硬度和摩擦磨损性能均得到了较大改善,最大硬度提高88.7%,磨损寿命延长超过4倍。     

TiN/ZrO2 multilayers synthesized on GCr15 bearing steel using plasma immersion ion implantation and deposition

TiN/ZrO₂ 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/ZrO₂ 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/ZrO₂ 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/ZrO₂ multilayers was improved significantly at the modulation period of 100 nm and 200 nm.     

Synthesis of indium oxide nanorods on indium phosphide substrate using plasma immersion ion implantation

We report the preparation of indium oxide (In₂O₃) nanorods on indium phosphide (InP) substrate by plasma immersion ion implantation (PIII). The InP substrate was first treated with PIII of acetylene (C₂H₂) ions, then followed by coating the surface with a 40 nm thick gold film. After rapid thermal anneal (RTA) at 750 °C for 15 s, In₂O₃ nanorods were found on InP surface. The In₂O₃ nanorods with diameters of 50-200 nm were examined by Raman spectroscopy, scanning electron microscopy (SEM) and cathodoluminescence (CL). Nanoparticles of gold were found at the tip of the nanorods, suggesting that a vapour-liquid-solid (VLS) mechanism was involved. However, the fact that other species such as nitrogen, argon or oxygen would not lead to the formation of In₂O₃ nanorods also suggests that the carbon liberated from C₂H₂ plays an important role as a catalyst. Carbon has previously been reported to be a reduction agent for the formation of group III sub-oxides. Such sub-oxides provide the vapour source for the growth of nano-materials through further oxidation.     

等离子体浸没离子注入与沉积合成TiN薄膜的滚动接触疲劳寿命和机械性能

采用等离子体浸没离子注入与沉积（PIII＆D）技术在AISI 52100轴承钢表面合成了高硬耐磨的TiN薄膜.膜层元素分布、化学组成和表面形貌分别用XRD,XPS表征.合成薄膜前后试样的滚动接触疲劳寿命和摩擦磨损性能分别由球棒疲劳磨损试验机和球-盘磨损试验机测定;疲劳破坏后的微观形貌通过SEM观察;薄膜力学性能经纳米压痕和纳米划痕实验评价.结果表明,TiN膜中还含有少量的TiO2和Ti,N,O的化合物.在优化条件下,TiN膜层致密均匀,与基体结合良好,纳米硬度和弹性模量分别达到25和350 GPa;最低摩擦系数由基体的0.92下降到0.2.被处理薄膜试件在90%置信区间下的最大L10,L50,La和-↑L寿命较基体分别提高了约4.5,1.8,1.3和1.2倍,疲劳寿命的分散性得到了显著改善.     

GCr15轴承钢的PIIID表面改性工艺研究

采用等离子体浸没离子注入与沉积(PIIID)技术在GCr15轴承钢表面制备了TiN、TiC薄膜，并对其进行了显微硬度和摩擦磨损测量。结果发现：注入时间、注入脉宽和工作气体对GCr15轴承钢表面改性效果具有显著的影响。通过对比分析，获取了最佳处理工艺参数。     

High frequency and low voltage plasma immersion ion implantation of nitrogen on industrial pure iron at different Rf power

Traditional plasma ion immersion implantation (PIII) can effectively improve material mechanical property and corrosion resistance. But the modified layer by PIII is too thin for many industrial applications. High frequency and low voltage plasma immersion ion implantation (HLPIII) has advantages of PIII and nitriding. Comparing with traditional ion nitriding, HLPIII can obtain higher implantation energy and create a thick modified surface layer. In the present paper nitriding layers were synthesized on industrial pure iron using high frequency and low voltage plasma immersion ion implantation with different RF power (400 W, 600 W, and 800 W). The microstructure of the nitriding layers was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The mechanical properties such as microhardness and wear resistance were analyzed using HXD1000 microhardness and CSEM pin-on-disk wear testing machine. The anodic polarization characteristics were measured in a 0.9% NaCl solution at room temperature to examine the corrosion resistance of the nitriding layer. The results reveal that Fe₂N, Fe₃N and Fe₄N coexist in the nitriding layer. The nitriding layer is a corrosion protective coating on industrial pure iron in 0.9% NaCl solution. The hardness, wear resistance and corrosion resistance of the nitrided layers on industrial pure iron increase with RF power.     

Nanoindentation response of PEEK modified by mesh-assisted plasma immersion ion implantation

Polyetheretherketone (PEEK) surfaces have been treated by mesh-assisted plasma immersion ion implantation, significantly altering the viscoelastic properties of the near-surface modified region. The plasticity index derived from nanoindentation load-displacement data indicates that the treated surfaces exhibit greater elastic recovery and reduced plastic deformation compared to unmodified PEEK. Scanning probe microscopy (SPM) images of the surface before and after indentation also show evidence of increased elastic recovery.     

Characterization and optimization of a plasma doping process using a pulsed RF-excited B2H6 plasma system

The P+ plasma doping (PLAD) process using B₂H₆/H₂ plasma in a pulsed, RF-excited plasma system has been systematically characterized and optimized. The correlations between the deposition, retained B dose/profile, carrier dose/profile, sheet resistance (R_S) as a function of the pulse voltage, nominal dose, and carrier gas dilution have been extensively investigated. It was found that diluting B₂H₆ with H₂ can be used as a method to control and minimize boron deposition. SIMS and SRP analyses indicate that B and carrier profiles are deeper for higher dilutions up to 5/95 of a B₂H₆/H₂ gas ratio, than they are for lower dilutions due to less B deposition. This results in a higher activation fraction because of the B_SS limit and compensates for the reduction of the retained B dose. The higher dilutions also improved the retained B dose and R_S saturation due to less deposition. The PLAD process of a pulsed, RF-excited plasma system using B₂H₆ diluted with 92.5% to 95% H₂ was found to be an optimal condition for high-dose, boron-doping applications.