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.     

Structure and properties of Ti–Al–Y–N coatings deposited from filtered vacuum-arc plasma

Ti_0.5Al_0.5N coatings with a small amount of Y (up to 1 at.%) were deposited by filtered vacuum arc plasma at pulsed high voltage negative substrate bias potential with amplitude up to 2.5 kV and their microstructure was studied. X-ray fluorescence analysis showed that this deposition method allows ensuring well the conformity of the elemental composition of the metallic components of cathodes and films. X-ray diffraction measurements of the films with yttrium revealed a solid solution (Ti,Al)N phase with a cubic NaCl-type structure as the only crystalline phase. The films deposited with an amplitude of the substrate bias potential in the range of 1–1.5 kV were characterized by a strong axial texture [110]. In these films an increase of the yttrium content leads to the reduction of the nitride lattice parameter and growth of coherent scattering zone dimension as well as to a decrease of the surface roughness. Coatings containing 1 at.% Y exhibited high hardness of 32–36 GPa and oxidation resistance.     

A biasing method for plasma immersion ion implantation and deposition process to enhance coating adhesion

A multi-purpose high voltage pulse (HVP) supply was developed for PIII&D process, to provide bias voltage of DC, HVP and HVP + DC to the workpiece. The pretreatment (sputtering cleaning) of the workpiece, ion implantation, hybrid PIII&D or normal deposition, can be finished in one vacuum cycle. In the system a vacuum bend-guide microwave ECR source is used to produce plasma. Ti/TiN_x coating was prepared in this biasing manner with the PIII&D system. The result shows that the adhesion of the coating is enhanced with the HVP + DC composite biasing when the pulse amplitude and the DC voltage are chosen properly. The deposition rate can be maintained relatively high at an intermediate level between the conditions with pure HVP and DC bias. This work shows that the composite biasing is an effective method to improve the coating's properties in PIII&D process.     

Fluorine and carbon ion implantation and deposition on metals by plasma source ion implantation

Deposition of fluorine containing diamond-like carbon films is an effective solution for the improvement of machine parts in an aggressive aqueous environment when the combination of a hydrophobic surface with good corrosion protection and low friction coefficients is required. Stainless steel and silicon were treated by plasma source ion implantation using the gases CF₄, C₆F₆ and C₆H₅F, in the latter case with previous methane implantation. Depending on the plasma gas there are differences in the fluorine content, depth distribution, film thickness, water contact angle and friction coefficient.     

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.     

Secondary electron suppression in nitrogen plasma ion implantation using a low DC magnetic field

Experiments aiming at the reduction or even total suppression of secondary electrons during the plasma immersion ion implantation were carried out using a plasma device with low DC magnetic field. Comparison of ion implantations in B = 0 and another case with B = 43 G, indicated that the magnetic field was effective to suppress SE flow in the direction transversal to B but only partial suppression was attained in the longitudinal direction. However, these results are already significant since the efficiency of implantation was increased and the flow of SE to the walls became localized to the regions with B crossing the walls.     

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。     

On the induction plasma deposition of tungsten metal

The central particle injection and long residence time characteristics of induction plasma have given rise to the complete melting of tungsten particles injected into an Ar- H₂ plasma under soft vacuum conditions. The influences of process variables such as power level, chamber pressure, and spray distance on splat morphology, apparent density, and deposition efficiency have been studied. Dense tungsten deposits with no oxidation have been obtained. Scanning electron microscopy (SEM) micrographs reveal a well-flattened lamellar structure in deposits. Radiative cooling is observed to play a significant role in the plasma spraying of this refractory metal.     

磁过滤等离子体制备TiN薄膜中沉积条件对薄膜织构的影响

在室温条件下,利用自行设计的平面"S"形磁过滤等离子体设备,在(111)面单晶硅上制备TiN薄膜,通过改变基底偏压和反应气体成分,即通过改变氮气和氩气的气体流量来改变沉积离子的能量和密度,从离子轰击的角度研究了沉积条件对TiN薄膜织构的影响.对薄膜的表面形貌进行观察,用(θ～2θ)和1.5°掠入射2种X射线衍射方法对薄膜晶体结构和晶面取向进行了分析,对薄膜进行了电子衍射研究.结果显示磁过滤等离子制备的TiN薄膜表面平整光滑,颗粒尺寸为20～70 nm,且基底偏压和氩气流量的增大促使薄膜发生(111)面的择优取向,且(111)晶面与膜表面平行,而在高氩气流量的情况下,(200)和(220)面在薄膜平面也发生了定向排列.     

Effect of metal ion implantation on thermal instability of diamond-like carbon films

In this work, molybdenum and tungsten ions were implanted onto the DLC films deposited by filtered cathodic vacuum arc. We investigated the effects of ion species and doses on carbon related bonding property such as the ratio of sp³ carbon to sp² phase, the chemical composition and tribological properties of the DLC films in the range of 200 to 600 °C. The oxidation starting temperature decreased with an increasing ion dose and ion mass owing to higher sp² carbon fraction. Oxidation of the implanted-metal element, however, keeps the DLC film from carbon sublimation by oxidation, offering stable tribological characteristics by covering it with a metal oxide layer at the high temperature.     

Pulsed ion extraction from a hybrid plasma using a shunting arc discharge

A hybrid plasma is generated by combining a burst methane rf (195 kHz) plasma with a carbon shunting arc discharge. The shunting arc discharge triggers the rf methane plasma. As a result, the rf plasma is initiated over a wide range of ambient gas pressure from 0.045 Pa as a base pressure to a methane pressure of 1.26 Pa, at which the rf plasma is not self-ignited. When a target is immersed in the rf- and shunting arc-hybrid plasma, and a negative pulse voltage is applied to the target, carbon ions are extracted from the hybrid plasma. When the carbon shunting arc ionizes the methane gas, an rf plasma is initiated and the ionization of methane is significantly enhanced in the rf plasma. The plasma density in the hybrid plasma increases by a factor of approximately 5-9 compared to that of the shunting arc discharge.     

Activation of non-metallic substrates for metal deposition using organic solutions

Non-metallic substrates, such as plastics or oxides, need to be activated before electroless metal deposition. In this paper, a novel process of using metal Pd and Pd-Cu ion loaded organic solutions for surface activation of non-metallic substrates is described. The organic media used are strong polarizing and low ionic conducting solutions of the type commonly used in the solvent extraction industry. Different types of non-metallic substrates, including polyester, alumina and carbon nanotubes, have been evaluated, and it was shown that a uniform and complete Cu coating can be electrolessly deposited after activation in metal ion loaded organic solutions.     

Comparison of ZrN and TiN formed by plasma based ion implantation & deposition

ZrN and TiN films have been deposited on Si substrates without additional heating using plasma based ion implantation & deposition (PBII&D) with pulse voltage from 0 to 5 kV. High quality columnar films have been obtained in both systems with a slight nitrogen deficiency. For ZrN, a marked reduction of the growth rate was observed when depositing with pulse bias, which was not observed for TiN, caused presumably by different partial sputter yields. A transition of the texture from (111) to (200) is again present in both systems, however with the transition occurring at a different pulse bias. Hardness values of 18-20 GPa and 22-24 GPa have been observed for TiN and ZrN, respectively.     

Optimizing the vacuum plasma spray deposition of metal,ceramic, and cermet coatings using designed experiments

The vacuum plasma spray (VPS) deposition of metal, ceramic, and cermet coatings has been investigated using designed statistical experiments. Processing conditions that were considered likely to have a significant influence on the melting characteristics of the precursor powders and hence deposition efficiency were incorporated into full and fractional factorial experimental designs. The processing of an alumina powder was very sensitive to variations in the deposition conditions, particularly the injection velocity of the powder into the plasma flame, the plasma gas composition, and the power supplied to the gun. Using a combination of full and fractional factorial experimental designs, it was possible to rapidly identify the important spraying variables and adjust these to produce a deposition efficiency approaching 80%. The deposition of a nickel-base alloy metal powder was less sensitive to processing conditions. Generally, however, a high degree of particle melting was achieved for a wide range of spray conditions. Preliminary experiments performed using a tungsten carbide/cobalt cermet powder indicated that spray efficiency was not sensitive to deposition conditions. However, microstructural analysis revealed considerable variations in the degree of tungsten carbide dissolution. The structure and properties of the optimized coatings produced in the factorial experiments are also discussed.     

强电流直流伸展电弧等离子体CVD金刚石沉积均匀性研究

采用特殊的等离子体技术成功研制出适合于金刚石涂层工具工业化生产的中试设备-强电流直流伸展电弧等离子体CVD-500型中试设备。单腔体沉积的沉积工件数量在100支以上;对该设备的沉积均匀性进行了系统的研究,位于等离子体扩散区同一柱面不同位置沉积的金刚石形貌及质量均匀、一致,涂层厚度的不均匀度在±3．5％的范围内;同一沉积试件不同位置处的金刚石形貌及质量稍有差别,但均在许可范围之内,涂层厚度的不均匀度在±2％的范围内;等离子体的扩散区的径向6 cm～8cm,轴向距阳极7 cm-19cm的范围为该设备的有效沉积区域。     

Structure and properties of amorphous diamond-like carbon films produced by ion beam assisted plasma deposition

The microstructure and tribological properties of carbon film produced by ion beam assisted plasma deposition in a plasma source ion implantation (PSII) chamber with energies varied from 0 to 30 keV are examined. The process is illustrated schematically, and Raman spectra as well as TEM images and corre-sponding diffraction patterns of carbon films are shown.     

直流辉光氧等离子体刻蚀金刚石膜的研究

在直流辉光放电等离子体装置上，利用不同直流功充和工作气压下产生的氧等离子体对CVD金刚石厚膜的表面进行了刻蚀。利用扫描电子显微镜、Raman光谱和电子微量分析天平，分别对刻蚀前后金刚石膜表面的形貌、结构和刻蚀速率进行了观测。结果发现：在工作气压一定时，刻蚀速率随着直流功率的增加而增大，并且刻蚀由各向同性转变为各向异性。但过高的直流功率会导致金刚石膜表面沉积出无定形碳。基于实验研究结果和相关基本理论建立了刻蚀模型，并根据模型得到了影响刻蚀的主要原因在于等离子体中的电子温度和金刚石膜的悬浮鞘电位。     

Effects of deposition parameters on microstructure and thermal conductivity of diamond films deposited by DC arc plasma jet chemical vapor deposition

The uniform diamond films with 60 mm in diameter were deposited by improved DC arc plasma jet chemical vapor deposition technique. The structure of the film was characterized by scanning electronic microcopy(SEM) and laser Raman spectrometry. The thermal conductivity was measured by a photo thermal deflection technique. The effects of main deposition parameters on microstructure and thermal conductivity of the films were investigated. The results show that high thermal conductivity, 10.0 W/(K-cm), can be obtained at a CH4 concentration of 1.5% (volume fraction) and the substrate temperatures of 880-920 ℃ due to the high density and high purity of the film. A low pressure difference between nozzle and vacuum chamber is also beneficial to the high thermal conductivity.