Properties of hydrogenated amorphous carbon films deposited by PECVD and modified by SF6 plasma

Hydrogenated amorphous carbon (a-C:H) films were grown at room temperature on glass and polished silicon substrates using RF-PECVD (Radio-Frequency Plasma Enhanced Chemical Vapor Deposition). Plasmas composed by 30% of acetylene and 70% of argon were excited by the application of RF signal to the sample holder with power ranging from 5 to 125 W. After deposition, the films were submitted to SF₆-plasma treatment for 5 minutes. SF₆ plasmas were generated at a pressure of 13.3 Pa by a RF power supply operating at 13.56 MHz with the output fixed at 70 W. The resulting films were characterized in terms of their molecular structure, chemical composition, surface morphology, thickness, contact angle, and surface free energy. During the SF₆ plasma treatment, fluorine species were incorporated in the film structure causing chemical alterations. The interaction of chemical species generated in the SF₆ plasmas with surface species was responsible for the decrease of the film thickness and surface energy, and for the increase of the film roughness and hydrophobicity.     

Surface analysis of nickel-oxide films modified by a reactive element

The surface morphology of oxide grown in the temperature range of 873–1173K on modified high-purity nickel has been observed and quantitatively analyzed by atomic-force microscopy. The modifications included one of two finishing techniques and either CeO₂ sol-gel coatings or Ce-ion implantation. There is an essential difference in the surface morphology and grain size for oxides formed on Ce/CeO₂-modified nickel in comparison to pure NiO. The oxide topography also depends on the substrate-surface-finishing technique and the method of applying the cerium. Both Auger electron spectroscopy and Rutherford backscattering spectrometry were used to evaluate the depth composition of the oxide. In the modified oxide formed on chemically polished substrates the Ce generally appeared to be located close to the outer surface, even after long oxidation times. In oxide grown on mechanically polished substrates Ce was detectable by these techniques only during the very early stages of oxidation. A general correlation exists between the parameters describing the oxide-surface morphology and the Ce-depth distribution, and the reduction of the NiO growth rate achieved by applying the reactive element. Detailed analysis of the oxide surface, internal microstructure, and chemistry gives new insights into the problem of the characterization of thin oxide films and the mechanism of oxide formation.     

空气等离子切割烟尘产生的特点及收集方式

一年一度的慕尼黑上海电子展（electronica＆Productronica China）于2006年3月21日在上海新国际博览中心拉开了帷幕。经过在中国的四年培育,第五届慕尼黑上海电子展已不再局限于电子业生产厂家展示新品的平台,更重要的是它已经成为中国,乃至全球电子行业领军企业济济一堂交流经验、寻找商机、预测行业发展方向的年度盛会。     

Nanostructured yttria stabilized zirconia coatings deposited by air plasma spraying

Nanostructured yttria partially stabilized zirconia coatings were deposited by air plasma spraying with reconstituted nanosized powder. The microstructures and phase compositions of the powder and the as-sprayed nanostructured coatings were characterized by transmission electron microscopy（TEM）, scanning electron microscopy（SEM） and X-ray diffxaction（XRD）. The results demonstrate that the microstructure of as-sprayed nanostructured zirconia coating exhibits a unique tri-modal distribution including the initial nanostructure of the powder, equiaxed grains and columnar grains. Air plasma sprayed nanostructured zirconia coatings consist of only the nontransformable tetragonal phase, though the reconstituted nanostructured powder shows the presence of the monoclinic, the tetragonal and the cubic phases. The mean grain size of the coating is about 42 nm.     

Properties of alumina-titania coatings prepared by laser-assisted air plasma spraying

Studies have shown that microstructures formed by post-laser remelting of air plasma sprayed coatings exhibit densification but also numerous macrocracks due to the rapid cooling and thermal stresses. In laser-assisted air plasma spraying (LAAPS) process, the laser beam interacts simultaneously with the plasma torch in order to increase the temperature of the coating and possibly remelt the coating at the surface. As a result, the microstructure is partially densified and macrocracks, which are generally produced in the post-laser irradiation treatment, may be inhibited. In this paper, LAAPS was performed to improve the hardness and wear resistance of Al₂O₃-13%TiO₂ coatings. These coatings prepared by air plasma spraying (APS) are widely used to protect components against abrasive wear at low temperatures. The coating microstructure was characterized by SEM and X-ray diffraction. The mechanical characterization was done by hardness measurements, erosive wear tests and abrasion wear tests. Results showed that laser assistance may improve the microstructural and mechanical properties. Phenomena involved in LAAPS of alumina-titania coatings are discussed in this paper.     

高功率等离子磁控溅射法制备含钛类金刚石碳膜(英文)

为了改善类金刚石碳膜的性能,采用高功率等离子磁控溅射法将含钛非晶碳薄膜沉积在304不锈钢基材上,气源为C2H2-Ar混合气体,金属钛为阴极靶材。为了改善附着力和降低残余应力,制备了含Ti/TiC/DLC多层结构的镀膜。利用GDS、XRD、SEM、Raman光谱法、纳米压痕仪和盘-销摩擦计研究基材偏压及基材与靶材的距离对薄膜性能的影响。结果表明,薄膜具有优良的粘合强度和韧性。     

Characterization of mixed-phase BN thin films deposited by plasma CVD

Boron nitride thin films have been deposited by plasma assisted chemical vapour deposition (PACVD) from non-toxic material and have been shown to have a high content of the cubic phase under certain conditions of substrate temperature and r.f. power, as measured by infrared absorption and refractive index. The electronic properties of these films have been measured and exhibited high resistivity and breakdown field strength. Al/BN/n-Si MIS diodes have been constructed and these show that the BN insulator contains negative charges. The interface state density is relatively low, however, and there is no Fermi level pinning within the bandgap     

等离子体氧化和自组装技术改性铝合金的摩擦学特性

对制备的铝合金试样进行等离子体氧化,并采用自组装技术对氧化的表面进行改性处理.利用接触角测量仪、原子力显微镜和UMT-2型微摩擦磨损试验机对制备的试样进行表征和摩擦学特性测试.结果表明:经等离子体氧化的铝合金表面平整均匀,在降低摩擦因数的同时,提高摩擦副的耐久性.OTS自组装分子膜改性处理的氧化表面具有疏水特性,摩擦学性能显著提高.     

Surface characterization of NiTi modified by plasma source ion implantation

This paper reports the novel application of an oxygen ion plasma for surface modification of a shape memory alloy. The surface characterization of oxygen ion implanted Ti–50.7 at% Ni alloy samples was performed with the assistance of Auger electron spectroscopy, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy techniques (TEM). TEM identified amorphous TiO₂ and crystalline phases of Ti₁₁Ni₁₄ and Ti₄Ni₂O_x. XPS results reveal that the surfaces of control samples are covered with predominantly TiO₂ and traces of TiO and NiTi, as well as NiO and Ni₂O₃. At the surface of oxygen-implanted samples, however, only TiO₂ and trace amounts of Ni₂O₃, NiO and NiTi were observed. TiO and NiO exist in much larger range than other oxides, and TiO extends to the oxide–metal interface. These results are especially noteworthy because of their implications for interpreting corrosion, wear, and biocompatibility behavior.     

2024 aluminium alloy wettability and superficial cleaning improvement by air cold plasma treatment

2024 aluminium alloy is used for parts and structures which demand high-strength/weight ratio. In particular, Al2024 is, for its high specific strength and good chemical stability, a suitable material for aerospace application. Aluminium alloys are involved in corrosive phenomena when they are used in critical applications, such as the aeronautic ones. The solution commonly adopted to solve corrosive problems is to paint aluminium alloy surface including 2024 aluminium alloy which is the subject of this study. The applied paint film protects the aluminium alloy from corrosion. In order to improve the adhesion of the paint film it is necessary to pre-treat the manufactured surface. The objective of the pre-treatment is to develop a cleaned, uniform, wettable surface. Cold plasma is an efficient, economic and environmentally attractive alternative to the use of the traditional pre-treatment. This work aims to study the relationship between cold plasma and 2024 aluminium alloy wettability and cleaning. Surface samples have been analysed by: (i) standard procedure to measure the quantitative wettability; (ii) Energy Dispersive X-ray Spectroscopy or EDS to determine a quantitative measure of organic contaminant.This work demonstrates that air cold plasma treatment improves significantly wettability and cleaning of 2024 aluminium alloy surfaces both associated with pre-cleaning by MEK^® and without pre-cleaning by MEK^®: the wettability reducing has been greater than 70% and the contaminants reducing greater than 65%.     

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.     

手工空气等离子切割技术及应用

介绍了几种常用空气等离子切割机主要技术参数。针对手工切割机,特别强调了三个重要工艺参数:切割速度、喷嘴高度和喷嘴角度,并提出具体要求。明确割口质量要求,对常见缺陷具体分析并提出相应预防措施。详细说明操作步骤、操作要领和割口质量检验。手工空气等离子切割机产生的电击、辐射、灰尘烟气等危害要强于焊条电弧焊,安全防护技术可对操作者提供可靠指导。     

Physico-chemical characteristics of high performance polymer modified by low and atmospheric pressure plasma

In this work, the effect of low pressure plasma and atmospheric-pressure plasma treatment on surface properties and adhesion characteristics of high performance polymer, Polyether Ether Ketone (PEEK) are investigated in terms of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and Atomic Force Microscopy (AFM). The experimental results show that the PEEK surface treated by atmospheric pressure plasma lead to an increase in the polar component of the surface energy, resulting in improving the adhesion characteristics of the PEEK/Epoxy adhesive system. Also, the roughness of the treated surfaces is largely increased as confirmed by AFM observation. These results can be explained by the fact that the atmospheric pressure plasma treatment of PEEK surface yields several oxygen functionalities on hydrophobic surface, which play an important role in increasing the surface polarity, wettability, and the adhesion characteristics of the PEEK/Epoxy adhesive system.     

Surface modification of PET films by atmospheric pressure plasma-induced acrylic acid inverse emulsion graft polymerization

In order to make polyester film surface hydrophilic, atmospheric pressure plasma jet (APPJ) is used to activate the film surface first followed by inverse emulsion grafting polymerization of acrylic acid (AA). The graft ratio and wettability test reveal that the effectiveness of APPJ on initiating graft polymerization increases with increasing plasma treatment duration and helium flow rate. As the jet-to-substrate distance increases, the graft efficiency goes through a maximum at 2 mm. When oxygen is added to the plasma treatment gas, the graft efficiency decreases substantially. Fourier transform infrared spectrometry (FTIR) analysis shows new bands appearing at 2500-3600 cm^− 1 and 1546 cm^− 1 for the plasma-grafted samples. Scanning electron microscopy (SEM) results show that the grafted layer is built with a large number of spherical particles at submicron or even nanoscale. With a high graft ratio, agglomeration of neighboring particles becomes more pronounced, and eventually a relatively continuous graft layer is obtained with a corresponding surface contact angle of 5° which is considered superhydrophilic.     

Low friction stainless steel coatings graphite doped elaborated by air plasma sprayed

A new process has been developed to incorporate graphite particles into a stainless steel coating during its formation. Four means have been tested to inject the graphite particles outside the plasma jet and its plume: graphite suspension, a graphite rod rubbed on the rotating sample, powder injection close to the substrate with an injector, or a specially designed guide. The last process has been shown to be the most versatile and the most easily controllable. It allows the incorporation of between 2 and 12 vol.% of graphite particles (2–15 μm) within the plasma sprayed stainless steel coatings. A volume fraction of 2% seems to give the best results with a slight decrease (6%) of the coating hardness. This volume fraction also gave the best results in dry friction on the pin-on-disk apparatus. Depending on the sliding velocity (0.1–0.5 m/s) and loads (3.7–28 N), the dry friction coefficient against a 100C6 pin is reduced by between 1.5 and 4 compared with that obtained with plasma sprayed stainless steel.     

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 sp² and sp³ ratio contents were characterized by Raman spectroscopy.     

Deposition and structure characterization of carbon films prepared at atmospheric pressure by plasma jet

Amorphous carbon films were deposited on stainless steel substrates by plasma jet chemical vapor deposition (PJCVD). The carbon coatings have been prepared at atmospheric pressure in an argon/acetylene mixture. The Ar/C₂H₂ gas volume ratio varied from 100:1 to 200:1, while the distance between the plasma torch nozzle exit and the samples was 0.005–0.02 m. Scanning electron microscope analysis demonstrated that the surface roughness and growth rate of the coatings increase with the decrease of the Ar/C₂H₂ ratio. The ERDA results showed that the hydrogen concentration rises from 5 at.% to 27 at.% with the increase of the distance from 0.005 to 0.02 m. The increase of the Ar/C₂H₂ ratio from 100:1 to 200:1 slightly increases the hydrogen and oxygen concentration in the films. The Raman spectroscopy results indicated that the sp³ C–C carbon sites are replaced by sp³ CH_2–3 bonds with the increase of the deposition distance. The microhardness of the carbon films deposited at 0.005 m was in range of 7.1–9.3 GPa.     

高等离子体功率密度下MPCVD法制备多晶金刚石膜

通过自制的MPCVD双基片台设备,在微波功率为1 400 W保持不变及中高气压,等离子体功率密度为357.5～807.4 W/cm³,基片温度为850±30℃,CH₄体积分数为1.0%～1.5%,沉积速率为1～8μm/h条件下,在直径11.5 mm的硅基片上沉积不同质量的多晶金刚石膜,并通过光谱仪、光学显微镜、拉曼光谱仪对等离子体中的氢原子及含碳基团、多晶薄膜的形貌及质量进行表征。结果表明：随着等离子体功率密度上升,等离子体椭球中的氢原子基团和含C的活性基团强度增加,金刚石膜生长速率大幅度提高,金刚石膜纯度也大幅度提升。在气压为21 kPa,等离子体功率密度为807.4 W/cm³,基片温度为850±30℃,生长时间为150 h,CH₄体积分数为1.0%及氢气流量为200 mL/min的条件下,金刚石膜的生长速率达到5μm/h,金刚石膜厚达752.0μm,金刚石拉曼峰的半高宽为6.48 cm^-1,且生长的金刚石膜质量良好。     

Hydrogen behavior in the iron surface layer modified by plasma nitriding and ion boronising

The effects of the plasma nitriding with the formation of compound nitride and diffusion zones and of the boronising with the different ion doses on hydrogen distribution and hydrogen induced deterioration of a surface layer were examined in the case of Armco iron. Electrochemical studies of hydrogen permeation rate, hydrogen vacuum extraction measurements, optical and scanning microscopy, X‐ray diffraction and elastic recoil detection analysis (ERDA) were used. Accumulation of entering hydrogen within the various constitutent zones of the modified layer inhibits the hydrogen transport into the metal and thus, decreases the mean hydrogen content in the deeper zones and in the core. Hydrogen accumulation within the compact nitride zone causes the expansion of the nitride lattice, nitride phase transformation and deterioration. The ion boronising enhances the hydrogen effects in the plasma nitrided layers. Therefore, modification of the surface layer by plasma nitriding and ion boronising may result in preventing of the bulk metal from hydrogen induced degradation, but may cause hydrogen deterioration of the surface layer, depending on the treatment parameters.     

Dielectric and semiconducting Ge-C and Si-C thin films prepared by plasma deposition from organic compounds

A new type of audio-frequency reactor for plasma deposition with three parallel electrodes is presented. It has been found that small changes in the coupling capacity of the system can cause a drastic change in the electronic structure of deposited films. This effect is discussed for hydrogenated amorphous Ge-C and Si-C films prepared from organic compounds, using investigations of the optical absorption and electrical conductivity of these films.