Effects of substrate temperature on the surface of polymer thin films prepared by R.F. sputtering with a polyimide target

In this study, we characterized polymer thin films deposited by a conventional radio frequency sputtering apparatus introduced into argon and nitrogen gases with a polyimide target onto copper substrates.Heating effects due to heating the copper substrate at 250 °C in the sputtering on tribological and adhesion properties of thin films were investigated with measuring friction coefficient, wear durability and pull strength. Surface roughness of the nitrogen sputtered thin film decreased by the heating. Friction coefficient of argon and nitrogen sputtered thin films prepared at 250 °C was almost the same level as that prepared at room temperature, respectively. Wear durability of these thin films and adhesion strength between these thin films and copper substrate decreased by the heating.     

用网状阴极法在碳钢表面沉积氮化钽薄膜

介绍了一种新型的在钢铁基体上制备氮化钽薄膜的方法－－网状阴极法。其设备简单、价格低廉。试验中发现，在各个参数配比合适的条件下，可制备出结构为fcc(面心立方）和hex（密排六方）的氮化钽薄膜。薄膜较致密且均匀，与其体的结合好。同时分析了在最佳工艺参数条件下合成氮化钽膜的成分、组织、表面、断口形貌和结合力等。该方法为氮化钽薄膜作为结构材料使用提供了一种新的途径。     

Ultrasonic cavitation test applied to thin metallic films for assessing their adhesion with mercaptosilanes and surface roughness

Evaluating the adhesion of micrometer or nanometer thick coatings is a challenging question which concerns many application fields. This is especially true for thin films deposited on a substrate of elastic modulus higher than that of the film, or for granular coatings, that do not allow the use of common adhesion tests. Usually, applied to characterize the wear resistance of bulk materials or thick coatings, the ultrasonic cavitation test is applied here to evaluate the adhesion strength of gold and copper thin films (~200 nm) that are evaporated on a silicon substrate. The test is shown to be sensitive enough to discriminate the influence of the surface chemistry on the adhesion strength of gold and copper films. Particularly, the role of (3-mercaptopropyl)triethoxysilane as an effective adhesion promotor is demonstrated. Furthermore, the role of surface roughness of the substrate is characterized and discussed in order to get further insights on the way this parameter interferes with the ultrasonic test and determines the adhesive strength of the coating. An estimate of the adhesive strength is given on the basis of the coating delamination kinetics.     

An investigation on the bonding of hot-hollow cathode deposited silver layers to type 304 stainless steel

The conditions prevailing during the deposition of thick metallic films by the hot-hollow cathode method were investigated. The spacial distribution of temperature, surface roughness, and depth of etch during the pre-deposition etching cycle was investigated for two different sample holder designs. The influence of substrate temperature and the angle of incidence of the vapour on the structure and adhesion of thick silver films to type 304 stainless steel was determined. The nature and strength of adhesion were evaluated on the basis of microscopic examinations and tensile test determinations. Similar evaluations were made on tensile test samples formed through electroplating copper and nickel onto the silver films instead of the joining of two silver-coated samples by hot-isostatic pressing.     

Characterization of Sol-gel-derived TiO2 and TiO2-SiO2 Films for Biomedical Applications

In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.     

Al／PET和Cu／PET蒸镀膜包装材料附着力及微观结构的研究

利用真空镀方法在聚酯(PET)薄膜上沉积Al(Cu),制得Al/PET(Cu/PET)复合薄膜包装材料。用直接牵引拉伸法和划痕法测定这两种薄膜的附着力,获得其附着力与蒸镀条件(真空度、温度、蒸发时间)的规律;用扫描电镜(SEM)观察镀层微观结构,得到镀层晶粒度与蒸镀条件的对应关系;用金相显微镜测量镀层厚度,获得镀层厚度与时间的对应关系。     

基体表面粗糙度对MoS_(2)/Ti薄膜摩擦磨损性能的影响EI北大核心CSCD

为揭示基体表面粗糙度对MoS_(2)/Ti固体润滑薄膜摩擦磨损性能的影响规律,并探究其摩擦磨损机理,采用磁控溅射方法,在不同表面粗糙度的轴承钢基体上沉积MoS_(2)/Ti薄膜。通过划痕测试仪、X射线衍射仪、场发射扫描电子显微镜和粗糙度轮廓仪,分别评价MoS_(2)/Ti薄膜的膜基结合力、物相成分、表面微观形貌以及表面粗糙度,并采用球-盘摩擦磨损实验研究干摩擦、固体-油复合润滑和固体-脂复合润滑条件下,MoS_(2)/Ti薄膜的摩擦磨损性能。结果表明:随着基体表面粗糙度的增加,MoS_(2)/Ti薄膜的表面粗糙度逐渐增加;薄膜中(002)_(MoS_(2))和(100)_(MoS_(2))衍射峰的强度先减弱后增加;薄膜与基体的结合性能降低。当基体表面粗糙度为0.01μm时,干摩擦条件下MoS_(2)/Ti薄膜具有良好的润滑特性,平均摩擦因数为0.101,磨痕浅且小;随基体粗糙度的升高,样品的平均摩擦因数和磨损率均是先增大后减小,薄膜的主要磨损机制由磨粒磨损转变为屑片形成和破碎。当基体粗糙度较大时(R_(a)=0.26μm),分子间相互作用的影响大于机械啮合作用。采用固体-油复合润滑,高基体粗糙度的薄膜磨损表面不再出现片层剥落现象,磨痕较浅,平均摩擦因数最高可减小19%。固体-脂复合润滑条件下,样品摩擦磨损性能较差,基体粗糙度对摩擦因数的影响不显著。     

Development of bioactive zirconium–tin alloy by combination of micropores formation and apatite nuclei deposition

In previous studies, Zr gained apatite‐forming ability by various methods; however, it took more than 7 days in simulated body fluid (SBF) to gain apatite‐forming ability. In this study, the authors developed the method to achieve apatite‐forming ability in Zr alloy within 1 day in SBF by a combination with apatite nuclei that promote apatite formation in SBF. First, Zr–Sn alloy was soaked in concentrated sulphuric acid, and pores in micro‐level were formed on the surface of Zr–Sn alloy. To attain apatite forming ability in Zr–Sn alloy, second, apatite nuclei were formed in the micropores. To evaluate apatite‐forming ability, thus‐obtained Zr–Sn alloy with apatite nuclei was soaked in SBF; hydroxyapatite formation was observed on the whole surface of the Zr–Sn alloy plates. From this result, it was clarified that higher apatite‐forming ability was attained on the apatite nuclei‐treated Zr–Sn alloy with micropores in comparison with that without micropores. When adhesive strength of formed hydroxyapatite film with respect to Zr–Sn alloy plates was measured, high‐adhesive strength of the formed apatite film was attained by forming micropores and subsequently precipitating apatite nuclei in the fabrication process because of an interlocking effect caused by hydroxyapatite formed in the micropores.Inspec keywords: precipitation, zirconium alloys, calcium compounds, bioceramics, tin alloys, adhesion, thin filmsOther keywords: apatite forming ability, micropore formation, hydroxyapatite film, bioactive zirconium‐tin alloy, apatite nuclei‐treated zirconium‐tin alloy, zirconium‐tin alloy plates, simulated body fluid, concentrated sulphuric acid, hydroxyapatite formation, adhesive strength, precipitating apatite nuclei, time 1.0 d, ZrSn, Ca₁₀ (PO₄)₆ (OH)₂      

利用氧等离子体预处理增强聚对苯二甲酸乙二醇酯/聚吡咯导电复合薄膜的界面粘附性

首先对聚对苯二甲酸乙二醇酯(PET)薄膜进行氧等离子体预处理,然后通过原位化学氧化聚合法使得吡咯单体在PET薄膜表面沉积聚合,制备了聚对苯二甲酸乙二醇酯/聚吡咯(PET-PPy)复合膜。通过原子力显微镜、X射线光电子能谱仪、ζ电位测试对经不同时长的氧等离子体预处理的PET薄膜进行表征;利用扫描电子显微镜、耐磨性实验和表面电阻测试对PET-PPy复合膜磨损前后的表面形貌和电阻进行分析与表征。结果表明,氧等离子体预处理显著增强了PET-PPy复合膜界面粘附性。氧等离子体预处理使PET薄膜表面粗糙度增大、电负性显著增强。特别地,当预处理时间为120s时,薄膜表面电负性明显增强,此时PET-PPy复合膜磨损后的电阻值变化最小,表明PET薄膜与PPy功能层界面粘附强度得到明显增强。     

TiNi shape memory alloy coated with tungsten: a novel approach for biomedical applications

This study explores the use of DC magnetron sputtering tungsten thin films for surface modification of TiNi shape memory alloy (SMA) targeting for biomedical applications. SEM, AFM and automatic contact angle meter instrument were used to determine the surface characteristics of the tungsten thin films. The hardness of the TiNi SMA with and without tungsten thin films was measured by nanoindentation tests. It is demonstrated that the tungsten thin films deposited at different magnetron sputtering conditions are characterized by a columnar microstructure and exhibit different surface morphology and roughness. The hardness of the TiNi SMA was improved significantly by tungsten thin films. The ion release, hemolysis rate, cell adhesion and cell proliferation have been investigated by inductively coupled plasma atomic emission spectrometry, CCK-8 assay and alkaline phosphatase activity test. The experimental findings indicate that TiNi SMA coated with tungsten thin film shows a substantial reduction in the release of nickel. Therefore, it has a better in vitro biocompatibility, in particular, reduced hemolysis rate, enhanced cell adhesion and differentiation due to the hydrophilic properties of the tungsten films.     

Pretreatment of polyethylene terephthalate substrate for the growth of Ga-doped ZnO thin film

The effect of the pretreatment of polyethylene terephthalate (PET) substrate on the growth of transparent conducting Ga-doped ZnO (GZO) thin film was investigated. Because of its high gas and moisture absorption and easy gas permeation, PET substrate was annealed at 100 degrees C in a vacuum chamber prior to the sputtering growth of GZO thin film for the outgassing of impurity gases. GZO thin film was deposited on the pretreated PET substrate by rf-magnetron sputtering and significantly improved electrical properties of GZO thin film was achieved. Electrical and structural characterizations of the GZO thin films were carried out by 4-point probe, Hall measurement, and scanning electron microscopy, and the effects of the pretreatment on the improved properties of GZO thin films were discussed. This result is not only useful to PET substrate, but also could be applicable to other plastic substrates which inevitably containing the moisture and impurity gases.     

Study of adhesion of carbon nitride thin films on medical alloy substrates

The adhesion improvement of biocompatible thin films on medical metal alloy substrates commonly used for joint replacement implants is studied. Diamond-like carbon (DLC) and carbon nitride (CN) thin films are, because of their unique properties such as high hardness, wear resistance and low friction coefficient, candidates for coating of medical implants. However, poor adhesion on substrates with high thermal expansion coefficient limits their application. We deposited CN films by pulsed DC discharge vacuum sputtering of graphite target on CoCrMo and Ti6Al4V substrates. Surface nitridation of the substrate, changing the deposition parameters and use of interlayer led to improved adhesion properties of the films. Argon and nitrogen gas flow, thickness of the film and frequency of the deposition pulses had significant influence on the adhesion to the substrate. Properties of deposited films were analyzed using Scanning Electron Microscopy, Raman spectroscopy and tribology tests.     

锌合金表面涂装前磷化处理对膜层结合力的影响

锌合金活泼、易腐蚀,在其表面直接喷涂涂层的结合力较差,为了提高锌合金表面与涂层的结合力,对锌合金基材作磷化处理和磷化后封闭处理再喷涂聚氨酯漆膜,探讨了磷化处理及封闭处理对锌合金表面膜层间结合力的影响,并应用扫描电镜(SEM)和X射线衍射仪(XRD)对磷化膜表面形貌、物相组成及成分等进行研究。结果表明:锌合金表面直接喷涂聚氨酯漆膜,漆膜与锌合金基材的结合力差,结合力等级大于5级;而锌合金表面不管是磷化后直接喷漆还是磷化后封闭处理再喷漆均能极大提高涂层与基体的结合力,其结合力等级均小于2级;封闭处理有助于降低磷化膜的孔隙率,磷化膜经封闭处理后孔隙率由13.9%降到3.5%;封闭处理会降低磷化膜与漆膜的结合力。     

Quantitative acoustic microscopy for characterization of the interface strength of diamond-like carbon thin films

Diamond-like carbon (DLC) films are emerging to be ideal materials in a variety of semiconductor, display, and film media applications. As with any deposited film, adhesion of the film to the substrate is of critical importance. The main objective of this paper is to report on the development of a technique based on acoustic microscopy for the quantitative characterization of the interface strength of thin (submicrometer) films. Preliminary results from 0.5 μm DLC films are presented to establish the feasibility of the new technique. Theoretical models of wave propagation indicate the Rayleigh wave velocity (at 600 MHz) is sensitive to the interface condition and could potentially be used to characterize the same. Acoustic material signatures (AMS) of DLC films which had varying levels of adhesion to silicon coated titanium substrates were obtained at 600 MHz using an acoustic microscope. The Rayleigh velocity (extracted from the AMS) had a strong correlation with the adhesion strength measured destructively using a pull tester. A model-based methodology for prediction of the interface strength of thin films through acoustic microscopy is also addressed.     

磁控溅射硅钼薄膜的抗氧化性能研究

用射频磁控溅射法在单晶Si基体上制备了硅钼薄膜,对薄膜进行真空退火处理以及高温氧化实验,借助SEM和X射线衍射仪(XRD)等仪器对退火前后的薄膜以及高温氧化后的薄膜进行了分析。结果表明沉积态的硅钼薄膜为非晶态,高温真空退火使薄膜由非晶态转变为晶态,致密的复合氧化物是硅钼薄膜具有良好的抗氧化性能的主要原因。     

磁控溅射法制备铁氧体薄膜的界面结合强度研究

利用磁控溅射法在单硅晶基底和玻璃基底上沉积铁氧体薄膜,采用AFM观察薄膜的微观形貌,采用划痕法测试薄膜的界面结合强度,测试结果表明:由于两种不同材质上沉积的薄膜粗糙度缘故,硅晶/铁氧体薄膜的临界载荷为19.7N,其划痕形貌为裂纹状扩展,玻璃/铁氧体薄膜的临界载荷为5.3N,其划痕形貌为剥落状。     

微波等离子体刻蚀处理对金刚石薄膜涂层刀具附着力和切削性能的影响

用HFCVD法在硬质合金（YG6）刀具衬底上沉积金刚石薄膜,用氢微波等离子体刻蚀的方法对衬底进行表面预处理,研究了该预处理技术对WC硬质合金衬底表面成分的影响,进一步探讨了所沉积金刚石薄膜的表面形貌和附着力,并通过难加工材料实际切削试验。研究了所制备的金刚石薄膜涂层刀具的切削性能。试验结果表明,Ar-H2微波等离子体刻蚀脱碳处理是提高金刚石薄膜附着力和改善涂层刀具切削性能的有效预处理方法。     

Adhesive properties of polypropylene (PP) and polyethylene terephthalate (PET) film surfaces treated by DC glow discharge plasma

In this study, the adhesive properties of the plasma modified polypropylene (PP) and polyethylene terephthalate (PET) film surfaces have been investigated. Hydrophilicity of these polymer film surfaces was studied by contact angle measurements. The surface energy of the polymer films was calculated from contact angle data using Fowkes method. The chemical composition of the polymer films was analyzed by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was used to study the changes in surface feature of the polymer surfaces due to plasma treatment. The adhesion strength of the plasma modified film was studied by T-peel strength test. The results showed a considerable improvement in surface wettability even for short exposure times. The AFM and XPS analyses showed changes in surface topography and formation of polar groups on the plasma modified PP and PET surfaces. These changes enhanced the adhesive properties of polymer film surfaces.     

The mechanism of adhesion and printability of plasma processed PET films

Of the several techniques available for the surface modification, plasma processing has proved to be very appropriate. The low temperature plasma is a soft radiation source and it affects the material only over a few hundred Å deep, the bulk properties remaining unaffected. Plasma surface treatment also offers the advantage of greater chemical flexibility. PET films are widely used for packaging and electrical insulation. The studies of adhesion and printability properties are important. In the present study PET films are treated in air plasma for different time of treatment. The improvement in adhesion is studied by measuring T-peel and Lap shear strength. In addition, printability of plasma treated PET films is studied by cross test method. It has been found that printability increases considerably for plasma treatment of short duration. Therefore it is interesting to study the surface composition and morphology by contact angle measurement, ESCA and AFM. Surface energy and surface roughness can be directly correlated to the improvement in above-mentioned surface related properties. It has been found that the surface oxidation occurs containing polar functional groups such as C-O, COO. A correlation of all such observations from different techniques gives a comprehensive picture of the structure and surface composition of plasma treated PET films.     

Three Filtered Vacuum Arc Plasma Sources Deposition & Implantation System

A deposition & implantation system, which includes three filtered vacuum arc plasma sources, has been built. Vacuum arc discharge is used to produce high-density metal plasma; Curved magnetic filtering technique is used to transfer the plasma into out-of-sight vacuum chamber and reduce macro-particles from the vacuum arc plasma in order to drastically reduce the macro-particles contamination of the films. The up to 30 kV negative bias applied to the target can be used for ion implantation in order to improve the film adhesion; or for ion sputtering to clear the substrate surface. The 0 to 300 V negative bias can be used to adjust the ion energy which forming films. The system is designed for various thin films synthesizing, such as single-layer, compound layer, multi-layer films. It's principle, components and applications are described in the literature.