Investigations of Mn-Co-O and Mn-Co-Y-O coatings deposited by the magnetron sputtering on ferritic stainless steels

Protective coatings for the metal interconnects of solid-oxide fuel cells have been produced by magnetron sputtering of metal targets sintered from mixtures of Co and Mn powders with a Y₂O₃ additive. Oxidizing heat-treatment of the metal coating in air at 800 °C and the reactive mode of coating deposition in which a cubic spinel structure formed immediately during coating deposition were used. The plasma providing for ion assistance was produced by ionizing the gas mixture in the working chamber with a low-energy broad electron beam. It has been demonstrated that the reactive mode promotes stabilization of the coating composition in the course of high-temperature testing. The effect of an yttrium additive (0.014-1.4 at.%) on the oxidation rate and area specific resistance (ASR) of the coated steel has been investigated. Thermogravimetric tests have shown that a 1.4 at.% Y additive to a spinel coating reduces the oxidation rate for AISI430 and Crofer 22 APU steels by a factor of 27.8 and 8.6, respectively. For the coated AISI430 steel, the ASR increased to 100 mΩ·cm² within 1-2 thousands of hours, depending on the Y content in the coating. For the Crofer 22 APU steel with a Y-doped coating, the ASR decreased to a 6 mΩ·cm² within several hundreds of hours and then increased to 15 mΩ·cm² within 5000 h. For the MnCo₂O₄-coated Crofer 22 APU specimens, the ASR gradually decreased from 11 to 6 mΩ·cm² within 5000 h.     

The effect of substrate bias voltage on PbTe films deposited by magnetron sputtering

The PbTe films were deposited onto ITO glass substrate by radio frequency magnetron sputtering. Effect of external direct current electrical field applied between substrate and target on the quality of films was investigated. Stylus surface profile, X-ray diffraction (XRD), atomic force microscope (AFM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the films. The film thickness was measured by a conventional stylus surface profile. The crystal structure and lattice parameters of films were determined by using XRD. The surface morphology of the films was measured by AFM. The absorption coefficients and optical band gaps of films were found from FTIR. The sheet resistance of the samples was measured with a four-point probe and the resistivity of the film was calculated. All the obtained films were highly textured with a strong (2 0 0) orientation. With increasing bias voltage to −30 V, the property of crystal structure, surface morphology and absorption coefficients and resistivity were improved. However, further increase of substrate bias leads to transformation of the property.     

磁控溅射沉积银薄膜/涂层的研究进展

银薄膜/涂层是一种在高新技术领域极具潜力的新材料,近年来在现代工业中得到了广泛的应用。采用磁控溅射制备的银薄膜/涂层具有优异的附着力,通过选择相应的沉积参数可以实现对银薄膜/涂层微观结构及性能的调控。本文综述了磁控溅射沉积银薄膜/涂层的主要制备工艺,评述了银薄膜/涂层在其主要应用领域内的研究进展,并对其未来的发展进行了展望。     

Characterization of metallic textiles deposited by magnetron sputtering and traditional metallic treatments

In this study, the surface appearance, light reflectivity and low-stress mechanical properties of magnetron sputter coated fabric were compared with traditional metallic treated fabrics. It is found that a layer of fine silver particles distributed evenly on the fabric surface with uniform grains and there were no obvious structural damages to the fabric after the sputtering. The sputter coated fabric has a greater value in reflectance and lightness than metallic powder printed fabric, but is lower than that of metallic foil laminated fabric. The values of surface geometrical smoothness (SMD) increased after metallic powder printing while decreasing slightly after sputter coating and decreasing significantly after metallic foil lamination. The tensile loading curves of both sputter coated and untreated cotton spandex fabrics are similar which indicate that the modification of sputter coating is minimal when compared with the other two metallic treatments. Therefore, sputtering has opened up new possibilities in the modification of textile materials and is an exciting prospect for usage in textile design and technical textiles.     

Corrosion behaviour of MoSx-based coatings deposited onto high speed steel by magnetron sputtering

MoS_x-based films were deposited using magnetron sputtering from a pure MoS₂ target. Alloying was accomplished by “co-deposition” from separate targets onto substrates having a two-fold rotation. An additional experiment had also a Cr⁺-ion etch for surface preparation, followed by a Cr adhesion layer, made using a Cr target mounted on a cathodic arc evaporation source. MoS_x and Al- and Ti-alloyed MoS_x coatings have been deposited onto high speed steel (HSS) and glass substrates for corrosion investigations.The coatings were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, hardness and adhesion measurements. The corrosion behaviour of the samples was electrochemically measured by open-circuit-potential (OCP) measurements and by potentiodynamic corrosion tests in 0.8 M NaCl solution (pH 7). Additionally the MoS_x-based coatings on HSS have been exposed to salt spray tests. The corrosion investigations revealed that the addition of Al and Ti to MoS_x shifts the open-circuit-potential of about 80 to 110 mV to lower values, i.e. the alloying elements make the MoS_x coating a little bit less noble. In agreement with the OCP measurements, the corrosion potential E_corr in potentiodynamic corrosion tests was the highest for non-alloyed MoS_x coatings on HSS substrates. After the potentiodynamic corrosion tests, a strong corrosive attack could be observed for all coated samples. In salt spray tests the lowest number of corrosion pits was found for the MoS_x-Al (Cr⁺) coating on HSS.     

High temperature corrosion behavior of a multilayer CrAlN coating prepared by magnetron sputtering method on a K38G alloy

A multilayer CrAlN coating of Cr_0.58Al_0.42N/Cr_0.84Al_0.16N/Cr_0.51Al_0.49N has been fabricated by a reactive magnetron sputtering method. It consists of a bonding layer, a Cr-rich intermediate layer and an Al-rich outer layer. The multilayer structure provides the coating with good protection against different types of high temperature corrosion, i.e., high temperature oxidation and hot corrosion. The outer Al-rich layer gives the coating good oxidation resistance at 1000 and 1100 °C due to the formation of a continuous alumina scale. The parabolic rate constants of the coated samples decrease by about 2 orders of magnitude compared with that of the bare alloy samples. The intermediate Cr-rich layer can form a Cr₂O₃ scale to provide good protection under the hot corrosion conditions in the Na₂SO₄ salt fluxing at 900, 950 and 1000 °C. The incubation period of the hot corrosion extends several times longer when the alloy was coated by the multilayer coating at the three selected temperatures.     

Growth morphology and corrosion resistance of magnetron sputtered Cr films

Chromium (Cr) films are commonly used as corrosion-resistant coatings because they form a passive protective scale. The film morphology and microstructure are important aspects of corrosion resistance. This paper presents growth mechanisms and morphologies of these films to provide insight into correlation between microstructure and corrosion resistance. Thin films of Cr were deposited on silicon wafers, and AISI 1018 carbon steel substrates using a plasma-enhanced magnetron sputtering technique. A tungsten filament was used to produce a plasma that enhances ion bombardment on the workpiece during the magnetron sputter deposition process. The deposited films were characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The film growth morphology and microstructure are correlated with sample orientation (with respect to the magnetron) and the deposition parameters. One important deposition parameter affecting Cr film properties is the level of plasma ion bombardment. This investigation demonstrated that at a low level of ion bombardment, a columnar structure is formed with large column widths resulting in a film that is discontinuous. As the level of ion bombardment increases, the films become denser and more continuous. Using the filament induced plasma enhancement method, a fully dense chromium film without indication of columnar structure was achieved. The corrosion behavior of the deposited films was studied using potentiodynamic polarization techniques. This study demonstrated that adequate ion bombardment is necessary to achieve good corrosion resistance.     

Thermal stability of tungsten nitride films deposited by reactive magnetron sputtering

The studies of thermal stability of nitride coatings are important since their structural, thermal, electrical and optical properties are drastically modified by the oxidation layer formed on the top of these coatings. Tungsten nitride films were deposited from metallic tungsten target using reactive pulsed d. c. magnetron sputtering. The films were annealed in air at different temperatures for 1 h. The structural, electrical resistivity and optical properties of the annealed films were analyzed. Besides the film analysis, powder of tungsten nitride was obtained by scratching the coating from the glass substrates. The oxidation kinetics of the scratched powder was studied using simultaneous thermal gravimetric/deferential thermal analysis measurements. X-ray diffraction patterns revealed that W₂N oxidizes to the two different phases WO₃ and WO_2.92. The oxide diffraction peaks appeared upon annealing at 773 K and the relative intensities increased with annealing temperature. The tungsten nitride was found to oxidize according a parabolic relation between mass gain and oxidation time. The activation energy of oxidation was evaluated by analyzing the Arrhenius relation from the temperature dependence of the weight gain. The obtained value was 1.76 eV. The activation energies of crystallization of the two phases were calculated. The electrical resistivity was found to increase drastically upon oxidation. The optical properties of the films are very sensitive to the oxidation temperature. The optical band gap values for the film oxidized at 773 K and 823 K are 2.71 and 2.58 eV, respectively.     

深振荡磁控溅射制备柔性硬质纳米涂层的研究进展

柔性硬质纳米涂层具有高致密性、高表面完整性、高硬度、高韧性和高裂纹抵抗力特性,是新一代高性能纳米涂层的一个重要发展方向,但其制备难度高,难以利用传统涂层制备技术实现。深振荡磁控溅射(deeposcillation magnetron sputtering, DOMS)技术是一种新型的高功率脉冲磁控溅射技术,现已成为国际涂层研究领域的热点。DOMS技术通过一系列调制的电压微脉冲振荡波形,能够实现完全消除电弧放电和靶材近全离化,获得高密度、低离子能量和高束流密度的等离子体,能制备出具有低缺陷、高表面完整性、高致密性的高性能纳米涂层,并且对纳米涂层的成分、结构和性能实现"剪裁化"的可控制备。本文综述了柔性硬质纳米涂层的特征以及DOMS制备柔性硬质纳米涂层的最新进展。     

非平衡闭合场磁控溅射CrTiAIN／MoST复合涂层的性能研究

采用非平衡闭合场磁控溅射方法在Cr12MoV冷作模具钢表面制备CrTiAlN单一涂层和CrTiAlN／MoST复合涂层，通过AFM、XRD、显微硬度、划痕和磨损试验综合分析涂层相结构和的表面性能。实验结果表明，CrTiAlN／MoST复合涂层比CrTiAlN单一涂层更光滑、致密，（Cr,Ti，Al）N在（111）晶面呈强烈的衍射峰，无明显的MoS2衍射峰．Cr12MoV经PVD处理后，表面显微硬度和耐磨性得到了明显的提高，尤其是复合涂层，由于CrTiAlN硬涂层抗磨和MoST软涂层减摩的综合作用表现出比CrTiAlN涂层更低的磨损率，主要的磨损机制为逐层剥落的疲劳磨损。     

磁控溅射制备SiC薄膜及其高温抗氧化性

用射频磁控溅射法在单晶Si(100)基片上制备了SiC薄膜.将制备的薄膜分别在800、900和1000℃空气气氛中退火120 min.用X射线衍射仪和傅里叶变换红外光谱仪测试了薄膜的结构,用X射线光电子能谱仪测试了薄膜元素的组成和状态,用场发射扫描电子显微镜测试了薄膜表面的形貌.结果表明:经800℃空气退火后,薄膜表面生成了一层SiO2保护层,阻止了内部SiC薄膜的继续氧化,因此SiC薄膜在800℃具有较好的高温抗氧化性;随着退火温度的升高,SiC薄膜被进一步氧化,经1000℃空气退火后,薄膜已大部分转变为SiO2.     

Thermal stability of electrical properties of ZnO:Al films deposited by room temperature magnetron sputtering

In order to investigate the thermal stability of electrical properties for aluminum doped zinc oxide (ZnO:Al, AZO) films deposited by direct current reactive magnetron sputtering, AZO films deposited from an alloy target (0.8 wt.% Al) on soda-lime glasses were annealed in argon gas at different temperatures. A data capturer was applied to monitor and collect real-time sheet resistance (R_s) of the films throughout the annealing. Results revealed that R_s of the film heated at 100 °C was reduced throughout the annealing, however, conductivity of the films annealed over 100 °C was improved at early stage but then deteriorated all along to the end. Some novel R_s change points which need more penetrations were detected. The experimental results obtained from electron diffraction spectrum, X-ray diffraction pattern, X-ray photoelectron spectrum, and Hall measurement were analyzed to explore the effect of the annealing on the electrical properties of AZO films. It was found that the exotic element, which might influence the film properties, was not observed. It was also suggested that the transformation of the crystalline structure and surface chemical bonding states, which resulted in the decrease of carrier concentration and mobility could be the reason for the conductivity degeneration of the films annealed at higher temperature.     

Influence of carbon sputtering power on structure, corrosion resistance, adhesion strength and wear resistance of platinum/ruthenium/nitrogen doped diamond-like carbon thin films

Platinum/ruthenium/nitrogen doped diamond-like carbon (PtRuN-DLC) thin films were deposited on conductive p-Si substrates using a DC magnetron sputtering deposition system by varying carbon sputtering power. The chemical composition, bonding structure, surface morphology and adhesion strength of the PtRuN-DLC films were investigated using X-ray photoelectron spectroscopy (XPS), micro-Raman spectroscopy, atomic force microscopy (AFM), and micro-scratch test, respectively. The corrosion behavior of the PtRuN-DLC films in a 0.1 M NaCl solution was investigated using potentiodynamic polarization test. The corrosion results indicated that the corrosion resistance of the PtRuN-DLC films increased with increased carbon sputtering power probably due to decreased porosity level in the films with increased growth rate and film thickness. The wear performance of the PtRuN-DLC films was investigated with a ball-on-disc micro-tribometer. It was found that the increased carbon sputtering power significantly improved the wear performance of the films by enhancing the adhesion strength of the films.     

Surface morphology and in vitro bioactivity of biocompatible hydroxyapatite coatings on medical grade S31254 steel by RF magnetron sputtering deposition

Hydroxyapatite (HA) is popularly used as a biocompatible coating material for metallic implants, in view of its improved bone fixation property, leading to an increased life of the implant. However, the deposition of HA on medical grade UNS S31254 stainless steel (SS254) for orthopaedic implant applications by the radio-frequency magnetron sputtering technique is unreported in the literature so far. The surface morphology of the deposited HA coatings was characterised using scanning electron microscopy and atomic force microscopy, while their phase composition was determined using X-ray diffraction. The thickness and adhesive strength of the HA coatings were determined using an ellipsometer and a tensometer, respectively. Finally, the antibacterial efficacy and bioactivity of the deposited coatings were confirmed using fluorescence activated cell sorting and immersion testing in simulated body fluid environment. The results obtained showed that the HA coatings grown on SS254 using magnetron sputtering possess desirable surface properties as well as good adhesion and biocompatibility properties, ideally suited for potential applications in orthopaedic implants.     

深振荡磁控溅射复合沉积CrN/TiN超晶格涂层的摩擦学性能

研究了IN718高温合金、WC-6%Co硬质合金和Si(100)基体上深振荡磁控溅射复合沉积CrN/TiN超晶格涂层的摩擦学性能。研究表明,涂层的生长对基体的类型没有选择性。随着基体硬度的升高,划痕结合力失效临界载荷增大,涂层结合力失效机制由翘曲失效转变为基体/涂层协同变形,未发现涂层的剥落失效。载荷为2N时,磨损机制由磨粒磨损和氧化磨损转变为轻微磨粒磨损。载荷为4 N时,IN 718基体上涂层的磨损机制为严重的氧化磨损,WC-6%Co基体上的涂层的磨损机制为磨粒磨损和氧化磨损,氧化物的产生、堆积和转移导致摩擦系数的波动。     

靶电流对磁控溅射AlSn20/C镀层耐蚀性的影响

采用非平衡磁控溅射技术在铝基轴承合金表面制备AlSn20/C复合镀层,通过扫描电镜形貌观察、交流阻抗和极化曲线的测量研究石墨靶电流对镀层组织与耐蚀性能的影响。结果表明:在电流0.2~0.8 A范围内,薄膜均以层状结构生长,且电流越小,薄膜组织越致密;镀膜后试样的电化学阻抗比基体的高5~6个数量级,石墨靶电流为0.2 A时,可将基体的自腐蚀电位由1.42 V提高到1.18 V,石墨靶电流是影响AlSn20/C复合镀层耐蚀性的一个重要因素,石墨靶电流越小,其耐蚀性越好。     

Corrosion behaviour of magnetron sputtered α- and β-Ta coatings on AISI 4340 steel as a function of coating thickness

The corrosion behaviour of magnetron sputtered α- and β-Ta coated AISI 4340 steels was studied with potentiodynamic polarization and electrochemical impedance spectroscopy. The coating porosity was observed to decrease with increasing coating thickness. For coatings less than 10 μm thick (α- or β-Ta), porosity was significant and open pores resulted in severe localized corrosion of the steel substrate, coating delamination, and overall coating failure. Additionally, the β-Ta coatings were more susceptible than the α-phase to delamination. As for the 50 and 100 μm thick α-Ta coatings, the electrochemical impedance behaviour was comparable to that of Ta foil, demonstrating the coating viability and corrosion resistance.     

Wear and corrosion resistance behaviours of autocatalytic electroless plating

Nickel–boron coatings were deposited on steel and aluminium substrates. Their morphology, roughness, hardness, wear resistance and electrochemical properties were investigated. A comparison between the coated systems was carried out. The plated aluminium was found to present better roughness and corrosion resistance behaviours than coated steel. The wear resistance of both coated systems is very similar. The aluminium-based system presents a more noble electrochemical behaviour than the coated steel.     

A comparative study of nanocrystalline Cu film deposited using anodic vacuum arc and dc magnetron sputtering

A comparative study of structural, electrical and thermoelectric properties of nanocrystalline copper thin films deposited using anodic vacuum arc plasma deposition technique and dc-magnetron sputtering is presented. The crystallographic texture and structural evolution of these films are investigated as a function of thickness within a range of 30 to 230 nm using XRD and SEM. AVA deposited Cu films possess smaller grains with a lesser degree of crystallinity than dc-sputtered ones. Electrical resistivity, temperature coefficient of resistance and thermoelectric power of both as-deposited and annealed Cu films of AVA and dc-magnetron sputtering is measured and their dependence on the film thickness is investigated. AVA deposited Cu films having thickness less than 100 nm show much higher resistivity than dc-sputtered ones. AVA deposited Cu films possess lower temperature coefficient of resistance values than dc-sputtered ones. The observed thickness dependence of thermoelectric power is larger in AVA deposited Cu films than in dc-sputtered ones. These electrical measurements reveal that AVA deposited Cu films possess more vacancies than dc-sputtered ones.     

非平衡磁控溅射Cp/AlSn镀层组织结构与性能

利用非平衡磁控溅射离子镀技术在铝基轴承合金表面沉积Cp/Al Sn复合镀层。采用原子力显微镜(AFM)和扫描电子显微镜(SEM)对镀层的微观形貌进行观察,并对镀层的维氏硬度和摩擦学性能进行了测试。结果表明,非平衡磁控溅射离子镀Cp/Al Sn镀层,当碳靶电流在0.2~0.8 A范围内,镀层呈等轴结构生长,随碳靶电流增大,镀层晶粒逐渐细化,且致密度增加;在Cp/Al Sn复合镀层中,Al、Sn和C元素分别以单质形式存在,且随掺碳量增加,Cp/Al Sn复合镀层非晶特征逐渐增强;随碳靶电流增加,镀层硬度增加,摩擦系数减小,电流为0.8 A时,镀层硬度最高为230 HV0.025。摩擦系数最低为0.09,磨损率先减小后增大,碳靶电流为0.4 A时,镀层的磨损率最低为6.6×10-16m3/(N·m),其磨损机制逐渐由粘着磨损转变为磨粒磨损。