DLC基纳米多层膜摩擦学性能的研究进展与展望

类金刚石（DLC）薄膜是一种良好的固体润滑剂,能够有效延长机械零件、工具的使用寿命。DLC基纳米多层薄膜的设计是耐磨薄膜领域的一项研究热点,薄膜中不同组分层具备不同的物理化学性能组合,能从多个角度（如高温、硬度、润滑）进行设计来提升薄膜力学性能、摩擦学性能以及耐腐蚀性能等。综述了DLC多层薄膜的设计目的与研究进展,以金属/DLC基纳米多层膜、金属氮化物/DLC基纳米多层膜、金属硫化物/DLC基纳米多层膜以及其他DLC基纳米多层膜为主,对早期研究成果及现在的研究方向进行了概述。介绍了以上几种DLC基纳米多层膜的现有设计思路（形成纳米晶/非晶复合结构、软/硬交替沉积,诱导转移膜形成,实现非公度接触）。随后对摩擦机理进行了分析总结：1）层与层间形成特殊过渡层,提高了结合力;2）软/硬的多层交替设计,可以抵抗应力松弛和裂纹偏转;3）高接触应力和催化作用下诱导DLC中的sp3向sp2转化,形成高度有序的转移膜,从而实现非公度接触。最后对DLC基纳米多层膜的未来发展进行了展望。     

再论现代表面工程

在以往研究成果的基础上,本文进一步完善和发展了表面工程学的内涵。提出了近代技术与传统工艺相结合,形成了近代表面技术．包括表面改性技术、薄膜技术与涂层技术,并详尽归纳了其内容。这三大技术再加上表面科学基础理论,表面涂(膜)层材料及加工技术．表面检测技术,表面质量控制以及表面工程设计及其管理,形成了一门完整的新兴的边缘学科——表面工程学。     

Time-dependent creep behavior of amorphous ZrCu and nanocrystalline Zr thin films – A comparison

Nanoindentation time-dependent relaxation tests were performed on the amorphous ZrCu, nanocrystalline Zr and multilayer ZrCu/Zr thin films aiming to explore the different time-dependent behaviors of these materials under the similar load level at room temperature. There appears an interesting crossing phenomenon of the creep rate as a function of applied stress. In comparison with the ZrCu thin films, the Zr film shows higher load/stress sensitivity for the creep response, suggesting the operating of dislocation creep along various slip systems and some minor grain-boundary-sliding creep mechanism. Multilayered ZrCu/Zr thin films also exhibit higher creep response due to the presence of numerous interfaces.     

Mechanical and electrical properties of NbMoTaW refractory high-entropy alloy thin films

Refractory high-entropy alloys (RHEAs) have opened a new chapter in the development of structural materials for use at high temperatures owing to their outstanding mechanical properties and thermal stability. In this study, we developed a NbMoTaW RHEA thin film via direct current magnetron sputtering from a single target that was synthesized by sintering a mixture of multiple elemental powders. The as-deposited thin film exhibited a single nanocrystalline solid-solution phase with body-centered cubic structure. Moreover, the film had a high hardness of 12 GPa and electrical resistivity of 168 μΩ·cm due to severe lattice distortion and the presence of nanoscale grains. Hence, RHEA films can be used as a hard coating for protective layers and as electrical resistors in nanofabricated devices owing to their favorable combination of hardness and electrical resistivity.     

Formation and performance of an Fe-based amorphous-nanocrystalline composite coating by laser cladding and remelting

Abstract

A very important research topic in the area of the surface performance of engineering components, in particular their wear properties, recently has been the application of high quality surface layers on relatively cheap substrates. An Fe-based composite coating with both amorphous and nanocrystalline structures on a mild steel substrate offers a combination of high quality coating and low materials cost, at the same time extending the range of applications of traditional materials. The difficulties posed by preparation of Fe-based amorphous alloys have limited progress for many years. However, the recent development of high power lasers, and of laser material processing technology in general, has made the preparation of a Fe-based amorphous and nanocrystalline composite coatings over a large area a real possibility.     

AgMgAl metallic glassy and intermetallic thin films for electric contact applications

The AgMgAl thin films, in an attempt in replacing the expensive pure Au contact films, are prepared by co-sputtering. The surface morphology, roughness, amorphous or crystalline atomic structure, grain size, and electric resistivity are systematically examined. Depending on the film compositions, the films can be fully amorphous or fully nanocrystalline, or a composite with the mixture of nanocrystalline phases dispersed in the amorphous matrix. Under the as-sputtered condition, the crystalline group has the lowest resistivity, ranging from 27 to 37 μΩ·cm, the composite group lies in the middle, 31–70 μΩ·cm, and the fully amorphous group possesses the highest resistivity, 87–122 μΩ·cm. Appropriate short thermal annealing for the amorphous films can drastically lower the resistivity down to as low as 9 μΩ·cm, already compatible to pure Au (3–7 μΩ·cm). This study demonstrates the feasibility of the AgMgAl films in replacing the pure Au.     

纳米高频软磁薄膜材料研究进展

由于高频软磁薄膜材料具有巨大的应用前景因此获得了人们广泛的关注。对纳米合金软磁薄膜、纳米软磁颗粒膜、多层膜以及图形化薄膜进行了分类综述,分别介绍了各类薄膜的制备方法、化学成分、微观结构特点和高频物理性能,并对影响其性能的主要因素进行了讨论。由于纳米高频软磁薄膜材料相对于传统磁性材料具有显著优势,所以纳米合金软磁薄膜有望取代铁氧体作为制作高频磁性器件的主要应用材料。由于纳米软磁颗粒膜、多层膜以及新兴的图形化薄膜具有材料结构设计和物性剪裁的自由度,因此将是今后的重点研究方向。     

预沉积ZnO薄膜对ZnO−MoS2/ZnO复合涂层结构与性能影响

目的 通过优化原子层沉积工艺获取不同厚度ZnO薄膜,研究ZnO薄膜晶体取向对ZnO?MoS2涂层生长结构的影响,获得具有优异摩擦学性能的ZnO?MoS2/ZnO复合涂层。方法 采用原子层沉积法在不锈钢基体上预沉积不同厚度的ZnO薄膜,再用射频磁控溅射技术继续沉积ZnO?MoS2涂层,制备ZnO?MoS2/ZnO固体润滑复合涂层。结果 X射线衍射分析发现,预沉积ZnO薄膜有诱导后续ZnO?MoS2涂层沉积生长的作用,预沉积100 nm厚ZnO薄膜的ZnO?MoS2/ZnO复合涂层显示出宽化的MoS2 (002)馒头峰,其截面形貌显示为致密的体型结构,获得的摩擦因数最低(0.08),纳米硬度最高(2.33 GPa),硬度/模量比显示该复合涂层的耐磨损性能得到提升;X射线光电子能谱分析结果表明,复合涂层表面游离S与空气中水发生反应程度大约为原子数分数5%,显示复合涂层耐湿性能较好;基于原子层沉积ZnO薄膜生长及其对后续ZnO?MoS2涂层生长的影响分析,提出了ZnO?MoS2/ZnO复合涂层磨损模型,阐明了ZnO薄膜对复合涂层结构及摩擦学性能的影响,并以该模型解释了200 nm厚 ZnO薄膜上沉积ZnO?MoS2涂层出现的摩擦因数由高到低的变化趋势及最终磨损失效现象。结论 合适的原子层沉积制备的ZnO薄膜有利于MoS2 (002)取向生长,可有效提升ZnO?MoS2/ZnO复合涂层的摩擦学性能;控制ZnO薄膜厚度,可实现ZnO薄膜与基底及ZnO?MoS2层间界面之间的优化结合,以制得具有较好摩擦学性能及使用寿命的ZnO?MoS2/ZnO复合涂层。     

Comparison in mechanical and tribological properties of Cr-W-N and Cr-Mo-N multilayer films deposited by DC reactive magnetron sputtering

Cr-W-N and Cr-Mo-N films were deposited on high speed steel substrate by unbalanced DC reactive magnetron sputtering. Cross-sectional scanning electron microscopy (SEM) morphologies of the films confirmed that the bilayer thickness of multilayer became thinner, and then structural transformation occurred from multilayer to composite with increasing the rotation velocity of substrate holder. X-ray diffraction (XRD) patterns indicated that the Cr-W-N films were composed of CrN and W₂N crystalline phases, and the Cr-Mo-N films consisted of crystalline CrN and amorphous/nanocrystalline Mo₂N. Mechanical and tribological properties were investigated by using a nanoindentor and a ball-on-disk tribometer, respectively. The Cr-W-N films exhibited excellent mechanical properties and wear resistance, while Cr-Mo-N films showed lower friction coefficient. Optimal mechanical and tribological properties were obtained in the Cr-W-N multilayer film with a bilayer period of 12 nm.     

聚乳酸-聚吡咯/银多层复合抗菌薄膜的制备与性能表征

目的提高聚乳酸(PLA)薄膜的抗菌性能。方法受到导电高分子材料可以通过静电作用方式起到抗菌作用的启发,利用Fe~(3+)引发吡咯(Py)在PLA薄膜表面发生化学氧化反应,聚合形成抗菌涂层(PPy),成功制备出PLA-PPy多层复合抗菌薄膜。采用等物质的量Ag~+替代Fe~(3+),引发Py在PLA薄膜表面聚合形成双重抗菌涂层(PPy/Ag),成功制备出PLA-PPy/Ag多层复合抗菌薄膜,并探讨了不同氧化剂和Py浓度对多层复合薄膜结构和性能的影响。结果当PLA薄膜表面积为72 cm~2,水溶液体积为40 mL,Fe Cl_3·6H_2O的浓度为0.047 mol/L,Py的浓度为0.223 mol/L时,PLA-PPy多层复合薄膜的表面PPy层结构致密,拉伸强度(40.1 MPa)和断裂伸长率(24.9%)分别降低了7.6%和12.6%,热稳定性得到较为明显的提高。此外,PLA-PPy/Ag与PLA-PPy多层复合薄膜表现出相似的力学性能和热稳定性。更为重要的是,相比于PLA-PPy多层复合薄膜,PLA-PPy/Ag多层复合薄膜表现出更为优异的抗菌特性,大肠杆菌的菌落总数降低至2.9×10~6 CFU/cm~2,相比于纯PLA薄膜(4.8×10~(10) CFU/cm~2),降低了超过4个数量级。结论相比于完全采用成本较高的纳米银离子负载抗菌方式来说,较低成本的双重抗菌涂层(PPy/Ag)将会在PLA活性包装领域具有一定的研究意义。     

RF deposition of soft hydrogenated amorphous carbon coatings for adhesive interfaces on highly elastic polymer materials

Developing soft and elastic coating materials is one of the future challenges in research on new coating materials for vacuum deposition processes. This development direction is in its infancy and fully contrary to the thin film research mainstream. Such coatings - tailor-made with gradients in hardness and elastic modulus - could work as adhesive and load-supporting layers on polymers bridging the properties from soft substrate to the stiff, wear-resistant hard top coating.In this work we used the approach of a chemical vapour deposition process with plasma assistance from an unbalanced RF (13.56 MHz) powered magnetron sputtering cathode in planar parallel plate arrangement. The characterization of the amorphous hydrogenated and polymer-like carbon films showed a high influence of the used precursor gas (acetylene, butane) on hardness and elasticity. The elastic moduli were found to be between 2 and 35 GPa for the fully amorphous films with a-C:H structure. Specific growth structures were found in HR-TEM imaging of the amorphous coatings. All coatings adhere strongly on a rubber-like polymer (thermoplastic polyurethane).     

ZrCo/Ti储氚复合膜的制备及性能研究

本文利用磁控溅射成功制备了Ti/ZrCo/Ti、ZrCo/Ti/ZrCo/Ti多层复合薄膜,研究了复合薄膜的微观结构与贮氢性能,深入探讨了所制备复合膜作为氘氚中子发生器氚靶部件的应用可能性。结果表明,所制备的多层复合薄膜是由ZrCo相和Ti相组成,各膜层间的界面清晰可辨。相比ZrCo 等单层薄膜,夹层Ti的引入不仅显著提升了复合薄膜的吸氢量,还使薄膜氢化物的具有较高的稳定性。更可喜的是所制备ZrCo/Ti储氚复合膜未发生明显歧化反应。本工作所构建的ZrCo、Ti相互交替的多层复合膜结构,拓展了ZrCo合金的应用领域,可为高容量、高热稳定性新型复合膜氚靶材料的设计开发提供了重要参考。     

A comparative study on the electrochemical behaviour of amorphous and nanocrystalline cobalt–tungsten electrodeposited coatings

Amorphous and nanocrystalline cobalt–tungsten coatings were electrodeposited from a citrate-ammonia bath on copper substrates. Both coatings showed a nodular surface morphology, but a microcrack network was observed in the amorphous coating. The cyclic voltammograms of both deposits revealed anodic and cathodic low-current plateaus around the open circuit potential, exhibiting a passive behaviour. Mott–Schottky analysis showed that the passive films exhibit n-type semiconductivity behaviour and that formed on the amorphous coating showed higher crystal defects. Electrochemical impedance spectroscopy revealed that the amorphous coating has higher corrosion resistance than the nanocrystalline one at both open circuit and anodic potentials. This was attributed to the higher pore resistance of passive film formed at the open circuit potential and more chemical stability of the amorphous coating which reduces its dissolution at the anodic potential. The plugging of the microcrack network in the amorphous coating by corrosion products eliminated the negative effect of microcracks.     

涂层和薄膜态准晶材料的研究现状及展望

准晶材料兼具硬度高、摩擦系数小、耐磨损、耐腐蚀、表面能低等特性,有着十分广阔的应用前景。但受限于本征脆性,准晶材料不能作为结构件单独使用,涂层和薄膜形态成为研究热点。综述了准晶涂层和薄膜的几种制备工艺,主要介绍了热喷涂技术、激光熔覆技术、电子束沉积技术、真空蒸镀技术、磁控溅射技术,并对这几种镀膜技术的特点进行了归纳、对比、总结。详细概述了制备过程中涂层和薄膜的生长过程、生长机理,为之后相关研究工作奠定了良好的基础。对结构和性能的研究现状及在界面结合、组织转变、后续热处理工艺中面临的问题进行了讨论,性能方面主要包括准晶涂层和薄膜优良的抗氧化、耐腐蚀、耐磨损性能及其优异的不粘性,并对存在的相关问题提出了一些可能的解决方案。最后对准晶涂层和薄膜更先进的制备方法以及准晶材料在热障涂层、不粘涂层和固体润滑剂等方面的应用前景进行了展望。     

Stabilization of metallic supercooled liquid and bulk amorphous alloys

Bulk metallic materials have ordinarily been produced by melting and solidification processes for the last several thousand years. However, metallic liquid is unstable at temperatures below the melting temperature and solidifies immediately into crystalline phases. Consequently, all bulk engineering alloys are composed of a crystalline structure. Recently, this common concept was exploded by the findings of the stabilization phenomenon of the supercooled liquid for a number of alloys in the Mg-, lanthanide-, Zr-, Ti-, Fe-, Co-, Pd–Cu- and Ni-based systems. The alloys with the stabilized supercooled liquid state have three features in their alloy components, i.e. multicomponent systems, significant atomic size ratios above 12%, and negative heats of mixing. The stabilization mechanism has also been investigated from experimental data of structure analyses and fundamental physical properties. The stabilization has enabled the production of bulk amorphous alloys in the thickness range of 1–100 mm by using various casting processes. Bulk amorphous Zr-based alloys exhibit high mechanical strength, high fracture toughness and good corrosion resistance and have been used for sporting goods materials. The stabilization also leads to the appearance of a large supercooled liquid region before crystallization and enables high-strain rate superplasticity through Newtonian flow. The new Fe- and Co-based amorphous alloys exhibit a large supercooled liquid region and good soft magnetic properties which are characterized by low coercive force and high permeability. Furthermore, homogeneous dispersion of nanoscale particles into Zr-based bulk amorphous alloys was found to cause an improvement of tensile strength without detriment to good ductility. The discovery of the stabilization phenomenon, followed by the clarification of the stabilization criteria of the supercooled liquid, will promise the future definite development of bulk amorphous alloys as new basic science and engineering materials.     

Microstructure of pulsed laser deposited FePd thin films on amorphous and crystalline substrates

Equiatomic FePd thin films have been deposited at room temperature by pulsed laser deposition (PLD) on amorphous, Si₃N₄ and SiO₂, and crystalline, (100)-NaCl, substrates. The resulting FePd film microstructures have been characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). We observed a complex orientation relationship between grains in nanocrystalline thin films of FCC FePd and the single crystal NaCl substrates. FePd films obtained under identical deposition conditions using the amorphous substrates also exhibited nanocrystalline morphology but with a fiber texture and consisted of a phase mixture of FCC FePd and the tetragonal ordered L1₀-FePd phase.     

纳米薄膜X射线吸收光谱的鉴定

采用X射线吸收光谱研究了热丝化学气相沉积(CVD)合成的纳米金刚石薄膜和脉冲激光沉积的纳米SiC薄膜.结果表明:纳米金刚石薄膜的碳K边X射线吸收精细结构光谱显示的激发峰相当于微米金刚石薄膜的蓝移,是量子效应的显著特征,证明制备的是纳米金刚石薄膜,与高分辨透射电镜的结果完全吻合;纳米SiC薄膜的硅K边X射线吸收精细结构光谱和扩展X射线吸收精细结构光谱也显示了纳米薄膜短程有序的结构特征,表明获得的是纳米SiC薄膜.     

Synergistic Effect of Mo,W, Mn and Cr on the Passivation Behavior of a Fe-Based Amorphous Alloy Coating

In this work, the electrochemical behaviors of SAM2 X5 Fe-based amorphous alloy coating and hard chromium coating were comparatively studied in 3.5 wt% Na Cl solution. In comparison with the hard chromium coating, the SAM2 X5 coating exhibited a wider and stable passive region with lower passive current density in the potentiodynamic polarization and showed a considerably lower current density at different anodic potentials in the potentiostatic polarization. In order to understand the passivation mechanism of the Fe-based amorphous coating, the components of the passive films formed at various polarization potentials were examined by X-ray photoelectron spectroscopy. The synergistic effect of Mo, W, Mn and Cr in the passive films was systemically analyzed. It has been revealed that Mo and W facilitate the formation of compact and stable Cr_2O_3 passive film at lower potentials, and the substantial enrichment of Mn in the passive film enhances the passivation ability at relatively higher potentials. The deep understanding of the passivation characteristics in multicomponent alloy systems could provide a guide for the design of corrosion-resistant amorphous alloy coatings for engineering applications.     

Effect of Al Film on the Electromagnetic Properties of Glass Fiber Reinforced Resin Matrix CompositeEI北大核心CSCD

Metallic thin films have many properties that bulk metals do not possess, such as high impedance. Recently, increasing attention has been paid to high impedance surface in the design of antennas and absorbers. Metallic thin films used in composite materials can realize the perfect matching of electromagnetic wave in different materials. The use of metallic thin films in electromagnetic functional materials results in significant increase of the absorbing intensity and operating bandwidth. But it usually needs to pay a huge amount of manpower, material resources and a longer period of time to design excellent electromagnetic functional materials with metallic films. So it is greatly significant to understand clearly the electromagnetic influence of metallic film for designing excellent performance materials and saving costs by simulation software. Al film is a typical non-magnetic metal film. In this work, the electromagnetic reflectivity of Al films and glass fiber reinforced resin matrix composite had been studied. High frequency electromagnetic field calculation software FEKO was employed to calculate the reflection coefficient of the composites. The effect of composites' real part of permittivity epsilon(r), dielectric loss tangent tan delta(epsilon), permeability mu(r) and magnetic loss tangent tan delta(mu) on microwave reflectivity had been discussed. The equivalent electromagnetic parameters of glass fiber reinforced resin matrix composite had been obtained through a comparison between simulation and experimental results. Due to resonance phenomena of the embedded Al film in the glass fiber reinforced resin matrix composite with certain thickness, there is an optimum resistance value of Al film that makes the composite structure have minimum reflection. Through the calculation of Al film and glass fiber reinforced resin matrix composite with different structure, the thickness relationship between Al films in calculation and Al films prepared by magnetron sputtering had been obtained. According to the theory of transmission line, the resistance of resonance is analyzed by MATLAB. This method is also applicable to the resistance solution of the homogeneous metal films at any position in the composite or frequency selective surfaces. The equivalent electromagnetic parameters of Al film and glass fiber reinforced resin matrix composite in simulation had been ascertained, and the simulation results agree well with the experimental results.     

微晶/纳米金刚石复合涂层的沉积与表征

采用偏压增强热丝CVD(HFCVD)法,通过引入惰性气体Ar,在经过甲醇新预处理方法处理后的硬质合金衬底表面成功沉积了微晶/纳米金刚石复合涂层。对金刚石复合涂层的表面形貌、成分、表面粗糙度进行了分析和研究。研究结果表明:新的预处理方法能够提高金刚石薄膜与衬底之间的附着强度。Ar的引入使得金刚石薄膜二次形核率更高,颗粒也更加细小,纳米金刚石复合涂层不但具有高的附着强度,而且具有非常低的表面粗糙度。对于拓展纳米金刚石涂层在精密加工领域中的应用具有一定的作用。