铁基非晶纳米晶涂层组织及磨损性能研究

利用高速电弧喷涂技术在45钢基体上制备了FeCrBSiMnNbY系非晶纳米晶涂层.采用扫描电镜、能谱分析仪、透射电镜和X射线衍射仪等设备对涂层的组织结构进行了表征,着重分析了非晶纳米晶的形成机制,并利用湿砂橡胶轮式磨损试验机对涂层的磨损性能进行了研究.结果表明:涂层的组织主要由非晶相和α(Fe,Cr)相纳米晶组成;α(Fe,Cr)相纳米晶均匀分布于非晶基体内.涂层的组织均匀,结构致密,平均孔隙率为1.7%;非晶纳米晶涂层具有较高的硬度和良好的耐磨性,其失效机制主要为脆性断裂机制.     

高速电弧喷涂FeAlNbB非晶纳米晶涂层的组织与性能

为了提高钢铁材料的耐磨性和硬度,利用高速电弧喷涂技术在45钢基体上制备了FeAlNbB非晶纳米晶涂层.采用扫描电镜(SEM)、能谱分析仪(EDAX),透射电镜(TEM)和X射线衍射仪等设备对涂层的组织结构和相组成进行了分析,研究了非晶纳米晶的形成机制.实验结果表明:FeAlNbB非晶纳米晶涂层是非晶相、α-Fe、FeAl纳米晶和Fe3Al微晶共存的多相组织,涂层中非晶相含量约36.2%,纳米晶尺寸约14.1 nm;涂层组织均匀,结构致密,平均孔隙率约2.3%;非晶纳米晶涂层具有较高的硬度,其耐磨性是相同实验条件下制备的3Cr13涂层的2.2倍.     

热喷涂纳米粉体材料及其涂层制备

介绍了国外喷涂用纳米结构喂料的制备方法，以及采用几种先进的热喷涂技术制备的纳米结构涂层，并指出非晶/纳米晶涂层是该领域研究的重中之重。与传统喷涂层相比，纳米结构涂层在耐磨、防腐性能方面呈现出优异性能和良好的发展前景。     

HVOF喷涂纳米WC-17Co涂层组织结构及力学行为研究

利用超音速火焰喷涂(HVOF)技术制备了普通、超细纳米WC-17Co涂层.研究了喷涂粉末、涂层的微观组织结构和物相成分,测试了涂层的显微硬度、弹性模量、断裂韧性.研究表明,纳米WC-17Co涂层中形成了纳米尺度的胞状结构和长条状结构,并有网状的非晶结构生成.WC-17Co涂层表面均匀致密,3种涂层均是由熔化再结晶区、半熔化区和未熔化区等构成.涂层中条带结构不明显,明显区别于等离子涂层.纳米涂层组织结构更致密,碳化物颗粒分布更均匀.3种涂层中,WC都是主相,W2C、Co6W6C的含量很少.纳米涂层的显微硬度、弹性模量、断裂韧性最高.     

电弧喷涂铁基非晶涂层的制备及其冲蚀磨损性能研究

为了筛选最佳的铁基非晶涂层制备工艺和研究涂层的冲蚀磨损机理,采用电弧喷涂技术在不同工艺参数下制备Fe基非晶态合金涂层,利用自制固液两相流冲蚀磨损试验机和电化学工作站对涂层的耐磨损、耐腐蚀性能进行研究;并用X射线衍射仪(XRD)、扫描电镜(SEM)等手段观察分析了涂层的相结构和组织形貌。结果表明:非晶涂层结构致密、组织均匀,并具有典型的层状结构;铁基非晶涂层具有良好的耐冲蚀性能,90°攻角下涂层冲蚀失重要高于30°攻角下涂层的失重;电弧喷涂电压上升,涂层冲蚀失重随之减小;送丝速度增加,涂层冲蚀失重先降低再升高;冲蚀磨损机制主要表现为脆性剥落;非晶涂层的耐腐蚀性能随喷涂电压的上升得到提高,随送丝速度增加先增强再减弱。     

非晶Fe基涂层的制备工艺研究

本文研究了电弧喷涂中工艺参数对非晶涂层的含量以及性能的影响,以45钢为基材,制备了不同工艺参数下的涂层。研究结果表明,利用电弧喷涂技术可以铁基体上成功制备出含非晶涂层。不同工艺参数条件下所得涂层皆存在非晶相,但所得涂层质量存在明显差异。电弧喷涂完成后,对所制备的涂层与45钢进行了摩擦磨损对比试验,结果显示,在Fe基体上制备的非晶涂层显著改善了摩擦磨损性能。     

块体非晶合金及其涂层的电化学行为

采用铜模吸铸法制备了直径为2mm的Fe58Cr12Mo7C15B6Y2和直径为4mm的Fe55Cr12Mo10Cu2C13B6Y2两种块体非晶合金.利用电弧喷涂方法将相同成分的粉芯丝材喷涂在Q235基板上.对涂层进行的结构分析表明,涂层由非晶相和晶化相共同组成,涂层中含有＜2%的孔隙.涂层和块体非晶合金电化学腐蚀研究结果表明,块体非晶合金在极化过程中发生了多次钝化现象,涂层在电化学反应过程中钝化现象比较短暂.非晶样品和涂层之间电化学性能的差异与涂层成分和结构的不均匀性有关.     

等离子喷涂法纳米结构WC-12Co涂层的微结构与形成机理的研究

使用独特的雾化干燥结合固定床技术合成WC-12Co纳米复合粉体,利用等离子喷涂法制备纳米结构WC-12Co涂层,通过X射线衍射、扫描电镜、透射电镜等分析手段对等离子喷涂纳米结构WC-12Co涂层进行显微结构分析.结果表明涂层中除了WC相,不仅有W2C,W等非WC/Co相的产生,还出现了CoxWyCz(Co3W9C4,Co3W3C),Co3C等相及非晶和孪晶组织,在此基础上本工作将对等离子喷涂纳米结构WC-12Co涂层的形成机理作初步的研究与讨论.     

钛合金表面生物活性涂层的发展历程及趋势研究

钛及钛合金表面经常被涂覆上羟磷灰石使其获得良好的生物学性能.指出了对钛及钛合金表面制备羟基磷灰石涂层的研究依次经历了单一羟基磷灰石涂层、复合涂层、纳米涂层、梯度涂层几个阶段,分别分析了不同的涂层所面临的问题,提出了纳米梯度涂层是将来钛和钛合金表面涂层发展的新方向.     

等离子喷涂氧化锆纳米涂层的组织结构与性能

研究了用纳米粉制备热障涂层的组织及性能与工艺参数的影响关系,对涂层制备具有指导作用.采用等离子喷涂方法以二次造粒的纳米ZrO2为喂料制备了熔炼隔离热障涂层,并利用X衍射物相分析、SEM、TEM、金相等分析手段观测了涂层的物相构成、组织结构和孔隙率.结果表明,涂层主要以四方相和立方相构成,并含有少量的单斜相.在喷涂过程中粉末熔化状况良好,涂层含有网状微裂纹,涂层致密度可达96%,比普通二氧化锆等离子喷涂层高.     

海上防滑涂层的研究及应用进展

简述了海上防滑涂层的分类及功能,重点介绍了船舶用高分子基防滑涂层和金属基防滑涂层的研究及应用现状,指出高分子基防滑涂层是目前海上主要的防滑涂层,金属基陶瓷涂层与非晶合金涂层是国内外研究的重点;并对其今后发展做了展望,明确了添加其他有益材料来增强复合涂层将是未来防滑涂层的研究方向。     

具有复相组织合金镀层中纳米晶粒含量的确定

非晶基上弥散分布着金属间化合物的复相合金镀层,具有优异的耐蚀性及良好的耐磨性.镍-钴合金镀是最新发展的高质量纳米镀技术,其镀层的硬度、耐磨性、摩擦系数、耐腐蚀性、表面粗糙度、深镀能力、复盖能力、电流效率和沉积速率等所有的性能都明显优于晶态的电镀镍-钴合金,这种合金镀层,在非晶基上弥散分布着纳米级的金属间化合物.但研究此类复合镀层,至今未有现成的方法来测定非晶与纳米晶粒的比例,本文采用小角X射线散射解决了这一新问题.     

Mikrostruktur und Eigenschaften lichtbogengespritzter Schichten auf Eisenbasis

Microstructure and properties of Fe‐based wire arc sprayed coatings Innovative iron based feedstocks for wire arc spraying are a promising alternative for conventional carbide reinforced feedstocks for wear applications. Recently the main area of research is focused on improving the properties of deposited functional coatings by varying the wire composition. The influence on the crystalline structure and the dimension of the hard phases in the resulting microstructure is of particular interest in this context. The objective of the investigation is to produce coatings with an amorphous phase, submicron and nanocrystalline structure. The forming of the amorphous phase is influenced by high cooling rates of the molten and partly molten particles impinging on the substrate. Thus, the achieved coatings are characterized by high hardness as well as high corrosion and wear resistance. The present paper introduces iron based coatings produced by wire arc spraying. Due to the application of cored wires with a modified alloy composition the forming of an amorphous phase as well as a submicron‐ and nanocrystalline structure is promoted. The filling of the cored wires are based on FeB with a eutectic composition and is varied by adding Cr₃C₂, FeSi, FeCrC and AlMg. The adding of further elements like Cr, C, Si, Al and Mg should improve the forming of the amorphous phase. The deposited coatings are analyzed regarding to the resulting coating properties and phase composition in connection with the composition of the cored wires. XRD‐analysis’ proved that the Fe‐based coatings contain an amorphous phase.     

Annealing of sputter-deposited nanocrystalline Cr-Ta coatings in a low-oxygen-containing atmosphere

As a protective hard coating on glass molding dies, Cr-Ta coatings were fabricated on binderless tungsten carbide substrates with a Ti interlayer by RF magnetron sputtering. The nanocrystalline Cr-Ta coatings were deposited at 550 °C, which revealed one nanocrystalline phase for the Ta-rich coating and two nanocrystalline phases for the Cr-rich coating. Annealing treatment was conducted at 600 °C in a 12 ppm O₂-N₂ atmosphere to evaluate the coating performance in a realistic glass molding environment. Both Auger electron spectroscopy and X-ray photoelectron spectroscopy depth profiles verified the outward diffusion of Cr, which formed a protective coating for the Cr-rich coatings. A scale of Cr₂O₃ and a Cr-depleted transition zone near the surface were identified by conducting a transmission electron microscopy investigation on the annealed Cr_0.71Ta_0.29 coating. The Cr-rich coating absorbed a smaller amount of oxygen, exhibited greater hardness, and maintained nanoscale surface roughness after annealing in the glass molding atmosphere, thus making it an appropriate protective coating for the die material.     

高熵合金涂层制备及其应用的研究进展

高熵合金涂层又称多主元合金涂层,是一种新型合金涂层。受高熵效应的影响,涂层的组织结构主要由单一的BCC、FCC或者HCP固溶体相构成,且易于形成非晶、纳米晶和纳米复合物,呈现出优异的综合力学性能、抗高温氧化性能、耐辐射性能和生物兼容性能等,具有重要的研究价值和应用前景。分别从涂层的主元数量和位形熵值两方面对高熵合金涂层的概念进行了阐述,比较分析了热喷涂、激光熔覆以及物理气相沉积等几类常用的高熵合金涂层制备工艺的优点和不足,总结了高熵合金涂层的工业应用现状,最后指出了高熵合金涂层在目前的研究中存在的问题并展望了其未来的发展方向。     

Microstructure and magnetic properties of plasma-sprayed Fe73.5Cu1Nb3Si13.5B9 coatings

Amorphous and nanocrystalline Fe_73.5Cu₁Nb₃Si_13.5B₉ coatings were formed by plasma-spraying micron-sized powders onto H62 brass substrates and aluminum pipes. The coatings are about 0.2-0.3 mm in thickness with fully dense and low porosity. The microstructure of the coatings is classified into two regions, namely, a full amorphous phase region and homogeneous dispersion of α-Fe nanoscale particles with a scale of 30-70 nm. The hardness of the amorphous and nanocrystalline coatings is about 960 HV_100g. Coercivity (Hc), saturation induction (B₈₀₀), and initial relative permeability (μ_i) of the coatings are 144 A/m, 0.27 T, 249, respectively, under 800 A/m direct current (DC) magnetic field. The magnetic shielding performance is good under DC magnetic field and its magnetic shielding effectiveness (SE) is 10-12 dB at coating thickness of 0.45 mm under static magnetic field of 2-40 Oe. The SE increases by increasing the coating thickness when the magnetic field frequencies are 50, 100 and 200 Hz with an intensity of 0.85 Oe. The results indicate that the amorphous and nanocrystalline alloy coatings can be good for some magnetic shielding applications.     

Influence of multi-interfacial structure on mechanical and tribological properties of TiSiN/Ag multilayer coatings

The TiSiN/Ag multilayer coatings with bilayer periods of ~50, 65, 80, 115, 150, and 410 nm have been deposited on Ti6Al4 V alloy by arc ion plating. In order to improve the adhesion of the TiSiN/Ag multilayer coatings, TiN buffer layer was first deposited on titanium alloy. The multi-interfacial TiSiN/Ag layers possess alternating TiSiN and Ag layers. The TiSiN layers display a typical nanocrystalline/amorphous microstructure, with nanocrystalline TiN and amorphous Si₃N₄. TiN nanocrystallites embed in amorphous Si₃N₄ matrix exhibiting a fine-grained crystalline structure. The Ag layers exhibit ductile nanocrystalline metallic silver. The coatings appear to be a strong TiN (200)-preferred orientation for fiber texture growth. Moreover, the grain size of TiN decreases with the decrease of the bilayer periods. Evidence concluded from transmission electron microscopy revealed that multi-interfacial structures effectively limit continuous growth of single (200)-preferred orientation coarse columnar TiN crystals. The hardness of the coatings increases with the decreasing bilayer periods. Multi-interface can act as a lubricant, effectively hinder the cracks propagation and prevent aggressive seawater from permeating to substrate through the micro-pores to some extent, reducing the friction coefficient and wear rates. It was found that the TiSiN/Ag multilayer coating with a bilayer period of 50 nm shows an excellent wear resistance due to the fine grain size, high hardness, and silver-lubricated transfer films formed during wear tests.     

Microstructural characterisation of nanocomposite nc-MeC/a-C coatings on oxygen hardened Ti-6Al-4V alloy

Nanocomposite coatings are novel, important systems composed of two or more nanocrystalline, or nanocrystalline and amorphous, phases. Such coatings offer a possibility of tailoring the coating microstructure and achieving new improved properties of coated materials. In this work a duplex surface treatment, consisting of an oxygen diffusion treatment and deposition of low friction nanocomposite nc-MeC/a-C (Me = transition metal, Ti, W or Cr) coatings, was applied for improvement of the Ti-6Al-4V alloy properties. The coatings composed of nanocrystallites of transition metal carbides (TiC or Cr_xC_y or WC) embedded in hydrogen-free amorphous carbon (a-C) matrix were deposited onto the surface of an oxygen hardened Ti-6Al-4 V alloy substrate by means of a simple DC magnetron sputtering. A nano/microstructure of the substrate material and coatings has been examined by scanning- and transmission electron microscopy complemented with the results of X-ray diffraction analyses.It was found that the nanocomposite coatings are composed of different carbide nanocrystals (with sizes of a few nanometres) embedded in an amorphous carbon matrix. The results of qualitative and quantitative analyses of the nanocrystalline phase in the coatings with use of high-resolution transmission electron microscopy combined with image analysis are given in the paper.An effect of the nano/microstructure parameters of the coated alloy onto its micro-mechanical (nanohardness and Young's modulus) and tribological properties (wear resistance and friction coefficient) is discussed in the paper.     

碱性和酸性体系对电沉积Pb-PANI-WC复合镀层性能的影响

为了寻找理想的电极材料,简化制备工序,采用2种不同组成的镀液(碱性、酸性),利用复合电沉积的方法在钛基材上制备出一种新型的Pb-PANI-WC复合镀层;分析了2种镀液体系对Pb-PANI-WC复合镀层的电化学性能、外观形貌、相组成的影响,并与铅银合金镀层和碱性体系纯铅镀层进行了比较。通过电化学性能测试结果对比可知:2种Pb-PANI-WC复合镀层的电化学性能均优于铅银合金和碱性纯铅镀层;与碱性纯铅镀层相比,复合电沉积制备的复合镀层具有较好的电催化活性、耐蚀性,较高的腐蚀电位和较低的腐蚀电流密度,加速试验寿命更长,并且碱性镀液制备的复合镀层性能最佳。