基体负偏压对CrAlN涂层组织和性能的影响

采用真空多弧离子镀技术,使用Cr30Al70(原子分数)复合靶,在不同的基体负偏压下,在不锈钢基体上制备了一系列CrAlN涂层;采用能谱仪、X射线衍射仪、扫描电子显微镜、粗糙度仪、显微硬度仪、摩擦磨损试验机和划痕仪等系统分析了涂层的成分、表面形貌、相结构、粗糙度、显微硬度、摩擦磨损性能和界面结合性能。结果表明:随着负偏压的增大,涂层中x(Cr)/x(Cr+Al)的比值先增大后减小,当负偏压为150V时,该值达到最大,并与靶材成分接近;基体负偏压为200V时,涂层的表面粗糙度最大,涂层结晶度、硬度最佳,晶体相为固溶铬的面心立方AlN;涂层的摩擦磨损性能不仅与涂层的表面粗糙度相关,还与涂层非晶相中铝元素的含量以及涂层的内应力大小密切相关;界面过渡层制备工艺相同时,基体偏压对涂层和基体之间的界面结合性能影响较小。     

Abrasive wear behavior of sprayed hydroxyapitite coatings by gas tunnel type plasma spraying

Hydroxyapatite (HA) coatings were sprayed using gas tunnel type plasma spraying at different arc currents. Abrasive wear test was carried out for the coatings sprayed at different arc currents under unlubricated conditions in air atmosphere. The abrasive wear rate was measured at different coatings thickness to study the effect of coating thickness on the anti-abrasion resistance of HA coatings. The results showed that the abrasive wear resistance of HA coatings increases as the operating arc current of the plasma torch increases. On the other hand, the abrasive wear rate reaches a minimum value near the substrate with coating thickness less than 50 μm. The results showed that the coating hardness increases in the region near the substrate and increases as the arc current increases. The experimental results indicated that there is a relation between the abrasion resistance and hardness properties of HA coatings.     

Structural and tribological characterization of tungsten nitride coatings at elevated temperature

Transition metal nitrides exhibit excellent mechanical properties (hardness and Young's modulus), high melting point, good chemical stability and high electrical conductivity. However, tungsten nitrides still stand aside of the main attention. In our previous study, tungsten nitride coatings with different nitrogen content showed excellent wear resistance at room temperature. Nevertheless, many engineering applications require good tribological properties at elevated temperature. Thus, the present study is focused on the tribological behaviour (friction coefficient and wear rate) of tungsten nitride coatings at temperature up to 600 °C.

The structure, hardness, friction and wear of tungsten nitride coatings with nitrogen content in the range 30–58 at.% prepared by dc reactive magnetron sputtering were investigated. The tribological tests were performed on a pin-on-disc tribometer in terrestrial atmosphere with Al₂O₃ balls as sliding partner. The coating wear rate was negligible up to 200 °C exhibiting a decreasing tendency; however, the wear dramatically increased at higher temperatures. The coating peeled off after the test at 600 °C, which is connected with the oxidation of the coating.     

氮气流量比对CrN涂层结构及摩擦磨损性能的影响

采用直流磁控溅射技术在不同氮气流量比下在YG6基体上制备CrN涂层,通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)及能谱仪(EDS)分析涂层相组成、涂层形貌与涂层元素成分,利用数字式显微硬度仪、划痕仪测定涂层硬度与涂层结合力,在摩擦磨损试验机考察涂层摩擦学性能。结果表明:氮气流量比(氮气流量占气体总流量的比例)为20%、30%时,CrN/YG6涂层结构相对疏松,呈柱状生长;氮气流量比为40%、50%时,CrN/YG6涂层结构较致密,呈三角颗粒状生长;随氮气流量比增大,涂层硬度先增大后减小,当氮气流量比为40%时达到最大值HV1 752.5;CrN涂层的摩擦因数随氮气流量比的增大变化不大,但磨损率先增大后减小再增大,当氮气流量比为40%时达到最小值2.03×10~(-8)mm~3/(N·mm)。研究表明,当氮气流量比为40%时,所制备的CrN涂层具有良好的综合性能。     

TiN薄膜的残余应力调控及力学性能研究

残余应力是制约物理气相沉积（Physical vapor deposition,PVD）硬质薄膜厚度的关键因素。采用多弧离子镀技术在高速钢基体上制备了厚度从3.7 m到15.5 m的TiN薄膜,结合曲率法和有限元法研究残余应力及结合性能随膜厚的变化规律。结果表明,随着膜厚的增加,基片弯曲程度加剧,而薄膜平均残余应力降低;膜层内残余应力的整体水平决定了界面切应力大小,薄膜结合性能随界面切应力的增加而降低。增加基体偏压、降低工作气压均导致薄膜内部残余应力的升高。当残余压应力较高时,TiN薄膜具有细小、致密的柱状晶结构,并呈现（111）择优取向,薄膜硬度及断裂韧度较高,耐磨性能良好。研究结果提示我们,通过残余应力的调控可提高硬质薄膜的力学特性。     

磁控溅射MoS2薄膜的生长特性研究

利用非平衡磁控溅射技术制备出二硫化钼薄膜,并通过扫描电子显微镜和X射线衍射仪研究了工作气压和沉积时间对薄膜表面形貌和结构的影响及其演化规律。实验结果表明,在小于0.40 Pa的气压下,沉积MoS2薄膜的（002）面平行于基体表面,而在高于0.60Pa的高气压下,膜层的（002）面垂直于基体表面.在沉积初期,无论工作气压的高低,薄膜均按（002）基面的方式生长;在沉积后期,低气压下形成的薄膜仍按（002）基面方式生长,而在高气压下薄膜将转向以（002）基面与（100）或（110）棱面联合的方式生长。薄膜的表面形貌、微观结构,与薄膜的生长速率和沉积粒子的能量有关。     

不同基体CrN/CrCN多层涂层海水环境摩擦学性能研究*

为研究不同基体材料对CrN/CrCN多层涂层在海水环境下摩擦学性能的影响,采用多弧离子镀技术在H65铜合金、TC4钛合金和316L不锈钢基体上沉积CrN和CrN/CrCN多层复合涂层,通过XRD、SEM等技术对涂层的结构进行表征,通过结合力、硬度测试和摩擦磨损试验分析涂层在大气环境和海水环境下的力学性能和摩擦学性能。结果表明:CrN/CrCN多层涂层的内应力相对于CrN明显减小,且硬度相对CrN涂层较高;TC4钛合金为基体的涂层结合力较好且涂层硬度较高;在海水环境下涂层的摩擦因数相对于大气环境都有较大幅度下降,其中,以TC4钛合金和316L不锈钢为基体的涂层摩擦因数较小;以H65铜合金为基体的2种涂层在海水中的磨损率高于大气中,而以TC4合金、316L不锈钢为基体的CrN/CrCN多层涂层在海水环境下的磨损率低于大气环境;TC4钛合金为基体的CrN/CrCN多层涂层在海水环境下具有最低的磨损率,表明TC4钛合金更适合作为海水环境下CrN/CrCN多层涂层耐磨的基体材料。     

丙烷压力对超声速微粒沉积铝青铜涂层组织和性能的影响

采用超声速微粒沉积技术在不同丙烷压力(0.469 MPa,0.496 MPa,0.524 MPa,0.551 MPa)条件下制备4种铝青铜涂层,采用环境扫描电子显微镜、X射线衍射仪、能谱仪等试验仪器表征涂层的微观组织、相结构以及氧元素质量分数等,运用显微硬度仪、拉伸试验机和CETR摩擦磨损试验机等试验设备分析涂层的力学性能和摩擦学性能。结果表明,丙烷压力对涂层组织结构及力学性能有显著的影响,随着丙烷压力的升高,涂层孔隙率与氧元素质量分数呈负相关关系,在丙烷压力为0.524 MPa时,涂层孔隙率为0.8%,氧元素质量分数为0.97%,更接近其平衡点;丙烷压力为0.524 MPa以下时,涂层较原始粉末物相无明显变化,主要仍为α+β'+K相;涂层显微硬度、结合强度及耐磨性能随丙烷压力的升高均呈先增大后减小的趋势变化,丙烷压力为0.524 MPa时,涂层的力学性能和耐磨性能达到最优。     

Tribological Properties of DLC Coatings in Helium

The aim of this research work was to investigate tribological properties of low-friction DLC coatings when operating in helium atmosphere. Two commercial DLC coatings (a-C:H and Me-C:H) were included in the investigation and compared to reference PTFE-based coatings, normally used on components operating in helium. Coatings were deposited on hardened 100Cr6 bearing steel discs and tested against uncoated steel balls in low-load pin-on-disc contact configuration. Investigation was focused on the effect of substrate roughness (R _a ?=?0.05?C0.2???m) and contact conditions, including contact pressure (150?C350?MPa) and sliding speed (0.2?C0.4?m/s) on the coefficient of friction of DLC coatings operating in helium. Results of this investigation show that for low-load sliding contact DLC coatings provide low friction in helium atmosphere, similar to soft PTFE-based coatings. At the same time DLC coatings investigated were found to substantially reduce wear of the coated surface. However, while the wear of the coated part has been more or less eliminated, application of DLC coating prolongs running-in and increases wear of the steel counter-part. Furthermore, also in helium atmosphere tribolgical behaviour of DLC coatings showed dependence on the coating type and contact conditions.     

Tribological characterization of tungsten nitride coatings deposited by reactive magnetron sputtering

The structure, hardness, friction and wear of tungsten nitrides prepared by d.c. reactive magnetron sputtering were investigated. The coatings were deposited with different nitrogen to argon ratios; the total pressure was kept constant. The tribological tests were performed on a pin-on-disc tribometer in terrestrial atmosphere with 100Cr6 steel, Al₂O₃ and Si₃N₄ balls as sliding counter-bodies. The wear tracks, the ball-wear scars and the wear debris were analysed by scanning electron microscopy in order to characterize the dominant wear mechanisms.The coatings exhibited different phases as a function of the nitrogen content: films with low N content exhibited the α-W phase; β-W phase was dominant for nitrogen contents from 12 to 15 at.% and β-W₂N was observed for nitrogen content higher that 30 at.%. The mechanical and tribological properties of the tungsten nitride coatings were strongly influenced by the structure. The hardness and the Young's modulus values were in the ranges (29–39 GPa) and (300–390 GPa), respectively; the lowest values correspond to the coatings with the highest nitrogen content. Generally, the friction and wear rate of tungsten nitride coatings sliding against ceramic balls increased with nitrogen content reaching a maximum at 12 at.%; further increase of the nitrogen content led to a decrease of the friction and wear. The sliding with the steel balls did not wear the coatings under the selected testing conditions.     

菜籽油润滑条件下TiN涂层摩擦学特性*

为探究TiN涂层在油润滑条件下的摩擦磨损性能,通过磁控溅射技术在AISI304不锈钢上制备TiN涂层,借助扫描电镜、纳米划痕仪、XRD和摩擦磨损试验机探究不同氮通比下TiN涂层的微观结构、力学性能及其在植物菜籽油润滑下的摩擦学性能。实验结果表明：在氮通比为0.45下制备的TiN涂层具有最致密的晶状结构,且力学性能最优;在菜籽油润滑下,随着氮通比的增大TiN涂层摩擦因数和磨损率呈现先降低后增加的趋势,在氮通比为0.45时两者均最小。XPS分析表明,TiN涂层表面存在的氧化层,增加了菜籽油在涂层表面的润湿性,从而更好地形成润滑膜而起到润滑特性。与橄榄油、聚α烯烃(PAO6)基础油、5W40润滑油3种润滑介质相比,TiN菜籽油润滑下涂层表现出更优的润滑性能。     

采煤机滑靴激光熔覆铁镍基涂层的抗磨性能*

为提高采煤机滑靴在无油工况下的耐磨性,采用激光熔覆技术在45钢为基体上分别制备FeNiMo和FeNiMoSi涂层,并对其物相组成及硬度等进行分析。结果发现：制备的涂层结构致密,与基底保持了良好的冶金结合;FeNiMoSi涂层的平均硬度为438HV,分别约为基体（153HV）的2.8倍以及FeNiMo涂层（385HV）的1.1倍。通过往复式摩擦磨损试验机研究涂层的干摩擦磨损性能,并探讨其磨损机制。结果表明：随着载荷和滑动速度的增大,涂层的摩擦因数均呈现出减小的趋势;随着载荷的增大,涂层的磨损率逐渐升高;随着滑动速度的增大,FeNiMo涂层的磨损率出现先下降后上升的趋势,而FeNiMoSi涂层的磨损率则逐渐下降;涂层的磨损机制主要为磨粒磨损、塑性变形以及轻微的氧化磨损。总体来说,FeNiMoSi涂层相比FeNiMo涂层表现出更好的耐磨性能,这是因为涂层中Si元素的添加,不仅起到细晶强化作用,而且促进了FeSi金属间化合物相的生成。     

FCVA沉积TiAlN薄膜的工艺研究

采用磁过滤阴极真空弧源(FCVA)沉积技术,在高速钢(HSS)基体上沉积TiAlN薄膜,用显微硬度计测定TiAlN薄膜的硬度和厚度,用X射线衍射(XRD)分析技术进行TiAlN薄膜的相分析并进行了摩擦磨损实验,为在刀具表面沉积TiAlN薄膜打下较好的工艺基础。     

离子镀TiCN和TiN工具涂层的微结构与切削性能

采用电弧离子镀技术在硬质合金铣刀和钻头上镀覆了TiCN和TiN涂层,研究并比较了两种涂层的微结构与力学性能,以及涂层铣刀的高速切削性能和涂层钻头的切削性能。结果表明,TiCN和TiN涂层同为单相的Na-Cl型结构,并都呈现(111)择优取向的柱状晶,TiCN涂层的硬度为34.6GPa,远高于TiN涂层25.1GPa的硬度。在高速铣削条件下,TiCN涂层铣刀的后刀面磨损速率仅为TiN涂层铣刀的约三分之一。TiCN涂层钻头在钻孔数为TiN涂层钻头两倍时的磨损量仍低于TiN涂层钻头。TiCN涂层的高硬度及在较高切削线速度下的减摩作用是这种涂层刀具寿命提高的重要原因。     

Evaluation of erosive wear resistance of TiN coatings by a slurry jet impact test

In this paper, it is proposed to use a new type of solid particle impact test (slurry jet) to swiftly evaluate wear properties of thin, single layered or multilayered coatings. By the slurry jet, 1.2 μm alumina particles were impacted at high velocity perpendicular to thin PVD coatings of TiN deposited on high speed steel substrate materials under various substrate temperatures. Since the coatings have a much higher wear resistance than the substrate material, the wear rate increases significantly to the higher level of the HSS material when the coatings are penetrated. This is utilized in the quantification of the assessment of coating wear. A ranking of wear resistance and correlations to the coating surface hardness measured by nano-indentation tests, and coating morphology and structures are given and discussed. The TiN deposited under the highest substrate temperature proved to have the highest wear resistance although it had a relatively low hardness. The wear rate of the TiN coatings varies with the orientation of grains, that is, the {1 1 1} orientation that dominates for the high temperature deposition shows a higher wear resistance than the {1 0 0} orientation, which corresponds with the cleavage fracture behavior. Thus, it can be recommended as a screening test when evaluating coatings and coated materials.     

Experimental examination of the wear behaviour of the VAlN tool coating by strip drawing process

Resistance to wear, and therefore the lifetime of forming tools, can be increased by surface functionalisation using novel, multifunctional coatings. Thereby, the tribological requirements on the coating are an essential factor. Within the scope of the research work presented here, tribological examinations were carried out on a metastable vanadium aluminium nitride (VAlN) tool coating when drawing the high-strength sheet metal material DP 800. It was shown that the wear of the VAlN tool coating can already be determined at stable frictional behaviour (μ?<?0.085). The wear analysis was carried out considering the topography and change in hardness of the tool surface during the drawing path of 110,000?mm under a contact stress of 150?MPa.     

Achieving High Tribological Performance of Graphite-like Carbon Coatings on Ti6Al4V in Aqueous Environments by Gradient Interface Design

A duplex treatment involving nitrogen ion pre-implantation and gradient interfacial transition was performed to obtain a high-performance graphite-like carbon (GLC) coating on a Ti6Al4V alloy. Characteristics of the as-deposited coating systems were systemically investigated by Raman spectrometry, scanning electron microscopy, atomic force microscopy, nano-indentation, and scratch tests. The friction and wear behaviors in distilled water and sea water environments were evaluated by a ball-on-disk tribometer. The results showed that the GLC multilayer coating on nitrogen ion-implanted Ti6Al4V possessed a greater hardness and adhesion strength than to that on un-implanted Ti6Al4V. The tribological performances of these duplex process systems showed a great improvement in both the distilled water and sea water environments. In particular, the Cr/CrN/GLC coatings on nitrogen ion-implanted substrates demonstrated the best friction and wear behaviors. These striking improvements were attributed to the greatly enhanced interface strength between substrate and coating by the nitrogen ion implantation process and improved adhesion strength between gradient layers by the appropriate gradient interlayers with a similar thermal expansion coefficient.     

硬质合金基体FCVA沉积TiAlN薄膜的试验研究

采用磁过滤阴极真空弧源(FCVA)沉积技术,通过改变氮气流量在硬质合金基体上沉积了TiAlN薄膜,用显微硬度计测定了TiAlN薄膜的硬度和厚度;采用X射线衍射(XRD)分析技术进行了TiAlN薄膜的相分析;并进行了摩擦磨损试验和对基体与薄膜的结合力进行定性的分析。结果表明:TiAlN薄膜厚度在450~520nm之间;最高硬度为2754Hv,对应氮气分压为N2分压在8.0×10-2Pa~1.1×10-1Pa;薄膜中主要存在Ti2AlN、Ti2N与TiN相。     

电沉积稀土改性陶瓷涂层磨损性能研究

探讨了在电火花加工机床上沉积碳化钛金属陶瓷涂层方法,利用TiC,WC,Mo,N i粉未添加不同比例稀土元素在高压下压制并烧结了试验电极,在45#钢表面沉积了不同稀土含量的TiC陶瓷涂层,并用扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计、环块式磨损试验机对涂层组成、组织形态进行、硬度及摩擦学性能分别进行了研究,并结合试验结果进行了理论分析。试验结果表明:用电火花放电法可沉积TiC陶瓷涂层,涂层中加入质量分数为0.5%的氧化镧后,涂层的耐磨性能较未加稀土涂层提高了3倍,摩擦因数减少10%,而加入过多的稀土镧氧化物则不利于涂层组织性能及耐磨性能的改善。稀土氧化镧对涂层的组织有改善作用,加入适量的稀土元素使得涂层致密性提高,减少涂层中的缺陷,涂层表面呈多孔结构特性。     

Effect of the microstructure of thermally sprayed coatings on friction and wear response under lubricated and dry sliding conditions

Five thermally sprayed coatings, considered for application in earth moving vehicle undercarriage components, undergoing consecutively lubricated and dry sliding wear, were prepared and investigated. Four different wear tests were employed to reveal the factors controlling the wear response under different contact conditions. An approach considering the local and overall strength of the coating in connection with the knowledge of contact stresses helped to understand the major wear modes under specific contact conditions for the materials tested. The testing illustrated that in situations with lower contact stresses the contact response of the coating may not be directly related to the intersplat binding strength and hardness, but rather to the local splat properties. It has been shown that a porous structure although limiting the wear resistance of nickel aluminum coating in dry under high contact stress may be beneficial in quasi-lubricated sliding. High local splat hardness measured for the molybdenum carbide coatings appeared to be crucial for its enhanced wear resistance. The testing configuration ‘rotating ring on flat’ newly employed in this study has been proven to be a highly reproducible and efficient way of wear testing for thermal spray coatings.