Ti6Al4V钛合金表面Ta2O5/Ta2O5-Ti/Ti多涂层的制备与性能研究

采用磁控溅射技术在Ti6Al4V钛合金表面制备了Ta_2O_5/Ta_2O_5-Ti/Ti多层涂层;利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和X射线光电子能谱仪 (XPS),分析了涂层的微观结构、物性组成和化学价态;通过划痕仪、纳米压痕仪、摩擦磨损试验机和电化学工作站,检测了涂层的结合强度、力学性能、摩擦系数和耐腐蚀性。研究结果表明,Ta_2O_5/Ta_2O_5-Ti/Ti多层涂层表面由峰型颗粒组成,粒径大小均匀,涂层结构致密。与Ti6Al4V相比,Ta_2O_5/Ta_2O_5-Ti/Ti多层涂层试样具有较小的摩擦系数,较高的腐蚀电位和较小的腐蚀电流密度,表现出良好的耐磨和耐腐蚀性能,能对Ti6Al4V合金植入材料起到较好的保护作用。     

V含量对磁控溅射CrAlVN涂层微观结构及力学和摩擦学性能的影响

采用磁控共溅射工艺在火炮身管PCrNi3Mo钢材料表面沉积了(Cr0.5Al0.5)1-xVxN(x=0%~10.6%,原子分数)涂层。利用电子探针显微分析仪(EPMA)、X射线衍射仪(XRD)、扫描电镜(SEM)对涂层的组成、微观形貌与相结构进行了表征,研究了V含量对涂层微观结构和形貌的影响。结果表明V的加入使得涂层中出现了CrVN新晶相,且随着V含量的增加CrVN特征峰越来越明显,晶粒簇尺寸减小,V元素起到了一定的细化晶粒簇作用。利用纳米压痕仪及摩擦试验机对涂层的硬度、弹性模量和摩擦系数进行了测试,研究了V含量对(Cr0.5Al0.5)1-xVxN涂层性能的影响。结果表明V含量在7.2%时涂层硬度和弹性模量达到最大值,分别为21.36GPa和297.8GPa;随着V含量的增加,涂层的摩擦系数逐渐减小,当V含量在10.6%时,涂层摩擦系数平均值为0.094,表现出良好的摩擦磨损性能。     

射频反应溅射(Al,Ti)N涂层的微结构与力学性能

采用Al-Ti镶嵌复合靶在不同氮分压下制备了一系列(Al,Ti)N涂层,并采用EDS,AFM,XRD,TEM和微力学探针表征了涂层的沉积速率、化学成分、微结构和力学性能,研究了氮分压对涂层的影响.结果表明,氮分压对(Al,Ti)N涂层影响显著:合适的氮分压可以得到化学计量比的(Al,Ti)N涂层,涂层为单相组织,并呈现(111)择优取向,最高硬度和弹性模量分别达到36.9GPa和476GPa.过低的氮分压不但会造成涂层贫氮,而且涂层中的Al含量偏低,硬度不高.氮分压过高,由于存在"靶中毒"现象,尽管涂层的成分无明显变化,但会大大降低其沉积速率,并使涂层形成纳米晶或非晶态结构,涂层的硬度也较低.     

Self-lubricating CrAlVN coatings for turning of Ti6Al4V: oxidation and wear behavior

The titanium alloy Ti6Al4V enables significant performance increases in various branches of industry. Nevertheless, it is difficult to machine, because of its material properties. Due to the low thermal conductivity of titanium, the heat generated while turning Ti6Al4V mainly flows into the tool leading to high temperature loads. In addition, the comparatively low Young's modulus and high yield strength contributes to high mechanical stresses during machining. Temperature active, self-lubricating physical vapor deposition hard coatings appear to be suitable for reducing friction and tool wear during turning of Ti6Al4V compared to the most commonly used uncoated carbide tools. The ability of the coating to form lubricating oxide phases at high temperatures is crucial for this purpose. This paper investigates the oxidation and diffusion behavior of vanadium doped chromium aluminium nitride (CrAlN) coatings after heat treatment at ϑ = 600 °C, ϑ = 700 °C und ϑ = 800 °C in atmosphere as well as the resulting coating properties. The wear behavior of certain coating variants while turning of Ti6Al4V is analyzed.     

Influence of boron doping on mechanical and tribological properties in multilayer CVD-diamond coating systems

Titanium alloy (Ti6Al4V) substrates were deposited with smooth multilayer coatings, by hot filament chemical vapour deposition technique. The effect of boron doping on lattice parameter, residual stresses, hardness and coefficient of friction in multilayer-diamond coating system was studied. The frictional behaviour of the coatings was studied using a ball-on-disc micro-tribometer by sliding the coated samples of titanium alloy (Ti6Al4V) substrates against alumina (Al₂O₃) balls, and increasing normal load from 1 to 10 N. The average friction coefficient decreased from 0.36 to 0.29 for undoped multilayer-diamond coating system and from 0.33 to 0.18 for boron- doped (BD) multilayer-diamond coating system. The average indentation depths for undoped and BD multilayer- diamond coating systems were found to be equal to ～>58 and ～65 nm, respectively, and their hardness values were 60 and 55 GPa, respectively.     

AlTiN layer effect on mechanical properties of Ti-doped diamond-like carbon composite coatings

Ti/Ti-doped diamond-like carbon (DLC) and Ti/AlTiN/Ti-DLC composite coatings were deposited by magnetron sputtering on W18Cr4V high speed steel substrates. The effect of the AlTiN support layer on the properties of these composite coatings was investigated through microstructure and mechanical properties characterization, including hardness, elastic modulus, coefficient of friction and wear properties measured by scanning electron microscopy, Raman spectroscopy, scratch and ball-on-disk friction tests. Ti and AlTiN interlayers have a columnar structure with 50-80 nm grains. The hardness and elastic modulus of Ti/Ti-DLC and Ti/AlTiN/Ti-DLC coatings is 25.9 ± 0.4, 222.2 ± 6.3 GPa and 19.3 ± 1, 205.6 ± 6.7 GPa, respectively. Adhesion of Ti-DLC, Ti/AlTiN/Ti-DLC and AlTiN/Ti-DLC coatings expressed as the critical lateral force is 26.5 N, 38.2 N, and 47.8 N, respectively. Substrate coefficient of friction without coatings is 0.44, and it is 0.1 for Ti/Ti-DLC and Ti/AlTiN/Ti-DLC coatings. Wear resistance of Ti/AlTiN/Ti-DLC composite coatings is much higher than Ti/Ti-DLC coatings based on the wear track width of 169.8 and 73.2 μm, respectively, for the same experimental conditions.     

Influence of composition and processing parameters on mechanical properties and erosion response of Ni–TiB2 coatings

Abstract

Sputtered Ni–TiB₂ coatings have been shown to protect Ti–6Al–4V and Inconel 718 substrates from solid particle erosion. However, before new erosion resistant coatings can be efficiently designed, it is essential that the role of mechanical properties in determining erosion resistance be fully understood. In this investigation, nanoindentation techniques were used to quantify the effects of substrate preparation, coating composition, and sputtering process parameters on the elastic moduli and indentation hardness of thin coatings deposited on Ti–6Al–4V and Inconel 718 substrates. The influence of these parameters on coating adhesion was determined using a conventional scratch test. Elastic moduli, indentation hardnesses, and coating adhesion were correlated with erosion behaviour. The erosion resistance of the coatings that exhibited microscopic ductility is dependent on the nodule diameter and coating properties such as hardness, elastic modulus, and fracture toughness.

MST/1697     

微弧氧化处理对钛铌合金力学及摩擦磨损性能的影响

采用微弧氧化的方法于磷酸盐电解液中在二元β型TiNbx(x=5,10,15,20,25)合金表面制备了微弧氧化涂层。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)表征各合金表面微弧氧化涂层的物相组成和微观形貌。采用纳米压痕仪、球-盘摩擦磨损实验仪分析了微弧氧化处理对钛铌合金力学性能、耐磨性的影响。结果表明,通过微弧氧化处理可以有效的在各基体表面制备出氧化涂层,表面微孔数目及大小无明显差别,拥有相似的致密度,氧化涂层主要由TiO₂相组成。随着基体Nb含量的增加,各基体表面微弧氧化涂层的硬度值与弹性模量表现出相同的变化趋势,Ti-15Nb合金表面微弧氧化涂层的硬度值和弹性模量值最大。经过微弧氧化处理后,Ti-5Nb和Ti-15Nb表面摩擦系数与基体相近,并无减摩效果;Ti-10Nb、Ti-20Nb和Ti-25Nb表面摩擦系数下降了55%以上,主要磨损机制由磨粒磨损变为粘着磨损,改善了合金的耐磨性能。     

Laser surface coating of Mo–WC metal matrix composite on Ti6Al4V alloy

Laser surface alloying of Mo, WC and Mo–WC powders on the surface of Ti6Al4V alloys using a 2 kW Nd-YAG laser was performed. The dilution effect upon the microstructure, microhardness and wear resistance of the surface metal matrix composite (MMC) coating was investigated. With a constant thickness of pre-placed powder, the dilution levels of the alloyed layers were found to increase with the incident laser power. The fabricated surface MMC layer was metallurgically bonded to the Ti6Al4V substrate. The microhardness of the fabricated surface layer was found to be inversely proportional to the dilution level. The EDAX and XRD spectra results show that new intermetallic compounds and alloy phases were formed in the MMC layer. With the existence of Mo content in the pre-placed powder, the β-phase of Ti in the MMC coating can be retained at the quenching process. With increasing weight percentage content of WC particles in the Mo–WC pre-pasted powder, the microhardness and sliding wear resistance of the laser surface coating were increased by 87% and 150 times, respectively, as compared with the Ti6Al4V alloy. The surface friction of the laser-fabricated MMC coatings was also decreased as compared with the worn Ti6Al4V substrate.     

A study of the nanostructure and hardness of electron beam evaporated TiAlBN Coatings

TiAlBN coatings have been deposited by electron beam (EB) evaporation from a single TiAlBN material source onto AISI 316 stainless steel substrates at a temperature of 450 °C and substrate bias of − 100 V. The stoichiometry and nanostructure have been studied by X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. The hardness and elastic modulus were determined by nanoindentation. Five coatings have been deposited, three from hot-pressed TiAlBN material and two from hot isostatically pressed (HIPped) material. The coatings deposited from the hot-pressed material exhibited a nanocomposite nc-(Ti,Al)N/a-BN/a-(Ti,Al)B₂ structure, the relative phase fraction being consistent with that predicted by the equilibrium Ti-B-N phase diagram. Nanoindentation hardness values were in the range of 22 to 32 GPa. Using the HIPped material, coating (Ti,Al)B_0.29N_0.46 was found to have a phase composition of 72-79 mol.% nc-(Ti,Al)(N,B)_1 − x+ 21-28 mol.% amorphous titanium boride and a hardness of 32 GPa. The second coating, (Ti,Al)B_0.66N_0.25, was X-ray amorphous with a nitride+boride multiphase composition and a hardness of 26 GPa. The nanostructure and structure-property relationships of all coatings are discussed in detail. Comparisons are made between the single-EB coatings deposited in this work and previously deposited twin-EB coatings. Twin-EB deposition gives rise to lower adatom mobilities, leading to (111) (Ti,Al)N preferential orientation, smaller grain sizes, less dense coatings and lower hardnesses.     

无氢DLC涂层的摩擦学性能

为了探究轮胎模具无氢类金刚石(DLC)涂层的摩擦学特性,增强轮胎模具的易脱模、防粘、自清洁性能以及提高轮胎质量与服役寿命,以轮胎模具常用的35钢为基体,利用电弧离子镀在基体试样上制备无氢DLC涂层,对涂层Raman光谱、表面粗糙度、表面微观形貌、纳米硬度、结合力和摩擦系数进行了分析,着重研究涂层摩擦前后表面微观形貌的变化以及摩擦磨损机理。结果表明:通过改变表面粗糙度可以有效降低涂层的摩擦系数,涂层摩擦系数随粗糙度减小而显著降低;在140℃高温条件下,摩擦系数最小低至0.363 4,且涂层纳米硬度可达32.45 GPa,弹性模量高达348.94 GPa。无氢DLC涂层完全满足轮胎模具减摩耐磨和自清洁性的使用要求,为制造高性能轮胎模具提供了一种可行的工艺选择。     

Fabrication mechanism of nanostructured HA/TNTs biomedical coatings: an improvement in nanomechanical and in vitro biological responses

In this paper, a mechanism for fabrication of nanostructured hydroxyapatite coating on TiO₂ nanotubes is presented. Also, the physical, biological, and nanomechanical properties of the anodized Ti6Al4V alloy consisting TiO₂ nanotubes, electrodeposited hydroxyapatite, and the hydroxyapatite/TiO₂ nanotubes double layer coating on Ti6Al4V alloy implants are compared. Mean cell viability of the samples being 84.63?% for uncoated plate, 91.53?% for electrodeposited hydroxyapatite, and 94.98?% for hydroxyapatite/TiO₂ nanotubes coated sample were in the acceptable range. Merely anodized prototype had the highest biocompatibility of 110?% with respect to the control sample. Bonding strength of hydroxyapatite deposit to the substrate increased from 12?±?2?MPa to 25.4?±?2?MPa using intermediate TiO₂ nanotubes layer. Hardness and elastic modulus of the anodized surface were 956?MPa and 64.7?GPa, respectively. The corresponding values for hydroxyapatite deposit were approximately measured 44.3?MPa and 0.66?GPa, respectively, while the average obtained values for hardness (159.3?MPa) and elastic modulus (2.25?GPa) of the hydroxyapatite/TiO₂ nanotubes double coating improved more than 30?% of the pure hydroxyapatite deposit. Friction coefficient (ξ) of the anodized surface was 0.32?±?0.02. The calculated friction coefficient enhanced from 0.65?±?0.04 for sole hydroxyapatite layer to the 0.46?±?0.02 for hydroxyapatite/TiO₂ nanotubes due to presence of nanotubular TiO₂ intermediate layer.     

In situ synthesis of TiN/Ti3Al intermetallic matrix composite coatings on Ti6Al4V alloy

The aim of this paper was to develop an in situ method to synthesize the TiN reinforced Ti₃Al intermetallic matrix composite (IMC) coatings on Ti6Al4V alloy. The method was divided into two steps, namely depositing pure Al coating on Ti6Al4V substrate by using plasma spraying, and laser nitriding of Al coating in nitrogen atmosphere. The microstructure and mechanical properties of TiN/Ti₃Al IMC coatings synthesized at different laser scanning speeds (LSSs) in laser nitriding were investigated. Results showed that the crack- and pore-free IMC coatings can be made through the proposed method. However, the morphologies of TiN dendrites and mechanical properties of coatings were strongly dependent on LSS used in nitriding. With decreasing the LSS, the amount and density of TiN phase in the coating increased, leading to the increment of microhardness and elastic modulus and the decrement of fracture toughness of coating. When the LSS was extremely high (i.e., 600 mm/min), only a thin TiN/Ti₃Al layer with thickness around of 100 μm was formed near the coating surface.     

Improved Tribocorrosion Properties of Ti6Al4V Alloy by Anodic Plasma Electrolytic Oxidation

Ti6Al4V alloy has good corrosion resistance due to the formation of the passive oxide films on the surface of Ti6Al4V alloy. However, Ti6Al4V alloy has poor tribocorrosion resistance in the seawater environment. Herein the present work, plasma electrolytic oxidation (PEO) with the electrolyte of glycerol and sodium borate is used to generate PEO coatings on the surface of Ti6Al4V alloy to improve its tribocorrosion properties. The microstructure and tribocorrosion properties of PEO coatings are investigated by using scanning electron microscopy, X-ray diffraction, and tribometer, respectively. The growth kinetics and the tribocorrosion mechanisms of PEO coatings are discussed in detail. It is shown in the results that PEO coatings deposited on the surface of Ti6Al4V alloy are composed of rutile and anatase phases. The surface hardness and thickness of PEO coatings are enhanced with the increase of the voltage and time. The wear rate of Ti6Al4V alloy with PEO coatings is significantly reduced in artificial seawater.     

CrNi3MoVA钢表面电火花沉积W-Ni-Fe-Co涂层的摩擦磨损性能

为进一步拓展火炮身管内膛强化手段,采用粉末冶金技术制备了W-Ni-Fe-Co合金,利用电火花表面沉积技术在CrNi3MoVA钢表面沉积了W-Ni-Fe-Co涂层,同时利用电镀技术在CrNi3MoVA钢表面制备了硬Cr涂层与之进行比较,用纳米压痕仪和摩擦磨损试验机研究了涂层的摩擦磨损性能,并利用XRD、SEM和EDS研究了沉积态和磨损后涂层的相结构、形貌及成分。结果表明电火花沉积W-Ni-Fe-Co涂层由α-W、γ-Fe和NiWO4组成,α-W在涂层中呈白亮带分布;W-Ni-Fe-Co涂层的硬度较电镀硬Cr涂层降低了18%,弹性模量较电镀硬Cr涂层提高了4%;W-Ni-Fe-Co涂层的磨损机制为轻微的粘着磨损,而电镀硬Cr涂层为严重的粘着磨损;CrNi3MoVA钢表面沉积W-Ni-Fe-Co涂层较电镀硬Cr涂层具有明显的减摩耐磨效果,随着摩擦速度的增加,W-Ni-Fe-Co涂层的摩擦系数降低,其原因是磨损表面氧化加剧,氧化物的自润滑作用加大。     

In-situ Forming Composite Coating by Laser Cladding C/B4C

B₄C and graphite(C) mixed powders were clad by laser at the surface of Ti–6Al–4V alloy in N₂ environment. X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray energy dispersive spectroscopy (EDS) were used to analyze the composite coatings. It was found that TiC, TiB, TiN, and TiB₂ which were comprised of the coating were hard strengthening phases in-stiu formed. The microstructure of the coating were mainly dendrites and whiskers-like crstals in white light area. When the mass ratio of graphite is up to 40%, the micro-hardness of coating in specimen A was up to 1245 HV_0.2, which was much greater than that of the substrate. The hardness of Ti–6Al–4V alloy was only 360 HV_0.2. The micro-hardness of the coating in specimen B was from 1060 HV_0.2 to 1358 HV_0.2. The hardness of specimen B was about three to four times greater than that of the substrate. However, the residual graphite in the coating acted as a lubricant, which increased the wear resistant property of the laser cladding coating. The wear resistant property of specimen B was 4 times as great as that of the substrate. It was twice as great as that of specimen A.     

Ni-Co/纳米ZrO_2复合材料的电化学行为及摩擦磨损性能

通过超声辅助电沉积的方法,在加入粒径为50nm的ZrO_2粉体的氨基磺酸盐镀液中制备了Ni-Co/纳米ZrO_2复合镀层。利用电化学方法(线性扫描伏安法、循环伏安法)对沉积动力学进行分析。通过XRD,SEM和EDS分别对复合镀层的微观结构、表面形貌和相组成等进行表征。同时,对镀层进行了纳米压痕测试和旋转摩擦测试。结果表明,Co~(2+)的电沉积行为遵循3D"成核/生长"机制,合金共沉积电位为-0.72V,复合共沉积电位为-0.70V。ZrO_2纳米粒子的加入降低了体系的极化度,使得电极过程更容易进行。纳米ZrO_2的添加量为15g/L时,镀层硬度、弹性模量以及硬模比分别为6.13GPa,291GPa和0.026;摩擦因数为0.3273,磨损量为0.55×10~(-5)g/m,分别为Ni/Co合金的3/4和1/2,超声和纳米粒子的协同作用能够明显改善镀层的力学性能。     

真空阴极电弧制备TiAlN涂层的硬度及摩擦学性能研究

采用真空阴极电弧制备了TiAlN涂层,研究了N2气压和基体负偏压对涂层硬度的影响规律,分析了涂层的致硬机理,探讨了硬度对摩擦学性能的影响。结果表明,N2降低入射离子能量,降低增原子扩散,导致晶粒细化;基体负偏压增大入射离子能量,导致涂层致密化并依次出现(200)、(111)、(220)、(200)择优取向。TiAlN涂层的硬度受Ti、Al、N原子间键能,生长面择优取向及晶粒显微组织的影响,其中最薄弱因素起决定作用。摩擦学性能研究表明,高硬度TiAlN涂层易形成磨粒磨损,摩擦系数和磨损率高;低硬度TiAlN涂层易发生粘着磨损,摩擦系数和磨损率低。     

Evaluation of the effects of plasma nitriding temperature and time on the characterisation of Ti 6Al 4V alloy

The effects of plasma nitriding (PN) temperature and time on the structural and tribological characterisation of Ti 6Al 4V alloy were investigated. PN processes under gas mixture of N₂/H₂ = 4 were performed at temperatures of 700, 750, 800 and 850 °C for duration of 2, 5 and 10 h. Cross section and surface characterisation were evaluated by means of SEM, AFM, XRD and microhardness test techniques. Dry wear tests were performed using a pin on disc machine. Mass loss and coefficient of friction were measured during the wear tests. Three distinguished structures including of a compound layer (constituted of δ-TiN and ɛ-Ti₂N), an aluminium-rich region and a diffusion zone (interstitial solid solution of nitrogen in titanium) were detected at the surface of plasma nitrided Ti 6Al 4V alloy. These structures increased surface hardness of Ti 6Al 4V alloy significantly and gradually distributed the hardness from the surface to the substrate. The "surface hardness", "surface roughness", "wear resistance" and "coefficient of friction" of the alloy were increased due to plasma nitriding process. Moreover, rising both process temperature and time led to increasing of "layers thicknesses", "surface hardness", "surface roughness", "dynamic load-ability" and "wear resistance" of Ti 6Al 4V alloy.     

电解液中Na_2WO_4对Ti_2AlNb微弧氧化膜结构及摩擦磨损性能的影响

选取硅酸盐/磷酸盐体系在Ti_2AlNb表面制备微弧氧化陶瓷膜,利用SEM,XRD,XPS等研究了电解液中Na_2WO_4对氧化膜生长过程、微观结构及成分的影响,同时评价了Ti_2AlNb微弧氧化膜的摩擦磨损行为。结果表明:硅酸盐/磷酸盐电解液中,氧化膜生长速率仅为0.08μm/min,膜层较疏松,表面存在大孔相连的"网状"结构,主要相组成为金红石TiO_2、锐钛矿TiO_2、Al_2O_3及Nb_2O_5。电解液中加入Na_2WO_4,缩短了Ti_2AlNb合金的起弧时间、提高了氧化膜的生长速率、改善了膜层均匀性,同时在膜层中引入了少量WO_3。此外,在Na_2WO_4参与下制备的微弧氧化膜的耐磨性更好。与Si_3N_4对磨时,Ti_2AlNb合金发生严重的磨粒磨损,摩擦因数高达0.5~0.7;含4g/L Na_2WO_4电解液中制备的Ti_2AlNb微弧氧化膜的摩擦因数、比磨损率分别为0.24及6.2×10~(-4) mm~3/(N·m),表面仅出现"鱼鳞状"疲劳磨损特征。