TiN/TiCN/Al2O3/TiN与TiN/TiCN/Al2O3/TiCNO多层涂层的组织性能比较

目的对比TiN/TiCN/Al_2O_3/TiN和TiN/TiCN/Al_2O_3/TiCNO两种多层涂层的组织性能。方法采用化学气相沉积(CVD)技术在硬质合金基体上沉积TiN/TiCN/Al_2O_3/TiN和TiN/TiCN/Al_2O_3/TiCNO两种多层涂层。通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)分析涂层的物相和组织形貌,采用纳米力学测试系统测试涂层顶层的硬度和弹性模量,利用显微维氏硬度计和划痕仪分别测量涂层的显微硬度和结合强度,利用往复式多功能摩擦磨损试验机研究涂层的摩擦磨损性能。结果顶层TiN晶粒为柱状晶,顶层TiCNO晶粒呈细针状。与顶层TiN相比,顶层TiCNO硬度更大,抗塑性变形能力更强。与以TiN为顶层的多层涂层相比,以TiCNO为顶层的多层涂层表面粗糙度、摩擦系数较大,结合强度较低。当磨损只发生在顶层时,耐磨性取决于顶层涂层的性能,TiN/TiCN/Al_2O_3/TiN的磨损体积和磨损率为TiN/TiCN/Al_2O_3/TiCNO的1.2倍。当磨损进行到顶层与Al_2O_3层界面时,结合强度对耐磨性也有重要影响,TiN/TiCN/Al_2O_3/TiN的磨损体积和磨损率是TiN/TiCN/Al_2O_3/TiCNO的82%。结论与TiN/TiCN/Al_2O_3/TiN相比,TiN/TiCN/Al_2O_3/TiCNO的顶层TiCNO硬度较大,抗塑性变形能力强,其顶层耐磨性较好。改善TiN/TiCN/Al_2O_3/TiCNO多层涂层表面粗糙度和结合强度将进一步提高该涂层的摩擦磨损性能。     

Optimum Me-DLC coatings and hard coatings for tribological performance

In this study, hard coatings (TiN, TiCN, CrN, and CrCN) and Me-DLC coatings (Ti _x%-C:H and Cr _x%-C:H) were deposited on tungsten carbide (WC) substrate by multiarc physical vapor deposition (MAPVD) and unbalanced magnetron (UBM) sputtering, respectively. Counterbodies of the AISI 1045 steel cylinder and the AA7075T651 aluminum cylinder were used in the cylinder-on-disk, line-contact wear mode under dry condition; a counterbody of the AISI 52100 steel ball was used in the ball-on-disk, point-contact wear mode, under both dry and lubricated conditions. All wear tests were conducted with a reciprocating machine. After the tests, the most suitable coating for various counterbodies and test environments was selected. For the coating/1045 steel cylinder, the Ti_10%-C:H coating possesses excellent tribological characteristics. For the coating/7075T651 aluminum cylinder, hard coatings display excellent wear resistance. For the coating/steel ball, CrCN and CrN coatings display very little wear under both dry and lubricated conditions. On TiN and TiCN coatings, special wear mechanisms of material transfer, adhesion wear, and fatigue fracture occurred during initial tests under kerosene lubrication.     

TaC_p增强YG11C合金表面改性工艺及性能研究

选用自制烧结的YG11C/TaC_p硬质合金作基体,介绍了采用电弧离子镀在试样上沉积TiN、TiCN和ZrN涂层的工艺.利用维氏硬度计、扫描电子显微镜、X射线衍射仪表征了涂层的力学性能和组织结构.通过比较切削实验中刀具的磨损性,得出涂层刀具有更好的耐磨性能.研究表明,电弧离子镀TiN等涂层能使硬质合金刀具获得更好的使用性能.     

TiC0.91N0.09和TiC0.77N0.23涂层高温抗氧化性能的研究

目的 研究2种不同碳含量的TiCN涂层的抗氧化性能,为改善TiCN涂层抗氧化性能提供理论依据。方法 在WC-Co硬质合金上化学气相沉积TiC_0.91N_0.09和TiC_0.77N_0.23涂层,采用热重法和静态氧化在900℃进行氧化试验。采用X射线衍射仪、拉曼光谱仪和场发射扫描电镜分析氧化前后涂层的物相组成和微观形貌。比较TiC_0.91N_0.09和TiC_0.77N_0.23涂层的抗氧化性能,分析涂层氧化动力学和氧化机理。结果 TiC_0.91N_0.09涂层的氧化质量增量和氧化膜厚度都大于TiC_0.77N_0.23涂层。TiCN涂层900℃下的热重曲线分线性、抛物线2个阶段。TiC_0.91N_0.09和TiC_0.77N_0.23涂层分别于0.225、0.8...     

等离子体增强磁控溅射TiN涂层与铝对摩时的摩擦磨损行为∗

铝挤压模具表面的摩擦磨损行为是影响铝制品质量和模具寿命的重要因素。为了进一步优化铝挤压模具表面耐磨涂层的沉积工艺，以 TiN 涂层为例，采用等离子体增强磁控溅射方法分别在基体偏流为 0.1 A、1.5 A、3.0 A 和 4.5 A 条件下制备 TiN 涂层，利用 XPS、SEM、AFM 和 XRD 分别测量 TiN 涂层的化学成分、表截面微观结构和相组成，利用纳米压痕仪和旋转式球-盘摩擦磨损试验机分别考察 TiN 涂层试样的综合力学性能和与铝对摩时的摩擦磨损行为。结果表明：基体偏流增加对 TiN 涂层的化学组成影响较小。随着基体偏流的增加，TiN 涂层的横截面形貌逐渐细化。涂层表面具有由岛状微凸起组成的微结构，随着基体偏流的增加，微凸起尺寸和数量逐渐减小，表面粗糙度逐渐降低。不同基体偏流条件下制备的涂层均具有明显的 TiN(111)择优生长趋势。当基体偏流从 0.1 A 增加到 1.5 A 时，TiN 涂层的晶粒尺寸明显减小，涂层的综合力学性能得到显著提高。TiN 涂层试样与铝对摩过程中主要发生粘着磨损和磨料磨损，涂层试样对铝的减摩抗磨性能与对摩过程中的铝粘着面积呈负相关。结论：基体偏流对等离子体增强磁控溅射 TiN 涂层的表截面微观结构、力学性能和摩擦磨损行为影响显著，基体偏流为 1.5 A 时制备的 TiN 涂层具有最低的摩擦因数和磨损率，分别为 0.41×10^?15 和 3.03×10^?15 m³ / (N·m)。研究结果对铝成型模具表面高性能长寿命防护涂层的研究开发具有一定的理论意义和实用价值。     

Tribological behavior and wear mechanisms of TiN/TiCN/TiN multilayer coatings

This work employs the PVD process to deposit coatings of single layer TiN, binary layer TiN/TiCN, multilayer TiN⇔⇔N, and sequenced TiN⇔CN⇔N multilayer coatings with variable individual TiN-layer and TiCN-layer thicknesses on tungsten carbide disks and inserts. Also investigated are the fracture mechanisms and the influence of sequence and thickness of these coatings on cylinder-on-disk, line-contact wear mode and ball-on-disk, point-contact wear mode through SRV reciprocating wear tests. Actual milling tests identify wear performance. Experimental results indicate that the coating with a total thickness of 7 Μm and layer sequence TiN/TiCN/TiN exhibits good wear resistance on SRV wear test and milling test. The thickest multilayer TiN/Ti/TiN coating, although having the highest hardness, has the worst wear resistance for all tests. No-tably zero-wear performance was observed for all coating disks under cutting fluid lubricated condition due to the transferred layers formed between the contact interface.     

Tribological behavior of a TiSiCN coating tested in air and coolant

One TiSiCN coating and one TiN coating as a comparison basis were investigated in this paper. The coatings were deposited on stainless steel substrates using a Plasma Enhanced Magnetron Sputtering (PEMS) process, a variation of the physical vapour deposition (PVD) technique. The XRD pattern for the TiSiCN coating implied that the coating either consists of TiN and TiC phases or C be incorporated in TiN as a single solid solution. Both coatings exhibited good adhesion, although their thickness (17 μm-45 μm) was much larger than that of many commercial PVD coatings. The TiSiCN coating showed higher hardness than the TiN coating. The sliding tribological behavior of the coatings against alumimium and alumina counterparts was studied both in air and in a coolant (Hangsterfer's S-500) by pin-on-disc tests. Scanning electron microscopy (SEM) was used to examine the wear tracks on the discs and the wear scars on the pins. Compared to the TiN coating, the TiSiCN coating exhibited lower wear rates and lower coefficients of friction (C.O.F.) against those two kinds of counterparts when tested in air. The cutting coolant provided a lubricant effect and reduced the adhesive wear and C.O.F. between the coating and the counterpart.     

Microstructure and properties of CVD coated Ti(C,N)-based cermets with varying WC additions

In this paper, multilayer coatings of TiN/TiCN/Al₂O₃/TiN are deposited on the Ti(C, N)-based cermets containing WC, and the effect of WC on the growth and adhesion strength as well as the mechanical properties of the coating are investigated. The multilayer coatings deposited by chemical vapor deposition (CVD) are uniform and dense. TiN coating exhibits a dense fine-grained structures and the Ti (C,N) on TiN coating shows dense columnar structure. The α-Al₂O₃ layer deposited on transition coating presents coarse grains with limited voids. The grain size of the columnar crystals deposited on the substrates gradually decreases with WC addition. The Al₂O₃ layer shows a preferred growth orientation of (104) plane. For TiN/TiCN phase, a change in orientation from (111) to (200) is observed. Generally, the (200) preferred orientation enhances and (111) preferred orientation diminishes with increasing WC addition. Strong adhesion of the CVD coating is obtained due to a sufficient amount of chemical elements, especially tungsten, diffusing from the substrate to the interfacial layer. Scratch tests show that the adhesion strength of TiN/TiCN/Al₂O₃/TiN films gradually increases firstly, and then decreases. With the addition of WC, the hardness, elastic modulus and plasticity index increase at the beginning, and then decrease. The change in nanohardness and elastic modulus is related to the grain size, elemental diffusion, and preferred orientation of the coating.     

Phase constituents and mechanical properties of laser in-situ synthesized TiCN/TiN composite coating on Ti-6Al-4V

Laser in-situ synthesis technology at room temperature was applied to obtain TiCN/TiN composite coating. A pulsed Nd:YAG laser (wavelength 1064 nm) was used to melt the mixture of Ti and C powder. Pure nitrogen gas with a pressure of 0.4 MPa was introduced coaxially together with laser beam to the melting pool to react with Ti and C atoms and in-situ synthesize TiCN/TiN composite coating. The coating consists of TiC_0.3N_0.7, TiN and TiN_0.3, but the proportions of these three constituents vary with the laser power density. SEM results revealed that dendrites were oriented in accordance with the heat flow and a metallurgical bonding between the coating and the substrate was achieved. The in-situ synthesized TiCN/TiN composite coating, with a thickness of about 200 μm, increased the hardness and wear resistance compared to the bare Ti-6Al-4V substrate. A remarkable improvement of the average microhardness (3-4 times) and an enhancement of the wear resistance (10-11 times) are observed by laser in-situ synthesizing TiCN/TiN composite coating.     

SEM-EDS Plane Scan and Line Scan Analysis of TiCN Coatings by Cathodic Arc Ion Plating

采用阴极弧离子镀在Cr12MoV冷作模具钢表面制备了TiCN涂层,通过扫描电镜(SEM)和能谱仪(EDS)分析了涂层表面化学元素的面分布和界面化学元素的线分布。讨论了涂层界面结合机理,用划痕法对结合强度进行了表征分析。结果表明,涂层主要是由TiN、TiC和C原子组成,其中TiN和TiC提高了涂层硬度,C原子改善了涂层摩擦润滑性能;涂层中N原子分数超过C原子分数,界面结合处发生了相互扩散,涂层中C原子扩散量最大,基体中Si原子扩散量最大,涂层与基体形成了冶金结合,利用划痕法测定TiCN涂层结合强度为79.6 N     

Wear, erosion and corrosion resistance of CrTiAlN coating deposited by magnetron sputtering

A nanolayered CrTiAlN coating, which was deposited on Ti6Al4V substrate using unbalanced magnetron sputtering technique, was tested to evaluate its performances against wear, erosion and corrosion. The coating, with a higher hardness compared to CrN, demonstrates significantly higher dry sliding wear resistance than CrN and TiN coatings. Different from the brittle TiN coating, the CrTiAlN coating has a maximum erosion rate at an impingement angle of 45° and shows better erosion resistance than TiN coating at 90°. The CrTiAlN coated Ti6Al4V, when tested in 3.5% NaCl aqueous solution, shows a markedly more noble corrosion potential in comparison with the uncoated Ti6Al4V substrate. Furthermore, it demonstrates a wide passive region with a low current density. All these properties make the CrTiAlN coating a good candidate for a variety of industrial applications.     

TiN, TiN gradient and Ti/TiN multi-layer protective coatings on Uranium

Single-layer TiN, gradient TiN and multi-layer Ti/TiN coating were deposited on silicon and uranium substrates by means of arc ion plating technique. The main phase in the single-layer TiN coating was TiN with a (111) preferred orientation. Ti and TiN were observed in the TiN gradient coating and Ti/TiN multi-layer coatings. The single-layer TiN coating has demonstrated the best wear resistance among the three coatings. Compared with the bare U substrate, the corrosion potential E_corr of the multi-layer Ti/TiN coatings is increased by 580 mV, and the corrosion current density I_corr is decreased at least by two orders of magnitude. The multi-layer Ti/TiN coatings possessed the highest corrosion resistance among the three coating in a 0.5 μg/g Cl⁻ solution.     

梯度过渡层对硬质合金沉积类金刚石膜的耐磨性影响

目的分析不同类型的梯度过渡层对硬质合金沉积类金刚石涂层耐磨性能的影响,制备出能有效改善硬质合金减摩抗磨性能的类金刚石涂层。方法采用真空阴极电弧离子镀和等离子体增强化学沉积技术,在硬质合金基底上制备了Ti/TiC/DLC、Ti/TiN/DLC、Ti/TiN/TiNC/DLC和Ti/TiN/TiNC/TiC/DLC四种类型的Ti多元梯度过渡类金刚石涂层。通过GNEHM-150型洛氏硬度计和电子显微镜、MFT-4000多功能材料表面性能试验仪、纳米硬度测试仪,分别评价不同类型多元梯度过渡层对硬质合金类金刚石涂层的膜基结合强度、摩擦磨损性能及纳米硬度。结果 Ti/TiC/DLC、Ti/TiN/DLC、Ti/TiN/TiNC/DLC和Ti/TiN/TiNC/TiC/DLC四种类型涂层的膜基结合强度等级分别为HF3-HF4、HF5-HF6、HF1-HF2、HF1,对两种膜基结合强度较好的涂层(Ti/TiN/TiNC/DLC、Ti/TiN/TiNC/TiC/DLC)进行摩擦磨损检测,其摩擦系数分别为0.2、0.1,且经过60 min对摩,Ti/TiN/TiNC/TiC/DLC涂层仍未出现明显剥落。结论梯度过渡层的类型对薄膜的膜基结合强度、摩擦性能有较明显的影响,Ti/TiN/TiNC/TiC/DLC结构的涂层膜基结合强度最好,具有最低的摩擦系数,表现出了优异的减摩抗磨性能,可有效改善硬质合金表面的耐磨性能。     

Corrosion behaviour of as deposited and PMMA treated TiN coating systems deposited by cathodic arc technique

Abstract

Vapour deposited coatings usually contain microscopic defects, which can provide corrosive media with easy access to the substrate. Consequently, formation of galvanic cells between the coating and substrate can initiate localised corrosion at the defective sites. In this study, TiN coatings were deposited on mild steel (MS) and stainless steel (SS) substrates using a cathodic arc technique. A post-deposition treatment with polymethyl methacrylate (PMMA) was applied to both TiN/MS and TiN/SS systems to block access of corrosion media to the substrates through the coating defects. The as deposited and PMMA treated coating systems were subjected to electrochemical tests in 3·5%NaCl solution. Potentiodynamic polarisation testing results indicated that the PMMA treatment led to a higher corrosion potential and a lower anodic current density for both TiN/MS and TiN/SS systems when compared with their as deposited counterparts. Extended exposure in 3·5%NaCl caused severe localised corrosion in the as deposited TiN/MS due to the presence of coating defects and poor corrosion resistance of the substrate. Electrochemical impedance spectroscopic measurements demonstrated that the PMMA post-deposition treatment significantly improved corrosion resistance of both TiN/MS and TiN/SS systems by effectively sealing the open voids or pores associated with the coating defects.     

保温时间对Ti/TiN/TiCN涂层结构、残余应力及耐磨性的影响

目的 改善镁合金表面硬度和耐磨性能。方法 采用磁控溅射法在AZ31表面制备复合Ti/TiN/TiCN涂层,在不同保温时间下对沉积后的复合涂层进行退火处理。借助X射线荧光光谱(XRF)测试复合涂层表面平均元素含量,采用X射线小角掠入射(GIXRD)技术研究涂层物相组成和残余应力,利用扫描电镜(SEM)观察涂层表面形貌和磨痕形貌,借助销盘式摩擦磨损试验机和纳米压痕仪评估涂层的耐磨性能。结果 退火涂层的晶粒尺寸增加,内部缺陷减少,涂层更致密,残余应力显著下降。退火前后涂层的物相均为FCC的TiCN,不同保温时间下的涂层具有不同的择优生长取向。随着保温时间的延长,涂层表面Ti、C含量先增后减,N元素含量先减后增,涂层表面硬度下降,摩擦因数增大,耐磨性能下降。沉积涂层的韧性较好,摩擦因数波动较大,磨损机制以刮擦磨损为主。退火30 min后,涂层的磨损率最低,磨损机制以磨粒磨损和黏着磨损为主。退火90 min后,涂层的磨痕最宽,韧性最差,磨损率最高,磨损机制以磨粒磨损和氧化磨损为主。结论 退火有助于降低残余应力,但退火时间不宜过长,时间超过30 min,涂层的耐磨性能下降。     

Comparative studies on corrosion and tribological performance of multilayer hard coatings grown on WC-Co hardmetals

Multilayer TiN/TiCN/TiCN/TiC/TiN and TiN/TiCN/TiCN/TiC/Al₂O₃ hard coatings with total thicknesses of 15.7 μm and 9.3 μm were deposited on WC-10Co substrates using a chemical vapor deposition system. Evaluation of surface, cross-section morphologies, chemical composition and phases of coatings were analyzed by field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) analyses respectively. Corrosion properties were evaluated in 3.5 wt% NaCl medium using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Tribological properties of fabricated multilayer hard coatings were evaluated using pin-on-disk tests. Results show that active dissolution of the WC-10Co occurred while the coated samples showed more anodic slopes as well as lower corrosion current densities. The corrosion current densities of 3.3 × 10⁻⁷ A/cm² and 7.5 × 10⁻⁸ A/cm² were obtained for the TiN/TiCN/TiCN/TiC/TiN and TiN/TiCN/TiCN/TiC/Al₂O₃ coated specimens which are much lower than 4 × 10⁻⁶ A/cm² of substrate. EIS analysis confirmed the results of potentiodynamic polarization curves. Delamination of the TiN coating and formation of titanium oxide compounds on the surface of the TiN/TiCN/TiCN/TiC/TiN coating revealed that oxidative wear mechanism is dominant for this sample, while adhesive wear mechanism was dominant for the TiN/TiCN/TiCN/TiC/Al₂O₃ coated sample.     

Comparative wear performance of titanium based coatings for automotive applications using exhaust gas recirculation

This paper reports tribological characterization of titanium based coatings ion bonded on steel balls for automotive applications using exhaust gas recirculation (EGR). It is well known that lubricating oil drawn from EGR operated engine is contaminated with soot and higher amounts of wear debris compared to non-EGR operated engine. In this study, steel balls coated with TiN, TiAlN and TiCN are investigated in both fresh lubricating oil and EGR stressed oil for a comparative assessment of their wear characteristics in two mediums. Normal load was applied on the samples, tested against a rotating cast iron disk, simulating ring-liner interaction. In each experiment, about one quarter of disk was dipped in the oil (a) to ensure the presence of a thin oil film on the disk-ball interface during the experiment, and (b) to avoid exposure of the worn surface to atmospheric air. The results reveal that the wear rates of the coatings based on the change in the scar diameters of the samples, tested in EGR oil was 2-4 times higher than that of fresh lubricating oil. It was found that despite lowest hardness, TiN coated samples showed smaller scar diameters than TiAlN and TiCN coated samples in both lubricating oil environments. A simple geometric model was used to calculate the thickness of the coating removed as a function of the test duration. Results show that TiN coatings last for 120 min in fresh oil as compared to 30 min in the EGR oil under normal loading, whereas TiAlN and TiCN coating last for 60 and 30 min respectively in fresh oil and wear out in 15 min in EGR oil.     

Friction and wear behavior of laser cladded WC-Co and Ni/WC-Co deposits at high temperature

This research investigates the wear performance of WC-12Co and electroless Ni/WC-Co deposits at high temperature. Dry sliding wear experiments were carried out for coated and uncoated steel substrate against alumina pin. The microstructure and wear performance of laser-cladded WC-Co and Ni/WC-Co were characterized by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) techniques. The mass reduction, friction coefficient, and wear rate of Ni/WC-Co deposits were measured and found to be significantly lower than WC-Co coatings. Due to the presence of Ni coating around the particle of the Ni/WC-Co coating, it showed a lower microhardness, more homogeneous microstructure, and a higher wear performance compared to WC-Co coating. The results of this paper indicated that the dominant mechanisms in wearing distance were adhesive, abrasive, and pulling out from the particles.     

Characteristics and machining applications of Ti(Y)N coatings

The Ti(Y)N coatings were successfully deposited onto 18-8 stainless steel substrates by the hollow cathode discharge ion-plating method. The influence of the rare-earth element yttrium on the TiN coating properties was studied. The results show that the adhesion of the coating to the substrate were evidently enhanced by adding a small amount (0.2 wt.%) of the rare-earth element yttrium, showing a critical load of about 390 g which is much higher than that (230 g) of the TiN coating/substrate. Investigation on the corrosion resistance of the Ti(Y)N coating and the TiN coating was performed in 0.5 N Na₂SO₄ + 0.1 N H₂SO₄ + 0.1 N NaCl corrosion media by means of an electrochemical potentiodynamic polarization. The Ti(Y)N coating exhibited much better corrosion resistance than the TiN coating, whose passivity maintaining current is about one order in magnitude smaller than that of the TiN coating.The Ti(Y)N coatings deposited on some HSS-based tools were presented and compared with the TiN coating. The service lifetime of Ti(Y)N coated tools is approximately 36% higher (on the pinion shape cutters) and about 50% higher (on punch side pin) compared to that of TiN coated. The Ti(Y)N coatings showed such excellent performance. It is attributed to that the transition area of Ti(Y)N/substrate consisted of three sublayers which revealed a gradual change of phase structure and composition, so that the adhesion of the coating/substrate was evidently enhanced. Moreover, Ti(Y)N coating showed a preferred orientation with (111) plane which is favorable to improve wear resistance and corrosion resistance of the coating.     

Tribological behavior of TiN and CrN coatings sliding against an epoxy molding compound

TiN and CrN coatings were deposited by unbalanced magnetron sputtering, and then rubbed against an epoxy molding compound (EMC). In sliding against an EMC, TiN exhibited an extremely high wear rate and a low friction coefficient, while the CrN-coated sample showed the opposite behavior. To understand this difference, Raman spectroscopy and thermal testing were used to study both coatings. Combining the results of oxidation, Raman spectroscopy and tribological testing, it can be concluded that the oxidation and pore generation occurring in the TiN coating during sliding deteriorated the mechanical properties of the coating and therefore its wear resistance. The excellent wear performance of the CrN coating against EMC was related to its good oxidation resistance, and adhesion to the substrate at high temperature.