TiBCN:CNx multilayer coatings deposited by pulsed closed field unbalanced magnetron sputtering

In this study, a combination of nanocomposite and multilayer coating design was investigated in an effort to reduce the coefficient of friction (COF) while maintaining good mechanical properties of the TiBCN coatings. The TiBCN:CN_x coatings consist of TiBCN and CN_x nanolayers which were deposited alternately by reactive sputtering a TiBC composite target (80 mol% TiB₂ + 20 mol% TiC) and a graphite target in an Ar:N₂ mixture using a pulsed closed field unbalanced magnetron sputtering system. Low angle X-ray diffraction and transmission electron microscopy characterizations confirmed that the coatings consist of different bilayer periods in a range of 3.5 to 7.0 nm. The TiBCN layers exhibited a nanocomposite structure, whereas the CN_x layers were in an amorphous state. The mechanical properties and wear resistance of the TiBCN:CN_x multilayer coatings were investigated using nanoindentation and ball-on-disk wear test. The TiBCN:CN_x coatings exhibited high hardness in a range of 20-30 GPa. The highest hardness of 30 GPa was achieved in the coating with a bilayer period of 4.5 nm. A low COF of 0.17 sliding against a WC-Co ball was obtained at a bilayer period of 4.5 nm, which is much lower than those of the single layer TiBCN and TiBC nanocomposite coatings (0.55-0.7).     

过氧化氢环境下1Cr18Ni9Ti不锈钢与不同陶瓷配副的摩擦学行为

本文研究了ZrO_2, Si₃N₄ 和SiC三种陶瓷配副对1Cr18Ni9Ti不锈钢在90%的H₂O₂溶液中摩擦学性能的影响。结果表明,1Cr18Ni9Ti不锈钢在该环境下的摩擦学性能受配副的影响明显。 与ZrO₂对磨,发生了粘着行为,导致了大的摩擦系数(0.17~0.27)和最高的1Cr18Ni9Ti不锈钢磨损量。与SiC对磨,发生了氧化和水解反应,形成的胶体膜起到了润滑作用,导致了小的摩擦系数(0.035)和最低的1Cr18Ni9Ti不锈钢磨损量。粘着行为和水解反应均发生于1Cr18Ni9Ti/Si₃N₄的磨损过程中,粘着与保护膜的耦合,导致了复杂的摩擦系数。对于配副,ZrO₂的磨损体积最大,SiC次之,Si₃N₄表面有粘着层,因此磨损体积最小。     

金属Cr层对Cr/Cr2N纳米多层涂层的性能影响

目的研究金属Cr层对Cr/Cr_2N纳米多层涂层结构和性能的影响,为多层硬质涂层在海洋等腐蚀性介质中的应用提供理论基础。方法采用多弧离子镀技术制备一系列不同金属Cr层厚度的Cr/Cr_2N纳米多层涂层,采用XRD、SEM、纳米压痕及划痕仪测试了多层涂层的结构、微观形貌和机械性能。采用电化学工作站评价了Cr/Cr2N纳米多层涂层在海水环境下的电化学行为,并采用摩擦实验机测试了涂层在海水环境下的摩擦学性能。结果 Cr层对Cr/Cr_2N纳米多层涂层的结构产生了一定的影响。不同Cr层厚度的Cr/Cr_2N纳米多层涂层在海水环境下的磨损率差别不大,均约为1.2×10-6 mm~3/(N·m),具有良好的耐磨损性能。Cr层厚度约为21 nm的Cr/Cr2N纳米多层涂层在海水环境下具有较高的阻抗值,呈现出较高的耐腐蚀性能。结论一定厚度的金属层(如Cr层厚度约为21 nm)和界面是多层涂层呈现较高耐腐蚀性能的关键。Cr/Cr2N纳米多层涂层在海水环境下良好的耐腐蚀和耐磨损性能,使其可应用于海洋等腐蚀性介质中,并发挥良好的表面防护作用。     

Effect of number of layers on erosion,corrosion, and wear resistance of multilayer Cr–N/Cr–Al–N coatings on AISI 630 stainless steel

In the present study, multilayered Cr–N/Cr–Al–N coatings were prepared by cathodic arc physical vapor deposition (PVD) with different numbers of layers and the same total thickness on AISI 630 steel in an attempt to improve the wear and erosion–corrosion resistance. Structural analysis of the coatings was performed by field scanning electron microscopy, X-ray diffraction (XRD), and energy-dispersive spectroscopy. Depth profiles and roughness parameters of worn surfaces were calculated after erosion and wear tests. XRD indicated that nitride compounds were formed in multilayer coatings by PVD. The Cr–N/Cr–Al–N coating exhibited superior corrosion resistance compared with AISI 630 substrate. The erosion–corrosion results revealed that the smoothest wear track with the minimum erosion rate and wear depth was obtained for five- and seven-layered coatings. The failure mechanism of the bare substrate was influenced by plastic deformation via cutting and plowing, while the failure mechanism for coated samples was chipping and delamination. According to the wear results, the multilayer coatings showed a lower friction coefficient and better surface morphology that demonstrated their high ability for wear protection.     

Sliding wear behaviors of electrodeposited Ni composite coatings containing micrometer and nanometer Cr particles

Micrometer and nanometer Cr particles were co-deposited with Ni by electroplating from a nickel sulfate bath containing a certain content of Cr particles. Cr microparticles are in a size range of 1-5 (m and Cr nanoparticles have an average size of 40 nm. The friction and the wear performance of the co-deposited Ni-Cr composite coatings were comparatively evaluated by sliding against Si3N4 ceramic balls under non-lubricated conditions. It is found that the incorporation of Cr particles enhances the microhardness and wear resistance of Ni coatings. The wear resistance of Ni composite coating containing Cr nanoparticles is higher than that of the Ni composite coating containing Cr microparticles with a comparable Cr particle content. The co-deposition of smaller nanometer Cr particles with Ni effectively reduces the size of Ni crystals and significantly increases the hardness of the composite coatings due to grain-refinement strengthening and dispersion-strengthening, resulting in a significant improvement of wear resistance of the Ni-Cr nanocomposite coatings.     

铝硅合金表面激光Cr／WC梯度层组织及抗微动磨损性能研究

利用5kWCO2激光器对铸造铝硅合金表面进行两次激光辐照,先后将不同成分的预置合金粉末和基体材料一起熔化后迅速凝固,在其表面获得Cr/WC激光表面梯度层,并对它们的显微组织进行分析,发现在表面梯度层中存在大量的Al/Cr化合物Al9Cr4。在激光表面梯度层中自表及里显微硬度基本呈连续变化趋势,而单次激光表面合金化层与基体之间的显微硬度值有一突变,在基体和激光表面改性层的微动磨损试验中发现,激光改性后的表面抗微动磨损的能力增强,磨损机制不同于铝硅合金基体,而表现出较好的抗粘着损伤性能。     

Surface Treatment of Cr12MoV Steel towards Long-Life Cold-Work Dies

With the rapid development of the automobile industry in China, there is an ever-increasing demand for long-life cold working dies used for punching automobile components. However, the full potential of such advanced surface engineering technologies as PVD coatings and duplex surface treatments in cold work dies has not been realized. In the present study, Crl2MoV steel has been surface engineered by single PVD Ti/TiN coating and duplex treatment combining low temperature plasma nitriding (LTPN) with PVD Ti/TiN coatings. The properties of Ti/TiN coatings in terms of surface morphology, microhardness, load bearing capacity, bonding strength and wear resistance were evaluated by microhardness,scratch and wear tests. The experimental results show that PVD Ti/TiN coatings can significantly enhance the surface load bearing capacity (especially for duplex treatments) and wear resistance of Cr12MoV steel by more than one order of magnitude. This can be mainly attributed to the hard and well-adherent PVD Ti/TiN surface coatings and strong mechanical support of the LTPN sublayer. While two-body abrasive wear prevails for uncoated Crl2MoV, the micropolishing action of the counterface dominates in surface engineered material.     

Al/Cr原子比对AlCrTiSiN多元复合刀具涂层微观结构及切削性能的影响

AlCrTiSiN多元复合涂层能显著改善刀具的表面特性,可大幅提高刀具的切削性能,延长刀具使用寿命。在高速钢样品和铣刀表面通过多弧离子镀制备AlCrTiSiN多元复合涂层,并研究了Al/Cr原子比对AlCrTiSiN多元复合涂层微观结构及切削性能的影响。采用X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、纳米压痕仪、划痕仪和球盘摩擦磨损试验对涂层的微观结构和力学性能进行研究,并通过切削试验对涂层刀具的寿命进行测试。研究结果表明:当Al/Cr比为0.4时,AlCrTiSiN涂层物相由fcc-AlCrN,fcc-Al Ti N,hcp-Al N和非晶态Si_3N_4相组成,涂层呈现(200)AlCrN择优取向;随Al/Cr比由0.4降低至0.2时,涂层物相由fcc-AlCrN,fcc-Al Ti N,hcp-Cr2N和非晶态Si_3N_4相组成,(200)AlCrN择优取向消失。随Al/Cr比由0.4降低至0.2时,AlCrTiSiN涂层硬度和结合力增加,摩擦因数和磨损率降低,与另两组相比,AlCrTiSiN-3涂层具有较好的抗摩擦磨损性能,其涂层刀具具有相对较高的切削寿命。     

Effect of Atmospheric Plasma Spraying Power on Microstructure and Properties of WC-(W,Cr)2C-Ni Coatings

WC-(W,Cr)₂C-Ni coatings were prepared by atmospheric plasma spraying (APS) with different spraying powers. The effect of spraying power on microstructure, phase composition, hardness, fracture toughness, and oscillating dry friction and wear behaviors of the coatings were studied. Simultaneously, the microstructure and properties of the as-sprayed coatings were compared with those of WC-17Co coating prepared under the optimal spraying power. It was found that spraying power had significant effect on the molten degree of feedstock powder and phase composition as well as microstructure and properties of WC-(W,Cr)₂C-Ni coatings. WC-(W,Cr)₂C-Ni coating deposited at a moderate spraying power of 22.5?kW had the highest fracture toughness and the best wear resistance. WC-17Co coating obtained under the moderate spraying power had poor fracture toughness and wear resistance. Moreover, the four kinds of coatings were all dominated by subsurface cracking and removal of materials when sliding against Si₃N₄ ball under unlubricated conditions.     

钛合金表面离子束增强沉积的Cr和CrMo合金膜层及其性能

利用多功能离子束增强沉积(IBED)设备，在Ti6Al4V钛合金表面制备Cr和CrMo合金膜层，以提高钛合金表面的耐磨性能。利用X射线衍射仪、扫描电子显微镜、辉光放电光谱仪和显微硬度计分析和测试了IBED膜层的结构、形态、成分分布、硬度和膜基结合强度的大小。利用球一盘磨损试验机和电化学综合测试仪研究了IBED膜层的摩擦学性能和电化学腐蚀特性。结果表明，利用IBED方法可以在难镀材料钛合金表面制备膜基结合强度高、结晶致密和晶粒尺寸达纳米级的高硬度Cr膜和CrMo合金膜层，显著提高了钛合金表面的抗磨性能，且膜层本身有很好的耐Cl^-介质环境电化学腐蚀性能，与钛合金基体之间有很好的接触腐蚀相容性。     

Effect of tribological media on tribological properties of multilayer Cr(N)/C(DLC) coatings

In this research, Cr(N)/C(DLC) multilayered coatings were deposited on M2 steel substrates by an unbalanced magnetron sputtering technique. By varying the substrate rotation speed, four multilayered coatings with different bilayer thickness were produced. The bilayer thickness and structure of multilayered coatings were characterized by low-angle XRD, XPS depth profile, and cross-section TEM observation. The tribological investigation focused on the effect of layer thickness and tribological media on tribological property of the multilayer coatings against Al counterface. A pin-on-disc tribometer with a tribological medium container was used to investigate the wear behaviours of the four multilayered coatings under dry and wet (distilled water and S500 coolant) sliding. A stylus surface profilometer was used to measure wear rate. The investigation of wear tracks and wear mechanism was performed using Scanning Electron Microscopy (SEM). The research results showed that coatings with different bilayer period performed different tribological behaviour. The proper tribological media applied in the wear tests could improve the wear properties of multilayer coatings.     

多弧离子镀制备Cr/CrN多层厚膜的微观结构和力学性能

通过多弧离子镀（MAIP）在室温下将具有不同调制比（1:2、1:3、1:5）的多层Cr/CrN厚涂层沉积在A100钢基底上。腔室温度在沉积过程中由室温逐渐升高到160~170 ℃。设计调制结构是为了使膜/基结合强度和机械性能最大化。调制比为1:2的Cr/CrN多层涂层表现出最高的膜/基结合强度（L_c=63.8 N）,这可能归因于最高的材料硬度(H)/弹性模量(E)和H³/E²数值比（分别为0.083和0.138）。Cr层越厚,多层Cr/CrN厚涂层的塑性和摩擦学性能越好。干摩擦试验表明,与单层CrN相比,Cr/CrN多层涂层的平均摩擦系数和比磨损率分别最高降低了24%和94%。随着Cr层变厚,磨损机理从表面疲劳磨损转变为磨料磨损,这种现象可归因于硬度和塑性的协调变化。     

不同纳米WS2含量Ni-P-Ti N-WS_(2)复合化学镀层的制备及其摩擦学性能EI北大核心CSCD

Ni-P-TiN化学复合镀层具有比Ni-P镀层更高的硬度和耐磨性,但其表面粗糙度大,与对偶件之间的摩擦因数高,应用潜力受到限制。通过在化学镀液中添加不同用量的纳米WS_(2)颗粒和固定用量的TiN颗粒,在低碳钢表面制备Ni-P-TiN-WS_(2)复合镀层。采用X射线能谱仪(EDS)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)对镀层的化学成分(质量分数)、表面形貌及微观结构进行表征,并利用球盘式摩擦磨损试验机测试复合镀层的摩擦磨损性能。结果表明:纳米WS_(2)颗粒与纳米TiN颗粒的共沉积可使镀层表面更加致密、平整。随着镀液中纳米WS_(2)用量的增加,复合镀层的硬度先减小后增大,与氮化硅陶瓷球的摩擦因数则先升后降,磨损率显著下降,耐磨性增强。镀液中纳米WS_(2)粉末的用量为2.5 g/L时复合镀层的摩擦学性能最佳。纳米WS_(2)颗粒的加入及用量优化可显著改善复合镀层的综合性能,可为发展高耐磨低摩擦因数的先进涂层提供借鉴。     

Influence of feedstock powder characteristics and spray processes on microstructure and properties of WC-(W,Cr)2C-Ni hardmetal coatings

The composition WC-(W,Cr)₂C-Ni (commercial designations WC-‘CrC’-Ni, WC-Cr₃C₂-Ni and WC-NiCr) is unique among the WC-based materials used for the preparation of thermally sprayed hardmetal coatings. These coatings show a significantly higher oxidation resistance and high-temperature sliding wear resistance than WC-Co and WC-CoCr coatings do. Unlike WC-Co and Cr₃C₂-NiCr, WC-(W,Cr)₂C-Ni is not a simple binary hard phase-binder metal composite as it is composed of two hard phases: WC and (W,Cr)₂C. Surprisingly this composition has been poorly investigated in the past.In this paper coating microstructures and properties obtained from five commercial feedstock powders of different origins using two different liquid-fuelled high velocity oxy-fuel (HVOF) systems (K2 and JP-5000) were investigated. Additional experiments were performed with one powder using atmospheric and vacuum plasma spraying (APS and VPS, respectively). The microstructures and phase compositions of the powders and the coatings were studied. Focus was on the appearance, composition and distribution of the (W,Cr)₂C phase which might form or might change its Cr/W ratio during the spray process. The composition of the (W,Cr)₂C phase was estimated from the lattice parameters. Hardness HV0.3 was measured for all coatings. The density, Young's modulus and abrasion wear resistance of HVOF-sprayed coatings were studied.     

Thermal stability behaviors of Cr(N,O)/CrN double-layered coatings by TGA/DTA analysis

In this study, Cr(N,O)/CrN double-layered coatings were synthesized using the cathodic arc deposition (CAD) process. CrN film was first deposited onto a substrate as an interlayer to ensure better adhesion, and Cr(N,O) film was subsequently deposited on top of the CrN layer as the surface layer. Variation in the Cr(N,O) coating composition was achieved through changing the O₂/N₂ flow ratio during the last stage of processing. Phase structure, chemical composition, and morphology of the resulting coatings were analyzed and observed using the X-ray diffractometer, Auger electron spectrometer and SEM. In addition, oxidation behavior of the coatings was investigated using TGA/DTA methods. The tests were carried out by increasing temperature up to 1000 °C in ambient air. With the introduction of oxygen gas during the CAD process, a superficial layer was produced in the Cr(N,O) constituent containing CrN and Cr₂O₃ phases. The formation of the oxide phase attributed to the reaction of chromium and oxygen was more favorable than that of chromium and nitrogen. The results also showed that Cr(N,O)/CrN double-layered coatings exhibited superior oxidation resistance at elevated temperature than that of CrN single-layer coated specimen (870 °C vs. 750 °C).     

The effects of immersion time on morphology and electrochemical properties of the Cr(III)-based conversion coatings on zinc coated steel surface

The main purpose of this paper is to develop a dynamic and non-destructive method to quantify and correlate the microstructure changes of the Cr(III) layer by electrochemical techniques. The open circuit potential (OCP) analysis reveals the nucleation growth mechanisms of the Cr(III) layer and the dissolution phenomena of Zn. In addition, the effects of immersion time to the corrosion behavior of Cr(III)-based conversion coatings (TCCCs) on electrogalvanized steel were studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution. Furthermore, surface morphology of the Cr(III) coatings under different immersion times was examined using both a scanning electron microscope and an atomic force microscope.From the potentiodynamic polarization experiment, the corrosion current density (I_corr) of the specimen with immersion time of 60 s was found appreciably small, representing the inheritance of the best anticorrosion performance. Additionally, the corrosion resistance of the Cr(III)-coating for the specimens obtained between 30 s and 60 s is two order higher than those of the untreated specimen from the EIS experiments. Results show that the quality of Cr(III)-based conversion coatings was strongly influenced by the immersion time of Cr(III) solution. And the optimal immersion time is recommended in the range of 30–60 s.     

等离子熔覆NiCr-Cr3C2复合涂层摩擦磨损性能的研究

目的研究碳化铬含量及磨损载荷力对复合涂层摩擦磨损性能的影响,探究不同磨损载荷下的磨损机制。方法采用5种Ni55和NiCr-Cr_3C_2的混合粉末(Ni Cr-Cr_3C_2质量分数分别为10%、20%、30%、40%、50%),通过等离子熔覆技术制备金属基复合涂层。采用XRD、SEM对涂层物相进行检测分析,使用Rtec万能摩擦磨损试验机对复合涂层表面进行不同载荷下的摩擦磨损性能测试。对涂层组织、摩擦系数、磨损体积及磨损表面微观形貌进行对比分析,探究碳化铬的含量以及摩擦载荷对复合涂层摩擦磨损性能的影响。结果 NiCr-Cr_3C_2在熔覆过程中发生熔化,XRD测得涂层中的碳化物主要以Cr_7C_3为主,其他主要物相包括Cr_3C_2、Cr_(23)C_6、Cr_5B_3、Ni_3Si。复合涂层的硬度及耐磨性能随着碳化铬含量的增加而增大,硬度最高达1500HV以上,耐磨性是基体Q235的2～16倍。当磨损载荷低于80 N时,主要发生磨粒磨损;当磨损载荷为100 N时,主要发生粘着磨损和磨粒磨损,其中S5的磨损机制为疲劳磨损和磨粒磨损。结论加入碳化铬,随着碳化铬含量增加,复合涂层的耐磨性不断提高,并且随着磨损载荷的增大,涂层磨损机制发生转变。     

Wear and corrosion resistance and electroplating characteristics of electrodeposited Cr–SiC nano-composite coatings

Cr–SiC nanocomposite coatings with various contents of SiC nanoparticles were prepared by electrodeposition in optimized Cr plating bath containing different concentrations of SiC nanoparticles. Direct current electrocodeposition technique was used to deposit chromium layers with and without SiC nanoparticles on mild carbon steel. The effects of current density, stirring rate and concentration of nanoparticles in the plating bath were investigated. Scanning electron microscopy was used to study surface morphology. Energy dispersive analysis technique was used to verify the presence of SiC nanoparticles in the coated layers. The corrosion behaviors of coatings were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy methods in 0.05 mol/L HCl, 1 mol/L NaOH and 3.5% NaCl (mass fraction), respectively. Microhardness measurements and pin-on-disc tribometer technique were used to investigate the wear behavior of the coatings.     

HVOF喷涂Cr3C2-NiCr涂层的磨粒磨损性能

探讨了氧气流量、燃气流量和喷涂距离三个喷涂工艺参数对ＨＶＯＦ喷涂Ｃｒ３Ｃ２－ＮｉＣｒ涂层硬度和磨粒磨损性能的影响。结果表明,燃气流量、氧气流量和喷涂距离对涂层的显微硬度和磨粒磨损性能的规律有所不同。在较高的燃气流量、适中的氧气流量和喷涂距离条件下,涂层具有较高的显微硬度;而氧气流量和燃气流量对涂层的磨粒磨损性能影响较大,适中的燃气流量条件下,涂层的磨粒磨损失重量较低,高的氧气流量条件下,磨损失重量     

铬锆铜表面等离子喷涂Cr3C2p/NiCr涂层的组织与性能

采用等离子喷涂技术在铬锆铜(CrZrCu)基体表面制备了Cr3C2 p/NiCr涂层。利用X射线衍射仪(XRD)、扫描电镜(SEM)等仪器研究了涂层的显微组织及结构,采用磨粒磨损试验机对Cr3C2 p/NiCr涂层与电镀NiCo层的磨损性能进行了测试比较。结果表明:涂层组织呈片层状结构,在NiCr合金片层上分布着未熔的Cr3C2和Cr7C3、Cr2Ni3、CrNi析出相。与电镀Ni-Co镀层相比,Cr3C2 p/NiCr涂层具有较高的硬度和耐磨粒磨损性能,其磨损量仅为电镀层的35%。