Tribological properties of duplex Cr-Si-N coatings on SS410 steel

Hardness and other mechanical properties of CrN can be enhanced by adding small amounts of Si, an effect that can possibly be attributed to solid solution hardening. In the present work, tribological properties of the Cr-Si-N coatings on SS410 steel substrates were studied. These samples were prepared by a duplex treatment consisting of surface nitriding and deposition of a Cr bond-coat, which also provides the highest adhesion. The influence of silicon concentration on the tribological properties was determined by ball-on-disc and ball-on-flat tests, while the wear mechanism against an alumina ball was assessed by analyzing the wear track and the wear debris using SEM, EDX and Raman spectroscopy. It was found that the coating containing 2.3 at.% of Si, corresponding to the solubility limit, exhibits the best mechanical and tribological performance: the wear rate of the SS410 substrate has been reduced by a factor of 500, corresponding to a hardness and wear coefficient of 25 GPa and 2-4 × 10^− 7 mm³/N m, respectively.     

Influence of the PVD sputtering method on structural characteristics of SiCN-coatings — Comparison of RF,DC and HiPIMS sputtering and target configurations

Si–C–N based materials exhibit promising properties such as excellent oxidation resistance and thermal stability even at temperatures above 1300 °C, thus making them promising candidates for high temperature applications. The properties of SiCN based coatings strongly depend upon the synthesis method and the synthesis parameters. In the present study, SiCN coatings were deposited by RF, DC and HiPIMS sputtering. Beyond this, the target configuration was varied for DC and HiPIMS sputtering. The coatings were characterized regarding their chemical, structural, mechanical and thermal properties. Since the SiCN coatings are amorphous, FT-IR and Raman spectroscopy as well as XPS were used to gather structural information. The structural and the thermal properties show a significant dependency on the sputtering method and target configuration, while the mechanical and chemical properties are only slightly affected.     

The effect of TiC transient layer on a DLC-based functionally gradient coating prepared by closed field unbalanced magnetron sputtering plating system

Recently, Diamond like carbon (DLC)-based functionally gradient coatings have been used in a variety of engineering applications as useful films with appropriate tribological properties verified in many tests. However, due to their inherent residual stresses, they have a tendency to peel off, thereby limiting their applications (involving high contact stresses) and deposition thickness. Their brittleness and low adhesion may stem from either a faulty layer design or the wrong choice of material and deposition method. Therefore, using both a suitable interleaving material and an appropriate deposition technology will create an inclusive vision to accommodate better film properties. In this study, Ti-a:C and Ti-TiC-a:C films on AISI M2 steel substrates were deposited by Closed Field Unbalanced Magnetron Sputtering (CFUBMS) method using pulsed-dc biasing, and the mechanical, the structural, and the tribological properties for both films were investigated. It was seen that the incorporation of a TiC buffer layer between the Ti interlayer and the a:C matrix played a positive role in terms of hardness, wear rate, and adhesion properties.     

氮气含量对CrNx薄膜相结构及摩擦磨损性能的影响

采用电弧离子镀技术,在45钢基体上制备了不同氮气含量的CrNx薄膜.采用X射线衍射技术(XRD)、扫描电子显微镜(SEM)、努氏硬度计和UMT型球-盘摩擦试验机,分别测试了薄膜相结构、表面形貌、显微硬度和摩擦磨损性能.结果表明:CrNx薄膜主要由CrN和Cr2N相组成;随着N2含量的增加,薄膜中Cr2N(211)衍射峰强度逐渐减弱,CrN(220)衍射峰强度逐渐增强;薄膜表面颗粒逐渐减少,表面趋于平整,薄膜硬度出现两个峰值,对应于薄膜为单相Cr2N和CrN的相组成处;与钢基体相比,氮气含量为35%时,CrNx薄膜具有良好的表面质量、最佳的硬度、优良的耐磨损性能.     

离子束增强沉积CrN膜层及其微动摩擦学性能研究

以不同氮离子辅助轰击能量制备CrN膜层．利用纳米压入仪及显微硬度计分别测试单晶Si片上膜层的硬度及断裂韧度K1C．使用XRD、XPS及EPMA分析离子轰击能量对镀层组织结构的影响。结果表明，采用能量较低的氮离子轰击得到的涂层，由于金属Cr的存在，涂层硬度虽有所降低，但断裂韧度K1C数值较高。选择较低的4keV辅助轰击能量，在M2高速钢基体上沉积CrN涂层，膜层在空气介质中表现出优异的耐磨减摩特性.但在水介质条件下，由于膜层接触区域的去钝化，再钝化使腐蚀和磨损相互加速，导致CrN膜层摩擦系数，尤其是磨损量明显高于基材。     

活塞环表面织构化镀层的摩擦性能研究

目的以缸套/活塞环为试验对象,研究激光织构化与固体润滑镀层的协同减摩作用。方法采用脉冲激光在活塞环表面进行微孔化处理,利用电脉冲沉积法在微孔内制备具有不同MoS_2微粒浓度的Ni-MoS_2复合镀层,通过往复式摩擦试验研究织构化表面沉积固体润滑剂对活塞环-缸套的影响机制。结果镀液中MoS_2微粒浓度对镀层的硬度和摩擦学性能影响较大,相同电流密度下,电镀液中MoS_2微粒的质量浓度为5g/L时的镀层硬度最高,该浓度下Ni-MoS_2复合镀层在干摩擦下具有最佳的摩擦系数和最低的磨损率。织构化复合镀层可以显著改善接触面间的摩擦性能,相比未织构化摩擦配副,摩擦系数降低约0.2,磨损率下降50%。结论干摩擦条件下,表面织构可以有效地储存摩擦副之间的固体润滑剂和磨粒,在接触表面形成连续润滑膜,减少磨粒磨损。     

氮气流量对CrCN镀层摩擦学性能的影响

目的研究氮含量对Cr CN镀层结构和摩擦学性能的影响。方法采用微弧离子镀技术制备Cr CN镀层,通过改变氮气的流量来改变镀层中氮元素含量。利用扫描电子显微镜(SEM)和原子力显微镜(AFM)观察镀层的截面和表面形貌,采用划痕法对镀层与基体的结合强度进行评价,采用维氏硬度计测试镀层的显微硬度,利用针盘式摩擦磨损试验机测定镀层的摩擦系数。结果当通入的氮气流量逐渐增大时,镀层由致密细小的颗粒逐步演变为含微孔的柱状组织。当氮气流量为3 m L/min时,镀层中生成的弥散分布的硬质相具有显著的强韧化作用,镀层的膜基结合力和硬度分别达到最大值41 N和1476HV,摩擦系数略微增大。继续增大氮气流量后,镀层性能有所下降。结论通过控制氮气流量来控制镀层中氮元素的含量,可以显著优化镀层结构和性能,达到结合强度、硬度和摩擦系数的最优化配置。     

Electrophoretic deposition of titanium/silicon-substituted hydroxyapatite composite coating and its interaction with bovine serum albumin

Silicon-substituted hydroxyapatite (Ca10(PO4)6-x(SiO4)x(OH)2-x, Si-HA) composite coatings on a bioactive titanium substrate were prepared by electrophoretic deposition technique with the addition of triethanolamine (TEA) to enhance the ionization degree of Si-HA suspension. The surface structure was characterized by XRD, SEM, XRF, EDS and FTIR. The bond strength of the coating was investigated. The results show that the depositing thickness and the images of Si-HA coating can be changed with the variation of deposition time. The XRD spectra of Ti/Si-HA coatings show the characteristic diffraction peaks of HA, and the incorporation of silicon changes the lattice parameter of the crystal. The FTIR spectra shows that the most notable effect of silicon substitution is the decrease of intensities of -OH and PO43- groups with the silicon contents increasing. XRD and EDS element analyses present that the content of silicon in the coating increases with increasing silicon concentration in the suspension. The bioactive TiO2 coating formed may improve the bond strength of the coatings. The interaction of Ti/Si-HA coating with BSA is much greater than that of Ti/HA coating, suggesting that the incorporation of silicon in HA is significant to improve the bioactive performance of HA.     

电弧离子镀制备 TiSiN 纳米复合涂层

目的在SiH4气氛下制备Si掺杂的TiSiN纳米复合涂层,为SiH4用于工业化TiSiN涂层生产提供依据。方法采用电弧离子镀技术,在SiH4气氛下,于单晶硅和硬质合金衬底上制备Si掺杂的TiSiN纳米复合涂层,研究SiH4流量对TiSiN涂层化学组分、微观结构、硬度和耐磨性能的影响。结果 SiH4流量对TiSiN纳米复合涂层的微观结构、硬度及摩擦系数的影响明显。随着SiH4流量的增加,TiSiN涂层由柱状晶生长的晶体结构逐渐转变为纳米晶镶嵌于非晶基体的复合结构。Si在涂层中以Si3N4非晶相存在,随着涂层中Si含量逐渐增加,TiN晶粒尺寸逐渐减小,Si3N4起到细化晶粒的作用。在42 m L/min的SiH4流量下,涂层硬度高达4100HV0.025。在对磨材料为硬质合金的条件下,TiSiN涂层摩擦系数小于0.6。结论 SiH4气氛下可以制备出Ti N纳米晶镶嵌于Si3N4非晶相结构的TiSiN纳米复合涂层,涂层的显微硬度较高。SiH4可以作为Si源用于TiSiN纳米复合涂层的工业化生产。     

A comparative study on Ti1 − xAlxN coatings reactively sputtered from compound and from mosaic targets

The aim of this work is to illuminate the influence of two widely applied target types, i.e. TiAl compound targets produced by powder metallurgy and mosaic TiAl targets, on the sputter deposition process as well as on the structure and properties of the obtained coatings. After development of a sputter process for the compound targets by optimization of cathode power and nitrogen partial pressure, this process was compared to the commercially applied mosaic target process by taking into account the sputter yields of Ti and Al and the respective deposition rates. The deposition rate achieved with the compound targets was ~ 44% higher than that obtained for the mosaic targets. The Al content in the coatings deposited from the compound targets was slightly higher and the domain size of the formed cubic Ti_1 − xAl_xN solid solution considerably larger than for the coatings deposited from the mosaic targets. The coatings grown from the compound targets showed, in contrast to those synthesized from the mosaic targets, tensile stresses. While the hardness of the coatings sputtered from the compound targets was slightly below that of the coatings synthesized from the mosaic targets, both their friction and wear behavior were slightly improved. In summary, it could be shown that using compound TiAl targets manufactured by powder metallurgy, Ti_1 − xAl_xN coatings with mechanical and tribological properties comparable to those grown from commercially applied mosaic targets can be deposited at significantly higher growth rates.     

A comparative study of microstructure,oxidation resistance,mechanical, and tribological properties of coatings in Mo–B–(N), Cr–B–(N) and Ti–B–(N) systems

M–B–(N) (M = Mo, Cr, Ti) coatings were obtained by the magnetron sputtering of MoB, CrB₂, TiB, and TiB₂ targets in argon and in gaseous mixtures of argon with nitrogen. The structure and composition of the coatings have been investigated using scanning electron microscopy, glow-discharge optical emission spectroscopy, and X-ray diffraction. The mechanical and tribological properties of the coatings have been determined by nanoindentation, scratch-testing, and ball-on-disk tribological tests. The experiments on estimating the oxidation resistance of coatings were carried out in a temperature range of 600–1000°С. A distinctive feature of TiB₂ coatings was their high hardness (61 GPa). The Cr–B–(N) coatings had high maximum oxidation resistance (900°С (CrB₂) and 1000°С (Cr–B–N)) and possessed high resistance to the diffusion of elements from the metallic substrate up to a temperature of 1000°С. The Mo–B–N coatings were significantly inferior to the Ti–B–(N) and Cr–B–(N) coatings in their mechanical properties and oxidation resistance, as well as had а tendency to oxidize in air atmosphere after long exposure at room temperature. All of the coatings with nitrogen possessed a low coefficient of friction (in a range of 0.3–0.5) and low relative wear ((0.8–1.2) × 10^–6 mm3 N^–1 m^–1.     

Ti-Al-N 涂层的组织结构与摩擦学性能

目的采用多元等离子体注入与沉积(MPIIID)技术制备Ti-Al-N涂层,系统研究涂层的微观组织结构、力学性能与摩擦学特性。方法借助XRD,XPS,SEM和TEM等,观察分析Ti-Al-N涂层的微观组织结构与物相组成,采用纳米压入试验仪、布氏硬度试验仪、摩擦磨损试验仪和激光共聚焦显微镜等测试分析Ti-Al-N涂层的力学性能、膜基结合力和摩擦磨损性能。结果 Ti-Al-N涂层表现出较高的膜-基结合强度。Al元素掺杂诱发Ti-Al-N涂层发生严重晶格畸变。当Al原子数分数为6.18%时,Ti-Al-N涂层以c-TiAlN相结构为主,表现出超高硬度(达到39.83 GPa);随着Al元素含量增加,涂层中的软质h-TiAlN相结构增多,硬度随之下降。摩擦试验结果表明,低Al含量Ti-Al-N涂层的抗磨损能力良好,其主要磨损机制为磨粒磨损;高Al含量Ti-Al-N涂层的抗磨损能力较差,其主要磨损机制倾向粘着磨损。结论 MPIIID技术成功实现了Ti-Al-N涂层的低温制备与成分调控,低Al含量的Ti-Al-N涂层具有优良的力学性能和优异的抗磨损能力。     

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.     

Disperse-strengthening by nanoparticles advanced tribological coatings and electrode materials for their deposition

Two types of electrode materials were developed using self-propagating high-temperature synthesis (SHS) and powder metallurgy: 1- composite with nanosized additives; 2- nanostructured cemented carbide WC-Co. Electrospark deposition (ESD) was applied to produce tribological coatings which were disperse-strengthened by incorporation of nanosized particles. Nanostructured electrodes of cemented carbides WC-8% Co provide increasing density, thickness, hardness, Young's modulus, and wear resistance of ESD-coatings. Positive effects of nanostructural state of the electrodes on the deposition process and structure/properties of the coatings are discussed. In that case the tungsten carbide phase becomes predominant in the coatings. A mechanism of the dissolution reaction of WC in Ni at the contact surface of the electrode was proposed. It was shown that formation of the coating structure is initiated on the electrode and accomplished on the substrate.     

Study of structure development of Titanium Nitride on inclined substrates

For magnetron sputter deposited coatings, the structure development during growth mostly depends on the mobility of the adatom over the substrate. The mobility is significantly affected by the orientation of the substrate with respect to the direction of the incident flux of sputtered atoms. The structural properties like crystallite size, crystallographic structure, column orientation, etc., are therefore influenced. This is relevant as the real work pieces over which the overlay functional coatings has to be applied are three dimensional in nature with the surfaces being off-normal to the incident flux. In the present investigation, the effect of incident angle on the various aspects of the structure development of Titanium Nitride coatings, having wide tribological applications, deposited on Si substrates by reactive magnetron sputter deposition was studied. A planar magnetron, with cathode diameter 75 mm and mounted with pure Ti target was used and TiN was deposited in a mixture of argon and nitrogen gas. The deposition was done for different durations. The deposited coatings were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results indicate the formation of well defined columnar microstructure in the coatings. The column inclination is compared with the well known ‘Tangent rule’.     

Mechanical and tribological properties of multi-element (AlCrTaTiZr)N coatings

Multi-element (AlCrTaTiZr)N coatings are deposited onto Si and cemented carbide substrates by reactive RF magnetron sputtering in an Ar + N₂ mixture. The influence of substrate bias voltage, ranging from 0 to − 200 V, on the microstructural, mechanical and tribological properties of these nitride coatings is studied. A reduction in concentration of N and Al is observed with increasing substrate biases. The (AlCrTaTiZr)N coatings show the face-centered-cubic crystal structure (B1-NaCl type). The use of substrate bias changes the microstructure of the (AlCrTaTiZr)N coating from the columns with microvoids in boundaries to the dense and less identified columns. The compressive macrostress increases from − 0.9 GPa to − 3.6 GPa with an increase of substrate bias. The hardness and adhesion increase to peak values of 36.9 GPa and 60.7 N at the bias voltage of − 150 V, respectively. The tribological properties of the (AlCrTaTiZr)N coatings against 100Cr6 steel balls are evaluated by a ball-on-disc tribometer with a 10 N applied load. With an increase of substrate bias, the wear rate reduces while the friction coefficient almost keeps constant at 0.75. The lowest wear rate of 3.65 × 10^− 6 mm³/Nm is obtained for the (AlCrTaTiZr)N coating deposited at the bias voltage of − 150 V.     

Effect of micro-blasting on the tribological properties of TiN/MT-TiCN/Al2O3/TiCNO coatings deposited by CVD

The effect of micro-blasting on the tribological properties of TiN/MT-TiCN/Al₂O₃/TiCNO coatings was studied. The multilayer coatings were deposited on cemented carbides by chemical vapor deposition. The microstructure, mechanical and tribological properties were investigated using X-ray diffraction, scanning electron microscopy (SEM), nano-mechanical testing system, scratch tester and reciprocating tribometer. The results show that micro-blasting significantly reduces the surface roughness and converts the residual tensile stress of Ti(C,N,O) top-layer and Al₂O₃ layer into compressive stress. Affected by the residual compressive stress, the hardness and adhesion strength are increased. More importantly, the friction coefficient is decreased attributed to the decreased surface roughness and improved hardness. Also, the wear resistance of micro-blasted TiN/MT-TiCN/Al₂O₃/TiCNO is superior due to higher hardness of Ti(C,N,O) top-layer, Al₂O₃ layer and adhesion strength of coatings. Especially for the total sliding time of 2 h, the wear volume and wear rate of micro-blasted coatings are 69.4% of as-deposited coatings, because micro-blasting helps to increase the adhesion strength and micro-cracking resistance, which play important roles in the improvement of wear resistance. Micro-blasting has a positive effect on the friction and wear properties of TiN/MT-TiCN/Al₂O₃/TiCNO multilayer coatings since the adverse impact of top-layer thinning is offset.     

预沉积ZnO薄膜对ZnO−MoS2/ZnO复合涂层结构与性能影响

目的 通过优化原子层沉积工艺获取不同厚度ZnO薄膜,研究ZnO薄膜晶体取向对ZnO?MoS2涂层生长结构的影响,获得具有优异摩擦学性能的ZnO?MoS2/ZnO复合涂层。方法 采用原子层沉积法在不锈钢基体上预沉积不同厚度的ZnO薄膜,再用射频磁控溅射技术继续沉积ZnO?MoS2涂层,制备ZnO?MoS2/ZnO固体润滑复合涂层。结果 X射线衍射分析发现,预沉积ZnO薄膜有诱导后续ZnO?MoS2涂层沉积生长的作用,预沉积100 nm厚ZnO薄膜的ZnO?MoS2/ZnO复合涂层显示出宽化的MoS2 (002)馒头峰,其截面形貌显示为致密的体型结构,获得的摩擦因数最低(0.08),纳米硬度最高(2.33 GPa),硬度/模量比显示该复合涂层的耐磨损性能得到提升;X射线光电子能谱分析结果表明,复合涂层表面游离S与空气中水发生反应程度大约为原子数分数5%,显示复合涂层耐湿性能较好;基于原子层沉积ZnO薄膜生长及其对后续ZnO?MoS2涂层生长的影响分析,提出了ZnO?MoS2/ZnO复合涂层磨损模型,阐明了ZnO薄膜对复合涂层结构及摩擦学性能的影响,并以该模型解释了200 nm厚 ZnO薄膜上沉积ZnO?MoS2涂层出现的摩擦因数由高到低的变化趋势及最终磨损失效现象。结论 合适的原子层沉积制备的ZnO薄膜有利于MoS2 (002)取向生长,可有效提升ZnO?MoS2/ZnO复合涂层的摩擦学性能;控制ZnO薄膜厚度,可实现ZnO薄膜与基底及ZnO?MoS2层间界面之间的优化结合,以制得具有较好摩擦学性能及使用寿命的ZnO?MoS2/ZnO复合涂层。     

From diamond to crystalline silicon carbonitride: effect of introduction of nitrogen in CH4/H2 gas mixture using MW-PECVD

Microwave plasma enhanced chemical vapor deposition (MW-PECVD) is considered as one of the most successful growth techniques in recent diamond and crystalline carbon nitride investigations. In this study, we tried to synthesize crystalline carbon nitride film using MW-PECVD by gradually increasing the content of nitrogen into H₂/CH₄ gas mixture. Well-faceted crystalline diamond films could be synthesized with a H₂/CH₄ gas ratio of 198:2. With the gradual increase of nitrogen content up to 3% in the gas mixture diamond film quality deteriorates seriously, and the morphological crystal size and growth rate of diamond coatings decreased significantly. With the nitrogen gas content increased to approximately 6–22%, a lot of separated round diamond or diamond-like carbon particles formed on the surface rather than a continuous film. Only with the nitrogen content increased above 72%, could some tiny crystals with a type of hexagonal facet form on the silicon surface, together with many large, round diamond particles. With the further increase of nitrogen gas content above 90%, many large, well-faceted hexagonal crystals formed on Si surface. However, XRD, energy dispersive X-ray spectrometry, X-ray photoelectron spectroscopy and nano-indentation analysis indicated that these crystals were actually silicon carbonitride (Si–C–N) with a crystalline structure of Si₃N₄ modified with the introduction of carbon atoms, rather than carbonitride as expected and regarded.     

Preparation and characterization of nickel-cobalt-diamond electro-composites by sediment co-deposition

Nickel-diamond and nickel-cobalt diamond coatings were produced by electrodeposition using sedimentation technique on mild steel substrate and their tribological properties evaluated. Electrodeposition was carried out from a conventional Watts bath with cobalt addition. The conditions to obtain nickel-cobalt alloy were optimized first and then the conditions for obtaining diamond composites from both systems were investigated. Natural diamond powder of 6-12 μm size was used in the study. The volume percent incorporation of diamond powder in the coatings was investigated with respect to its concentration and cobalt concentration in bath, cathode current density, pH and temperature. The diamond powder distribution in the composite coatings, as examined with SEM, are uniform at low powder concentration in the bath and agglomerated at high concentrations. Physical properties of the composites including hardness, wear resistance and roughness were measured. Presence of cobalt increased volume percent incorporation of diamond powder, hardness and wear resistance of the coatings.