Properties and tribological performance of ceramic-base chromium and vanadium carbide composite coatings

In the current study, the surface of AISI D2 steel was coated with the powder blends of ferro-vanadium (Fe-V) and ferro-chromium (Fe-Cr). The coatings were performed using a thermo-reactive diffusion (TRD) treatment by the pack cementation method at three different temperatures (900 °C, 1000 °C, and 1100 °C) and three different durations (1 h, 2 h, and 3 h). The structural and mechanical characteristics of the coatings were compared between the treatment groups. For this aim, the types of the formed phases, the microstructure, the microhardness, the surface roughness, and the wear and friction performance of the coated samples were examined. XRD analysis found composite carbide coatings including chromium carbide (Cr-C), vanadium carbide (V-C), and chromium vanadium carbide (Cr-V-C). The coatings' thickness was 11.3–23.2 μm, hardness was 2100–2500 HV, and average surface roughness (R_a) was 0.286–0.550 μm, depending on the treatment condition. The vanadium containing phase contents of the coatings increased with the elevating coating temperatures. The formed composite coating layers caused a change in the appearance of wear track and wear mechanism on the material surface. After the coating process, there found to be a decrease in the friction coefficient as well as an improvement in the wear resistance up to 7 times. In the composite coating layers, the increase in V-C content in comparison to Cr-C led to an enhancement in wear resistance on the material surface.     

电弧离子镀和高功率脉冲磁控溅射AlTiN涂层及其切削性能研究

目的 比较两种沉积方法制备的AlTiN涂层的切削性能.方法 利用高功率脉冲磁控溅射技术(HiPIMS)和电弧离子镀技术(AIP),在硬质合金车刀片上沉积AlTiN涂层,比较和研究两种AlTiN涂层的组织形貌特性及综合性能.利用扫描电子显微镜和X射线能量色散谱仪,观察和检测涂层的生长形貌和元素含量.采用激光共聚焦扫描显微...     

双辉等离子渗钽对TiAlN/Ta复合涂层结构和性能的影响

采用Ta层作为过渡层,通过双辉等离子渗金属（DGPSA）与射频磁控溅射（RFMS）辅助直流脉冲磁控溅射技术（DCPMS）制备TiAlN/Ta复合涂层。借助掠入射XRD、SEM、AFM、纳米压痕、划痕以及摩擦磨损测试了不同工艺制备的Ta过渡层对复合涂层的相结构、表面（截面）形貌、硬度、结合力、韧性和摩擦磨损性能的影响。结果表明,TiAlN复合涂层在高偏压作用下结构致密,RFMS技术制备的Ta过渡层为柱状晶结构,复合涂层表面粗糙度较小,硬度较大而磨损稳定性和耐磨性较差;而DGPSA技术制备的Ta过渡层为纳米晶结构,复合涂层表面粗糙度较大,硬度降低但磨损稳定性与耐磨性都增强。对比发现,通过DGPSA技术制备Ta过渡层使得TiAlN/Ta复合涂层的结合力与韧性大幅度提高。     

Cross-sectional nanoindentation and nanoscratch of compositionally graded mullite films

Nanoindentation and nanoscratch have become well-established techniques for measuring mechanical properties of thin films. Conventionally, these tests are performed on the surface of the films to evaluate their mechanical integrity: elastic modulus, hardness and adhesion strength. However, in complex systems such as compositionally graded thin films, small spatial variations in mechanical properties are difficult to distinguish using this approach. In this work, the evaluation of the above parameters was conducted on cross-sections of compositionally graded mullite coatings, chemical-vapor deposited on silicon carbide substrates. To assess the intrinsic mechanical properties and their spatial variation, nanoindentation tests were carried out on mullite coatings with constant and graded Al/Si ratios. Additionally, transverse nanoscratch tests to evaluate the cohesive and adhesive resistance of the coatings as well as the coating/substrate systems, respectively, were performed. Different damage morphologies were identified within the coating and at the interface by using complementary characterization techniques. In the case of functionally graded coatings a gradual rise in the hardness and elastic modulus with increasing distance from the coating/substrate interface was observed. Nanoscratch tests on the cross-sections allowed determining the critical loads for cohesive and adhesive damage by following this approach. Compositionally graded mullite coatings exhibited the best combination of hardness/stiffness and cohesive/adhesive scratch strength.     

Al_2O_3+TiO_2 13%涂层磨损特性的研究

本文对包复型、电熔型两种Al2O3＋TiO213％热喷涂粉末，经等离子喷涂形成的涂层进行往复磨损实验和单摆冲击划痕实验．并结合形貌分析对比评价，结果表明：包复型粉末形成的涂层其耐磨性优于电熔型粉末所形成的涂层，前者涂层致密，硬度、结合强度均高于后者。     

超音速等离子喷涂沉积可磨耗封严涂层研究

采用超音速等离子喷涂沉积Ni-C及NiCr-BN可磨耗封严涂层,通过实验对比研究两种涂层的结合强度、表面硬度及在不同冲蚀角下的冲蚀磨损性能.结果表明:NiCr-BN涂层中的润滑相尺寸比Ni-C涂层更为细小;NiCr-BN涂层的结合强度及表面硬度均高于Ni-C涂层;NiCr-BN涂层的抗冲蚀性能要优于Ni-C涂层.     

The Microstructure and Wear Resistance of Microarc Oxidation Composite Coatings Containing Nano-Hexagonal Boron Nitride (HBN) Particles

The composite coatings containing HBN were prepared on 2024 aluminum alloy by microarc oxidation in the electrolyte with nano-HBN particles. The microstructure, surface roughness, phase composition, hardness, adhesion strength and wear resistance of composite coatings were analyzed by SEM, EDS, laser confocal microscope, XRD, Vickers hardness tester, scratch test and ball-on-disc abrasive tests. The results revealed that composite coatings were mainly composed of γ-Al₂O₃, α-Al₂O₃, mullite and HBN. With increasing the content of HBN particles in the electrolyte, the size and number of the pores on the surface of composite coatings decreased significantly. Compared to the MAO coatings without HBN, the composite coatings exhibited better wear resistance, as demonstrated by the lower friction coefficient and the lower wear rate.     

Experimental Investigations to Study the Effects of Microwave Treatment Strategy on Tool Performance in Turning Operation

In the present study, microwave treatment has been used to enhance the tribological properties of single-point tungsten carbide (WC) cutting tool inserts such as wear resistance and hardness. The tool hardness and cutting parameters were considered to evaluate the performance of microwave-treated WC inserts in turning operation. The optimum cutting parameters were identified using response surface method (RSM)-based desirability approach. The relationship between cutting parameters and output responses, viz. flank wear, cutting force and surface roughness, was developed using the RSM. The investigations revealed that the increase in tool hardness due to complex carbide formation results in a significant reduction in tool wear, cutting forces and improvement in the surface finish of workpiece. Further, the statistical models results were validated with the experimental results. Metallurgical properties of treated and untreated tool inserts were analyzed using scanning electron microscope, x-ray diffraction method and Vickers microhardness tests. The results highlighted the importance of microwave treatment in enhancing the machining performance in turning operation.     

Formation of the structure of wear-resisting coatings in electron beam deposition of tungsten carbide

The method of out-of-vacuum electron beam deposition of tungsten carbide powder on low-carbon steel is used to produce the coatings whose structure, hardness and wear resistance are determined by the specific surface energy of radiation. It is shown that the highest properties are exhibited by the structure of the carbide inclusions – the austenitic matrix, similar to the structure of the hard alloy whose working principle is based on a compromise between strength and plasticity. Heat treatment of the deposited layers improves the structure and increases hardness and wear resistance. Additional improvement of the properties is achieved by adding a modification agent.     

球形碳化钨增强钴基堆焊涂层的组织及低温耐磨性

目的提升低温钢的摩擦磨损性能,为极地特殊船板的焊补和延寿技术提供试验依据。方法利用等离子转移弧技术,在低温钢E32表面堆焊制备3组球形不同碳化钨含量的钴基涂层,比较该改性涂层和E32钢在低温条件下(–20℃)的摩擦磨损性能。通过X射线衍射仪、扫描电子显微镜、能谱分析仪、3D光学轮廓仪等研究手段,分析碳化钨含量对堆焊层耐磨损性能和显微组织的影响规律,并揭示其耐磨损机理。结果在载荷为50 N、滑动速度为20 mm/s条件下,经2 h干滑动摩擦磨损后,3组涂层较低温钢E32的摩擦系数和体积磨损率均下降,磨痕的宽度和深度均变小。富含WC、W₂C增强相以及Cr₂₃C₆、Cr₇C₃、Co₆W₆C和Fe₆W₆C等碳化物硬质相的涂层,显著提升了E32钢的硬度和低温耐磨性。涂层的低温耐磨性能随着碳化钨含量的增大而提高,未添加碳化钨的涂层的主要磨损机理为磨粒磨损和粘着磨损,当碳化钨的质量分数为30%和60%时,主要磨损机理为三体磨粒磨损。结论通过在E32钢表面进行等离子转移弧堆焊,得到了结构致密、高硬度和抗低温耐磨性的球形碳化钨增强钴基表面改性涂层,在一定程度上提升了低温钢的服役寿命。     

Effects of TiB2+TiC content on microstructure and wear resistance of Ni55-based composite coatings produced by plasma cladding

TiB₂-TiC reinforced Ni55 matrix composite coatings were in-situ fabricated via plasma cladding on steels using Ti, B₄C, and Ni55 as precursor materials at different proportions. Effects of TiB₂+TiC content of ceramics phase on the microstructure and wear resistance were studied. The results showed that ceramic phases TiB₂ and TiC were in-situ synthesized by plasma cladding, and the ceramic phase content significantly affected tribological performance and the wear mechanism of coatings under different loads. The composite ceramics protected coatings from further delamination wear by crack-resistance under a load of 30 N. Severe abrasive wear and adhesive wear were prevented when the load increased to 60 N because of the high hardness and strength of ceramic phases. Moreover, a compacted layer appeared on the wear surface of coatings with high content of ceramic phases, which effectively decreased the friction coefficient and wear rate. The TiB₂-TiC composite ceramics significantly improved the wear performance of metal matrix composite coatings by different mechanisms under loads of 30 and 60 N.     

Effects of High Current Pulsed Electron Beam Irradiation on the Mechanical Properties and Cutting Performance of TiAlN-Coated Tools

Commercial TiAlN-coated carbide tools were post-treated using the high current pulsed electron beam irradiation method. The influence of the energy density of the electron beam on the morphology, phase composition, surface roughness and Vickers hardness were investigated. The higher energy density imposed on TiAlN-coated carbide tools resulted in a flatter and harder modified surface. After the beam irradiation, the XRD diffraction peak intensity of the hardening phase (Ti,Al)N was changed, and the diffraction peak position was shifted; these changes are attributed to the improved microhardness of the irradiated coatings. Investigations on the cutting experiments of turning Ti-6Al-4V alloy showed that the irradiated TiAlN-coated carbide tool exhibited longer cutting life and better wear resistance than those of an unirradiated tool. This improvement is attributed to the combined effect of low surface roughness and high microhardness that resulted from the high current pulse electron beam irradiation.     

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。     

纳米Cr2O3微粒对2024-T4微弧氧化膜结构及耐磨性能的影响

摘 要: 在含有不同浓度纳米Cr2O3微粒的硅酸盐体系电解液中对2024-T4铝合金进行微弧氧化处理,使用SEM观察陶瓷膜的表面形貌和截面形貌,使用EDS能谱仪分析膜层中各主要成分沿截面方向的分布,使用XRD分析陶瓷膜的相结构,使用纳米压痕硬度计测量陶瓷膜的硬度,使用粗糙度仪测量陶瓷膜的表面粗糙度,使用摩擦磨损试验机测量陶瓷膜的摩擦系数,使用激光共聚焦显微镜测量磨痕体积,评估磨损率,使用SEM观察磨痕形貌,结果表明：在电解液中加入纳米Cr2O3微粒后,制备的陶瓷膜中出现了Cr2O3相,电解液中纳米Cr2O3微粒浓度达到2.4g/L时,陶瓷膜的硬度最高,摩擦系数最小,磨损率最低,耐磨性最好。     

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.     

TiAlN,TiAlSiN涂层的制备及其切削性能

目的研究TiAlN及TiAlSiN涂层的微观结构及力学性能,以及硬质合金涂层刀具切削SUS304不锈钢的切削性能及磨损行为。方法采用阴极电弧离子镀技术在硬质合金试片及铣刀上分别制备纳微米TiAlN及TiAlSiN涂层。通过X射线荧光测量系统测量涂层的厚度,用扫描电镜(SEM)观察涂层表面形貌,用能谱仪(EDAX)分析涂层元素成分,用X射线衍射(XRD)分析涂层晶相结构,用纳米压痕仪表征涂层硬度,用洛氏硬度计定性测量涂层结合力,通过高速铣削试验探究涂层刀具的切削性能及磨损行为。结果 TiAlN及TiAlSiN涂层的厚度分别为3.32μm和3.35μm,表面致密、光滑,高分辨率(20 000×)下观察到涂层表面有液滴、针孔及凹坑存在。Si元素促进了Ti N(200)晶相的生长,晶粒尺寸减小,硬度增加。TiAlN及TiAlSiN涂层的显微硬度分别为29.6 GPa及37.7 GPa,结合力分别满足VDI-3198工业标准的HF3和HF1等级。在130 m/min的高速切削条件下,TiAlSiN涂层刀具寿命约为未涂层刀具的5倍,TiAlN涂层刀具的1.5倍。结论 Si掺杂制备的TiAlSiN涂层具有高的硬度及良好的抗粘附性,更适用于不锈钢材料的高速切削加工。     

Adhesion and dynamic impact wear of nanocomposite TiC-based coatings prepared by DCMS and HiPIMS

Nanocomposite nc-TiC/a-C:H coatings exhibit a unique combination of mechanical properties such as high hardness, and low friction and wear. These physical and mechanical properties make those coatings attractive for application in industry. However, the properties of the whole coating/substrate system such as adhesion of the coating to substrate and its response on repeated impact loading known such as dynamic impact wear are also important for industrial applications. Thus, this paper is focused on the adhesion and the dynamic impact wear of nc-TiC/a-C:H coatings prepared by the hybrid PVD-PECVD process. Two series of nc-TiC/a-C:H coatings with a different amount of carbon were deposited onto commonly used industrial cemented tungsten carbide substrates using DC magnetron sputtering (DCMS) and the high power impulse magnetron sputtering (HiPIMS) of a titanium target in argon and acetylene mixture atmosphere. Both series of coatings were analysed using a scratch test and dynamic impact tester with an impact load of 600 N. The HiPIMS prepared coatings exhibited lower thickness and lower thicknesses of the Ti adhesive interlayers between the substrates and coatings than the DCMS prepared coatings. Thus, the adhesion and the impact wear of both series were discussed separately. These properties were discussed with respect to the coating microstructure, phase composition and mechanical properties such as the hardness H, the effective elastic modulus E, and the H/E and H³/E² ratios. The scratch adhesion of coatings depended on the H³/E² ratio and coating microstructure, hardness and surface roughness. The impact wear of the nc-TiC/a-C:H coatings depended on the H/E ratio and coating microstructure.     

Wear mechanisms of PVD ZrN coated tools in machining

Medium-frequency magnetron sputtered PVD ZrN coatings (ZrN, ZrN/Zr) were deposited on YT15 (WC + 15%TiC + 6%Co) cemented carbide. Microstructural and fundamental properties of these ZrN coatings were examined. Dry machining tests on hardened steel were carried out with these coated tools. The wear surface features were examined by scanning electron microscopy. Results showed that deposition of the PVD ZrN coatings onto the YT15 cemented carbide causes great increase in surface hardness. The ZC-1 coated tool (ZrN/YT15 without interlayer) has the highest surface hardness; while the ZC-2 (ZrN/Zr/YT15 with a Zr interlayer) shows the highest adhesion load for the coatings to the substrate. The ZrN coated tools exhibit improved rake and flank wear resistance to that of the YT15 tool. The coated tools with a Zr interlayer (ZC-2) have higher wear resistance over the one without Zr interlayer (ZC-1). The rake wear of the ZrN coated tools at low cutting speed was mainly abrasive wear; while the mechanism responsible for the rake wear at high cutting speed was determined to be adhesion. Extensive abrasive wear accompanied by small adhesive wear were found to be the predominant flank wear mechanisms for the ZrN coated tools.     

工具的材料和涂层对其切削性能的影响

对同种材料不同涂层和不同材料同种涂层的刀具进行了切削试验。结果表明,在铣削淬硬的40Cr钢时,用硬质合金A制作、带TiAlCN涂层的6刃立铣刀使用寿命最高。这既与涂层的耐磨性、表面粗糙度和抗氧化性能有关,也与硬质合金A的硬度、韧性和抗弯强度有关。