阴极弧离子镀AlCrN涂层高温氧化后XPS分析

采用阴极弧离子镀方法在Ti C基金属陶瓷刀具表面沉积了Al Cr N涂层,进行了900℃下2 h高温氧化试验。通过SEM、EDS、XRD、XPS等手段分析了Al Cr N涂层高温氧化前后表面形貌、元素组成、物相组成及元素结合能,并讨论了Al Cr N涂层高温氧化及失效机理。结果表明,氧化前Al Cr N涂层由Al N、Cr N和Cr2N物相组成,其中Cr N表现出(200)的择优取向,氧化后其物相转变为抗高温的Al2O3、Cr3O4和Ti4O3氧化物;氧化前Al Cr N涂层中Al和N以Al—N键、Cr和N以Cr—N键存在,氧化后Al与O以Al—O键、Cr与O以Cr—O键方式存在,在涂层-基体结合界面处形成了致密的扩散层。     

Thermal analysis in coated cutting tools

This work studies the heat influence in cutting tools considering the variation of the coating thickness and the heat flux. K10 and diamond tools substrate with TiN and Al₂O₃ coatings were used. The numerical methodology utilizes the ANSYS^® CFX software. Boundary conditions and constant thermo physical properties of the solids involved in the numerical analysis are known. To validate the proposed methodology an experiment is used. The TiN and Al₂O₃ coatings did not show satisfying results during a continuous cutting process. It showed a slight reduction in the heat flux for the 10 (µm) TiN and Al₂O₃ coatings.     

AlCrN涂层的残余热应力分析

采用ANSYS有限元分析软件中的瞬态分析方法,对涂层刀具沉积过程中残余热应力进行了仿真分析。研究了AlCrN涂层残余热应力的大小、分布和影响因素。结果表明:由于涂层与基体材料的热膨胀系数不匹配,结合面区域存在严重的应力集中;基体材料、涂层厚度、沉积温度以及中间层的使用对残余应力有很大影响;基体材料为高速钢时,AlCrN涂层内残余应力大以压应力为主并随着涂层厚度的增加而减小;基体为硬质合金时,残余应力相对较小,涂层内以拉应力为主并随基体钴含量和涂层厚度的增加而减少;增加中间层可以减小残余应力。因此,通过涂层和不同基体匹配以及增加中间层可以缓和界面应力增强界面结合强度。     

The effect of Ti and Si on the mechanical and electrochemical behaviors of the AlCrN coating deposited by CAPVD on 304SS

This study aimed to investigate the effect of adding titanium (Ti) and silicon (Si) elements on the mechanical and electrochemical properties of the AlCrN-based coating. For this purpose, a cathodic arc physical vapor deposition machine was used. Scanning electron microscopy, X-ray diffraction, and nanoindentation tests were utilized for morphological, microstructural, and mechanical characterization of the coatings. The hardness value and plastic deformation index of CrAlN-based coating increase with the presence of Si element. The mechanical properties improvement is attributed to the reduction of crystallite size as well as to the tendency of the coating structure to become amorphous. The specimens were subjected to 3.5 wt% NaCl solution to electrochemical impedance corrosion and potentiodynamic polarization tests. The results showed that by increasing the coatings’ titanium content, the coatings’ corrosion resistance improved. Moreover, by adding 3% and 5% of Si elements to the coatings’ composition, the corrosion resistance of the AlCrTiSiN coatings was enhanced by 35% and 78%, respectively. Improving the corrosion resistance of the AlCrN-based coatings by adding the Si element is attributed to the change in the microstructure and reduction in the porosity of the coatings.     

暖通用316L不锈钢表面离子镀AlCrN硬质涂层性能表征

利用多弧离子镀技术在暖通用316L不锈钢表面制备了一种同时具备高硬度与低摩擦系数的AlCrN涂层,研究不同转速下涂层的组织和摩擦性能,并进行不同氧化温度性能测试。研究结果表明:涂层元素组成基本不会受到转速的影响。当转速增加后,得到的颗粒密度也随之降低。涂层形成了致密的截面组织,未形成柱状晶,涂层厚度基本都介于3.3~4.1μm范围内。当转速增加后,涂层的硬度不断升高,硬度最大可以达到3968 HV。随着转速增加,摩擦系数快速降低后变化趋于稳定。经过700℃氧化处理后,之前的氮化物衍射峰已经不存在,此时涂层已全部完成氧化。经过氧化的涂层发生了硬度快速减小的现象,涂层摩擦系数由0.455上升高为0.612以上。     

Hard machining performance of PVD AlCrN coated Al2O3/TiCN ceramic inserts as a function of thin film thickness

In the present work, AlCrN coating was deposited on Al₂O₃/TiCN ceramic inserts with varying thin film thickness using physical vapor deposition (PVD) technique. The thickness, surface morphology, chemical composition, hardness and adhesion strength of the coating to the substrate were characterized by field-emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), micro-indentations and scratch tests respectively. The machining performance of uncoated and coated tools was investigated in hard turning of AISI 52100 steel (62 HRC) under dry environment. The cutting behavior was analyzed in terms of machining forces, tool temperature, wear, friction and chip morphology. Further, a 3D finite element model with hybrid friction criterion has been adopted to support the experimental findings. The results revealed that coating/substrate adhesion and edge radius were the deciding criteria for the machining performance of coated tools with 3 µm coating thickness tool exhibiting best turning performance on Al₂O₃/TiCN mixed ceramic insert.     

高能离子源清洗对AlCrN刀具涂层结构及性能的影响

采用自主研发的离子源增强多弧离子镀设备,研究涂层沉积前不同清洗工艺对基材表面粗糙度以及所制备的AlCrN涂层的表面形貌、硬度、膜基结合力、摩擦磨损和切削性能的影响。研究结果表明,高能Ar⁺清洗可以更有效清洁基材表面。与传统弧源清洗技术相比,经高能离子源清洗后的基体表面粗糙度降低,沉积态涂层的表面粗糙度更低。相比于传统弧源清洗工艺,高能Ar⁺清洗可以显著提高膜基结合强度,达到48.7 N,摩擦因数和磨损率均降低,涂层刀具寿命提高了3倍。     

具有纳米调制结构的AlTiN/AlCrN复合涂层在干摩擦条件下的摩擦磨损性能研究

目的 研究干摩擦条件下不同AlTiN/AlCrN多层膜纳米调制结构对摩擦磨损行为的影响。方法 将处理过的合金工具钢和单晶硅片作为膜层生长的基底材料,在膜层制备之前,先对基底材料进行预处理,然后使用多靶磁控溅射纳米膜层系统沉积一系列不同调制周期和调制比的AlTiN/AlCrN纳米多层膜。通过控制涂层总厚度不变,在调制比为1︰1时,设计不同的调制周期,择优选出磨损量最小、耐磨性最好的调制周期,并以此为恒定值,进而设计不同调制比的试样。采用X射线衍射仪(XRD)、摩擦磨损试验机分析与表征纳米多层膜的微观结构和性能,研究调制周期和调制比对AlTiN/AlCrN纳米多层膜微观结构和干摩擦条件下摩擦磨损性能的影响。结果 AlTiN/AlCrN纳米多层膜主体均为面心立方结构,且在(111)、(200)和(220)晶面择优取向。调制结构对多层膜的磨损特性影响较大,当调制周期为14.4 nm时,在干摩擦条件下AlTiN/AlCrN纳米多层膜的摩擦磨损量最小;在调制周期恒定为14.4 nm情况下,当调制比为3︰1时,在干摩擦条件下AlTiN/AlCrN纳米多层膜的耐磨性能最好;AlTiN/AlCrN纳米多层膜的磨损机理主要以磨粒磨损和黏附磨损为主。结论 优化的AlTiN/AlCrN多层膜纳米调制结构技术可应用在切削刀具的表面再制造领域,从而延长刀具工作寿命,通过涂层良好的耐磨性能提升设备的加工效率。     

AlCrN涂层转动微动摩擦学行为

在新型转动微动摩擦磨损试验装置上,采用球/平面接触方式,对多弧离子镀制备的AlCrN涂层与Si3N4陶瓷球进行转动微动试验,变化转角位移幅值,研究了涂层的转动微动摩擦磨损行为。结果表明:AlCrN涂层的转动微动摩擦行为明显依赖于转角位移幅值,随着转角位移幅值的增加,摩擦界面从部分滑移向完全滑移转变,摩擦因数明显增大且曲线走势明显不同。AlCrN涂层转动微动在转角位移幅值θ=0.5°时处于部分滑移状态,损伤极其轻微,界面主要由弹性变形协调;当θ增大为1°,微动运行于完全滑移状态,但涂层的损伤仍较轻,为轻微的磨粒磨损和氧化磨损;当θ进一步增大为2°,涂层损伤明显加重,且磨痕中心处有明显的塑性隆起的痕迹,与同处于滑移区的较小转角位移幅值(θ=1°)的情况明显不同。因此,转角位移幅值对AlCrN涂层的转动微动摩擦磨损行为有重要影响。     

Micromechanical characterization and dynamic wear study of DC-Arc coated cemented carbide cutting tools for dry titanium turning

The present study investigates the micromechanical properties of ceramic coated WC/Co tools and their influence on wear performance during dry Ti6Al4V turning. Physical and micromechanical characterization have been performed for the evaluation of the PVD coating properties. Higher hardness, elastic modulus, and adhesion strength have been obtained for dual-layer (AlTiN/AlCrN) coated tool than monolayer AlTiN and AlCrN coated tools. Micromechanical properties influence the wear mechanisms in thermally activated and abrasion dominant crater zones. Dual-layer coated tools reduced the flank wear at the corner radius and crater wear by 35–50% and 40%, respectively. Dynamic wear and abrasion-dissolution wear mechanisms have been explored over the tool rake face. Dual-layer coatings have improved wear performance by diminishing delamination, micro-fracturing of WC grains, binder dissolution and fractured interface boundaries.