Tribological properties of Zr-C:H:Nx% coatings with different amounts of nitrogen addition

A closed field unbalanced magnetron (CFUBM) sputtering system is used to deposit Zr-C:H:N_x% coatings with nitrogen contents ranging from 0 to 29 at.% on AISI M2 steel disks. The microstructures of the various coatings are analyzed using Raman spectrometry, while the hardness and adhesion strength are measured via nanoindentation tests and scratch tests, respectively. The tribological properties of the coatings are tested against AISI 52100 steel balls under loads of 0.5-10 N using a ball-on-disk wear tester. The wear testing results reveal that the Zr-C:H:N_12% coating has excellent tribological properties, including a low wear depth, a low friction coefficient and an extended lifetime.     

Tribological properties of multilayer DLC/W-DLC films on Si

Multilayer films of diamond-like carbon (DLC) and tungsten-containing diamond-like carbon (W-DLC) films were deposited onto silicon wafers using radio frequency chemical vapor deposition (RFCVD) and a magnetron sputtering method. The W-DLC layer was deposited on the silicon wafer with less than 60 W magnetron output. The DLC layer was then deposited on the W-DLC layer.Surface morphology was investigated by atomic force microscopy and the film structure by transmission electron microscopy. Friction tests for multilayered films were performed in a nitrogen atmosphere at room temperature using a ball-on-disk tribometer. A conventional stainless steel ball was used for the test.The surface profiles seen by atomic force microscopy showed that round-shaped clusters of around 100 nm were observed in just the single W-DLC layer. These clusters were considered to be tungsten or tungsten-carbon composites. In the case of the DLC/W-DLC multilayered structure, the top DLC layer covered the W-DLC single layer and smoothed the surface of the W-DLC film.Friction tests demonstrated that the friction coefficient of the W-DLC single layer was above 0.6 and increased gradually as the number of cycle increased. The W-DLC films partially broke down during our measurements. However the DLC/W-DLC multilayer films showed stable friction properties and were observed for up to 100,000 cycles. Their friction coefficient was typically less than 0.1 at 10 cm/s rotating speed. The DLC/W-DLC multilayer films exhibited stable low friction properties in a long term test under a nitrogen atmosphere.     

Tribological properties of Ti2N-Wx% coatings deposited by magnetron sputtering

Ti₂N-W_x% coatings with different tungsten contents were deposited using unbalanced magnetron sputtering technology. The microstructures and mechanical properties of Ti₂N-W_x% coatings have been characterized by SEM, X-ray diffraction (XRD), nanoindentation and adhesion techniques. The tribological performance of the coatings was investigated using an oscillating friction and wear tester under dry conditions. Indexable inserts with Ti₂N-W_x% coatings were applied to turning AISI 1045 steel material by a lathe. Micron-drills with Ti₂N-W_x% coatings were adopted in the ultra-high speed (10⁵ rpm) Printed Circuit Board (PCB) through-hole drilling test. Experimental results indicate that the coating microstructure, mechanical properties and wear resistance vary according to the tungsten content. Ti₂N-W_14% coated inserts showed the best wear resistance in 1045 steel turning and PCB through-hole drilling tests. The service life of a Ti₂N-W_14% coated tool is five times greater than that of an uncoated tool in PCB through-hole drilling test.     

Cr基过渡层对CrWN涂层摩擦学性能的影响

本文探究了 Cr过渡层及Cr-CrN过渡层对CrWN涂层耐磨性能的影响,制备具有良好的减磨耐磨性能的CrWN涂层.采用等离子增强磁控溅射工艺,在碳化钨基体表面制备CrWN涂层,Cr-CrWN涂层、Cr-CrN-CrWN涂层.通过扫描电子显微镜,X射线光电子能谱仪,X射线衍射仪,纳米压痕仪,洛氏硬度计和摩擦磨损实验机对涂...     

聚苯酯填充聚四氟乙烯复合材料力学性能和摩擦学性能的研究

考察了不同含量聚苯酯对聚四氟乙烯复合材料力学性能和摩擦学性能的影响。结果发现,聚苯酯的加入降低了复合材料拉伸强度和弯曲强度,但提高了材料的硬度。同时,填料有效地改善了聚四氟乙烯复合材料的摩擦学性能,当聚苯酯含量(质量分数)为27%时,磨损体积仅为纯PTFE的1.5%。     

Preparation and Tribological Properties of Ni-P Electroless Composite Coating Containing Potassium Titanate Whisker

Nickel-phosphorus （Ni-P） composite coatings containing potassium titanate （K2Ti6O13） whiskers （PTWs） were prepared by electroless plating. The surface morphology and component of coatings were investigated by scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX）, respectively before and after wear test. The tribological performance was evaluated using a pin-on-disk wear tester under dry conditions. It is found that the Ni-P-PTWs composite coatings exhibit higher wear resistance than Ni-P and Ni-P-SiC electroless coatings. The favorable effects of PTWs on the tribological properties of the composite coatings are attributed to the super-strong mechanical properties and the specific tunneling structures of PTWs. The PTWs greatly reinforce the structure of the Ni-P-based composite coatings and thereby greatly reduce the adhesive and plough wear of Ni-P-PTWs composite coatings.     

Mechanical integrity analysis of multilayer insulator coatings on flexible steel substrates

The cohesive and adhesive properties, and related critical radius of curvature of thin multilayer insulator coatings on a 152 μm thick flexible steel substrate were investigated using tensile experiments carried out in-situ in an optical microscope. This method was found to be well adapted for the two types of coatings studied: SiO₂ single layers with different thickness and SiO₂/SiN_x/polyimide stacks. Special attention was paid to the influence of surface roughness and yielding of the steel substrate. Coating delamination and spallation was observed at low strain in case of SiO₂ coatings on unpolished steel, resulting from roughness-induced stress concentrations and slippage of grain boundaries. Polishing the steel substrate, or using a polyimide interlayer, was found to be useful to avoid premature delamination of the layers. In all investigated cases, a critical radius of curvature for layer damage of approximately 5 mm was found.     

Studies on drilling of glass/epoxy laminates using coated high-speed steel drills

Drilling studies were conducted on glass/epoxy composite laminates having two different lay-ups [(0/90)_4s and (0/±45/90)_2s]. Normal drills (2 flute with cone angle of 118°) made of high-speed steel (HSS), TiN-coated HSS, and TiC-coated HSS were used. Drilling parameters were optimized in terms of least thrust and torque. Parameters studied were thrust, torque, tool wear, form deviation, acoustic emission peak, and root mean square (RMS) of acoustic energy. It was observed that coated HSS drills perform little better than uncoated HSS for small number of holes, while their performance is inferior to uncoated HSS for larger number of holes. This is mainly due to peeling or chipping of the coating from base material (HSS). Also, the performance of TiN-coated HSS drill was observed to be better than TiC-coated HSS.     

Tribological behavior and wear mechanisms of Ti-C : H/TiC/TiCN/TiN/Ti coatings when sliding against steel, bronze and aluminum alloy rods

Ti _x%-C : H coatings of differing thicknesses and with various titanium concentrations were deposited on tungsten carbide disks by unbalanced magnetron sputtering. The mechanical properties, microstructure, and adhesion strength of these coating were measured. The tribology properties of the coatings against AISI 1045 steel, AA7075, AA6061 aluminum alloy, and bronze rods were tested by an oscillation sliding test machine with a line-contact wear mode under dry conditions. The microhardness of Ti _x%-C : H coatings increased with an increasing Ti concentration. The optimum coatings are composed of an intermediate layer of TiC/TiCN/TiN/Ti and a top layer of Ti _x%-C : H with x 20%. These coatings have an excellent wear resistance and a low friction coefficient when paired with a carbon steel or copper alloy. These pairs are marked by the mildly wear of the counterbodies of AISI 1045 steel and bronze. The coatings are less suitable for oscillation with the aluminum alloy under dry conditions due to severe adhesion damage.     

Nano-indentation of hybrid silica coatings on surgical grade stainless steel

Hybrid silica-based coatings with tetraethoxysilane (TEOS), methyltrietoxysilane (MTES), hydroxyethyl-methacrylate (HEMA) and methacrylopropyl-trimethoxysilane (γMPS) as precursors, were employed to improve the performance of stainless steel used as orthopaedic material. Mechanical properties of the films, such as Young's modulus and hardness, were studied using the load and depth sensing indentation technique known as nano-indentation. The elastic/plastic and creep behaviours were also analyzed. Coatings with a high proportion of organic components (HEMA, γMPS) presented a more plastic response compared to the more vitreous coatings (containing only TEOS and MTES). They also showed the lowest Young's modulus and hardness. Therefore, the more vitreous coatings presented lower creep deformation that increased with the load applied.     

内燃机用GH4169合金表面等离子喷涂Fe-Cr-Ni-C涂层的组织和摩擦性能分析

通过等离子喷涂工艺在内燃机用GH4169合金表面上制得Fe-Cr-Ni-C与Fe-Cr-Ni两种涂层,采用实验测试的方式分析其组织和摩擦性能。研究结果表明:Fe-Cr-Ni-C涂层硬度以及结合强度优于Fe-Cr-Ni-C涂层,其硬度为536 HV,结合强度38.63MPa。在涂层中产生了完全熔融与部分熔融的两种区域,熔化区具备致密组织结构以及很高的硬度,部分熔融区能够对熔化区脆性得到有效改善。涂层摩擦系数均随温度的上升而减小,Fe-Cr-Ni-C涂层比Fe-Cr-Ni更低。Fe-Cr-Ni-C涂层具有比Fe-Cr-Ni更小的磨损率,并且当温度升高后,两种涂层都发生了磨损率减小,温度到达900℃时,两种涂层获得最小磨损率。在室温下Fe-Cr-Ni涂层形成了比Fe-Cr-Ni-C涂层更多的磨粒,发生了磨粒磨损,在Fe-Cr-Ni-C涂层的磨损区域产生了层状结构薄片,呈现剥落磨损特征。温度900℃时,在Fe-Cr-Ni涂层的磨损表面存在许多断裂的润滑膜,发生塑性变形。     

退火温度对DLC膜热稳定性及摩擦学性能的影响

采用非平衡磁控溅射技术分别在氮化硅陶瓷球和高速工具钢圆盘表面制备了类金刚石(DLC)膜。使用箱式电阻炉对DLC膜在大气环境中进行高温退火处理以研究环境温度对DLC膜摩擦学性能的影响;并分别采用激光拉曼光谱仪和球-盘式摩擦磨损试验机对退火处理前后DLC膜的结构和摩擦学性能进行了研究。采用金相显微镜观察了摩擦副磨损表面的形貌。研究发现,随着退火温度的升高,DLC膜中sp3杂化键向sp2杂化键的转化加快,当退火温度为600℃时,DLC膜发生严重的石墨化。而当退火温度为400℃时,DLC膜的摩擦系数及磨损率最小。拉曼测试表明400℃退火处理后DLC膜表层含有Si及SiO2,在摩擦过程中形成了含SiC的转移膜,使得DLC膜的摩擦系数明显降低,磨损减小。研究结果表明,退火处理对DLC膜的热稳定性和摩擦学性能有重要的影响。     

Study on tribological property of CrCN coating based on magnetron sputtering plating technique

The influence of carbon doping on tribological properties of CrCN coating was studied through preparation of coatings deposited on single crystal silicon and M2 high-speed steel (HSS) substrate using closed-field unbalanced magnetron sputtering ion plating technique. The friction coefficients were measured by pin-on-disc set-up and the wear traces of the coatings were observed by optical microscope. The microstructure and bond states of the coatings were characterized by atomic force microscope (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the friction coefficient of coating decreases from 0.75 to 0.38, the micro-hardness increases from 1930 HV to 2300 HV, and the specific wear ratio of the coatings decreases from 8.351 × 10⁻¹⁵ m³/Nm to 3.859 × 10⁻¹⁵ m³/Nm with the increasing of carbon target current (I_C) from 0 A to 1.5 A. The grain size and the roughness of the coatings both decrease with the increasing of carbon target current, at the same time the coatings transform from crystalline state to amorphous state.     

环氧基倍半硅氧烷杂化膜的摩擦性能研究

采用溶胶-凝胶法,将不同含量的正硅酸乙酯(TEOS)与r-缩水甘油醚基丙基三甲基硅烷(GPMS)共水解缩合,所得终产物为有机-无机纳米杂化材料,用浸渍法使其在玻璃基体上成膜,并利用扫描探针电镜(SPM)对膜的形貌进行了表征.通过MTS Nano Indenter XP纳米压痕仪研究了TEOS的含量对杂化体系摩擦性能的影响.结果表明,环氧基倍半硅氧烷杂化膜在TEOS含量为5%时表面粗糙度最小、弹性恢复能力最大,TEOS含量为10%时摩擦系数最小.     

Influence of CaCO3 Whisker Content on Mechanical and Tribological Properties of Polyetheretherketone Composites

The mechanical and tribological properties of polyetheretherketone (PEEK) composites filled with CaCO3 whisker in various content of 0-45% (wt pct) were investigated. The composite specimens were prepared by compression molding. Tribological testing of composites in dry wear mode against carbon steel ring was carried out on a MM200 block-on-ring apparatus. Data on neat PEEK were also included for comparison. It was observed that inclusion of CaCO3 whisker affected the most mechanical properties and the friction and wear in a beneficial way. With an increase in CaCO3 whisker content, friction coefficient continuously decreased but the trends in wear performance varied. The specific wear rate showed minima as 1.28×10-6 mm3/Nm for 15% CaCO3 whisker inclusion followed by a slow increase for further CaCO3 whisker addition. In terms of friction applications, when the tribological and mechanical properties are combined, the optimal content of CaCO3 whisker in the filled PEEK should be recommended as 15% to 20%. Fairly good correlations are observed in friction coefficient vs bending modulus and wear rate vs bending strength, confirming that the bending properties prove to be the most important tribology controlling parameters in the present work.     

Super304H奥氏体耐热钢微观组织研究

为了深入认识新型奥氏体耐热钢Super304H(0.1C-18Cr-9Ni-3Cu-Nb,N)的微观组织,利用光学显微镜、扫描电子显微镜、电子探针和X射线衍射等手段,研究了Super304H钢合金元素的分布和析出相的组成及分布形态.试验结果表明,Super304H钢在供货状态下的显微组织由γ-基体和析出相组成.与传统的18-8不锈钢相比,这种奥氏体钢晶粒均匀细小,晶粒尺寸约46μm.析出相主要由Nb(C,N)和富铜相组成,Nb(C,N)有呈方向性分布的条块状和呈弥散分布的细小颗粒状两种形态,条块状的Nb(C,N)是软化过程中残留下来的,而弥散分布的是固溶处理及冷却过程中析出形成的.其中弥散分布的Nb(C,N)与富铜相对细化晶粒和改善钢的高温强度起重要作用,而多种复合强化机制使得Super304H钢具有优异的高温性能.     

Electrochemical study of hydroxyapatite coatings on stainless steel substrates

Hydroxyapatite coatings were synthesized electrochemically onto stainless steel. In this study, the composition and morphology of the coatings changed with the deposition and sintering conditions. The electrolyte was kept close to the composition of simulated body fluid with an adjusted pH of 8.0. Deposition temperature affected the purity of the deposits with higher temperatures (65 °C) giving better coatings. The sintering techniques were also shown to affect the deposits, with x-ray diffraction patterns showing well-defined peaks for hydroxyapatite when sintering under vacuum conditions. Coating density and corrosion resistance was improved when applying a double-layer coating technique versus a single-layer. Grain sizes were 30 to 40 nm even after sintering of these coatings in air. The formed coatings were characterized by powder x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and x-ray photoelectron spectroscopy.     

Crystallography of magnetron sputtered TiN coatings on steel substrates

Structure formation processes in TiN coatings deposited by reactive CFUBMS on steel substrates have been investigated by X-ray diffraction experiments in symmetric Bragg-Brentano (B-B) and grazing incidence asymmetric Bragg diffraction (GIABD) modes and by SEM. The results show that the deposits with thicknesses of 500 and 4000 nm are built-up of polycrystalline stoichiometric TiN, in addition to which, some negligible amount of Ti-O and Ti-N-O phases have also been observed predominantly at their surfaces. In the thinner 500 nm films only columnar crystallites with {1 1 1}, {2 0 0} and {2 2 0} crystallographic planes parallel to the surface were formed. The share of the micro-volumes belonging to the 〈1 1 1〉 out-of-plane texture component varied between 70% and 80% depending on the target current (I_d) used (4 or 8 A in the present experiments). During the more advanced stages of growth the 〈1 1 1〉 texture weakens and new texture components appear; the process being more pronounced when the application has been performed at higher I_d values. The obtained crystallographic texture results for the thinner films and their changes during the more advanced stages of the coatings formation are discussed with particular consideration of the crystallography of the TiN lattice and the anisotropy of its elastic parameters. Based on a precise estimation of the interplanar distances, d_{〈u v w〉}, corresponding to the main texture components of the investigated films in the direction along the surface macro-normal, it has been revealed that the elastic strain, ε_{〈u v w〉}, caused by the compressive residual macro-stresses acting parallel to the film surfaces and the corresponding elastic stored energy, U_{〈u v w〉}, values obey the following relationships: ε_{〈1 1 1〉}>ε_{〈2 2 0〉}> ε_{〈2 0 0〉} and U_{〈1 1 1〉}>U_{〈2 2 0〉}>U_{〈2 0 0〉}, respectively. The observed ε_{〈u v w〉} and U_{〈u v w〉} anisotropy is found to be more pronounced in the thinner coatings and is such that, at more advanced stages of growth, it would be expected to favour the transition from 〈1 1 1〉 to 〈2 0 0〉 out-of-plane preferred orientation. However, the experimental results do not confirm this expectation, which points out that the texture-formation at these stages is not governed solely by the minimization of the stored elastic energy, but is a rather complicated process depending on a larger number of factors, some of which are discussed in the paper.     

Microstructure and tribological properties of in situ synthesized TiN/Ti3Al intermetallic matrix composite coatings on titanium by laser cladding and laser nitriding

TiN reinforced Ti₃Al intermetallic matrix composite (TiN/Ti₃Al IMC) coatings were in situ synthesized on a pure Ti substrate with Ti + Al mixed powders in nitrogen atmosphere by laser cladding and laser nitriding. It was found that the growth morphologies of the TiN reinforced phase in the TiN/Ti₃Al IMC coatings were granular-like, flake-like, and undeveloped dendrites at lower N₂ flow rate; and granular-like, undeveloped and developed dendrites at higher N₂ flow rate. In addition, the volume fraction of the TiN phase increased with increasing nitrogen flow rate. The hardness of the TiN/Ti₃Al IMC coatings was higher than that of the Ti₃Al coating, which increased with increasing volume fraction of the TiN phase. Friction and wear tests revealed that the wear resistance of TiN/Ti₃Al IMC coatings was superior to those of pure Ti and Ti₃Al coating. It is well worth noting that the TiN/Ti₃Al IMC coatings showed excellent wear resistance under lower normal loads.     

平板玻璃表面涂料的研究及应用

透明装饰性涂料在玻璃上的应用使其表面功能多样化,应用范围更加广泛.本文阐述了平板玻璃涂料制备技术中基料树脂的选取、涂膜耐久性以及涂装工艺,并综述了几类玻璃涂料,如普通装饰性涂料、低辐射涂料、防反射涂料以及新型玻璃建材的应用研究进展.