碳靶电流对磁控溅射GLC/Ti薄膜结构及摩擦学性能的影响*

为改善掺杂Ti的GLC/Ti薄膜的摩擦学性能,采用非平衡磁控溅射技术在不同C靶电流下制备了类石墨碳基薄膜。利用扫描电子显微镜(SEM)、拉曼光谱仪(Raman)对薄膜结构进行表征;采用纳米压痕仪测量薄膜的硬度及弹性模量;利用HSR-2M型高速往复试验机测试薄膜在干摩擦条件下的摩擦磨损性能,并用白光干涉仪观察磨痕表面形貌。结果表明:随着C靶电流的增大,薄膜的柱状生长趋势日趋明显,其致密性降低,sp~2键含量减小,石墨化程度和结合力降低,而硬度和弹性模量略增;随着C靶电流的增大,摩擦因数和磨损率均增大。因此,适当降低C靶电流可以提高磁控溅射GLC/Ti薄膜干摩擦条件下的减摩耐磨性能。     

调制周期对纳米多层类石墨薄膜力学性能及摩擦学性能的影响

采用等离子增强多靶磁控溅射系统在溅射沉积类石墨(Graphite-like carbon,GLC)薄膜过程中交替掺杂金属W制备了6种纯GLC子层和W-GLC子层交替堆垛的纳米多层GLC薄膜。薄膜调制周期分别为300 nm、180 nm、90 nm、40 nm、15 nm以及8 nm共6种。研究了调制周期对薄膜力学性能和摩擦学性能的影响。结果表明:各纳米多层GLC薄膜均具有良好的力学性能与摩擦学性能,且随着调制周期的减小,薄膜的力学性能与摩擦学性能均大幅提高,并表现出显著的协同效应。纳米多层GLC薄膜中WC或W_2C纳米晶的弥散强化效应和纳米多层膜的界面效应是薄膜具有优异力学性能的主要原因,而薄膜在摩擦对偶表面形成的厚实致密的富碳转移膜又确保了薄膜具有良好的摩擦学性能。当调制周期减小至8 nm时,薄膜的硬度高达35.13 GPa,结合强度为45.28 N,H/E为0.109 5,H~3/E~2为0.375,且在"100 r/min,12 N"条件下连续摩擦480 min,平均摩擦因数仅为0.002,磨损率低至9.0×10~(-18)m~3/(N·m),综合性能极为优异。     

铝掺杂类石墨薄膜的构筑及其摩擦学性能研究

利用磁控溅射技术在硅片表面上制备铝掺杂类石墨(Graphite-like carbon,GLC)薄膜,采用原子力显微镜、场发射扫描电镜、X射线光电子能谱仪、纳米压痕仪等考察铝掺杂对薄膜表面形貌、结构及其机械性能的影响规律;利用旋转的球一盘微摩擦试验机考察薄膜的摩擦行为.结果表明:铝的引入使GLC薄膜表面更加平整、致密;GLC薄膜的硬度和弹性模量随着掺铝量的增加而增加;低载低速时,薄膜摩擦因数随着铝含量的增加而增加,高载高速时,摩擦因数随铝掺入量的增加明显降低且更稳定.     

非平衡磁控溅射制备Cr掺杂DLC复合薄膜的高温摩擦学性能

元素掺杂是提升DLC薄膜摩擦学性能和耐温性能的重要途径。采用直流磁控溅射技术在304不锈钢基体表面沉积了含氢DLC薄膜,同时利用射频磁控溅射技术完成Cr元素的掺杂,研究Cr元素掺杂对DLC薄膜的力学性能及摩擦学性能的影响。采用纳米压痕仪测试薄膜硬度并利用划痕试验测试膜基结合力,采用拉曼光谱分析薄膜sp²和sp³键含量的变化和转移膜的生成。采用UMT多功能摩擦磨损试验机评价薄膜在常温和高温环境下的摩擦磨损性能,并利用扫描电镜观察磨损表面,分析其磨损机制。结果表明,Cr元素掺杂会显著提高薄膜的膜基结合力,但会使薄膜硬度有一定的下降。常温摩擦学性能测试显示,DLC薄膜的摩擦因数随着Cr含量的增加呈现出先下降后上升的趋势,在Cr质量分数为3.34%时达到最低;但薄膜的磨损率随Cr含量的增加略有升高。高温摩擦学性能测试表明,Cr元素掺杂显著改善了DLC薄膜的高温摩擦学性能,未掺杂的DLC在150℃以上摩擦时会失效,Cr元素掺杂使薄膜在250℃下也能保持较低的摩擦因数和较长的抗磨寿命。Cr元素的加入能够提高DLC薄膜的膜基结合力,降低摩擦因数,并提高薄膜...     

偏压对掺钨含氢类金刚石碳膜摩擦学性能的影响

利用非平衡磁控溅射技术在单晶硅片及9Cr18基体表面制备不同偏压下的掺钨含氢类金刚石碳膜。采用Ra-man光谱分析薄膜结构,采用纳米硬度测试仪和纳米划痕仪研究薄膜的纳米硬度、弹性模量和膜基附着力,在球-盘摩擦试验机上测试薄膜在大气环境中的摩擦学性能,研究薄膜的摩擦学性能与偏压的关系。结果表明:制备的薄膜样品均具有典型的类金刚石碳膜结构;基体偏压强烈影响薄膜的力学和摩擦学性能,薄膜硬度和弹性模量在0～150 V范围内随着偏压增加而增大,薄膜的摩擦因数在偏压为100 V时最小,在此参数下的耐磨寿命也最长。     

钨含量对WC/DLC复合薄膜摩擦学性能的影响

利用等离子体辅助化学气相沉积技术复合非平衡磁控溅射技术制备具有不同钨含量的WC/DLC复合薄膜。通过调节WC靶功率实现薄膜中钨含量的控制,用EDS能谱仪测量薄膜中的钨含量,采用SEM分析薄膜的表面形貌和结构,采用Raman光谱分析不同钨含量对薄膜结构的影响,采用纳米硬度测试仪测试薄膜的纳米硬度,在球-盘摩擦试验机上测试薄膜在大气环境中的摩擦学性能,研究薄膜的力学性能、摩擦学性能与薄膜中钨含量之间的关系。结果表明:薄膜中的钨含量随着WC靶功率的增加而增加;制备的薄膜具有典型的类金刚石碳膜结构,并且薄膜中的sp3键含量以及薄膜硬度都随着钨含量的增加而增大;摩擦因数和耐磨寿命随着钨含量的增加呈先减小后增加的趋势,薄膜的摩擦因数在钨原子质量分数为41.67%时最小,在此参数下的耐磨寿命也最优异。     

非平衡线圈电流对掺钨含氢类金刚石碳膜力学和摩擦学性能的影响

利用非平衡磁控溅射技术在单晶硅片及9Cr18不锈钢基体表面制备不同非平衡线圈电流下的掺钨含氢类金刚石碳膜。采用Raman光谱以及红外光谱分析薄膜结构,采用纳米硬度测试仪和纳米划痕仪研究薄膜的纳米硬度和膜基附着力,在球-盘摩擦磨损试验机上测试薄膜的摩擦学性能。结果表明:制备的薄膜样品具有典型的类金刚石碳膜结构,薄膜中含氢量较高;非平衡线圈电流对等离子体的限制条件影响着薄膜的力学和摩擦学性能,薄膜硬度和弹性模量随着非平衡线圈电流增加而增大,薄膜的摩擦因数在非平衡线圈电流增加到最大值8 A时达到最小值0.118,在此参数下的耐磨寿命也最长。     

Ag掺杂对TiO2纳米薄膜结构及摩擦学性能的影响

采用溶胶凝胶法在普通载玻片上制备了TiO2和Ag/TiO2纳米结构薄膜,利用X射线衍射仪(XRD)、X光电子能谱(XPS)、原子力显微镜(AFM)及UMT-2摩擦试验机,考察了Ag掺杂量对薄膜组成结构、表面形貌及摩擦学性能的影响。实验结果表明,Ag掺杂量对TiO2薄膜表面形貌和减摩抗磨性能产生重要影响,低掺杂时Ag自润滑性能对薄膜摩擦性能的增强作用占主导,而高掺杂时其对薄膜的影响主要表现为恶化表面,从而导致摩擦性能下降。本研究测试条件下,掺杂量为5.0%(摩尔分数)时具有最佳的耐磨寿命和最低的摩擦因数。     

溅射沉积MoS2薄膜中掺杂Ti对其结构与性能的影响研究

采用非平衡磁控溅射沉积技术制备纯MoS2和不同Ti掺杂量的MoS2-Ti复合薄膜。用SEM和XRD对薄膜的形貌和结构进行分析,用纳米划痕仪测试薄膜与基底间的附着力,用球-盘摩擦试验机评价薄膜在大气和真空环境中的摩擦学性能。研究结果表明:在溅射沉积MoS2薄膜过程中掺杂金属Ti,有效地阻断了MoS2疏松、多孔柱状晶的优势生长,从而生成组织结构致密、无定形态的薄膜,提高了其与基底间的附着力。掺Ti复合薄膜在大气和真空环境中的摩擦学性能都得到显著改善,真空环境中10%Ti含量的薄膜耐磨寿命最长,是纯MoS2膜的37倍,大气环境中20%Ti含量的薄膜耐磨寿命最长,是纯MoS2膜的67倍。     

轴承表面钨掺杂类金刚石薄膜性能研究

利用物理气相沉积技术在圆柱滚子轴承表面制备钨掺杂类金刚石(W-DLC)薄膜,通过试验考核了Cr4Mo4V高温轴承表面W-DLC薄膜的均匀性和断油条件下的减摩耐磨特性。结果表明:薄膜层间以及膜层与基体之间结合力不小于55 N;与未镀膜的基体表面相比,镀膜后表面的摩擦因数降低了70%,磨损量减少了约80%;经过30 min断油试验后镀膜轴承表面W-DLC薄膜仍保持完整,可继续使用,未镀膜轴承滚道表面出现烧蚀斑块、点状剥落,滚子表面出现较大的剥落坑与划痕等缺陷。     

Friction and Wear Properties of Graphite-Like Carbon Films Deposited on Different Substrates with a Different Interlayer Under High Hertzian Contact Stress

Four types of graphite-like carbon (GLC) films were deposited on different substrates (Ti6Al4V, WC-27CrNi) with a different interlayer (TiC/Ti, TiC/Ti/TiN) using an unbalanced magnetron sputtering system. The effect of substrate and interlayer on the microstructure and properties of the studied GLC films was then investigated using different characterization techniques. The results show that both the substrate and interlayer had an obvious influence on the tribological properties of the studied GLC films even though there was no significant structural difference between these films. Specifically, a substrate with a high hardness was propitious to achieving superior tribological behaviors for carbon film even with a different interlayer. However, the interlayer had a distinct influence on the tribological properties of the carbon film deposited on different substrates, and this effect varied with the hardness property of the substrate. For a hard substrate, the wear rate and wear life were similar irrespective of the interlayer. For a soft substrate, the addition of a TiN interlayer improved the wear life sevenfold compared to the film with only a TiC/Ti interlayer, but the wear rate for a film with and without a TiN interlayer was approximately the same. The obvious discrepancy between wear life and wear rate for a carbon film deposited on soft substrate was closely related with the film adhesion strength and plastic deformation of the substrate materials. Based on these results, it can be concluded that the wear life is a better parameter than wear rate in terms of characterization of the wear resistance of carbon film once the applied load causes the plastic deformation of the substrate.     

Micro/Nanotexture Design for Improving Tribological Properties of Cr/GLC Films in Seawater

Microdimples with different diameters and Cr/graphite-like carbon (GLC) films were fabricated on silicon by laser surface texturing and magnetron sputtering technology, respectively. The texturing effects on the microstructures and tribological performance in seawater were comparatively investigated. The results showed that both the friction coefficients and wear rates in seawater decreased with an increase in dimple diameter in the lower range and then increased with a further increase in diameter. The Cr/GLC film with an appropriate diameter of dimples (1.5 µm) is effective in enhancing the tribological properties due to entrapment of wear particles and seawater in the dimples. In addition, the roughness and graphitization contact area have obvious effects on the wear resistance. If the surface roughness is too high, the graphitization contact area will decrease, and the ratio of minimum aqueous film thickness to the surface roughness is so small that the load is almost totally borne by the boundary film.     

Achieving High Tribological Performance of Graphite-like Carbon Coatings on Ti6Al4V in Aqueous Environments by Gradient Interface Design

A duplex treatment involving nitrogen ion pre-implantation and gradient interfacial transition was performed to obtain a high-performance graphite-like carbon (GLC) coating on a Ti6Al4V alloy. Characteristics of the as-deposited coating systems were systemically investigated by Raman spectrometry, scanning electron microscopy, atomic force microscopy, nano-indentation, and scratch tests. The friction and wear behaviors in distilled water and sea water environments were evaluated by a ball-on-disk tribometer. The results showed that the GLC multilayer coating on nitrogen ion-implanted Ti6Al4V possessed a greater hardness and adhesion strength than to that on un-implanted Ti6Al4V. The tribological performances of these duplex process systems showed a great improvement in both the distilled water and sea water environments. In particular, the Cr/CrN/GLC coatings on nitrogen ion-implanted substrates demonstrated the best friction and wear behaviors. These striking improvements were attributed to the greatly enhanced interface strength between substrate and coating by the nitrogen ion implantation process and improved adhesion strength between gradient layers by the appropriate gradient interlayers with a similar thermal expansion coefficient.     

Microstructure, Morphology and Properties of Titanium Containing Graphite-Like Carbon Films Deposited by Unbalanced Magnetron Sputtering

A series of graphite-like carbon films with a titanium concentration of about 3.0 at.% were successfully deposited on silicon wafer substrates using an unbalanced magnetron sputtering system with different bias voltages. The microstructure, surface morphology, and properties of the titanium-containing graphite-like carbon films were subsequently studied using different characterization techniques. The results show that the resulting titanium-containing graphite-like carbon films are completely dominated by sp² sites and that these films have moderate hardness, low internal stress, and superior tribological properties with low friction and a high load-bearing capacity. The hardness (H), elastic modulus (E), H/E, H ³/E ², and internal stress of the titanium-containing graphite-like carbon films initially increase with increasing bias voltage, only to be followed by a decrease with further increases in the bias voltage. Tribologically, the studied carbon film shows a slight increase in friction with increasing bias voltage, while the wear rate initially decreases, followed by an obvious increase. The tribological properties of the studied titanium-containing graphite-like carbon films are greatly improved under the liquid paraffin-lubricated condition, achieving extremely low friction (~0.045) and wear (~10^?9 mm³/Nm). The effect of bias voltage on the microstructure and properties of the titanium-containing graphite-like carbon films is discussed in detail.     

Wear behavior of low-cost, lightweight TiC/Ti–6Al–4V composite under fretting: Effectiveness of solid-film lubricant counterparts

The wear behavior of low-cost, lightweight 10 wt% titanium carbide (TiC)-particulate-reinforced Ti–6Al–4V matrix composite (TiC/Ti–6Al–4V) was examined under fretting at 296, 423, and 523 K in air. Bare 10 wt% TiC/Ti–6Al–4V hemispherical pins were used in contact with dispersed multiwalled carbon nanotubes (MWNTs), magnetron-sputtered diamond-like carbon/chromium (DLC/Cr), magnetron-sputtered graphite-like carbon/chromium (GLC/Cr), and magnetron-sputtered molybdenum disulfide/titanium (MoS₂/Ti) deposited on Ti–6Al–4V, Ti–48Al–2Cr–2Nb, and nickel-based superalloy 718. When TiC/Ti–6Al–4V was brought into contact with bare Ti–6Al–4V, bare Ti–48Al–2Cr–2Nb, and bare nickel-based superalloy 718, strong adhesion, severe galling, and severe wear occurred. However, when TiC/Ti–6Al–4V was brought into contact with MWNT, DLC/Cr, GLC/Cr, and MoS₂/Ti coatings, no galling occurred in the contact, and relatively minor wear was observed regardless of the coating. All the MWNT, DLC/Cr, GLC/Cr, and MoS₂/Ti coatings on Ti–6Al–4V were effective from 296 to 523 K, but the effectiveness of the MWNT, DLC/Cr, GLC/Cr, and MoS₂/Ti coatings decreased as temperature increased.     

Role of the Transfer Film on the Friction and Wear of Metal Carbide Reinforced Amorphous Carbon Coatings During Run-in

The relationship between friction, wear, and transfer films of three metal carbide-reinforced amorphous carbon coatings (TiC/a:C, TiC/a:C–H, and WC/a:C–H), sometimes referred to as metal-doped diamond-like carbon coatings, has been investigated. Tribological tests were performed in an in situ tribometer with sapphire or steel hemispheres run against coated flats in dry or ambient air. The sliding contact interface was observed and recorded by optical microscopy during reciprocating sliding tests. The friction and wear behavior during run-in depended on the number of sliding cycles to form a stationary transfer film on the hemisphere. Stationary transfer films formed rapidly (within ten cycles) and the friction coefficient fell to 0.2 (ambient air) or 0.1 (dry air), except with sapphire against WC/a:C–H in dry air; with the latter, a stationary transfer film required nearly 100 cycles to form, during which the friction remained high and the wear rate was from 10 to 100 times higher than the other two coatings. For all coatings, three velocity accommodation modes (VAM) were observed from run-in to steady-state sliding and were correlated with the friction and wear behavior. The delayed adherence of the transfer film to sapphire from WC/a:C–H coatings in dry air is discussed in terms of equilibrium thermochemistry. Friction and wear behavior during run-in, therefore, depended on transfer film adherence to the hemisphere and the VAM between transfer films and the coating.     

沉积温度对脉冲真空弧源沉积类金刚石薄膜性能的影响

利用脉冲真空弧源沉积技术在Cr17Ni14Cu4不锈钢和Si(100)基体上制备了类金刚石(DLC)薄膜,研究了基体沉积温度对DLC薄膜的性能和结构的影响。研究表明,随着沉积温度由100 ℃提高到400 ℃,DLC薄膜中sp3 键质量分数减少,sp2键质量分数增多,薄膜复合硬度逐渐降低。当DLC薄膜沉积温度达到400 ℃时,薄膜中C原子主要以sp2键形式存在,与沉积温度为100 ℃时制备的DLC薄膜相比,薄膜复合硬度降低50%。DLC薄膜具有优异的耐磨性,摩擦因数低,随着沉积温度由100 ℃提高到400 ℃,Cr17Ni14Cu4不锈钢表面沉积的DLC薄膜耐磨性降低。沉积温度为100 ℃时,Cr17Ni14Cu4不锈钢表面沉积的DLC薄膜后,耐磨性大幅度提高。DLC薄膜与不锈钢基体结合牢固。     

Cr12MoV钢表面磁控溅射TiB2-TiN薄膜的摩擦磨损性能

采用磁控溅射技术在淬火态Cr12MoV表面制备SiC/TiN、SiC/TiB2-TiN薄膜(SiC为中间层),研究TiN、TiB2-TiN薄膜的组织结构和摩擦磨损性能。结果表明,SiC薄膜与基材和TiN、TiB2-TiN薄膜间都具有明显的且呈梯度的元素扩散,界面结合良好。在水润滑条件下与钢球对摩时(载荷0.5 N,时间0.5 h),TiN薄膜、TiB2-TiN薄膜具有良好摩擦磨损性能,其平均摩擦因数分别为0.33、0.31,低于淬火态Cr12MoV的0.45,磨损速率分别为2.0×10-8和1.5×10-8mm3/(N.m),低于淬火态Cr12MoV的8.66×10-7mm3/(N.m),其中在水润滑条件下TiB2-TiN薄膜比TiN薄膜具有更好的摩擦磨损性能。     

Nanocomposite Microstructure and Environment Self-Adapted Tribological Properties of Highly Hard Graphite-Like Film

Graphite-like carbon (GLC) nanocomposite films were fabricated by DC magnetron sputtering using high pure graphite target at ambient temperature. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) investigation showed that the as-deposited GLC films have high concentration of sp²-hybridized carbon. High-resolution transmission electron microscopy (HRTEM) images and selected area diffraction patterns (SADP) indicated a complex nanocomposite microstructure of the GLC films. As well as nanocrystalline graphite, a face-center cubic (fcc) diamond with a grain size in the range of 3–8 nm were dispersed in the amorphous carbon matrix inhomogenously and integrally. The nanocomposite GLC film had high hardness of 23 GPa, which was attributed to the mutual strengthening effect of nanoparticles and amorphous matrix. More importantly, the as-deposited nanocomposite GLC film exhibited excellent self-adapted tribological properties in different environments of ambient air, different relative humidity and water. The friction coefficients were 0.053 in ambient air and 0.046 in distilled water, while specific wear rates were 4.5 × 10⁻¹⁶ m³ N⁻¹ m⁻¹ and 1.6 × 10⁻¹⁶ m³ N⁻¹ m⁻¹, respectively. The friction regimes and mechanisms in different environments were elaborated. This film is foreseen to high potential in protecting and solid lubricating material in humidity or water environment.