不同涂层在甘油环境下的摩擦学性能对比研究

为提高甘油环境下摩擦副的抗磨能力,采用磁控溅射技术在单晶硅P(111)、316L不锈钢上分别制备DLC、CrN、TiN涂层。分别在大气及甘油环境下,利用多功能摩擦磨损试验机对涂层摩擦磨损性能进行对比研究,分析摩擦因数、磨损率及磨痕形貌的变化规律,并对比分析甘油环境中不同涂层与涂层配副在重载高速下摩擦力矩变化规律。结果表明:DLC涂层在大气环境下具有最优的减摩抗磨性能,DLC涂层和CrN涂层在甘油环境下均具有优良的减摩耐磨性能;在100 N载荷下DLC-CrN涂层配副在甘油环境下在整个测试过程中摩擦力矩比较小,且样块表面均无明显的磨损及划痕,表明DLC-CrN涂层配副在甘油环境及重载高速工况下具有优异的摩擦学性能。     

不同温湿度下风电轴承表面防护DLC薄膜微动摩擦特性

针对湿热环境下风电绝缘轴承的微动磨损失效问题，采用等离子体增强化学气相沉积工艺在绝缘涂层Al₂O₃表面沉积类金刚石碳(DLC)薄膜，研究温湿度对其微动摩擦特性的影响。结果表明：DLC薄膜在适当高温下均具有良好的摩擦学性能，在湿度为80%RH时的平均摩擦因数较小；温湿度较高的环境有利于降低DLC薄膜的微动磨损程度，提高绝缘轴承的防护程度；对磨痕处进行拉曼光谱分析表明摩擦过程中DLC薄膜磨痕表面杂化键sp²/sp³比值均大幅上升，且薄膜发生了石墨化转变。DLC薄膜在高温下的低摩擦行为主要是由于DLC薄膜表面石墨化过渡层和磨损表面石墨化的协同作用。     

柴油机活塞环表面类金刚石薄膜在模拟工况下摩擦学性能

大缸径、长冲程的大功率柴油机的活塞环-缸套摩擦副易发生异常磨损,使柴油机动力性能丧失,甚至发生拉缸等重大事故,通过先进的表面处理技术可显著改善活塞环-缸套摩擦副的润滑条件,提高活塞环-缸套摩擦副的摩擦学性能。采用阴极电弧离子镀技术在铬-陶瓷复合镀(CKS)活塞环表面制备厚度为7 μm的DLC薄膜,研究CKS活塞环表面的DLC薄膜在柴油机模拟工况下的摩擦学性能。结果表明：在干摩擦、室温贫油和高温贫油的工况下,CKS活塞环表面的DLC薄膜可以显著减小活塞环-缸套摩擦副对摩的摩擦因数,降低缸套的磨损;摩擦过程中DLC薄膜与润滑油的协同润滑作用以及DLC薄膜的石墨化是改善活塞环-缸套摩擦副摩擦学性能的主要原因。     

TiNi表面磁控溅射DLC薄膜的纳米压痕与摩擦性能

采用室温磁控溅射技术在TiNi合金表面制备出DLC/SiC(类金刚石/碳化硅)双层薄膜(SiC为中间层),采用拉曼光谱仪、纳米压痕仪和球-盘式摩擦磨损仪研究DLC薄膜的结构、纳米压痕和摩擦性能.结果表明:制备的DLC/SiC薄膜石墨含量高、纳米硬度(5.493 GPa)低、弹性模量(62.2447 GPa)低.在以氮化硅球(半径为2mm)为对摩件,4.9N载荷、室温、Kokubo人体模拟体液润滑下,该DLC/SiC薄膜具有低且稳定的摩擦因数,其平均值约为0.094.     

碳离子束注入辅助蒸发低温沉积DLC薄膜研究

采用碳离子束注入辅助蒸发技术低温沉积了DLC薄膜,对薄膜沉积的工艺参数进行了优化,并对该薄膜的摩擦学行为进行了探讨。研究发现:碳离子束注入辅助蒸发技术沉积的DLC薄膜在离子量为3.0×1017ions/cm2,沉积率为0.1nm/s时具有最小的摩擦因数(<0.1);电流为2.0mA比3.0mA条件下所沉积的DLC薄膜表面光滑;磨损试验后,DLC薄膜的表面只有轻微磨损的痕迹。     

润滑油缺失工况下不同活塞环涂层对缸套摩擦磨损对比研究

为研究润滑油缺失工况下不同活塞环涂层在不同温度下与缸套的摩擦学性能,选取5种商用活塞环涂层,利用扫描电子显微镜观察不同涂层的截面形貌,利用往复式摩擦磨损试验机,在润滑油缺失工况下,分别在常温、200 ℃和350 ℃条件下进行摩擦磨损试验,利用轮廓仪和光学显微镜分别观察摩擦试验后的磨损量和磨痕形貌。结果表明：CrN基涂层和CKS涂层主要为黏着磨损,对缸套磨损大,不同温度下摩擦学性能稳定;含DLC涂层主要为磨料磨损,常温摩擦因数小,高温下不同涂层有较大差异,其中CDC+DLC涂层综合性能最佳。     

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...     

空间飞轮轴承DLC涂层表面改性的工艺研究

使用类金刚石薄膜(Diamond Like Carbon,DLC)作为涂层,采用等离子体离子浸没注入技术Plasma Immersion Ion Implantation and Deposition,PIIID)对空间飞轮长寿命轴承沟道表面进行改性。结果表明,陪试件表面DLC改性后表面粗糙度、轴承内外沟道轮廓形状误差等特性未发生明显改变,改性层表面纳米硬度提高2倍左右;陪试件摩擦试验结果表明,改性后表面的摩擦学性能得到了明显改善;DLC涂层的稳定摩擦因数仅为基体的1/3～1/4,有利于延长空间飞轮轴承的工作寿命。     

等离子弧表面淬火钢件的摩擦特性及耐蚀性

采用等离子弧表面淬火方法对45#钢和38CrMoA lA合金结构钢进行表面硬化处理,硬化深度分别为0.311和0.388 mm。在球-盘式摩擦磨损实验机上研究不同速度和载荷条件下,上述两种钢件的摩擦磨损特性。采用SEM观测磨损后涂层的表面形貌,探讨涂层的摩擦磨损机制。研究发现:38CrMoA lA硬化层表面硬度比45#钢高,且淬硬带无明显的硬度梯度;38CrMoA lA的磨损率低于45#钢,且随载荷和速度的增加而增加;不同载荷条件下,磨粒磨损、塑性流动和黏着磨损控制摩擦过程;38CrMoA lA的耐蚀性优于45#钢。     

Cr/x/DLC复合涂层刀具切削铝硅合金切削性能研究

类金刚石(Diamond-Like Carbon,DLC)涂层刀具结合了基体强度高、韧性好以及涂层硬度高、耐磨性高的优点,可以有效降低刀-屑间摩擦,提高刀具切削寿命和加工效率。采用直流磁控溅射和等离子体辅助化学气相沉积(Plasma-Assisted Chemical Vapor Deposition,PACVD)法分别在硬质合金刀具基体上制备了单一DLC涂层、Cr/W-DLC/DLC复合涂层和Cr/CrN/DLC复合涂层。对比研究了具有不同Cr/x/DLC过渡层的DLC复合涂层硬质合金刀具加工过共晶结构铝硅合金AC9B的切削性能。研究结果表明:切削铝硅合金时,相对于无涂层硬质合金刀具,DLC涂层硬质合金刀具可以明显降低切削力和切削温度,并且具有更长的刀具切削寿命;Cr/W-DLC/DLC复合涂层硬质合金刀具的切削力最小,切削寿命最长。经显微分析,发现DLC涂层硬质合金刀具切削铝硅合金时的磨损机理主要是黏结磨损和硬质点磨损。     

ECR结合中频磁控溅射制备掺Cu类金刚石膜工艺及性能研究

为改善DLC膜的内应力及导热问题,采用ECR微波等离子体化学气相沉积及中频磁控溅射的方法制备掺Cu类金刚石膜,研究溅射电流对薄膜中Cu含量、薄膜表面形貌、结构及机械性能的影响.结果表明:改变溅射电流能有效地控制类金刚石膜中金属含量,拉曼光谱显示,制备的薄膜为典型的类金刚石薄膜结构;Cu的掺入使得类金刚石膜的硬度和耐磨损性能下降,但在一定溅射电流下可得到薄膜结构及机械性能均较好的掺Cu类金刚石膜.     

纳米碳球作为合成酯抗磨剂的摩擦学性能研究

采用表面化学改性的方法得到硬脂酸修饰的纳米碳球,在四球摩擦试验机上考察纳米碳球在合成酯类润滑油中的抗摩擦性能,探讨纳米碳球的抗磨与润滑机制。结果表明,通过表面改性,显著提高纳米碳球在润滑油中的分散稳定性;纳米碳球作为合成酯润滑油抗磨剂表现出优良的抗磨减摩性能;在转速1.200 r/min,载荷150 N的实验条件下,质量分数0.07%的改性纳米碳球可使三羟甲基丙烷混酸酯平均摩擦因数减小幅度达到30%左右,磨损率降低33%,质量分数0.15%的改性纳米碳球可使季戊四醇油酸酯的平均摩擦因数降低幅度达到50%以上,磨损率降低14.6%     

Nanometre scale mechanical properties of extremely thin diamond-like carbon films

Abstract

Extremely thin diamond-like carbon (DLC) films are deposited by the filtered cathodic vacuum arc (FCVA) and plasma chemical vapour deposition (p-CVD) methods. The target thicknesses of the extremely thin protective DLC films deposited on a Si (100) surface by FCVA and p-CVD are 0·1, 0·4, 0·8, 1·0, 2·0, 5·0 and 100·0 nm. Nanoindentation hardness and nanowear resistance are evaluated by atomic force microscopy (AFM). The nanoindentation hardnesses of 100 nm thick DLC films deposited by FCVA and p-CVD are 57 and 25 GPa respectively. The nanowear test by AFM clarifies the mechanical properties of extremely thin DLC films. The wear depths of 1 and 2 nm thick FCVA-DLC films are extremely shallow. The wear depths of the 1·0 and 2·0 nm thick p-CVD-DLC films exceed the film thicknesses after five sliding cycles. These results reveal differences in the wear resistance of extremely thin DLC films and the superior mechanical properties of FCVA-DLC thin films.     

Tribological Performance of Diamond and Diamondlike Carbon Films at Elevated Temperatures

In this study, the authors investigated the tribological performance of diamond and diamondlike carbon (DLC) films as a function of temperature. Both films were deposited on silicon carbide (SiC) by microwave plasma chemical vapor deposition and ion-beam deposition processes. Tribological tests were performed on a reciprocating wear machine in open air (20 to 30% relative humidity) and under a 10 N load using SiC pins. For the test conditions explored, the steady-state friction coefficients of test pairs without a diamond or DLC film were 0.7 to 0.9 and the average wear rates of pins were 10^?5 to 10^?7 mm³/N·m, depending on ambient temperature. DLC films reduced the steady-slate friction coefficients of the test pairs by factors of three to five and the wear rates of pins by two to three orders of magnitude. Low friction coefficients were also obtained with the diamond films, but wear rates of the counterface pins were high due to the very abrasive nature of these films. The wear of SiC disks coated with either diamond or DLC films was virtually unmeasurable while the wear of uncoated disks was substantial. Test results showed that the DLC films could afford low friction up to about 300° C. At higher temperatures, the DLC films graphitized and were removed from the surface. The diamond films could withstand much higher tempera-lures, but their tribological behavior degraded. Raman spectroscopy and scanning electron microscopy were used to elucidate the friction and wear mechanisms of both films at high temperatures.     

DLC coating of boundary lubricated components—advantages of coating one of the contact surfaces rather than both or none

The influence of conventional extreme-pressure (EP) and anti-wear (AW) additives on the wear and friction behaviour of DLC coatings has been investigated. Special emphasis was put on exploring if it is most beneficial to coat only one or both the contacting surfaces and on when and how the coatings may improve the friction situation in sliding contact boundary lubricated systems. Tests were performed in a load-scanning test rig, which allows the normal load to gradually increase during the forward stroke and to correspondingly decrease during the reverse stroke. The sliding speed was set to 0.1 m/s, while the normal load was in the range between 140 and 1700 N (2.4–5.6 GPa).This investigation indicates that, under boundary lubrication conditions, addition of commercial AW and EP additives to PAO oil may significantly improve the tribological properties of DLC coatings. Furthermore, the DLC/steel combination was found to give a smoother running-in process and a better tribological performance than the DLC/DLC and steel/steel combination.     

Tribological Properties of Diamond-Like Carbon Films in Low and High Moist Air

Diamond-like carbon (DLC) film was deposited on Si wafer by a plasma CVD deposition system using benzene. Tribological properties of the DLC film were evaluated using a ball-on-disk tribo-meter in low (RH 1720 %) and high humidity (RH 9095 %) conditions in air. The effect of sliding speed (4.2 mm/s to 25 mm/s) and load (1.06 N to 3.08 N) on friction and wear was investigated. The friction behavior of the DLC film was obviously different in low and high humidity. When tested under low humidity conditions, the friction coefficient decreased significantly with increasing speed, and increased with load. However, under high humidity conditions, the friction coefficient increased with the speed and decreased with increasing load. The wear of the DLC film was little influenced by the sliding speed, normal load and humidity; a level of 10^-8 mm³/Nm could be obtained in all tests. The formation of a uniform transfer layer would be the main factor which controlled the friction coefficient of the DLC films. Unlike the friction, the wear resistance of the DLC film is not so easy to discuss and may be affected mainly by the tribo-chemical reaction in all the test conditions.     

环境与工况对柴油机缸套-活塞环磨损的影响

为研究柴油机实车使用状况下缸套-活塞环磨损规律,建立某12150型多缸柴油机面向使用工况的缸套-活塞环磨损仿真计算方法并进行验证,研究环境与工况参数对缸套磨损的影响规律。结果表明:大气温度升高,缸套磨损深度呈现先减小后增大的趋势,气温-5℃时磨损最小,与-35℃相比下降了5.89%,与40℃相比下降了9.15%;大气压力降低,缸套磨损深度先减小后增大,气压80 kPa时最小,与100 kPa相比下降了6.45%,气压50 kPa时磨损最大,与100 kPa相比升高了8.48%;缸套磨损深度随柴油机转速升高而呈现出增加的趋势,在1 600 r/min时出现极小值点,转速为2 000 r/min相比1 200 r/min磨损深度增加了46.76%;柴油机负荷增加引起缸套磨损深度不断增大,100%负荷时较20%负荷的磨损深度升高了133.96%。     

Friction and wear behaviour of hard and superhard coatings at cryogenic temperatures

The work presents data on friction and wear behaviour of pin-on-disc pairs with superhard diamond-like carbon (DLC) coatings and hard coatings of zirconium nitride (ZrN) and titanium nitride (TiN) in liquid nitrogen with loads of 2.5 and 10 N and sliding speed of 0.06 m/s. It is shown that at cryogenic temperatures the friction coefficients of pairs of two types of DLC coatings obtained by vacuum-arc deposition of filtered high-speed carbon plasma fluxes depend to a great deal on the mechanical properties of the coatings defined by predominant sp² or sp³ hybridization of valence electrons. A friction coefficient of 0.76 was observed for friction pairs of superhard (90 GPa) DLC coatings having properties similar to those of diamond. For “softer” DLC coatings of 40 GPa and properties similar to those of graphite the friction coefficient shows lower values (0.24–0.48) dependent on normal load and counterbody material. The DLC coatings obtained by the filtered arc technology exhibit good wear resistance and have strong adhesion to the substrate under friction in liquid nitrogen. With a normal load of 10 N under cryogenic temperature a low wear rate (of the order of 7.2×10⁻⁴ nm/cycle) was found for superhard DLC coatings. The friction coefficient of pairs with hard ZrN and superhard DLC coatings on steel discs was revealed to be linearly dependent on the counterbody material hardness between 20 and 100 GPa. The hardness of the pin was varied by means of depositing TiN or DLC coatings and also by using high-hardness compounds (boron nitride and synthetic diamond). Proceeding this way can be promising since it offers the possibility of creating low-temperature junctions of required friction properties.     

纳米ZnO填充的PTFE基复合材料摩擦学性能研究

得胜０００型摩擦磨损试验机研究了不同体积含量的纳米氧化锌（ＺｎＯ）填充的ＰＴＦＥ基复合材料在于摩擦条件下与不风对摩时的摩擦学性能,并利用扫描电子微镜（ＳＥＭ）对ＰＴＦＥ及纳米ＺｎＯ／ＰＴＦＥ复合材料的微观结构、磨损表面和转移膜进行了观察和分析。结果表明,纳米ＺｎＯ／ＰＴＦＥ复合材料的摩擦性能与纯ＰＴＦＥ基本相当,但耐磨性明显优于后者,纳米ＺｎＯ在复合材料中的最佳含量为１５ｖｏｌ．％左右。