AISI 316L不锈钢表面沉积Ti掺杂类金刚石薄膜及其性能

为了进一步评价医用材料AISI 316L不锈钢表面沉积掺杂Ti类金刚石薄膜的应用性能,采用离子束辅助沉积技术在AISI 316L不锈钢表面沉积了掺杂Ti类金刚石(DLC-Ti)薄膜。分别利用X射线衍射仪、扫描电子显微镜、摩擦磨损试验机、电化学工作站及纳米压痕仪对DLC-Ti薄膜的晶体结构,表面与截面形貌,摩擦磨损性能,电化学性能,硬度和弹性模量进行了表征。结果表明:DLC-Ti薄膜的摩擦系数超低(0.017~0.029)且未出现磨损,自腐蚀电位和点蚀电位相对于基体向正电位方向移动。DLC-Ti薄膜综合性能较好,在整形外科及刀具等应用方面具有很好的前景。     

316不锈钢表面沉积厚类金刚石膜层的性能研究

采用脉冲辉光放电等离子体气相沉积法在316不锈钢表面沉积膜层较厚的类金刚石膜层。利用拉曼光谱仪(Raman)、X射线光电子能谱仪(XPS)、傅里叶变换红外光谱仪(FT-IR)、光学显微镜、显微硬度计和摩擦磨损实验机分别对膜层组成和微观结构及机械性能进行了表征。研究发现,通过脉冲辉光放电等离子体气相沉积法,在316不锈钢表面制备的类金刚石膜层光滑致密;Raman分析得到的ID/IG和IT/IG比值分别为0.72和0.22;FT-IR分析可知膜层含有较多的CHx组成的sp3键;摩擦磨损试验得到膜层的摩擦系数低至0.100,XPS分析膜层sp3含量高达60.7%和光学显微镜测量膜层的厚度达到7mm。由此可知沉积类金刚石膜层后,可以显著地改善316不锈钢表面的机械性能。     

掺氮类金刚石薄膜的制备与性能研究

利用空心阴极放电在玻璃基底表面沉积掺氮类金刚石(DLc)薄膜.拉曼光谱(Raman)分析表明,所制备的碳膜具有典型的类金刚石结构.扫描电镜(SEM)和原子力显微镜(AFM)分析了薄膜表面形貌和粗糙度;利用摩擦磨损仪测量膜的摩擦磨损性能.结果表明,氮的掺入使得薄膜中颗粒致密平整,改变了薄膜的表面微观形貌,进而改善了薄膜的摩擦磨损性能.     

1-乙基-3-甲基咪唑硫酸乙酯盐离子液体中采用电化学法合成聚苯胺薄膜及其耐蚀性

为了进一步扩大质子交换膜燃料电池(PEMFC)的实际应用,提高其双极板的耐腐蚀性能至关重要。在不锈钢基体上电化学沉积导电聚苯胺(PANI)薄膜,有可能满足PEMFC对导电性和耐蚀性的要求。前人关于电化学合成PANI主要集中在硫酸、高氯酸等水溶液体系,鲜见离子液体中采用电化学法合成聚苯胺薄膜及其耐蚀性的研究。本工作以1-乙基-3-甲基咪唑硫酸乙酯盐(EMIES)离子液体作为聚合反应电解质,采用循环伏安法在316L不锈钢(SS)表面电化学合成PANI薄膜,制备了PANI/316L SS复合材料双极板。用红外光谱、拉曼光谱、紫外可见光谱、X射线光电子能谱和扫描电子显微镜对PANI膜进行结构表征,用开路电位、极化曲线和电化学阻抗谱研究PANI/316L SS腐蚀性能。结果表明:PANI具有中间氧化态结构,EMIES离子液体的阴离子(CH3CH2SO4-)和乙二酸的阴离子(HOOC-COO-)作为"对阴离子"在PANI共轭分子链中发生了共掺杂。本工作在316L SS表面获得了平整致密的PANI薄膜。与316L SS裸金属相比,PANI/316L SS的腐蚀电位E0提高0.2～0.4 V,腐蚀电流密度I0降低一个数量级,PANI薄膜使316L SS耐腐蚀性能显著增强。     

直流金属真空弧源沉积Ti-O薄膜在模拟人体液中的耐腐蚀性能研究

采用直流金属真空弧源沉积(DC-MVAD)在316L不锈钢基体上沉积合成了Ti-O系薄膜.在Hank's模拟人体液中,对DC-MVAD合成钛氧薄膜进行了开路电位、电化学极化以及电化学阻抗图谱分析,显示合成薄膜可明显改善在人体环境中的耐腐蚀性能.随着合成氧分压的增加,薄膜的耐蚀能力增强.这主要是由于高O/Ti比的钛氧薄膜具有更为稳定的能量状态、低的孔隙率所致.     

类金刚石薄膜在不锈钢表面结合强度及耐腐蚀性研究

类金刚石(DLC)薄膜与不锈钢的结合强度是DLC薄膜应用于血管支架表面改性的关键技术问题.利用磁过滤阴极真空弧源沉积方法在316L不锈钢表面沉积DLC薄膜,研究沉积时基体偏压、薄膜厚度以及钛过渡层对DLC薄膜与基体结合强度的影响.研究结果表明,316L表面制备相同厚度的DLC薄膜,采用-1000V脉冲偏压制备的薄膜结合强度明显优于-80V直流偏压下制备的DLC薄膜;随着DLC薄膜厚度的增大,DLC薄膜与316L基体的结合力下降;316L不锈钢表面制备一层100nm的钛过渡层之后可以改善DLC薄膜的结合状况,并且经过20%的拉伸变形后,DLC薄膜完整,耐蚀性优于未表面处理的316L不锈钢.以上研究结果表明,磁过滤阴极真空弧源方法制备DLC薄膜与316L结合强度高,可以有效的提高316L的耐腐蚀性,是一种具有应用前景的血管支架表面改性方法.     

类金刚石薄膜的摩擦学特性及磨损机制研究进展

类金刚石薄膜已显示了重要的摩擦学应用价值,其中化学气相沉积的类金刚石薄膜(DLC)具有膜层致密、厚度均匀、摩擦学性能优良等特点成为广泛采用的一种沉积方法.本文介绍了气源成分、基体材料、摩擦环境、摩擦对偶、载荷及速度对化学气相沉积制备类金刚石薄膜的摩擦学特性的影响,概述了其摩擦磨损机理,同时探讨了进一步研究工作的方向.     

调制结构对Ti/TiB_2多层膜在模拟体液中摩擦学行为影响

采用磁控溅射法在316L不锈钢表面制备了具有不同调制结构的Ti/TiB_2多层膜,研究了调制结构对Ti/TiB_2多层膜在Hank’s模拟体液中与超高分子聚乙烯配副的摩擦学行为的影响。结果表明:多层膜的摩擦学行为与调制层数n间存在着一定的依赖关系。n=4的多层膜平均摩擦因数约为0.126,与316L不锈钢相比降低了34.3%;对磨副UHMWPE的磨损量明显降低,呈现出良好的减摩和耐磨效应。与316L不锈钢相比,多层膜在摩擦前后的自腐蚀电位提高,自腐蚀电流密度降低了2-3个数量级。n=4的多层膜开路电位为-0.237 V,也明显高于316L不锈钢。316L不锈钢磨损机理为磨粒磨损合并粘着磨损,多层膜的引入有效降低了316L不锈钢的磨粒磨损和粘着磨损程度。Ti/TiB_2多层膜在人工关节、人工椎间盘等医疗器械的表面改性有着广阔的应用前景。     

Si3N4和52100钢对磨副材料对CrN薄膜干摩擦学行为的影响

利用阴极电弧离子镀技术在316L不锈钢基体上制备了CrN薄膜。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、纳米压痕仪对CrN薄膜的形貌、成分和力学性能进行了表征。为了研究Si_3N_4和52100钢对磨副材料对CrN薄膜和316L不锈钢干摩擦行为的影响,在2N、5N、8N三种载荷下,将CrN薄膜和316L不锈钢基体与Si_3N_4陶瓷球和52100钢球分别进行了往复式滑动干摩擦实验。采用扫描电子显微镜观察了磨痕的微观形貌,并对CrN薄膜和316L不锈钢基体的磨损机制进行了分析。结果表明:CrN薄膜表面平整,缺陷较少;CrN薄膜的纳米硬度约为28GPa,弹性模量约为350GPa;与Si_3N_4陶瓷球相比,CrN薄膜与52100钢球摩擦时摩擦因数相对较小(保持在0.7左右)且更加稳定;316L不锈钢的摩擦因数远大于CrN薄膜且波动较大;对磨球为Si_3N_4陶瓷球时,CrN薄膜的主要磨损机制为磨粒磨损,伴有少量的氧化和黏着磨损,316L不锈钢的磨损机制主要为磨粒磨损和塑性变形,伴有少量的氧化和黏着磨损;对磨球为52100钢球时,CrN薄膜的主要磨损机制为黏着磨损,伴有少量的氧化,316L不锈钢的磨损机制主要为黏着磨损,伴有少量的氧化和磨粒磨损。CrN薄膜与两种对磨球的磨损量均小于316L不锈钢基体的磨损量,说明CrN薄膜有效提高了基体的耐磨性。     

高温化学气相沉积TiC/Ti(CxN1-x)/TiN层的组织结构及摩擦磨损性能

Ti(CxN1-x)涂层具有硬度大、强度高、耐磨等性能,而目前采用化学气相沉积法在不锈钢表面制备Ti(CxN1-x)多层涂层的报道较少。用高温化学气相沉积法在316L不锈钢表面分别制备了TiN单层涂层和TiC/Ti(CxN1-x)/TiN多层涂层,比较分析了2种涂层的显微形貌、相结构、硬度、界面结合力及耐磨性能。结果表明:TiC/Ti(CxN1-x)/TiN多层涂层结构致密,厚约10μm;TiN单层及TiC/Ti(CxN1-x)/TiN多层涂层均提高了316L不锈钢的硬度、耐磨性;与TiN单层涂层相比,TiC/Ti(CxN1-x)/TiN多层涂层的显微硬度和界面结合力更好,摩擦系数更低,磨损量更小,耐磨减摩性能更好;2种涂层的磨损破坏机制较一致,主要为磨粒磨损和摩擦氧化。     

Fe-0.03Te-0.3Pb-0.9Mn易切削不锈钢润滑滚动磨损机理研究

采用润滑滚动磨损实验测试Fe-0.03Te-0.3Pb-0.9Mn易切削不锈钢的表面摩擦磨损特性。比较不同磨损时间球珠作用下合金表面磨损形貌、体系硬度、摩擦因数和磨损体积的差异,并对其润滑滚动磨损机理进行深入研究。结果表明:磨损启动期,合金表面磨损性能相对稳定,在MnS和Pb等易切削相交互作用下,合金表面犁削底部开始产生裂纹;磨损稳定期,合金表面性能逐渐变化,犁削底部裂纹持续生长,交织的裂纹开始产生片状或块状凸起物;磨损失效期,合金表面润滑膜和剥落物大量脱落,剥落物形成磨料磨损,犁削逐渐贯通消失,合金表面体系相结构快速瓦解。     

Tribological property and drilling application of Ti-C:H and Cr-C:H coatings on high-speed steel substrates

This study investigates the tribological properties and cutting performance of Ti-DLC and Cr-DLC doped metal coatings. The tribological properties of the coatings are evaluated by testing coated disks against an AISI 1045 steel counterbody under dry conditions using an oscillating friction wear tester, and then measuring the subsequent wear depth on the coated disk, the wear width on the steel counterbody, and the friction coefficient. The cutting performance of the coatings is evaluated by using coated high-speed drills to machine stainless steel workpieces, and then measuring the resulting flank wear and hole surface roughness. The results of the wear tests show that the Ti-C:H and Ti-C:H/TiC/TiCN/TiN coatings possess excellent tribological properties, including low coefficients of friction, low wear depths, and low wear widths. Regarding the machining tests, the Ti-C:H/TiC/TiCN/TiN coating has the lowest flank wear and yields the highest hole surface quality under both dry and cutting fluid drilling conditions. The single Ti-C:H coating has excellent tribological properties, but demonstrates a relatively poorer performance in the drilling of stainless steel. Finally, the Cr-DLC coatings all exhibit a poor cutting performance under dry cutting conditions.     

Ni-金刚石复合涂层的结构优化及基础磨削性能

采用电沉积技术在304不锈钢基体上制备了Ni-金刚石复合涂层。通过金刚石掺入量、加厚镀时间优化了金刚石复合涂层结构,利用球-盘式摩擦磨损试验仪研究了优化后的金刚石复合涂层对不同材料偶件(GCr15、SiC、304不锈钢)的磨削性能。结果表明:金刚石掺入量为1.5g/L时,金刚石上砂均匀且密集;加厚镀15min时,金刚石埋入率约为2/3,附着强度较好,适合磨削加工;GCr15、SiC、304不锈钢3种材料偶件的磨损体积依次减小,分别为:0.353 76mm~3、0.315 90 mm~3、0.194 01 mm~3,金刚石复合涂层对GCr15有较好的磨削性能;金刚石复合涂层磨削GCr15、SiC、304不锈钢均发生了磨粒磨损,此外,GCr15还发生了微弱的化学磨损,不锈钢发生了较明显的化学磨损和粘着磨损。     

Effects of Mixing the Steel and Carbon Fibers on the Friction and Wear Properties of a PMC Friction Material

Friction, fade and wear characteristics of a PMC friction material containing phenolic resin, short carbon fiber, graphite, quartz, barite and steel fiber were investigated through using a small-scale friction testing machine. Four different friction materials with different relative amounts of the carbon fiber and steel fiber were manufactured and tested. Comparing with our previous work which contained only steel fiber as reinforcement, friction characteristics such as fade and recovery and wear resistance were improved significantly by adding a small amount of carbon fiber. For the mixing of carbon and steel fiber, the best frictional and wear behavior was observed with sample containing 4 weight percentage carbon fiber. Worn surface of this specimen was observed by optical microscopy. Results showed that carbon fibers played a significant role in the formation of friction film, which was closely related to the friction performance. The brake pad with Steel fibers in our previous work, showed low friction coefficient and high wear rate. In addition, a friction film was formed on the surface with a relatively poor quality. In contrast, the samples with mixing the steel and carbon fiber generated a stable friction film on the pad surface, which provided excellent friction stability with less wear.     

Wear characteristics of a new type austenitic stainless steel

In order to solve the problem of the poor wear resistance in conventional austenitic stainless steels, a new type austenitic stainless steel was designed based on Fe–Mn–Si–Cr–Ni shape memory alloys in this article. Studies on its wear resistance and wear mechanism have been carried out by comparison with that of AISI 321 stainless steel using friction wear tests, X-ray diffraction, scanning electron microscope. Results showed that the wear resistance of Fe–14Mn–5.5Si–12Cr–5Ni–0.10C alloy was better than that of AISI 321 stainless steel both in dry and oily friction conditions owing to the occurrence of the stress-induced γ → ε martensitic phase transformation during friction process. This article also compared the corrosion performance of the two stainless steels by testing the corrosion rate. Results showed that the corrosion rate of Fe–14Mn–5.5Si–12Cr–5Ni–0.10C alloy was notably lower in NaOH solution and higher in NaCl solution than that of AISI 321 stainless steel.     

Surface damage of unidirectional carbon fiber reinforced epoxy composites under reciprocating sliding in ambient air

For many technical applications friction and wear are critical issues. Reinforced polymer-matrix composites are widely used under vibrating contact condition in various automotive and aerospace applications as well as in structural engineering. In this paper, the friction and wear of bulk epoxy and unidirectional carbon fiber reinforced epoxy composite have been investigated under reciprocating sliding against either alumina or stainless steel balls in ambient air. The effect of sliding direction with respect to the long and unidirectional carbon fibers has been studied. We demonstrate that the carbon fiber reinforcement greatly improves the tribological properties of the thermoset epoxy: it reduces the coefficient of friction and the debris formation. It was found that on sliding in the anti-parallel direction a more significant degradation takes place than in the parallel direction. The coefficient of friction measured on bulk epoxy sliding against either stainless steel or alumina is around 0.65, whereas the coefficient of friction measured on epoxy reinforced with carbon fibers is significantly lower, namely down to 0.11. It was found that sliding with a stainless steel ball in a direction parallel to the fiber orientation results in a lower coefficient of friction than sliding in anti-parallel direction. The reduced coefficient of friction is largely influenced by the carbon fiber reinforcement due to the auto-protecting film formed as a paste in the contact area and along the wear track edges. The relationship between friction and degradation of the composite material including surface wear and debris formation are discussed based on an in-depth analysis of the worn surfaces by optical and scanning electron microscopy, micro-Raman spectroscopy, and white light interferometry.     

A tribological study of tetrahedral amorphous carbon films prepared by filtered cathodic vacuum arc technique

In this study, a series of tetrahedral amorphous carbon films (ta-C) were deposited on silicon, W18Cr4 V high-speed and Cr18Ni9 stainless steel substrates respectively by using pulsed filtered cathodic vacuum arc system with a MEVVA source, and ta-C film’s tribological properties, including the structure, mechanical performance, adhesion, friction and wear character, were investigated. The results show: the hardness and elastic modulus of ta-C film on a high-speed substrate were reached to 76 and 453 Gpa, respectively; and the effects of substrate and film thickness on ta-C film’s friction coefficients have been studied as well; moreover, the corresponding adhesion damage mechanism and wear damage mechanism have been investigated, respectively.     

基于RFPECVD方法不锈钢上沉积类金刚石薄膜的机械与摩擦特性

讨论用射频等离子体增强化学气相沉积(RFPECVD)工艺,在室温下实现在1Cr18Ni9Ti不锈钢基底上镀类金刚石(DLC)膜.为提高DLC膜的结合力,首先在不锈钢基底上沉积Ti/TiN/TiC功能梯度膜.借助所设计的界面过渡层,成功地在不锈钢基底上沉积了一定厚度的DLC膜.通过优化沉积参数,所沉积的DLC膜在与100Cr6钢球对磨时摩擦系数低于0.020.在摩擦过程中DLC膜的磨损机制借助SEM、Raman分析进行了研究.     

AISI 316奥氏体不锈钢等离子体源渗氮及其耐磨抗蚀性能

目前,对AISI 316奥氏体不锈钢单一面心结构γΝ相改性层耐磨抗蚀性能的报道差异较大,有些甚至相互矛盾。采用等离子体源渗氮技术,于450℃,6 h改性AISI 316奥氏体不锈钢,获得了厚度约为17μm、峰值氮浓度20%(原子分数)、最大显微硬度1 510 HV0.1 N、单一面心结构的γΝ相改性层。分别采用WTM-2E球盘式磨损仪和PARSTAT2273电化学工作站,研究了干摩擦条件下γN相/Si_3N_4陶瓷球的摩擦磨损行为和在3.5%NaCl溶液中的电化学腐蚀行为,揭示了γN相改性层的耐磨抗蚀机理。结果表明:γΝ相改性层的磨损机制由原不锈钢的黏着磨损转变为氧化磨损,摩擦系数由0.88降低至0.65,磨损体积由0.13 mm~3降低到9.50×10-3mm~3,耐磨性能显著提高;γΝ相改性层阳极极化曲线未发生点蚀击穿过程,容抗弧直径增大,相位角平台变宽;采用等效电路Rs-(Rct//CPE)拟合的电荷转移电阻Rct由原不锈钢的1.006×105Ω·cm~2增至1.377×106Ω·cm~2,计算的双电层电容Cdl由88.4m F/cm~2降低至77.8 m F/cm~2,抗蚀性能明显得到了改善。