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基于超音速火焰喷涂(High Velocity Oxygen Fuel, HVOF)技术,在7075高强铝合金表面制备出碳化钨(WC)颗粒来增强镍基合金的耐磨层,分别利用光学显微镜、扫描电镜对喷涂层及界面过渡区(Interface Transition Zone, ITZ)微观组织进行表征,技术制造分别使用显微硬度仪和万能试验机对喷涂层的显微硬度和抗剪强度进行测试,探求铝基复合制动盘超音速火焰喷涂工艺。结果表明,超音速火焰喷涂制备铝基复合制动盘的工艺参数为铝基合金表面WC颗粒含量为35%,氧油比约为3∶1,送粉量为80 g/min,喷涂距离为330 mm,入射速度为450 m/s,制动盘转速为7 r/min,氮气流量为10 L/min;铝基复合制动盘喷涂层微观组织为奥氏体基体上弥散分布着大量WC颗粒,致密度高达94%;喷涂层显微硬度约为1 500HV,剪切强度约为147.3 MPa,满足制动盘力学性能要求。 相似文献
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研究激光强化及超音速火焰喷涂CuNiIn涂层对阻尼器安装螺栓疲劳性能的影响。结果表明,采用激光强化工艺可提升阻尼器安装螺栓的疲劳性能,超音速火焰喷涂制备的CuNiIn涂层致密均匀,与螺栓基体结合良好,且对基体的疲劳极限影响不大;涂层防护后,为粘着磨损和磨粒磨损,CuNiIn涂层可以有效改善抗微动磨损性能。在试验条件下,涂层使用后磨损体积减少了41%~55%,采用激光强化及超音速火焰喷涂CuNiIn涂层在设计给出的五级疲劳载荷的试验条件下没有发生断裂。 相似文献
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超音速火焰喷涂技术可制备性能优异的耐腐蚀、耐磨、导电等涂层。超音速喷涂技术应用于机械零部件的再制造,可显著提高其性能和使用寿命,符合优质、高效、节能、节材、环保的要求。可达到修旧利废的目的,产生良好的经济效益。超音速火焰喷涂技术制备的涂层均匀致密,孔隙率低,结合强度高,在长效防腐、耐磨强化方面有广泛的应用。能满足多种材料的喷涂要求,特别是其制备的碳化物陶瓷涂层,综合机械力学性能和耐磨耐蚀性能好,在机械零部件表面强化领域应用广泛。本文针对严重磨蚀的石油化工流程泵中的叶轮的修复,采用激光熔覆工艺将受损叶轮整形后,再用超音速火焰喷涂工艺在叶轮表面制备耐腐蚀及耐磨层,使叶轮的使用寿命比原装新叶轮提高了4.5倍。 相似文献
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针对煤化工用调节阀的特殊工况,为了提高阀内件表面的耐磨性,采用超音速火焰喷涂(high velocity oxy-fuel,HVOF)、等离子喷涂(atmospheric plasma spray,APS)及熔敷、等离子堆焊(plasma transferred arc,PTA)3种典型的处理工艺,并结合上述工艺选取与之相匹配典型的喷涂材料.通过磨损试验、硬度测试和显微组织结构的研究发现:APS喷涂的温度较高,引起碳化物分解并溶解于基体内,经过熔敷,涂层韧性增加,磨损表面不易产生裂纹和剥落;HVOF喷涂过程中,粒子的撞击速度高,不会产生过热现象,涂层受压应力、密度高,耐磨性好;PTA堆焊的涂层和基体的结合力较强,硬度高,涂层厚度大,耐磨性介于APS和HVOF之间. 相似文献
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介绍超音速火焰、等离子,氧乙炔火焰三种喷涂方法,在钢基体上喷涂钴包碳化钨粉末所制备涂层的工艺性能,结合强度,耐磨性能和机理。结果表明,三种喷涂方法都可制备WC-Co金属陶瓷涂层;超音速火焰喷涂涂层的性能最好,其耐磨性能与硬质合金YT5相当;氧乙炔火焰喷涂层具有一定的耐磨性能。 相似文献
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冷喷涂Cu-Zn-Al_2O_3修复斯太尔发动机水道腐蚀区域的涂层性能分析 总被引:2,自引:0,他引:2
采用冷气体动力喷涂技术,喷涂超细Cu-Zn-Al2O3复合粉来修复斯太尔发动机水道腐蚀区域,并对冷喷涂层的显微结构、物相组成和力学性能进行了表征。实验表明,超细Cu-Zn-Al2O3复合粉经超音速冷喷涂制备的涂层可与发动机缸体基体结合牢固,显微组织致密,测得的涂层抗拉强度值达到28.87 MPa,涂层表面硬度均值143.6HV0.05,耐磨性是斯太尔发动机基体的5.035 5倍,延长了设备服役期。 相似文献
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空气助燃超音速火焰喷涂WC涂层的性能及应用 总被引:1,自引:0,他引:1
采用空气助燃超音速火焰喷涂(HVAF)技术制备了WC涂层,对该涂层的耐磨性、耐腐蚀性、韧性、涂层结合强度等性能进行了研究,并与电镀硬铬层进行了性能与实际使用寿命对比。结果表明:采用HVAF制备的WC涂层的耐磨性是电镀硬铬层的10倍,涂层的耐腐蚀性和韧性明显优于电镀硬铬层的;以WC涂层在瓦楞辊中的应用为例,采用上中下位置喷涂方法制备的WC涂层厚度均匀,控制喷涂角度大于60°和基体硬度小于60 HRC对WC涂层的结合强度有利,WC涂层瓦楞辊的使用寿命是电镀硬铬瓦楞辊的4~6倍。 相似文献
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本文研究了铸铁及电镀铬层复合表面的电刷镀修复工艺,并比较了几种工艺路线,选择其中最佳工艺,成功地修复了大进口液压系统。 相似文献
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用氧乙炔焰加熔剂助熔一步法在12CrlMoV珠光体耐热钢和25号钢高温高压阀门密封面基体.上喷熔铁547B合金粉末.对喷熔工艺及喷熔层的硬度、时效硬化特性、热耐久性能、抗擦伤性能等使用性能进行较系统的试验研究。证明用喷熔铁547B合金粉末工艺修复电站高温高压阀门密封面裂纹是可行的。 相似文献
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A ferrous-based coating with significant chromium was fabricated on aluminum alloy substrate using a plasma spray technique. The tribological performance of the as-fabricated ferrous-based coating sliding against different coatings including Cr, CrN, TiN, and diamond-like carbon (DLC) in an engine oil environment were comparatively studied. Results showed that the high hardness of the sprayed ferrous-based coating was achieved due to the dispersion strengthening effect of Cr7C3 phase embedded in the austenite matrix. The ferrous-based coating exhibited low friction coefficients when coupled with these four coating counterparts, which could be attributed to the boundary lubricating effect of engine oil. However, both friction and wear of the ferrous-based coating were different when sliding against these different coating counterparts, which might be closely related to the surface roughness, self-lubricating effect, and mechanical properties of the coupled coatings. Ferrous-based coating sliding against CrN and DLC coatings exhibited good tribological performance in engine oil. The best coating counterpart for the ferrous-based coating in an engine was DLC coating. 相似文献
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Experimental data are presented to show that engineering chromium plating on cast iron fails catastrophically after a given number of sliding cycles depending upon the applied load and the coating thickness. The failure mechanism involves the initiation of cracks in the chromium both at its sliding surface and at the coating-substrate interface adjacent to graphite flakes. The cracks propagate through the coating to give fracture and mechanical breakdown of the coating. The use of durability limit curves to identify ‘fail-safe’ conditions is discussed. 相似文献
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Nicholaos G. Demas Robert A. Erck Oyelayo O. Ajayi George R. Fenske 《Lubrication Science》2012,24(5):216-227
The presence of coatings and surface topography play an important role in the tribological performance of sliding components. Depending on the coating used, it is possible to reduce friction and/or reduce wear. However, although there may be low friction and wear‐resistant coatings suitable for use in pistons, some coatings may hinder the tribological performance by changing the lubrication regime or by preventing additives from their intended function through chemical mechanisms. In this work, piston skirt segments extracted from a commercial aluminium alloy piston were coated with a diamond‐like carbon (DLC) coating, a graphite–resin coating or a nickel–polytetrafluoroethylene (Ni–PTFE) coating and were tribologically tested using a reciprocating laboratory test rig against commercial grey cast iron liner segments. The tribological tests used commercial synthetic motor oil at a temperature of 120 °C with a 20 mm stroke length at a reciprocating frequency of 2 Hz. Results showed that the graphite–resin coating, although it may serve as a good break‐in coating, wears rapidly. The Ni–PTFE coating showed friction reduction, whereas the DLC coating wore off quickly due to its small thickness. Furthermore, the higher hardness of the DLC coating relative to the cast iron liner surface led to pronounced changes on the liner counterface by polishing. In contrast with the uncoated piston skirt segments, all of the coatings prevented the formation of a visible tribochemical film on the cast iron surface. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Sliding-Wear Behavior of TiN- and CrN-Coated 2024 Aluminum Alloy Against an Al2O3 Ball 总被引:1,自引:0,他引:1
Dry sliding friction and wear behavior of TiN and CrN deposited on 2024 aluminum alloy by arc ion plating was investigated using the ball-on-disk wear test. The effects of normal load and ceramic coating on the friction coefficient and wear-resistance of 2024 aluminum alloy were studied. The worn surfaces were observed by scanning electron microscopy (SEM). The results show that wear volume increases while the friction coefficient decreases with an increase in normal load. The wear resistance of CrN is higher than that of TiN. The wear mechanism of TiN-coated 2024 Al is related to the oxidation of TiN coating and plastic deformation of 2024 Al. Conversely, the wear mechanism of CrN-coated 2024 Al is related to the fatigue fracture of the coating, which was affected by residual stress and plastic deformation of 2024 Al. 相似文献
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Friction and wear experiments on steel–chromium plating pairs were carried out with nanoscale serpentine (a magnesium silicate mineral) as a lubricating oil additive at 400°C. The tribological test results showed that self-repairing protective layers formed on the contact surfaces of both the steel matrix and hard chromium coating. Field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the morphology and elements of self-repairing layers were in accordance with that of serpentine. A generation mechanism of the layer was proposed that suggests that isomorphic replacement between Fe/Cr and serpentine mineral silicate occurs, which is the wear mechanism of the tribochemical reaction. 相似文献