电泳-电镀沉积制备纳米Al_2O_3颗粒增强镍基复合镀层的耐磨性能

先采用电泳沉积工艺在铜基体上均匀沉积了粒径为20 nm的Al2O3涂层,然后采用电镀技术在Al2O3涂层中沉积金属镍,得到具有较高含量的纳米Al2O3增强镍基复合镀层;用扫描电镜及附带的能谱仪分析了镀层的表面形貌及成分,研究了镀层在干摩擦条件下的摩擦磨损性能,并对其磨损机理进行了探讨.结果表明:相比于纯镍镀层,纳米Al2O3颗粒增强镍基复合镀层的表面更加平整光滑,组织更加致密均匀;镀层中纳米Al2O3颗粒含量对镀层耐磨性能具有显著影响,当其体积分数约为30%时,镀层的耐磨性能最好.     

喷射纳米Al2O3增强镍基复合镀层的摩擦行为研究

采用摩擦喷射电沉积工艺制备了纳米Al2O3镍基复合镀层，观察了镀层的表面形貌，测试了镀层的显微硬度，并考察了镀层在不同载荷下的摩擦行为，并初步探讨了其磨损机制。结果表明：当纳米Al2O3质量浓度为50g/L时，获得的复合镀层表面平整、晶粒细小、组织致密；显微硬度达到最高，较纯镍镀层提高了39％；在500N、油润滑条件下复合镀层耐磨性提高了30．4％。复合镀层的磨损机制主要是磨粒磨损，而纯镍镀层主要是粘着磨损和磨粒磨损。     

镍基纳米Al2O3复合电刷镀层含磨粒油润滑条件下的磨损性能

对比研究了润滑油中磨粒尺寸和含量对镍基纳米Al2O3复合电刷镀层和快速镍刷镀层磨损性能的影响。结果发现，由于纳米颗粒的作用，存相同条件下纳米复合镀层的耐磨性比快速镍镀层提高了30％～50％，而且复合镀层的磨损体积随磨粒尺寸和含量的影响不如快速镍镀层显著。     

油润滑条件下镍基纳米Al2O3复合刷镀层磨粒的铁谱分析及其磨损机制研究

为研究纳米颗粒复合电刷镀层在含沙粒油润滑条件下的磨损机制，首先制备了镍基纳米Al2O3复合电刷镀层，采用T-11球盘式磨损试验机进行复合刷镀层在含沙粒油润滑条件下的磨损试验，采用FTP-X2型分析式铁谱仪对复合镀层磨损试验后的润滑油中的磨粒形貌进行了研究。结果表明，含磨粒油润滑条件下，复合镀层的磨屑表现出以下3种形貌特征：切削状磨粒、蠕虫状磨粒和岩石状磨粒。这说明，在本实验条件下，复合刷镀层的磨损失效机制主要有磨粒磨损、粘着磨损和疲劳剥层。     

纳米复合镍电镀层的摩擦学性能

采用纳米复合电沉积方法制备了纯镍、Ni-纳米CeO_2、Ni-纳米ZrO_2和Ni-纳米(CeO_2-ZrO_2)四种镍电镀层,研究了不同镀层的显微硬度及摩擦磨损性能,并用扫描电子显微镜分析了其磨损机理。结果表明:在干摩擦条件下,镀层中纳米颗粒含量相同时,上述四种镀层的显微硬度依次升高,摩擦因数依次降低,并且波动范围变小;磨损率也是依次降低;纯镍镀层呈现严重的粘着磨损特征,Ni-纳米CeO_2镀层表现为严重的磨粒磨损和粘着磨损,Ni-纳米ZrO_2镀层的磨损特征为粘着磨损;而Ni-纳米(CeO_2-ZrO_2)镀层的磨损形式以轻微磨粒磨损和粘着磨损为主。     

纳米和微米SiO2颗粒对PPESK复合材料摩擦学性能的影响

用热压成型法制备了纳米、微米SiO2填充聚醚砜酮(PPESK)复合材料，考察了复合材料的硬度和抗弯强度，并研究了干摩擦条件下纳米、微米SiO2颗粒对复合材料摩擦磨损性能的影响，用扫描电镜观察分析了复合材料磨损表面形貌及磨损机理。结果表明：干摩擦条件下，纳米SiO2填充PPESK主要是轻微的磨粒磨损；而微米SiO2填充PPESK主要是严重的磨粒磨损。     

Ni-La2O3纳米复合镀层制备工艺研究

将La2O3纳米颗粒添加到氨基磺酸镍镀液中采用电沉积方法制备Ni-La2O3纳米复合镀层，研究了多种因素对复合镀层中La2O3含量的影响，分析了复合镀层的表面形貌和显微硬度。结果表明：试验条件下最佳工艺为电流密度2A／dm^2、镀液温度50℃、搅拌速度800r／min、镀液中La2O3含量30g／L；与纯镍镀层相比，复合镀层表面平整光滑、组织致密均匀；其显微硬度也高于纯镍镀层，并随着复合镀层中La2O3含量的增加而升高。     

纳米α-Al2O3颗粒弥散强化镍基复合涂层的耐磨性能研究

将纳米α-Al2O3颗粒或Ni包裹的纳米α-Al2O3复合粉和镍基粉用湿法混合，采用火焰热喷涂工艺制备了复合涂层，用磨粒磨损试验机进行磨损试验，研究了纳米α-Al2O3的体积分数、粒径和是否预先进行包裹处理对涂层喷焊性和耐磨粒磨损性能的影响。结果表明，纳米α-Al2O3以包裹形式加入能有效改善弥散相与Ni基涂层的相容性，相应涂层的耐磨性优于未包裹处理；当纳米Al2O3的体积分数为2％时，涂层的耐磨性能最好，为Ni基涂层的2倍多；在相同的体积分数下，随着涂层中弥散强化相尺寸的减小，涂层的耐磨性提高。     

Ni-P-纳米Al_2O_3复合镀层的抗微动磨损性能

以纳米Al2O3为增强相,利用化学镀技术,制备了Ni-P-nanoAl2O3复合镀层,以球-面接触方式评价了复合镀层在300 μm振幅下的微动摩擦学行为,并与Ni-P二元镀层进行了性能对比.研究了不同载荷、频率下复合镀层的摩擦因数和磨损量.结果表明,Ni-P-nanoAl2O3复合镀层的摩擦因数比Ni-P二元镀层的高,相对Ni-P二元镀层而言,复合镀层的抗微动磨损能力得到了有效地提高,相对耐磨性最大达到2.24,其磨痕呈浅而窄的"W"型,在低载下的微动属于轻微的擦伤式磨损,高载下则转变为明显的磨粒磨损机制.     

铬颗粒尺寸对镍-铬复合镀层900℃抗空气氧化和耐Na_2SO_4熔盐腐蚀性能的影响

采用复合电镀技术,在镍基体上分别制备了纳米铬-镍复合镀层和微米铬-镍复合镀层,用XRD、SEM/EDS等仪器分别对两种复合镀层在900℃空气中的氧化行为和在900℃Na2SO4熔盐中的热腐蚀行为进行了研究.结果表明:与微米铬粒子增强的Ni-30%Cr复合镀层相比,纳米铬粒子增强的Ni-11%Cr复合镀层表现出更好的抗高温氧化和耐腐蚀性能;铬颗粒尺寸的减小增加了单位面积内Cr2O3的形核量,缩短了不同Cr2O3核间的距离,从而加速了保护性Cr2O3氧化膜的快速形成,这是Ni-11%Cr复合镀层抗氧化和耐腐蚀性能更好的主要原因.     

La2O3对ZL108镍基激光熔覆层摩擦学性能的影响

利用激光在ZL108的表面上熔覆镍基自熔合金粉末,并对添加和不添加La2O3的熔覆层进行检测和比较。结果表明,添加La2O3可以提高熔覆层的硬度、耐磨性,降低摩擦因数。La2O3对改善熔覆层的摩擦学性能起到了较大的帮助。     

Wear Behavior of Ceramic Powder and Solid Lubricant Cladding on Carbon Steel Surface

Thick composite coatings of carbides on a metal matrix are ideal for use in components that are subjected to severe abrasive wear. It is a metal matrix composite (MMC) that is reinforced by an appropriate ceramic phase, a solid lubricant coating to reduce friction and to protect the opposing surface. This study tested the wear behavior of a carbon steel surface after cladding by a gas tungsten arc welding (GTAW) method to enhance wear resistance. The microstructures, chemical compositions, and wear characteristics of the cladded surfaces were analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The coating was uniform, continuous, and almost defect-free, and particles were evenly distributed throughout the cladding layer. The results of wear tests indicate that the friction coefficient of the TiC coating is lower than that of AISI 1020 carbon steel. Thus, the wear depth of the TiC coating is only one tenth of that exhibited by the AISI 1020 carbon steel. The experiments confirm that the cladding surfaces of TiC particles reduce the wear rate and friction.     

纳米SiO2对火焰喷涂尼龙1010涂层干摩擦磨损性能的影响

为了探讨纳米SiO2(n-SiO2)对火焰喷涂尼龙(PA)1010涂层干摩擦磨损性能的影响,采用MRH-3型环-块摩擦磨损试验机对不同n-SiO2含量的尼龙1010涂层的干摩擦磨损性能进行了测试;并利用扫描电子显微镜(SEM)对复合涂层的磨损表面进行观察,以探讨n-S iO2对火焰喷涂尼龙1010涂层摩擦磨损性能的影响机制。结果表明:n-SiO2的加入能明显提高尼龙涂层的耐磨性,降低摩擦因数,疲劳磨损、粘附磨损及犁切现象明显减轻;当n-SiO2含量为1.5%(质量分数)时,复合涂层摩擦磨损性能最佳,试验条件下磨损量降低近4倍,摩擦因数降低23%,跑合期降低44%,复合涂层与GCr15钢环对磨时的磨损机制主要为疲劳磨损和轻微的粘附磨损。     

镍基Si3N4复合镀层的摩擦磨损特性

通过复合电镀法制备了N i-Si3N4和N i-P-Si3N4两种复合镀层,分别与热处理45#钢组成摩擦副,进行环-环摩擦磨损试验,测试了摩擦因数和磨损量,并观察了磨损表面形貌,探讨了摩擦副的摩擦磨损机理。结果表明,N i-P-Si3N4/45#钢摩擦副的摩擦因数较小,磨损量低,具有良好的减摩耐磨性能。镀层基体的性能明显影响复合镀层的摩擦磨损性能。磨料磨损是N i-Si3N4/45#钢摩擦副的主要磨损形式,导致45#钢的磨损量增大;N i-P-Si3N4镀层对Si3N4颗粒具有良好的把持力,避免了磨料磨损的产生,摩擦副处于稳定的边界润滑摩擦状态。     

La2O3对铜基自润滑复合材料高温摩擦磨损性能的影响

为进一步提高铜基自润滑复合材料的硬度和高温摩擦磨损性能,采用粉末冶金热压法向铜-石墨烯-WS2复合材料中引入La2O3增强相颗粒,并对铜-石墨烯-WS2复合材料和La2O3增强铜-石墨烯-WS2复合材料在不同温度下的摩擦磨损性能进行对比研究。结果表明:复合材料烧结过程中各组元没有发生分解或互相反应,烧结后材料结构致密并且各组元均匀分布于基体中,La2O3增强相的引入在提高复合材料硬度的同时会降低材料热导率;室温下2种复合材料摩擦因数和磨损率比较相近,而高温下石墨烯和WS2的氧化导致Cu-RGO-WS2复合材料摩擦磨损性能下降,而La2O3则能发挥增强相作用和高温自润滑作用,使Cu-RGO-WS2-La2O3复合材料的高温摩擦磨损性能更优异。室温下铜-石墨烯-WS2复合材料的磨痕处仅发生了轻微的塑性变形,而La2O3增强铜-石墨烯-WS2复合材料的磨损机制主要是磨粒磨损;高温下铜-石墨烯-WS2复合材料的磨损机制为黏着磨损,而La2O3增强铜-石墨烯-WS2复合材料的磨损机制则为磨粒磨损和疲劳磨损。     

石墨烯/MoS2复合涂层多环境下的摩擦学性能

以MoS2作为润滑剂,以石墨烯(GE)作为润滑添加剂,采用喷涂法在GCr15钢样片表面制备不同含量的GE/MoS2复合涂层。利用HSR-2M型高速往复式摩擦磨损试验机测试涂层在干摩擦及海水环境中的摩擦磨损性能,并分析了磨痕形貌及磨损机制。结果表明:添加适量石墨烯可明显改善MoS2涂层的摩擦磨损性能,且海水环境中涂层的摩擦因数、磨损率均低于干摩擦;在干摩擦和海水环境下,随着石墨烯含量的增加,GE/MoS2复合涂层的摩擦因数和磨损量均呈现先下降后上升的趋势,当石墨烯质量分数为0.8%时,摩擦磨损性能最优。干摩擦下MoS2涂层的磨损机制为疲劳磨损、黏着磨损和磨粒磨损,GE/MoS2复合涂层主要为磨粒磨损;而在海水环境下几种涂层均仅出现磨粒磨损。     

Abrasive wear behavior of thermally sprayed diamond reinforced composite coating deposited with both oxy-acetylene and HVOF techniques

Diamond and diamond-based coatings have long been studied for their exceptional properties. Although a great deal of research has been carried out in this field, little is known about their tribological wear behavior. In the present work, diamond reinforced composite (DRC) coatings of varying diamond content was deposited on mild steel substrates using both oxy-acetylene (OA) and high velocity oxy fuel (HVOF) thermal spraying techniques. The high stress abrasive wear behavior of these coatings is studied by performing two body abrasion tests for varying experimental parameters. It is observed that the HVOF-sprayed coatings suffered abrasion at a relatively low wear rate. The reasons for variations observed in the wear rate as a function of displacement during abrasion and grit size could be attributed to the deterioration of abrasive particles and the particle size effect respectively. While the disparity in the wear rates with respect to composition of the coatings was primarily controlled by the diamond content in the coating. The abrasive wear mechanism was found to be the same in both the coatings except that the coating deposited by HVOF spray technique, offered better abrasion resistance and therefore abraded at a slower rate. This is possibly due to lower porosity in the coating and higher bond strength between reinforced diamond particulates and the bronze matrix in HVOF-sprayed specimens.     

火焰喷涂PA1010/n-SiO2复合涂层干摩擦磨损性能

利用火焰喷涂法制备PA1010/n-SiO2复合涂层,并采用均匀试验设计方法研究涂层在干摩擦条件下同GCr15 钢环配副时的摩擦学性能;利用SPSS 12.0统计软件对试验结果进行回归分析, 建立涂层摩擦系数和磨损质量损失同pv值 (摩擦载荷与摩擦速度的乘积)相关性的数学模型;利用示差扫描量热仪(Differential scanning calorimetry, DSC)和扫描电子显微镜(Scanning electron microscope, SEM)对复合涂层的热性能和磨损表面形貌进行分析。结果表明,n-SiO2的加入能明显提高涂层的结晶性能、耐磨性能。当n-SiO2含量为1.5%时,复合涂层摩擦磨损性能最佳,在试验条件下磨损质量损失降低近4倍,摩擦因数降低23％,跑合期缩短44％,复合涂层与GCr15钢环对磨时的磨损机理主要为疲劳磨损和轻微的粘附 磨损。     

Role of Third Bodies in Friction and Wear of Cold-Sprayed Ti and Ti–TiC Composite Coatings

Titanium (Ti) and Ti-based alloy wear performance is often poor unless coating or lubricants are used. An alternative is to use hard phase reinforcement. Cold spray is a relatively new method to deposit composite coatings, where here we report the deposition of a Ti–TiC coating and its sliding wear behavior. Mixtures of mechanically blended Ti–TiC with various TiC content were injected into a de Laval nozzle and sprayed onto substrates. Two composite coatings and a pure Ti coating are reported here, where the as-sprayed compositions of the composites were 13.8 and 33.4 vol% TiC. Reciprocating dry sliding wear was performed using a custom-built in situ tribometer. All tests were conducted with a sliding speed of 3 mm/s and at a normal load of 0.5 N. Using a transparent sapphire hemisphere of 6.25 mm as counterface, dynamic behavior of third bodies was directly observed. It was found that adhesive transfer of Ti was the primary wear mechanism for the Ti coating, with oxidative and abrasive wear also occurring for longer sliding cycles. The superior wear resistance of the composite coatings compared to Ti was related to dual function of TiC particles, where they reinforced the Ti matrix and facilitated the formation of a stable and protective tribofilms. The tribofilms contained carbonaceous material that provided easier shear and lower friction. The formation of these tribofilms was highly dependent on the TiC particles, which contained excess carbon compared to the equilibrium composition. Higher TiC content was more effective in quickly developing and sustaining the tribofilms.