镁合金微弧氧化涂层高温磨擦磨损性能（英文）

在硅酸盐和磷酸盐复合电解液体系下,通过微弧氧化技术在AZ91D镁合金表面制备一层陶瓷涂层。利用XRD、SEM、激光共聚焦显微镜(LSCM)分别对涂层物相、涂层表面、截面和磨痕形貌进行观察分析。采用UMT-3高温摩擦磨损试验机研究涂层在150℃范围内的摩擦磨损性能。结果表明:涂层的平均摩擦系数随温度的变化先逐渐升高,当环境温度高于100℃时涂层平均摩擦系数开始降低。涂层磨损率远远低于镁合金基体磨损率并且涂层磨损率随温度的升高而降低,这说明微弧氧化涂层具有良好的耐磨损性能,尤其在高温条件下耐磨损性能更好。通过分析载荷为2 N作用时的磨痕微观形貌可知不同温度条件下涂层的磨损机理都主要为磨粒磨损。     

镁合金微弧氧化涂层高温磨擦磨损性能

在硅酸盐和磷酸盐复合电解液体系下,通过微弧氧化技术在AZ91D镁合金表面制备一层陶瓷涂层。运用XRD、SEM、激光共聚焦显微镜(LSCM)分别对涂层物相、涂层表面、截面和磨痕形貌进行观察分析。采用UMT-3高温摩擦磨损试验机研究涂层在150℃范围内的摩擦磨损性能。结果表明：涂层的平均摩擦系数随温度的变化先逐渐升高,当环境温度高于100℃时涂层平均摩擦系数开始降低。涂层磨损率远远低于镁合金基体磨损率并且涂层磨损率随温度的升高而降低,这可以说明微弧氧化涂层具有良好的耐磨损性能尤其在高温条件下耐磨损性能更好。通过分析载荷为2N作用时的磨痕微观形貌可知不同温度条件下涂层的磨损机理都主要为磨粒磨损。     

DZ125合金表面Cr-Al-Y涂层抗高温氧化性能及摩擦性能

目的 提高DZ125合金的抗高温氧化性能和耐磨性。方法 采用包埋渗技术在DZ125合金表面制备Cr-Al-Y涂层,分析Cr-Al-Y涂层经高温氧化后的组织结构和相组成,对比研究涂层与基体的摩擦行为。结果Cr-Al-Y涂层具有多层组织结构,经高温氧化100 h后,涂层的平均质量损失量仅为0.85 mg/cm²。由于在高温氧化过程中Cr-Al-Y涂层形成了连续致密的Al₂O₃和Cr₂O₃氧化膜,随着氧化温度的升高,涂层表面的氧化速率增大,导致氧化产物剥落,并出现表面缺陷。Cr-Al-Y涂层的摩擦因数明显低于DZ125基体的摩擦因数,DZ125合金的摩擦因数约为0.45,Cr-Al-Y涂层的摩擦因数约为0.2。在摩擦过程中,DZ125合金发生了犁削磨损和磨粒磨损,涂层表面发生了磨粒磨损。结论 该涂层具有优异的抗高温氧化性能,连续致密的Al₂O₃氧化膜和Cr₂O₃氧化膜能够有效阻挡氧化性气氛与基体直...     

NiCrBSi超音速火焰喷涂层在不同温度下的磨损行为

采用超音速火焰喷涂在铸铁表面制备了NiCrBSi喷涂涂层,以研究其在不同温度下的摩擦磨损行为. 采用pin-on-disc试验设备在室温和300 ℃下对NiCrBSi涂层进行了摩擦磨损试验,分析了温度对NiCrBSi涂层摩擦系数和磨损率的影响规律;采用XRD和SEM对NiCrBSi喷涂态涂层进行了微观组织结构分析;通过SEM对涂层磨损样品的表面和截面进行了微观组织观察,探索涂层在不同温度下的磨损机制. 结果表明,NiCrBSi涂层结构致密,具有典型的喷涂层状结构,主要由γ-Ni相、Cr₇C₃相、Ni₃B相和CrB相组成;孔隙率为1.11%,硬度为742 HV0.1 ± 24 HV0.1. NiCrBSi涂层在室温下发生明显的粘滑现象,随着试验温度的升高,涂层的摩擦系数降低;升高的试验温度导致涂层硬度降低,涂层磨损率升高,耐磨性能下降. 涂层在室温及300 ℃下的磨损机制由磨粒磨损和疲劳磨损组成,随着温度的升高,磨粒磨损越加严重.     

WS2增强CoCrTi复合材料的制备及高温摩擦学性能

采用热压烧结技术制备了CoCrTi-(2.5, 4.0, 6.0)WS₂复合材料,并优化了WS₂的含量。通过球-盘式高温摩擦试验机研究了复合材料在室温至1000 ℃范围内的摩擦学性能。使用X射线衍射仪和扫描电镜等分析了复合材料的显微组织和物相组成。结果表明:适量WS₂的添加显著提高了材料的硬度与摩擦学性能。3种复合材料的摩擦因数和磨损率均表现出大致相同的变化趋势:在室温至400 ℃的试验条件下,摩擦因数随温度的升高而降低,磨损率变化趋势则相反。在400 ℃到1000 ℃,摩擦因数随温度的升高小幅增大;磨损率随温度的升高先减小后增大最后减小,在800 ℃时达到最大值。在给定的试验条件下,WS₂含量为4.0wt%的复合材料具有最佳的高温摩擦学性能。在低温下试样表现出不同程度的磨粒磨损,在高温下的磨损机理为氧化磨损。     

高速高温条件下刷式封严环涂层与刷丝摩擦副磨损行为

目的 研究高速高温刮削条件下Ni Cr-Cr₂C₃涂层和SG37合金刷丝组成的摩擦副的磨损行为。方法 利用自制的高速高温刮擦试验机,在不同进给速度和过盈量条件下进行封严环涂层与刷丝摩擦副的高速高温刮削试验。用轮廓测量仪测量刷式封严环表面涂层的磨痕深度。用超景深显微镜(OM)和扫描电镜(SEM)观察涂层及刷丝样品的原始形貌和磨痕形貌,并利用配备的EDS能谱仪分析磨痕表面元素成分,同时分析了摩擦过程中的磨损机理。结果 NiCr-Cr₂C₃涂层与SG37A合金刷丝在高速高温刮擦过程中发生了磨粒磨损、黏着磨损和刷丝材料向涂层的转移。刷丝之间也存在摩擦变形和磨损,这主要是由于刷丝与刷丝在磨损过程中发生了高温变形和挤压,由于“拖尾”现象的存在,使刷丝尖端的变形和挤压更加明显,高温下金属流动性的增加进一步促进了菱形的形成。通过分析不同过盈量和进给速度对磨痕深度的影响,发现过盈量和进给速度均对涂层磨痕深度存在影响,随过盈量和进给速度的增加,涂层磨痕深度增大。结论 高速高温的苛刻工况下,刷丝在磨损过程中具有显著的变形...     

等离子喷涂NiCrAlY-Cu涂层中Cu在宽温域环境下的扩散及摩擦耗散机制

含软金属自适应涂层在摩擦过程因软金属独特的性能而具备良好的摩擦学性能,然而在不断摩擦过程中软金属会发生一定的耗散导致涂层失效。为了研究软金属润滑剂在宽温域摩擦过程中的耗散机制,利用等离子喷涂技术制备NiCrAlY-Cu涂层;通过分析热处理及宽温域摩擦前后涂层的组分与形貌演变,揭示NiCrAlY-Cu涂层中Cu的高温扩散及宽温域摩擦耗散机制。结果表明：Cu以片层状分布在NiCrAlY基础相中,软金属Cu在温度单因素影响下垂直向涂层表面扩散,随着温度的升高扩散加剧。在1000℃环境下Cu在涂层内部发生平行扩散,并最终呈现弥散态分布。在中低温环境下随着温度的升高Cu的剪切强度降低进而使得涂层摩擦因数逐渐下降,但是由于Cu呈片层状分布,随着温度的升高涂层发生疲劳剥落导致磨损率升高。随着温度的进一步升高,Cu扩散加剧,片层状Cu减少,同时发生氧化,使得摩擦因数升高,磨损率降低。在宽温域摩擦过程中由于温度和载荷的共同影响,Cu在涂层中的摩擦耗散机制为Cu垂直向涂层表面扩散,由磨痕区域内向磨痕外平行扩散。同时,磨痕内聚集的Cu以磨屑形式逐渐损耗。提出在不同温域摩擦过程中受力-热耦合影响的软金属耗散机...     

TA15钛合金高温摩擦磨损性能研究

目的 为探究TA15钛合金高温耐磨性能的潜力,研究了TA15钛合金在室温~800 ℃下的摩擦磨损性能。方法 利用Rtec摩擦磨损试验机(Rtec,San Jose,USA)进行TA15钛合金的摩擦磨损性能测试,通过激光共聚焦显微镜、JSM-7800F扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)等手段,分析了TA15钛合金在不同温度下的磨痕形貌、成分变化以及磨损机理。结果 在不同试验温度下,微观组织没有出现明显变化,主要为等轴α相和β相;不同温度下的摩擦因数波动不大,从室温的0.279下降到600 ℃的0.224,而在800 ℃时,表面严重氧化导致摩擦因数增大到0.309;在室温~400 ℃时,试样表面磨痕不断变窄变浅,犁沟和磨屑不断减少,而到400 ℃以上时磨痕逐渐变宽,比磨损率也大幅增大,且在600 ℃时的磨损量最大;在600 ℃时,以氧化磨损为主,并伴随着磨粒磨损和黏着磨损,且表面磨痕形貌和宽度比较均匀;在800 ℃时磨损表面以黏着磨损和氧化磨损为主,并伴随着高温焊接的发生。结论 TA15合金表面的O元素含量随温度的升高而逐渐升高,并且氧化反应主要发生在β相内。随着试验温度的升高,TA15钛合金磨损表面的氧化磨损现象也更加明显。     

多层梯度结构对TiAlSiN涂层摩擦磨损性能的影响

为提高304不锈钢耐磨损性能,采用磁过滤阴极弧等离子体沉积的方法制备TiAlSiN多层梯度涂层,研究多层梯度结构对涂层摩擦磨损性能的影响。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)、纳米压痕仪和划痕仪等方法对涂层的表面形貌、物相结构以及力学性能进行表征,并通过MST-3001摩擦磨损试验仪测试不同结构涂层的摩擦磨损性能。结果表明:与TiAlSiN单层涂层相比,TiAlSiN多层梯度涂层具有更高的结合力和韧性;两种涂层的摩擦因数和磨损率都远小于304不锈钢,其中TiAlSiN多层梯度涂层具有比单层涂层更低的磨损率,磨损率由2.6×104μm3/(N·m)降至8.5×103μm3/(N·m),降低了67.8%,TiAlSiN多层梯度涂层磨痕表面光滑致密,主要磨损机制为轻微粘着磨损、磨粒磨损和氧化磨损的协同作用。     

大气等离子喷涂FeCoCrNiAl高熵合金涂层的高温摩擦磨损性能

目的 研究环境温度对FeCoCrNiAl高熵合金涂层摩擦磨损性能的影响,探讨将其应用于高温及富氧环境中的可行性。方法 采用大气等离子喷涂制备FeCoCrNiAl高熵合金涂层,考察喷涂功率对涂层微观组织的影响;测试涂层的纳米力学性能,分析其对涂层摩擦磨损性能的影响;基于涂层及对偶磨球磨损表面形貌、元素分布及含量、物相组成,讨论涂层在室温及高温环境中的摩擦磨损特性与机制。结果 涂层中形成了白色、浅灰色、深灰色及黑色4种区域,区域颜色随O元素含量增加而加深,涂层纳米力学性能逐渐增加,进而将对其摩擦磨损性能造成影响。20 kW喷涂功率制备涂层的室温摩擦因数、磨损率及磨痕深度均达最佳值,分别为(0.70±0.02)、(9.22±0.01)×10^-5 mm³/(N·m)及(130±10)μm。室温环境下,磨粒磨损、疲劳磨损及塑性变形为涂层的主要磨损机制。20 kW功率制备涂层的摩擦因数、磨损率、磨痕深度等均随摩擦环境温度的升高先增加而后降低,经600℃摩擦试验后分别低至(0.58±0.01)、(6.14±0.01)×10^-5 mm<...     

High temperature friction and wear behaviour of Ni–P–Ag–Al2O3 hybrid nanocomposite coating

Abstract

Codeposition of silver and alumina particles has been performed within an Ni–P coating on carbon steel samples by electroless deposition to form an Ni–P–Ag–Al₂O₃ hybrid nanocomposite coating. The structure of heat treated coatings was evaluated by XRD analysis. Tribological properties of the coatings were investigated by a pin-on-disc test method using a 52100 steel pin as counter body at high temperature. A 3D optical profiler was employed to measure the wear rate of the deposits. Surface morphology, cross section and wear scars of the coatings were studied by using SEM equipped with EDS analysis. The results showed that tribological properties of Ni–P–Ag–Al₂O₃ hybrid coating are similar to Ni–P–Ag conventional composite coating. Moreover, friction coefficient and wear resistance of the hybrid coating are strongly influenced by self-lubricating silver thin layers formed between mating surfaces during high temperature sliding wear.     

Influences of the compositions and mechanical properties of HVOF sprayed bimodal WC-Co coating on its high temperature wear performance

In this work, the bimodal WC-Co coatings were sprayed by high-velocity oxygen-fuel (HVOF), and the conventional WC-Co coatings were also fabricated for comparison. The microstructure, mechanical properties and high temperature wear performance were investigated. The bimodal WC-Co coating presented denser structure (porosity lower than 1.0%), higher average hardness (1164 HV0.1) and fracture toughness (11.5 ± 1.4 MPa·m^1/2) than that of conventional coating. The Weibull analysis of microhardness data of the bimodal coating presents a mono-modal distribution. The friction coefficient and wear rate of the bimodal coating were 0.61 and 2.96 × 10^− 6 mm³·N^− 1·m^− 1, respectively, which is lower than that of conventional coating at the test temperature of 450 °C. The tribofilm could be formed on the worn surface of bimodal WC-Co coating, which is composed of WO₃ and CoWO₄. The formation of tribofilm could reduce friction and wear.     

Dry sliding wear behavior of PVD TiN,Ti55Al45N,and Ti35Al65N coatings at temperatures up to 600 °C

Three PVD nitride coatings (TiN, Ti₅₅Al₄₅N, and Ti₃₅Al₆₅N) with different Al content were deposited on the cemented carbides by cathode arc-evaporation technique. Microstructural and fundamental properties of these nitride coatings were examined. The friction and wear behavior of these coatings were evaluated at temperatures up to 600 °C. The wear surface features of the test samples were examined by scanning electron microscopy. Results showed that the friction coefficient of these nitride coatings is different depending on the temperature. The friction coefficient of TiN coating increased with the increase of test temperature; while the friction coefficient of Ti₅₅Al₄₅N and Ti₃₅Al₆₅N coatings with the addition of Al decreased with the increase of test temperature. The Ti₅₅Al₄₅N and Ti₃₅Al₆₅N coatings exhibited higher wear resistance over the one without Al (TiN coating). The wear resistance of these nitride coatings at high temperature wear tests is significantly dependent on their tribological oxidation behavior. The Ti₅₅Al₄₅N and Ti₃₅Al₆₅N coatings with the addition of Al exhibited improved wear resistance as compared to the TiN coating, which was attributed to that their tribo-chemically formed Al₂O₃ exhibited better tribological properties than the TiO₂ of the latter.     

Influence of Rare Earth on the High-Temperature Sliding Wear Behavior of WC-12Co Coating Prepared by HVOF Spraying

In this work, WC-12Co coatings were prepared by high-velocity oxygen fuel spraying (HVOF) technology. The high-temperature sliding wear tests at 450, 550 and 650 °C were conducted on a pin-on-disk tribometer, and effects of CeO₂ on the high-temperature wear behavior were investigated. The results showed that CeO₂-modified WC-12Co coating possessed better sliding wear resistance than that of conventional WC-12Co coating at the tested temperatures. The maximum microhardness value of 1333 ± 25HV_0.5 was available at the temperature of 550 °C for CeO₂-modified WC-12Co coating worn track. The oxides formed on the worn surface played a significant role on the wear behavior. W₂C, Co₃O₄ and ratio of CoWO₄/WO₃ dominated the wear behavior of the coating at 450, 550 and 650 °C, respectively.     

TiC颗粒增强镍基合金复合涂层的摩擦学性能(英文)

运用等离子喷涂技术制备了TiC颗粒增强镍基合金复合涂层,分析了TiC颗粒增强镍基合金复合涂层的微观结构,研究了其摩擦磨损行为与机理。结果表明:TiC颗粒增强镍基合金复合涂层主要由γ-Ni,CrB,Cr7C3和TiC构成;复合涂层与基底材料间形成了厚度为9.4μm的过渡层,达到了冶金结合。当TiC颗粒含量为30%(体积分数)时,复合涂层的摩擦系数和磨损率均最低,即其摩擦系数为0.33,较纯镍基合金涂层降低了30%;其磨损率为0.3×10-3mm3/m,是纯镍基合金涂层的1/3。当载荷在6～10N的范围内时,复合涂层呈轻微磨损,其磨损机理主要为粘着磨损;当载荷达到12N时,复合涂层产生严重磨损,其磨损机制转变为硬质相的脱落和转移层的层脱剥落。     

Improvement of the oxidation and wear resistance of pure Ti by laser cladding at elevated temperature

NiCrBSi and NiCrBSi/WC-Ni composite coatings were produced on pure Ti substrates by the laser cladding technology. Thermal gravimetric (TG) analysis was used to evaluate the high temperature oxidation resistance of the laser cladding coatings. The friction and wear behavior was tested through sliding against the Si₃N₄ ball at elevated temperatures of 300 °C and 500 °C. Besides, the morphologies of the worn surfaces and wear debris were analyzed by scanning electron microscopy (SEM) and three dimensional non-contact surface mapping. The results show that the microhardness, high temperature oxidation resistance and high temperature wear resistance of the pure Ti substrates are greatly increased. For the pure Ti substrate, the wear behavior is dominated by adhesive wear, abrasive wear and severe plastic deformation, while both laser cladding coatings, involving only mild abrasive and fatigue wear, are able to prevent the substrates from severe adhesion and abrasive wear. In particular, the laser cladding NiCrBSi/WC-Ni composite coating shows better high temperature wear resistance than the NiCrBSi coating, which is due to the formation of a hard WC phase in the composite coating.     

Effect of plasma surface tungstenising on the friction and wear of Ti2AlNb-based alloys

To obtain a strong bond between W coatings and the substrate, a novel graded tungstenised layer on Ti-Al-Nb alloys was produced using a double glow plasma surface alloying technology and a special graded tribological coating was designed. The microstructural results showed that the tungstenised layer was distributed in a graded manner and was mainly comprised of W- or Ti-rich Ti_xW_1?x phases. Varying the friction conditions indicated that an increase in the load and sliding speed led to an increase of the friction coefficient and wear rate of the tungstenised layer at room temperature. These changes were mainly caused by the graded distribution of the W composition and the change in surface contact status. The results indicated that the friction and wear properties of Ti-Al-Nb alloys were greatly improved by the surface tungstenising.     

Microstructure and high-temperature friction and wear behavior of WC-(W,Cr)2C-Ni coating prepared by high velocity oxy-fuel spraying

WC-(W,Cr)₂C-Ni coating was prepared by high velocity oxy-fuel spraying (HVOF). The microstructure and phase composition of the as-sprayed coating and that after oxidation at high temperature were analyzed by means of scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The oxidation behavior of as-sprayed coating and starting powders was evaluated by thermogravimetry. Dry sliding friction and wear behavior of the WC-(W,Cr)₂C-Ni coating sliding against Si₃N₄ ball at different temperatures (room temperature 20 °C and elevated temperature of 700 °C and 800 °C) was evaluated using an oscillating friction and wear tester. Besides, the microhardness and fracture toughness of the coating was also measured. Results show that sintering agglomerated WC-20 wt.%Cr-7 wt.%Ni powder is an effective method to prepare agglomerated and sintered WC-(W,Cr)₂C-Ni composite powder. The excellent oxidation resistance of WC-(W,Cr)₂C-Ni coating is mainly resulted from a double-decker shell-core microstructure formed in the coating. The composition of the outer shell is (W,Cr)₂C phase and that of the inner shell is Cr₃C₂. During high-temperature friction and wear test, well remained hard WC phase in the WC-(W,Cr)₂C-Ni coating can guarantee its good mechanical properties and wear resistance, and newly generated nano NiWO₄, CrWO₄ and Cr₂WO₆ particles can further improve these properties significantly.     

不同纳米WS2含量Ni-P-Ti N-WS_(2)复合化学镀层的制备及其摩擦学性能EI北大核心CSCD

Ni-P-TiN化学复合镀层具有比Ni-P镀层更高的硬度和耐磨性,但其表面粗糙度大,与对偶件之间的摩擦因数高,应用潜力受到限制。通过在化学镀液中添加不同用量的纳米WS_(2)颗粒和固定用量的TiN颗粒,在低碳钢表面制备Ni-P-TiN-WS_(2)复合镀层。采用X射线能谱仪(EDS)、扫描电子显微镜(SEM)和X射线衍射仪(XRD)对镀层的化学成分(质量分数)、表面形貌及微观结构进行表征,并利用球盘式摩擦磨损试验机测试复合镀层的摩擦磨损性能。结果表明:纳米WS_(2)颗粒与纳米TiN颗粒的共沉积可使镀层表面更加致密、平整。随着镀液中纳米WS_(2)用量的增加,复合镀层的硬度先减小后增大,与氮化硅陶瓷球的摩擦因数则先升后降,磨损率显著下降,耐磨性增强。镀液中纳米WS_(2)粉末的用量为2.5 g/L时复合镀层的摩擦学性能最佳。纳米WS_(2)颗粒的加入及用量优化可显著改善复合镀层的综合性能,可为发展高耐磨低摩擦因数的先进涂层提供借鉴。     

原位生成 WC-B4C 增强镍基激光熔覆层及其性能研究

目的通过激光熔覆技术,在Q235钢表面原位生成WC-B4C增强镍基熔覆层。方法以WO3,B2O3,C和Ni60混合粉末为预涂原料,采用激光熔覆技术原位生成WC-B4C增强镍基熔覆层,对熔覆层的显微组织和物相构成进行分析,研究其摩擦磨损性能。结果采用合适的工艺参数,通过原位生成WC-B4C形成的增强镍基涂层形貌良好,与基材呈现较好的冶金结合。熔覆层平均硬度1200HV0.3,摩擦磨损失重仅为纯Ni60熔覆层的1/3。结论熔覆层硬度较高,耐磨性很好。大量原位生成的WC-B4C增强相及其均匀分布是熔覆层硬度和耐磨性提高的原因。