电沉积方式对Ni-CeO_2纳米复合镀层摩擦磨损性能的影响

采用直流电沉积、脉冲电沉积和超声辅助脉冲电沉积制备Ni-CeO2纳米复合镀层,研究电沉积方式对纳米复合镀层表面形貌、显微硬度和摩擦磨损性能的影响,并用扫描电子显微镜分析其磨损机理。结果表明:电沉积方式对Ni-CeO2纳米复合镀层的晶粒尺寸和性能有较大影响;当超声波引入脉冲电沉积过程时,超声波的强力搅拌作用和超声空化效应能促进CeO2纳米颗粒在镀层中均匀分布,进一步减小镀层的晶粒尺寸,明显提高镀层的显微硬度,从而改善镀层的摩擦磨损性能;Ni-CeO2纳米复合镀层的摩擦磨损性能均优于纯Ni镀层的;而超声辅助脉冲电沉积制备的Ni-CeO2纳米复合镀层的晶粒更加细小、显微硬度最高,其摩擦因数最低,耐磨损性能最佳。     

晶粒尺寸对纳米晶钴摩擦磨损性能的影响

采用脉冲电沉积法制备了不同晶粒尺寸的纳米晶钴镀层,考察了晶粒尺寸对纳米晶钴硬度和摩擦磨损性能的影响.结果表明:随着晶粒尺寸的减小,钴镀层的硬度显著升高,符合经典的Hall-Petch效应;而纳米晶钴的抗磨性并没有随着晶粒的减小而显著增加,同时其摩擦系数随着晶粒的减小而略有增加.     

纳米结构Cu中动态再结晶主导的磨损机制

研究了干摩擦和油润滑滑动条件下纳米结构Cu的摩擦磨损性能与磨痕亚表层结构特征.比较了不同条件下纳米结构Cu耐磨性的差异,并对亚表层结构进行深入研究.结果表明,2种条件下纳米结构Cu均表现出以动态再结晶为主导的摩擦磨损机制,其耐磨性与磨痕亚表层再结晶晶粒尺寸之间的关系为磨损率随着动态再结晶晶粒尺寸增大而增加.     

脉冲电沉积纳米镍镀层摩擦磨损性能的研究

采用脉冲电沉积的方法制备纳米镍镀层,研究了纳米镍镀层的微观组织结构,考察了脉冲电流密度和外加载荷对纳米镍镀层摩擦磨损性能的影响.结果表明,脉冲电沉积方法制备的纳米镍镀层的晶粒均匀致密;电流密度的增大使得纳米镍镀层晶粒尺寸减小,显微硬度和耐磨性提高;随着晶粒尺寸的减小,纳米镍镀层磨损机制从粘着磨损转变为磨料磨损.     

金属-纳米金刚石复合镀层的摩擦磨损性能

本文研究在正交优化工艺条件下获得的镍-钴-纳米金刚石复合电镀层的摩擦学性能，镀层致密无孔隙．讨论了纳米金刚石的加入对镀层组织的影响。结果表明，纳米金刚石的加入，使镍-钴合金层的组织细化，不加纳米金刚石的镀层晶粒尺寸约为0．5—0．6μm，加纳米金刚石的镀层晶粒尺寸约为0．1-0．2μm。镍钴合金镀层的摩擦系数为0．35左右，寿命在摩擦半径为14m时平均为0．022km。纳米金刚石复合镀层摩擦系数为0．3左右。镀层寿命在摩擦半径为14m时为0．15km。并使摩擦磨损性能显著提高。     

85Al2O3/SiC纳米复合陶瓷的耐磨损性能研究

通过控制无压埋烧条件制备了85Al2O3/SiC纳米复合陶瓷,重点研究了纳米碳化硅对复合陶瓷耐磨损性能的影响.结果表明,纳米复合陶瓷表现出显著优于基体材料的表面耐磨损特性.SEM分析表明,纳米碳化硅的加入使材料的磨损去除机制发生了改变,由大范围的深层晶粒拔出变为小尺寸的浅层去除和塑性变形.     

85Al2O3/SiC纳米复合陶瓷的耐磨损性能研究

通过控制无压埋烧条件制备了85Al2O3/SiC纳米复合陶瓷,重点研究了纳米碳化硅对复合陶瓷耐磨损性能的影响.结果表明,纳米复合陶瓷表现出显著优于基体材料的表面耐磨损特性.SEM分析表明,纳米碳化硅的加入使材料的磨损去除机制发生了改变,由大范围的深层晶粒拔出变为小尺寸的浅层去除和塑性变形.     

Effect of Nanocrystalline Surface and Iron-containing Layer Obtained by SMAT on Tribological Properties of 2024 Al Alloy

采用表面机械研磨处理技术,选用陶瓷球和钢球作为弹射介质,在 2024 铝合金表面分别制备出纯净的纳米晶层和含铁纳米晶层。表面机械研磨处理前后2024铝合金摩擦磨损性能在载荷为1.5 N的条件下与直径为 5 mm 的 GCr15 钢球对磨进行了研究。结果表明,表面机械研磨处理 30 min 后,陶瓷球处理铝合金表面纳米晶层平均晶粒尺寸达到 49.2 nm,钢球处理铝合金表面纳米晶层平均晶粒尺寸细化到 52.1 nm。此外,采用钢球作为弹射介质进行表面机械研磨处理在纳米晶表层引入了厚度约为 5 μm 的含铁层。在晶粒细化、硬度增加和含铁层的润滑作用共同作用下,2024铝合金的耐磨性能得到显著改善     

表面机械研磨处理2024铝合金表面纳米晶层和含铁层对摩擦学行为的影响机制研究（英文）

采用表面机械研磨处理技术,选用陶瓷球和钢球作为弹射介质,在2024铝合金表面分别制备出纯净的纳米晶层和含铁纳米晶层。表面机械研磨处理前后2024铝合金摩擦磨损性能在载荷为1.5 N的条件下与直径为5 mm的GCr15钢球对磨进行了研究。结果表明,表面机械研磨处理30 min后,陶瓷球处理铝合金表面纳米晶层平均晶粒尺寸达到49.2 nm,钢球处理铝合金表面纳米晶层平均晶粒尺寸细化到52.1 nm。此外,采用钢球作为弹射介质进行表面机械研磨处理在纳米晶表层引入了厚度约为5μm的含铁层。在晶粒细化、硬度增加和含铁层的润滑作用共同作用下,2024铝合金的耐磨性能得到显著改善。     

碳纳米管和碳化硅对铜混合纳米复合材料显微组织和干滑动磨损行为的影响（英文）

研究了多壁碳纳米管和碳化硅包覆铜增强铜基混合纳米复合材料的显微组织和摩擦性能。碳纳米管含量为1%~4%,碳化硅含量固定在4%。铜杂化纳米复合材料的合成过程包含球磨、冷压、烧结,随后热压。对混合纳米复合材料进行了密度、晶粒尺寸和硬度测试。在不同载荷条件下,在销-钢盘摩擦仪上采用干滑动磨损评估纳米复合材料的摩擦性能。结果表明,与纯铜相比,混合纳米复合材料的晶粒尺寸明显减小,4%碳纳米管增强杂化纳米复合材料的显微硬度提高了80%。混合纳米复合材料中碳纳米管含量的增加导致材料的摩擦因数和磨损率降低。     

氧化物润滑材料的研究进展

随着航空航天等高新技术装备的发展,要求相关运动部件在极高的温度下具有优异的摩擦学性能,因此开发适应极高温度的自润滑材料具有重大意义。综述了二元氧化物润滑材料和三元氧化物润滑材料用作高温固体润滑材料的研究与发展。重点介绍了含有Magnéli同源相的二元和三元氧化物润滑材料,在高温和宽温域环境下的摩擦学性能,同时也说明了通过控制材料的生长结构和缺陷形式,来生成具有高温润滑性的氧化物,成为实现材料高温润滑的一种潜在方法,并讨论了这些氧化物的结构、化学性能和电性能与其摩擦学性能的相关性。最后概括了氧化物润滑材料在工业中的应用前景,并提出了研发单一润滑材料实现室温至高温(25~1000℃)宽温域下的连续润滑成为未来的发展趋势。     

不同热处理下滑动速度对SiCp/Al复合材料摩擦学性能影响研究

SiCp/Al复合材料非匀质性微观结构使其摩损机制较传统匀质材料更为复杂,不同工况及热处理工艺下复合材料的摩擦学性能也存在差异。以SiCp/2024Al复合材料为研究对象,进行球-面接触干滑动摩擦磨损实验,探究它在不同热处理状态及滑动速率下的摩擦磨损性能及磨损机制。结果表明:热处理对复合材料力学性能和摩擦学性能有显著影响,固溶+人工时效态复合材料具有更高的强度、硬度及耐磨性;滑动速度影响复合材料的表面接触性质及磨损程度,摩擦因数和磨损量随滑动速度提高逐渐增大;随滑动速度增加,复合材料主要磨损机制由剥层磨损向磨粒磨损转变,而磨损机制的转变明显加快了复合材料的磨损,在实际应用中应尽量避免此现象发生。     

Evaluation of effect of alloy elements in copper based CuSn10 and CuZn30 bearings on tribological and mechanical properties

Brass and especially bronze in copper based alloys are widely used as journal bearing material. Pure copper materials are not used as journal bearing material due to their low mechanical and hardness properties. These materials having acceptable tribological and mechanical performance give satisfactory results in journal bearings. In this study, tribological and mechanical properties of journal bearings manufactured from copper based CuSn10 bronze and CuZn30 brass were investigated. Moreover, the effect of alloy elements of Cu, Sn and Zn on tribological and mechanical properties of journal bearings was evaluated. SAE 1050 steel shaft (journal) was used as counter abrader. Wear experiments were carried out at 20 N loads, 1500 rpm for 2.5 h by using radial journal bearing wear test rig.     

Keramische Beschichtungen im Pumpenbau

Ceramic coatings for pump components The objective of the present paper is to develop a SiC-based ceramic coating for critical tribological pump components. The paper presents the results obtained for different types of coatings tested under pump-specific loads in comparison with conventional materials. The coatings (WC/Co, WC/Ni, Cr₃C₂/NiCr, Ni-SiC/INCONEL) were applied using the vacuum plasma spraying process. Laboratory tests were carried out on model test stands. The materials were tested with regard to their resistance to corrosion, cavitation and erosion as well as their behaviour in a tribologically critical environment. The coatings examined proved to be suitable for pump engineering applications involving tribological and erosive loads; while they do not provide sufficient protection against cavitation and corrosion attacks in highly concentrated acids.     

Spark plasma sintering for multi-scale surface engineering of materials

Recently, significant progress has been made in understanding the effect of multi-scale microstructural features, including nano-, micro-, and macro-features, on the properties of materials. Controlling the length scale of micro-structural features provides tremendous opportunities for enhancing the properties of materials, including extraordinary strength and hardness, unprecedented damage from tribological contacts, and improvements in a number of functional properties of the materials. Spark plasma sintering (SPS) process which combines the effects of uniaxial pressure and pulsed direct current is becoming increasingly important for the processing of bulk shapes of amorphous and nanostructured materials. These materials can also be good candidates for high-performance coatings. This article presents a review of our ongoing efforts to use SPS to produce engineered coatings of amorphous and nanostructured materials for various applications, including structural, tribological, and biomedical applications.     

Improving the tribological characteristics of tool and mould surfaces by machine hammer peening

The surface treatment by machine hammer peening can be applied in order to functionalise surfaces made of different materials. Especially in mould and die making high potentials can be found by improved tribological properties. Particularly due to the fact that an orthogonal impact direction of the used plunger tool cannot be realised at all events, the influence of a given impact angle is investigated as part of this work. Furthermore the possibility of embedding WC particles into the near-surface zones of tool steel materials is presented, which offers new possibilities to improve the tribological performance of components.     

A critical review of diamond like carbon coating for wear resistance applications

In recent years innovation in carbon based materials have encouraged both researchers as well as industrialists to develop materials/composites with improved tribological properties. Researchers have been fascinated to develop diamond like carbon (DLC) or carbon nanotubes (CNTs) reinforced coatings to their good corrosion resistance, excellent wear resistance, good adhesion strength, and self -lubricious nature. The present review article is mainly focused on various techniques employed in order to process DLC/CNTs coatings as well as provide a summary of DLC/CNTs deposition on different substrates. The present study includes major types, properties and tribological behavior of carbon based materials and mechanisms involved in coating deposition. The study also discusses that deposition of DLC/CNTs coatings on the substrate materials enhances the wear, corrosion and mechanical properties of the substrate.     

铁基粉末冶金含油材料摩擦学性能

采用粉末冶金方法制备多孔含油铁基材料，在自制的HDM-10型端面摩擦磨损试验机上进行摩擦磨损试验，考察了含碳量及材料密度对含油铁基材料摩擦磨损性能的影响。结果表明：铁基粉末冶金含油材料的含碳量应选择0．6～0．8％（质量）为宜，组织为珠光体加少量铁素体，综合摩擦学性能最佳；密度与含油铁基材料的摩擦学性能有密切关系，有一最佳的密度选择范围。     

多孔储液材料的仿生制备及其摩擦学性能研究进展∗

多孔储液材料因其优异的自润滑性能备受关注,特别是其孔隙结构参数与性能间对应关系的研究一直是学术界和工业界亟待解决的问题。 针对该类多孔储液材料,从来源、制备方法以及摩擦学特性等方面对其发展脉络及面临的问题进行梳理和分析,认为在仿生关节软骨制备适合工业应用的摩擦副方面,如何提取关键仿生特征参数是关键。 目前在进行服役可靠性、工况适应性分析时,多用孔隙率来表征多孔结构特征,在明晰孔隙形态参数(孔径,分布,贯通型等)与力学-物理性能、润滑状态之间的映射关系方面存在明显的不足,导致从优化孔隙形态参数入手实现多孔储液材料力学-物理性能与摩擦学性能的统一方面仍具挑战性。 3D 打印技术的快速发展有望解决当前多孔材料成形过程中孔隙形态参数不可精确控制的问题,并为其自润滑理论的发展提供有效试验手段。     

A comparative study of tribological behavior of plasma and D-gun sprayed coatings under different wear modes

In recent years, thermal sprayed protective coatings have gained widespread acceptance for a variety of industrial applications. A vast majority of these applications involve the use of thermal sprayed coatings to combat wear. While plasma spraying is the most versatile variant of all the thermal spray processes, the detonation gun (D-gun) coatings have been a novelty until recently because of their proprietary nature. The present study is aimed at comparing the tribological behavior of coatings deposited using the two above techniques by focusing on some popular coating materials that are widely adopted for wear resistant applications, namely, WC-12% Co, A1₂O₃, and Cr₃C₂-MCr. To enable a comprehensive comparison of the above indicated thermal spray techniques as well as coating materials, the deposited coatings were extensively characterized employing microstructural evaluation, microhardness measurements, and XRD analysis for phase constitution. The behavior of these coatings under different wear modes was also evaluated by determining their tribological performance when subjected to solid particle erosion tests, rubber wheel sand abrasion tests, and pin-on-disk sliding wear tests. The results from the above tests are discussed here. It is evident that the D-gun sprayed coatings consistently exhibit denser microstructures and higher hardness values than their plasma sprayed counterparts. The D-gun coatings are also found to unfailingly exhibit superior tribological performance superior to the corresponding plasma sprayed coatings in all wear tests. Among all the coating materials studied, D-gun sprayed WC-12%Co, in general, yields the best performance under different modes of wear, whereas plasma sprayed Al₂O₃ shows least wear resistance to every wear mode.