超音速微粒轰击表面纳米化及其对耐磨性的影响

采用超音速微粒轰击技术对20钢进行表面纳米化处理。研究了表面纳米化工艺对材料流失与形貌变化的影响，并采用往复磨损试验机研究了纳米化表面的磨损性能。结果表明：超音速微粒轰击在表面形成纳米层过程中使材料发生流失和表面粗糙度增大。在干摩擦和油润滑条件下，微粒轰击样品的磨损率分别是未轰击样品的2．77和1．83倍，轰击抛光样品的磨损率则比未轰击样品分别降低了26％和42％。对其影响耐磨性的原因作了初步讨论。     

Characterization and wear behavior of modified silicon nitride

Silicon nitride-based materials are applied to many tribological components because of their superior thermal and mechanical properties and corrosion resistance. The purpose of this study is to investigate the wear performance of modified silicon nitride which contained 3 wt.% La₂O₃ and 3 wt.% Y₂O₃. The relationships between microstructure and mechanical properties have been also addressed. Vickers microhardness and toughness were measured, the later being determined by means of the direct crack measurement method (DCM). Scanning electron microscopy technique (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) was used for the morphological characterization of the samples as well as for the characterization of the wear scars. Wear properties were studied under a load of 10 N by using the ball-on-disk tribometer. AISI 52100 steel balls and balls of WC + 6% Co (6 mm diameter) were used as static counterparts, respectively. Steady state friction coefficients of 0.66 and 0.62 were measured for the tribological pairs WC + 6 % Co/Si₃N₄ and AISI 52100/Si₃N₄, respectively. The wear mechanism was determined in each case, and comparison between the wear performance of the traditional and modified silicon nitride is also presented.     

Microstructure and Sliding Wear Behaviour of Ni(Cr)-TiB_2 Coatings Deposited by HVOF Spraying of SHS Powders

THERMAL SPRAYING provides a large range ofcoatings,which increase the wear resistance ofsubstrates[1].One of the major coating families is thecermet,composed of hard ceramic particles with ametallic binder.The most commonly used cermetcoatings in industrial applications are based on eitherthe WC-Co or the Cr3C2-Ni(Cr)systems with WC-17wt%Co and Cr3C2-25wt%Ni(Cr)being typicalcompositions[2,3].Although WC-Co deposits are hardand wear resistant at ambient temperatures their rangeof ap…     

Wear resistance of ceramic coating on AZ91 magnesium alloy by micro-arc oxidation

The ceramic coating formed on AZ91 magnesium alloy by micro-arc oxidation （MAO） was characterized. The results show that the ceramic coating （3.4-23 μm in thickness）on the surface ofAZ91 alloy was attained under different micro-arc oxidation treatment conditions, which consist mainly of MgO, Mg2SiO4 and MgSiO3 phases. Nano-hardness in a cross-sectional specimen was determined by nano-indentation experiment. The MAO coatings exhibit higher hardness than the substrate. Dry sliding wear tests for the MAO coatings and AZ91 alloy were also carded out using an oscillating friction and wear tester in a ball-on-disc contact configuration. The wear resistance of the MAO coatings is improved respectively under different treatment time as a result of different structures of ceramic coatings formed on AZ91 alloy.     

等温淬火球铁在铁道车辆耐磨件上的应用研究

考虑到等温淬火球铁具有强度高、韧性好、出色的耐磨性等优点，根据铁道车辆斜楔和衬套配件的服役要求，对等温淬火球铁和传统的金属材料进行了大量摩擦磨损性能比较试验，结果表明，等温淬火球铁斜楔和衬套具有比传统材料高得多的耐磨性，特别是等温淬火球铁斜楔的使用寿命是以往ZG230-450斜楔的6～10倍。因此，等温淬火球铁斜楔和衬套件已在我国铁路车辆上得到了广泛应用。     

Tribological behavior of high specific strength PTFE-Al alloy composite

Solid lubricants lead to substantial weight savings relative to the use of liquid lubricant, especially in the weight-conscious aerospace industry. A new PTFE-Al alloy composite（A） containing 60% area proportion of PTFE composite was developed. Another type of common metal-plastics multilayer composite, also called DU, was selected for a comparative investigation. Friction and wear tests were carried out in an oscillating sliding tribotester in air at an oscillating frequency of 0.13 Hz and contact mean pressures from 10 to 80 MPa. The composites slid against a 38CrMoAlA steel shaft. The results show that the composite A exhibits low coefficient of dry sliding friction less than 0.1 and long wear life of 2 000 m. This is because the composite A can provide a sufficient solid lubrication during the whole tests. SEM examination of the transfer films for the composite A confirms that uniform, thin and coherent transfer films are prerequisites for low friction and good wear resistance.     

柴油机活塞环耐磨性探讨

通过分析活塞环的基体组织、径向弹力与气缸套的匹配以及对其施行表面处理，以提高活塞环的耐磨性。对活塞环进行调质或渗氮处理，可显著提高其使用寿命。     

碳氮共渗提高空心圆柱滚子轴承寿命的研究

通过GCr15钢碳氮共渗,在表层获得大量的残余奥氏体。磨损中,马氏体组织剥落,残余奥氏体则成小岛状,进而在表面迁移发生形变诱发马氏体相变,使耐磨性得以提高。同时,共渗在空心滚子内表面造成的压应力对改善弯曲疲劳性能有利。     

铈对Fe-Ni-Cr合金耐磨耐蚀性能的影响

根据磨蚀理论,设计了一种含Ce耐磨耐蚀合金,用SEM、X-ray对磨损形貌进行了观察分析.结果表明,加入Ce可以获得致密化程度较高、分布均匀的组织,明显增加了合金碳化物中铬的含量,使碳化物的显微硬度提高,表面有CeFe7新相产生,并引起奥氏体、铁素体含量的增加,改变了试样表面的微观结构,从而提高了Fe-Ni-Cr合金的耐磨耐蚀性能.     

耐磨白口铸铁的综合性能与价格比

采用模糊数学对耐磨白口铸铁性能进行综合分析,通过大量计算得出了耐磨白口铸铁的综合性能价格比,计算结果表明,在这些材料中,Cr27的综合性能价格比最好,Ni1最差,而Cr24,15-3和Ni4依次介于两者之间。本方法对于工程技术方案评价将具有实用价值。