ISSN   1004-0595

CN  62-1224/O4

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镀铜Ti3SiC2和石墨双相增强铜基复合材料的制备及摩擦学性能研究

Preparation and Tribological Properties of Copper-Based Composites Reinforced with Dual Phases of Cu-Coated Ti3SiC2 and Graphite

  • 摘要: 采用电化学镀方法在石墨和钛碳化硅(Ti3SiC2)颗粒表面镀覆铜层以提高其与铜基体的界面结合强度,进一步,通过热压烧结制备了镀铜石墨和镀铜Ti3SiC2单相或双相增强的铜基复合材料,并对复合材料的组织结构、物理力学性能和摩擦学性能进行研究. 研究发现,镀铜石墨单相增强的铜基复合材料具有最低的摩擦系数(0.26),但物理力学性能和耐磨性1.86×10−6 cm3/(N·m)较差. 添加镀铜Ti3SiC2能显著提高铜基复合材料的物理力学性能和耐磨性0.88×10−6 cm3/(N·m),但摩擦系数降低程度较小(0.49). 镀铜Ti3SiC2和镀铜石墨双相增强铜基复合材料具有优异的物理力学性能和减摩耐磨性. 此外,研究发现:小尺寸石墨(40 μm)使材料的均匀性得到提高,有利于基体中的石墨在摩擦过程中均匀地向摩擦接触面提供润滑介质,从而提高材料的摩擦学性能和物理力学性能. 而大尺寸石墨在摩擦过程中,石墨易发生剥落形成三体磨损,从而增加摩擦系数和磨损率. 摩擦过程中,Ti3SiC2氧化分解与石墨一起在摩擦表面形成润滑膜从而起到较好的减摩耐磨效果,但当载荷过高时,摩擦表面的润滑膜遭到破坏,磨损加剧.

     

    Abstract: In this study, electroless plating was used to deposit a Cu layer on the surfaces of graphite and titanium silicon carbide (Ti3SiC2) particles to improve their interfacial bonding strength with the Cu matrix. Furthermore, copper-based composite materials reinforced with either copper-coated graphite or copper-coated Ti3SiC2, either singly or in combination, were prepared by ball milling, cold pressing and hot pressed sintering. The organization structure, physical mechanical properties, and tribological properties of the composite materials were studied. It was found that the copper-based composites reinforced with Cu-coated graphite exhibited the lowest friction coefficient (0.26), but their physical and mechanical properties and wear resistance 1.86×10−6 cm3/(N·m) were poor. Cu-coated Ti3SiC2 could significantly improve the composites’ physical and mechanical properties as well as wear resistance 0.88×10−6 cm3/(N·m), while the decrease in friction coefficient (0.49) was not significant. The copper-based composites reinforced with dual phases of Cu-coated Ti3SiC2 and graphite exhibited excellent physical and mechanical properties, friction reducing and wear resistance performances. In addition, it was found that research had found that overly large graphite sizes could adversely affect the local uniformity of the material, leading to internal damage within the graphite during testing and subsequently reducing the physical and mechanical properties of the material. In friction tests, the use of smaller graphite sizes (40 μm) enhanced the uniformity of the friction material structure, facilitating the even distribution of graphite from the matrix to the friction contact surface, thereby improving the tribological properties of the material. Conversely, larger graphite sizes were prone to flaking during the friction process, leading to three-body wear, which increased the friction coefficient and wear rate. Composite materials reinforced with 40 μm copper-coated graphite and Ti3SiC2 exhibited superior physical and mechanical properties, with the lowest friction coefficient (0.35) and wear rate 0.54×10−6 cm3/(N·m). During the friction process, graphite, due to its special lamellar structure, adhered easily to the worn surface, providing lubrication, while Ti3SiC2 oxidizes and decomposes to form a Ti-Si oxide film, thereby reducing friction. The friction performance of the sample largely depended on the coverage of its lubricating film on the friction surface. When the load too low, it's difficult for the sample surface to form a dense and continuous lubricating film. Under the friction conditions of 80 N and 800 r/min, the copper-coated Ti3SiC2 lubricant was sufficiently enriched on the worn surface and fully oxidized, together with graphite, to form a smooth and well-dense lubricating film, thus exhibiting excellent anti-friction and anti-wear properties. However, when the load and speed were too high, the friction film was destroyed and cannot be replenished, resulting in a sharp increase in the friction coefficient and wear rate of the sample.

     

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