【作者】 涂川俊；

【导师】 陈振华；

【作者基本信息】 湖南大学 ， 材料加工工程， 2009， 博士

【摘要】 作为电力机车供电系统从接触网获取电能的关键部件,受电弓滑板材料的研究是当前弓网耦合系统研究的热点之一。目前国内外高速电气化线路上主要使用双润滑铜基粉末冶金滑板、铝包覆纯炭质滑板和铝包覆浸金属炭滑板,但在机车运行时上述滑板均存在不同程度的缺陷,且国内外相关研究者对滑板/铜高速载流磨损性能及其起弧、灭弧机理仍缺乏深入研究。为了克服现有滑板因自身材质的缺陷难以协调弓网耦合系统载流磨损过大等问题,进一步降低滑板的载流磨损率。本文基于树脂型功能材料的结构和性能具有良好可控性及其成型工艺相对简单等特点,开展了对树脂型滑板材料的制备、磨损性能及抗磨机理研究。（1）对树脂热压型滑板配方和制备工艺进行了研究。以热固性树脂作粘结剂,提出了采用三次压制-固化法制备树脂热压型滑板试样。研究了粘结剂种类及含量、石墨种类及含量、成型工艺等因素对树脂热压型滑板材料结构和性能的影响。研究表明,采用以聚双马来酰亚胺树脂（PBMI）/腰果壳油改性酚醛树脂（YM）作粘结剂,经过氧化处理的P鳞片石墨作润滑相制得的树脂热压型滑板试样具有良好的抗磨损性能,当改性粘结剂含量为10.5 mass%、P鳞片石墨含量为10 mass%时制得的树脂热压型滑板试样综合性能最佳。（2）模拟滑板/导线的工况条件,系统地研究了树脂热压型滑板/铜的常温变速磨损性能、热态磨损性能和载流磨损性能。研究表明,电流是影响树脂热压型滑板磨损率的最主要因素,其磨损率随载流密度的增加而增大。树脂热压型滑板试样的常温变速磨损率和环境温度为200℃时的热态磨损率均与Siemens炭滑板的磨损率基本相当;环境温度为350℃时的树脂热压型滑板试样的热态磨损率、载流条件下的载流磨损率均大于Siemens炭滑板的磨损率。（3）对树脂焙烧型滑板配方和制备工艺进行了研究。提出了采用镀锌石墨粉作灭弧介质和润滑剂,添加改性树脂作粘结剂,利用共混热压-炭化法制备树脂焙烧型滑板试样。研究了焙烧工艺制度、粘结剂种类及含量、镀锌石墨粉含量等因素对树脂焙烧型滑板材料结构和性能的影响。研究表明,在135⁴25℃升温速率为20℃/h、425⁶30℃升温速率为15℃/h、630℃保温4h的条件下,当PBMI/YM树脂含量为3⁵ mass%、镀锌石墨粉含量为28 mass%时制得的树脂焙烧型滑板的抗磨损性能和导电性能最优。镀锌石墨粉的加入明显改善了石墨和金属铜的界面结合状态,降低了滑板的载流磨损率,当载流密度为285A/cm2、滑行速度为41.7m/s时,镀锌石墨-铜焙烧型滑板磨损率比未镀锌石墨-铜焙烧型滑板降低了约3.2倍。（4）模拟滑板/导线的工况条件,系统地研究了树脂焙烧型滑板/铜的载流磨损性能。研究表明,树脂焙烧型滑板的载流磨损率随载流密度和滑行速度的增加而增大。在未受流条件下,新型树脂焙烧型滑板的磨损率与Siemens炭滑板、Toyo浸金属炭滑板和株洲新方圆电碳有限公司某炭滑板（简称为国产某型号炭滑板）的磨损率基本相当;在载流密度为285A/cm²、滑行速度为41.7m/s条件下,新型树脂焙烧型滑板的磨损率为1.51×10^-5mm³/（N·m）,是国产某型号炭滑板磨损率的91.7%,是Siemens炭滑板、Toyo浸金属炭滑板磨损率的1.53倍和1.42倍。（5）研究了树脂型滑板/铜的磨损特性及机理。研究表明,在未受流条件下,树脂热压型滑板/铜的磨损机理主要是低应力连续磨粒磨损和轻微的粘着磨损;随着环境温度的升高,其热态磨损机理发生由粘着磨损向伴随有轻微剥层磨损的热磨损转变。在载流条件下,树脂热压型滑板/铜的磨损机理主要是电弧侵蚀磨损、氧化磨损和粘着磨损的交互作用;而树脂焙烧型滑板/铜的磨损机理主要是电弧侵蚀磨损和氧化磨损的综合作用。（6）研究了在接触-分离条件下树脂型滑板/铜的电弧侵蚀过程及作用模型。研究表明,树脂热压型滑板依次经历了接触-分离起弧;燃弧时的聚合物热分解、炭质材料氧化和金属热熔融的相变;高温阶段的树脂炭化、液态金属流动及金属氧化物高温分解;恢复接触熄弧时的熔融金属冷凝及氧化物脱落等循环过程。树脂焙烧型滑板则依次经历了接触-分离起弧;软金属受热软化;炭质材料氧化、金属热熔融和气化的相变;金属冷凝及材料转移等循环过程。（7）探讨了灭弧介质的抗电弧侵蚀机理。分别研究了硅油浸渍剂对树脂热压型滑板/铜载流磨损性能和抗电弧侵蚀磨损性能的影响,软金属灭弧介质对树脂焙烧型滑板/铜载流磨损率和动态载流稳定性的影响。研究表明,在树脂热压型滑板中的硅油浸渍剂减缓了接触区接触电阻的波动,降低了接触点的瞬时高温和滑板的载流磨损率;树脂焙烧型滑板中的镀锌石墨、金属锡促进了滑板中的金属相间的界面冶金结合。在电弧侵蚀过程中,具有较高电离能的金属锌吸热蒸发,降低了电弧中的电子浓度。同时金属蒸气与铜基体形成的合金覆层降低了接触区的接触电阻,减小了电弧产生的几率,从而使得滑板的载流磨损率降低。此抗电弧侵蚀机理为树脂型滑板材料的抑弧研究和实际应用提供了科学依据。更多还原

【Abstract】 As the key component, pantograph contact strip helps electric locomotive power supply system to obtain electrical energy from the contact wire, which has become a hot research point in the field of the coupling system of pantograph/catenary. At present, the contact strips, such as dual-lubricating copper matrix powder metallurgy contact strip, Al-coated pure carbon contact strip, Al-coated metal impregnation carbon contact strip, were mainly applied on high-speed electrification railway at home and abroad, which were limited by different shortcomings during the operation. Furthermore, few investigations and reports about the electrical sliding wear behavior of high speed were presented on arc starting and extinguishing mechanism of contact strip against copper. In order to resolve the problems that contact strip is difficult to coordinate the coupling system of pantograph/catenary due to material defect to avoid high abrasion with current and to reduce the wear rate of contact strip. Based on the structure and property of resin-type function composite well controlled and relatively simplicity in manufacture, the preparation process and wear behavior and anti-wear mechanism of the resin-type contact strip materials were investigated in this paper.（1） The batch formula and preparation process of the resin hot-pressing type contact strip were investigated in this paper. With modified resin as bonding agent, three-step pressing and solidification technology was presented to prepare the resin hot-pressing type contact strip. The effects of the kinds and content of bonding and graphite, the moulding process on the structure and performance of the resin hot-pressing type contact strip were studied. The result showed that the resin hot-pressing type contact strip which was prepared with polybismaleimide resin （PBMI）/cashew nut oil phenol formaldehyde resin （YM） as bonding agent and P flake graphite as lubricating phase had perfect wear resistance. The combination property of the resin hot-pressing type contact strip was the best when the content of bonding agent is 10.5 mass% and the content of P flake graphite is 10 mass%.（2） The variable-speed wear behavior at room temperature, thermal wear behavior and electrical sliding wear behavior of the resin hot-pressing type contact strip against copper were studied systematically under laboratory conditions with a wear tester which simulated the train motion. The results showed that current is the most important factor which affects the wear rate of the resin hot-pressing type contact strip and the wear rate increases with the increase of current density. They also showed that variable-speed wear rate at room temperature and thermal wear rate of the resin hot-pressing type contact strip when initial ambient temperature is equal to 200℃are both equal to the Siemens carbon contact strip. And the thermal wear rate when initial ambient temperature is equal to 350℃, electrical sliding wear rate of the resin hot-pressing type contact strip are higher than those of Siemens carbon contact strip.（3） The batch formula and preparation process of the resin-calcination type contact strip were investigated in this paper. With Zn-coated graphite as the arc extinguishing agent and lubricating agent, modified resin as the bonding agent, the resin-calcination type contact strip was prepared by the methods of blending hot-pressing and carbonization technology. The effects of roasting technics, the kinds and content of bonding agents, the amount of Zn-coated graphite on the structure and property of the resin-calcination type contact strip were studied. The results showed that the resin-calcination type contact strip with the best properties of wear behavior and conductivity are those which was produced by using 3⁵ mass% PBMI/YM resin and 28 mass% Zn-coated graphite at the heating rate 20℃per hour at 135⁴25℃, and at the heating rate 15℃per hour at 425⁶30℃and then keeping at 630℃for 4 hour. The results showed that the electroplating Zn on graphite greatly improve the interfacial combination between graphite and copper and remarkably decrease the wear rate of the contact strip. The wear rate of the former was only one-third of the latter with the current density of 285A/cm² and at the sliding velocity of 41.7m/s.（4） The electrical sliding wear behavior of the resin-calcination type contact strip against copper was also studied systematically under laboratory conditions with a wear tester which simulated the train motion. The results showed that the electrical sliding wear rate of the resin-calcination type contact strip increases with the increase of current density and the sliding velocity. It also showed that the wear rate of the new resin-calcination type contact strip is approximately equal to Siemens carbon strip, Toyo metal impregnation carbon contact strip and Zhuzhou Xinfangyuan Electrical Carbon Co., Ltd. carbon strip （a certain type of domestic carbon contact strip） without current. The wear rate of the new resin-calcination type contact strip is 1.51×10^-5mm³/（N·m）, which is almost 0.917 times lower than a certain type of domestic carbon contact strip, 1.53 times that of Siemens carbon strip and 1.42 times that of Toyo metal impregnation carbon strip with the current density of 285A/cm² and at the sliding velocity of 41.7m/s.（5） The wear behavior and mechanism of resin-type contact strip were investigated in this paper. The results showed that the main wear mechanism of the resin hot-pressing type contact strip against copper without current is low stress grain abrasive and slightly adhesive wear. At elevated temperature, the wear mechanism evolves from adhesive wear to thermal wear with slight delamination wear. While arc erosion wear and oxidation wear are the dominate mechanisms of the resin hot-pressing type contact strip against copper with current, which is accompanied by adhesive wear during electrical sliding wear process. Moreover, the main wear mechanism of the resin-calcination type contact strip against copper is arc erosion wear and oxidation wear.（6） The arc erosion processes and function mechanism models of the resin-type contact strip with current were investigated in this paper when the contact between the contact strip and the copper disk was broken. The results showed that the arc discharge drive contact regions of the resin hot-pressing type contact strip to sequentially experience four cycle stages: arc generation when the contact was broken; the thermal decomposition of polymer during the stage of arc arising, the oxidation of carbon based materials, the phase transition of hot molten metal; the carbonization of resin at high temperature, the flow of molten metal, the thermal decomposition of metal-oxide; the solidification of molten metal during arc quenching and the shedding of oxide, etc. The resin-calcination type contact strip sequentially experienced the circulation processes such as: the occur of arc when the contact was broken; the soft metal softened; the oxidation of carbon based materials, the phase transition of hot molten metal and vaporization; the solidification of metal and material transfer, etc.（7） Arc erosion resistance mechanism of arc-extinguishing medium was investigated. The effects of impregnating agents with silicon oil on electrical sliding wear behavior and arc erosion wear resistance of the resin hot-pressing type contact strip and the resin-calcination type contact strip against copper were respectively studied in this paper. The effects of arc extinguishing medium with soft metal on electrical sliding wear rate and the dynamic stability with current of the resin-calcination type contact strip against copper were investigated as well. The results showed that silicone oil, as the impregnating agent in the resin hot-pressing type contact strip, could abirritate the fluctuation of contact resistance, lower the instantaneous high temperature of the contact point and the wear rate of contact strip with current. The Zn-coated graphite and the soft metal tin of the resin-calcination type contact strip can promote the forming metallurgical bonding structure of metal phase on the corresponding interface. In the courses of arc erosion, the evaporation related heat absorption of metallic zinc with high ionization energy and can decrease the electron concentration among the arc gap. Meanwhile, the cladding of formation between metal vapor and copper-matrix can reduce contact resistance at the contact zone and the probability of electric arc occurring, and thus reduce electrical sliding wear rate of the contact strip. These studies on arc erosion resistance mechanisms can provide a scientific basis for arc extinguishing researches and their practical applications of resin-type contact strip.更多还原