共查询到20条相似文献,搜索用时 78 毫秒
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铝合金微弧氧化陶瓷层生长过程研究 总被引:5,自引:0,他引:5
采用硅酸钠溶液体系,制得250μm左右的微弧氧化陶瓷层。研究了溶液电导率以及电流密度对Al合金微弧氧化陶瓷层生长过程和厚度的影响。结果表明,提高溶液电导率能加速陶瓷层的生长,降低陶瓷层粗糙度。提高电流密度能加速陶瓷层的生长速率,但不宜过高,以10A/dm^2左右为佳。采用金相显微镜观察微弧氧化陶瓷层截面发现陶瓷层呈连续结构,较厚的陶瓷层中有少量金属颗粒存在。 相似文献
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采用熔融挤出法将热致性液晶聚合物(TLCP)与酚醛树脂(PF)熔融挤出,分别加入改良Hummers法制备的氧化石墨烯(GO)、硅烷偶联剂改性GO(KH550 GO、KH560 GO),制备了TLCP/PF/GO混杂复合材料,研究了加入GO对TLCP/PF/GO混杂复合材料的力学性能、摩擦磨损性能的影响。结果表明,硅烷偶联剂处理的GO能一定程度提高复合材料的摩擦磨损性能和力学性能,特别是TLCP/PF/KH560 GO混杂复合材料的摩擦因数稳定,在150 ℃和250 ℃下的体积磨损率分别降低了20.6 %和23.1 %,材料的冲击强度提高了18.6 %。 相似文献
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详细综述微弧氧化电解液中主要成分、添加剂及在电解液中加入纳米微粒对镁合金表面形成的陶瓷膜层性能的影响.此外还介绍了几种能获得性能优异陶瓷膜的电解液最佳组成,并对微弧氧化技术存在的问题和发展趋势进行了探讨. 相似文献
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黄珂 《合成材料老化与应用》2019,48(3)
通过扫描电镜(SEM)、X射线衍射仪和摩擦磨损试验机等手段,研究了磁控溅射和微弧氧化对AZ91合金表面改性层组织与性能的影响。结果表明,磁控溅射Ti膜与AZ91合金基体结合良好,界面处没有发现气孔或者微裂纹等缺陷,Ti膜厚度约为4μm,与基体实现了良好冶金结合;随着微弧氧化时间从3min增加至12min,复合改性层的厚度不断增加,经过微弧氧化处理后,不同微弧氧化时间膜层的磨损率都有不同程度降低,氧化时间为3min、6min、9min和12min的微弧氧化膜的磨损率分别为1.62×10~(-3)mm~3·N~(-1)·m~(-1)、0.63×10~(-3)mm~3·N~(-1)·m~(-1)、1.25×10~(-3)mm~3·N~(-1)·m~(-1)和1.51×10~(-3)mm~3·N~(-1)·m~(-1),微弧氧化时间为6min的复合改性层具有最佳的耐磨性能。 相似文献
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介绍处理生物难降解有机物的各种深度氧化处理技术——光化学催化氧化、湿式催化氧化、超临界水氧化、电解氧化及其他深度氧化技术,阐述了各种技术的机理及研究进展,探讨了各项技术发展的前景与趋势。 相似文献
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April Russell 《Catalysis Reviews》2013,55(4):337-423
The diesel oxidation catalyst (DOC) has been part of diesel exhaust systems since regulations were introduced to limit the amount of harmful emissions released to the environment from diesel engines. The DOC primary functions are oxidation of CO, unburned hydrocarbons, and NO, while active hydrocarbon oxidation can also be used to generate exotherms required for downstream components. This review will describe work that has attempted to understand the reactions, both desired and undesired, that occur over the catalyst. First, the history, configuration, and components of the DOC will be discussed, followed by in-depth coverage of the fundamental reactions that occur over a DOC, including reaction mechanisms, reaction inhibition, and other reactivity effects. Finally, DOC deactivation mechanisms and their effects on the DOC are described. While there is a lot of research literature regarding Pt- and Pd-based catalysts for many different reaction schemes, this review tries to highlight work most relevant to DOC applications. 相似文献
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生物难降解有机污染物废水深度氧化治理技术进展 总被引:6,自引:0,他引:6
本文综述了处理废水中生物难降解有机污染物的深度氧化技术—湿式空气氧化法、超,临界水氧化法、复合空气氧化法、光化学氧化法及其相应的催化氧化法,评论这些方法的特点及应用前景有38篇参考文献。 相似文献
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Selective oxidation with air on metal catalysts 总被引:5,自引:0,他引:5
Pierre Gallezot 《Catalysis Today》1997,37(4):40-418
Oxidation of organic molecules with air on metal catalysts has been known for a long time but there has been a renewed interest in recent years because these catalytic reactions are environmentally safe and could replace stoichiometric oxidations. This paper describes several oxidation reactions conducted either at high temperatures in the gas phase or at moderate temperatures in the liquid phase; in both cases they proceed via a mechanism of oxidative dehydrogenation on the metal surface. Ethylene glycol was converted to glyoxal at 550°C on Ag/SiC catalyst with a 70% yield provided promoters were added to the reaction feed (diethylphosphite or iodine) or deposited on the catalyst (LiPO4 or H3PO4). The promoters improve the conversion and selectivity by modifying the structure and the oxygen concentration on the surface of silver. Oxidation of glyoxal to glyoxylic acid, glucose to gluconic acid and glycerol to various oxygenated derivatives were conducted in water at 60°C in the presence of carbon-supported palladium or platinum catalysts. Bismuth promoter, deposited on the platinum metals by redox reaction, improves the catalyst activity by preventing over-oxidation of the metal surface and favors the oxidation of secondary alcohol functions into keto-derivatives. At higher reaction temperatures, platinum catalysts produce C-C bond rupture with the formation of carboxylic acids with smaller chains. Thus, cyclohexanol was converted into C6, C5, and C4 diacids with a 45% selectivity to adipic acid on Pt/C catalysts at 150°C. 相似文献
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结合催化湿式氧化法和电催化氧化法为水热电催化氧化法处理高浓度苯酚模拟废水((ρCOD)为7500mg/L):以C/Ru作催化剂(w(Ru)为0.5%),自制DSA阳极(釜体为阴极),加入NaCl作支持电解质(w(NaCl)为1%),充入氧气使PO2为3.5MPa,升温至设定温度后:开初0.5h进行苯酚的催化湿式氧化,后0.5h进行电催化氧化,并改变条件进行苯酚的单一催化湿式氧化和电催化氧化。结果表明:85℃时水热电催化氧化条件下,苯酚去除率为100%,COD去除率达92.34%,而单一催化湿式氧化和电催化氧化的COD去除率却依次为68.46%、39.73%,可见水热电催化氧化法利用了催化湿式氧化法和电催化氧化法的协同作用,取得了更佳的效果。该方法是一种新型、低温、高效的废水处理技术,为处理苯酚废水提供了另一种可能途径。 相似文献
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