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镁合金双稀土转化膜及其耐蚀性能的研究 总被引:1,自引:0,他引:1
已有的铬酸盐转化膜技术因污染环境而被限制使用.采用硝酸铈和硝酸镧混合溶液对AZ31镁合金进行了双稀土转化处理,讨论了浸渍时间对转化膜耐腐蚀性能的影响.采用点滴试验、盐水浸溃试验和Tafel极化法评价了双稀土转化膜的耐腐蚀性能.结果表明,经过双稀土处理后,镁舍金的变色时间由6s提高到79 s;在3.5%NaCl溶液中转化膜的腐蚀速率是基体的1/5;转化膜的腐蚀电位提高了0.313 V,腐蚀电流密度由4.03×10-2 mA/cm2降为2.31×10-4 mA/cm2;双稀土转化膜的微观形貌呈破裂的干泥状;双稀土转化处理提高了镁合金的耐蚀性能,随处理时间的延长耐蚀性呈先增加后降低的趋势. 相似文献
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通过在植酸基础转化液中添加两种不同组成的成膜促进剂制备镁合金植酸转化膜,采用SEM、EDS及失重法研究了添加剂对转化膜结构、形貌及耐蚀性能的影响.结果表明:经植酸转化处理后,镁合金表面耐蚀性能均得到了大幅提高,120 h盐水浸泡后失重率仅为镁合金基材的1/5;Ca(NO3)2、NH4VO3及Na2C4 H4O6·2H2O组合添加剂的加入有利于改善膜层结构和致密性,转化膜由完整、致密且与基材结合紧密的内层和网纹的外层组成,耐蚀性能较纯植酸转化膜提高1倍,而NaF、Na2B4O7及Na2C4H4O6·2H2O的组合添加剂则对转化膜结构和耐蚀性能影响不显著. 相似文献
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镁合金无铬化学转化工艺研究 总被引:6,自引:3,他引:6
镁合金的耐蚀性差,用铬酸盐法处理污染环境.用正交试验法研究了一种适合于AZ91D镁合金的无铬化学转化膜成膜工艺,可获得白色均匀的膜层.优选了转化液组分含量、pH值及转化时间等工艺条件,用扫描电镜和X射线衍射法观察分析了转化膜的微观形貌和相结构,用点滴法和盐水浸泡法对膜层耐蚀性能进行了评价,并与铬酸盐转化膜进行了比较,二者耐蚀性相当. 相似文献
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作为一种新型柔性成形技术,三维自由弯曲技术特别适用于具有复杂空间轴线、异形截面的空心构件。主要综述了三维自由弯曲成形技术的发展历程、成形装备的发展过程以及国内外的研究现状。在此基础上,重点分析了三维自由弯曲成形装备的5种典型构型及其机构运动原理,介绍了5种构型的各自特点及工程应用,并对自由弯曲成形装备的关键技术如过渡段处理技术、有限元数值模拟技术、难变形材料自由弯曲热成形技术等方面进行综述,并结合笔者的研究经历对管材自由弯曲成形研究中存在的问题进行了简要分析。最后,对管材三维自由弯曲成形技术及装备在航空航天、核电、汽车、医疗等领域的应用前景进行了分析和展望。 相似文献
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电磁成形是一种典型的高速率成形技术,能显著提高材料的成形性能,并已经成功应用于金属板材成形领域,获得了很好的成形效果.为了能够继续扩大电磁成形技术在板材成形方面的应用,对目前板材电磁成形技术研究进展进行了综述.首先介绍了电磁成形工艺的原理与主要特点;分析了目前电磁成形技术、电磁辅助冲压成形技术在金属板材成形方面的研究进展;提出了电磁成形技术在应用研究方面存在的主要问题,并展望了该技术的发展趋势;最后,分别从成形材料和成形工艺两个方面分析了后续研究的突破点以实现扩大该技术应用的目的. 相似文献
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This paper examined the drivers of blockchain technology adoption and carbon performance using the theory of technology-organization-environment (TOE) as the basis for the development of a technology adoption framework. Blockchain technology has passed the proof testing phase and is attracting early adopters who can gain benefits from it. Manufacturing firms that had adopted the blockchain technology and voluntary reported the carbon emission were targeted as the sample and survey data were collected from manufacturing firms that were registered with the Association of Malaysian Manufacturers. Unfavourable support of top management and the lack of technology competence were the main barriers to the adoption of blockchain technology among manufacturing firms. The results indicate that firms did not achieve low carbon performance and that a lack of pressure from competitors and technical competency to undertake blockchain technology were factors. No evidence existed demonstrating a linkage of early adopters of blockchain technology with and low carbon performance. Recommendations of this study include that firms should take the initiative to record the energy consumption, engage in the transfer of carbon credits, and monitor carbon performance using reliable technology to improve business transparency and sustainability. 相似文献
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庞前涛 《中国材料科技与设备》2008,5(3):45-47
本文主要介绍了一种粉末烧结技术——放电等离子烧结。首先从结构设计上进行了介绍,放电等离子烧结的主要原理是在粉末进行压力烧结的同时施加电流,最终实现材料的致密化。放电等离子烧结的主要优点是烧结温度低、时间短、升温快、材料致密等。最后列举了放电等离子烧结技术在热电材料、硬质材料、功能梯度材料等的应用实例,论述表明放电等离子烧结技术是一种可以制备高性能材料的烧结技术。 相似文献
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Szu-chia S. Lo 《Scientometrics》2010,82(1):109-120
In this study, the author tried to demonstrate the linkage between science research and technology development through non-patent
citation analysis to reveal that the important knowledge resources from science research had significant impact on technology
development. Genetic engineering technology was the field examined in this study. From the references listed in the patents,
it was observed that the technology development in genetic engineering was influenced heavily by the research done by public
sector. Over 90% of the citations were non-patent literatures, and the majority of non-patent citations were journal articles.
Citing preferences, such as country preference and institute preference were observed from the data included in this study. 相似文献
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精密锻造成形技术是应用范围越来越广泛的一种先进制造技术。本文简要介绍了精密锻造成形技术的发展概况,列举了大量的工程应用实例来阐明冷锻成形、温锻成形、闭塞锻造成形、铝合金的精密锻造成形、精密热模锻成形、复合成形、等温锻造成形等精密锻造成形工艺在我国的应用情况。在给出了我国精密锻造成形技术目前发展中存在的主要问题的基础上,指出了精密锻造成形技术的发展趋势。 相似文献