共查询到19条相似文献,搜索用时 500 毫秒
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对Cr12钢进行了稀土诱导离子溅射渗氮试验,利用显微硬度计测量了试样表面渗氮层的硬度与层深,结合XRD衍射仪分析了复合渗氮层的相组成,最后用摩擦试验机检测试样表面的摩擦磨损特性。结果表明,稀土能够影响Cr12钢离子溅射渗氮效果,且其效果随两者距离的增加而急剧下降。当稀土与Cr12钢试样距离小于25 mm时,试样表面硬度相对普通离子渗氮工艺明显减小,表面摩擦因数及磨损率略差,但其渗氮层深度却明显增加;当两者距离超过25 mm时,稀土诱导效果明显减弱,试样表面的硬度及摩擦因数与普通离子渗氮工艺基本相同,但磨损率明显增大。分析表明,稀土元素能增大试样表面氮离子的吸附能力且为其渗入提供路径优势,当两者距离过大时稀土离子吸附性减弱,诱导效果消失,同时也使试样表面产生晶格缺陷,降低了其表面抗磨损的能力。 相似文献
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目的探索循环离子渗氮与常规恒温离子渗氮技术的工艺效果。方法先对试样进行调质处理,分组进行离子渗氮,固定氨气和乙醇的流量,改变渗氮时间和渗氮温度两种工艺参数及渗氮工艺,分别测定渗氮后各试样的表面硬度及渗层厚度,观察其金相组织,并分析每组试样渗氮层的性能。结果循环离子渗氮530 6 h℃试样的表面硬度最高,随着渗氮温度的升高和渗氮时间的延长,试样的表面硬度增加,但是当温度超过530℃、时间超过6 h后,试样的表面硬度反而降低。循环渗氮550 10 h℃试样的渗层厚度最厚,随着渗氮温度的升高和渗氮时间的增加,试样的渗层厚度变厚,但时间超过6 h后,渗层厚度的增加较缓慢,6、8、10 h试样的渗层厚度差别不大。相同的渗氮温度下,循环渗氮6 h的试样的渗层厚度基本与常规恒温渗氮10 h试样的渗层厚度一样,相同渗氮时间内,循环渗氮510℃的试样的表面硬度高于恒温渗氮550℃试样的表面硬度,且两者的渗层厚度相差不多。结论循环离子渗氮工艺优于常规的恒温离子渗氮,循环离子渗氮550 8 h℃试样的综合性能最好。 相似文献
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温度对AISI304奥氏体不锈钢离子渗氮的影响 总被引:1,自引:0,他引:1
对AISI304奥氏体不锈钢进行脉冲电流辉光离子渗氮处理,在不同处理温度(480 ℃、520 ℃、580 ℃)下渗氮8 h后,获得了一定厚度的渗氮层.通过对渗层进行金相分析和硬度测试表明,随着渗氮温度升高,渗层厚度增大,显微硬度先增大后减小.综合温度对渗层厚度与显微硬度的影响,AISI304奥氏体不锈钢卡套辉光离子渗氮温度可采用520 ℃,渗氮后渗层厚度为90 μm,显微硬度为1317 HV0.1. 相似文献
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《Surface & coatings technology》2001,135(2-3):238-249
Pre-sputtering and plasma-assisted nitriding of pure aluminium and 2024 aluminium alloy were studied in situ by plasma monitoring and ex situ by several surface analysis methods. The influence of the process parameters, time, temperature, pressure and gas composition on mass and energy distributions of ions, as well as on topography and chemical composition, was examined. The chronology of the sputtering process could thus be clarified. An oxide film which is relatively thick compared to the native oxide layer and enriched with magnesium is formed at the initial stage of the sputtering treatment, followed by the removal of this film with a subsequent roughening of the surface. The cleaning effect of the plasma can be enhanced by increasing the argon pressure or by an intermixture of hydrogen. Due to a supplementary chemical etching, hydrogen admixture reduces the surface roughness and effectively decreases the oxygen content of the surface. During the nitriding treatment, nanocrystalline hexagonal aluminium nitride AlN is formed. Growth rate and nitrogen content of the nitride layer were found to strongly depend on the gas composition during sputtering and nitriding. The positive effect of addition of argon and hydrogen, respectively, arises from an intensification of the nitrogen plasma, the production of nitrogen–hydrogen molecular ions and an increase of the ion energy. The nitrogen pressure affects the layer thickness due to higher nitrogen activity and ion energies. The chemical composition of the cathode material influences discharge current and, as a result, the ion energies. 相似文献
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Li Zhong Xi Han Shangqi Zhou Qin Ren Teng Yun 《Journal of Materials Engineering and Performance》2003,12(6):687-692
The properties of nitrided parts are closely related to the component phases of their compound layers and microstructure shape
of their diffusion layers. Based upon the influence of nitriding temperature and nitrogen (N) potential on formation and decomposition
of ion nitriding layer, the component phases and microstructure shape of ion nitrided layer, which was processed under cyclic
N potential, was studied with x-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The mechanism of
rapid ion nitriding is also discussed in this paper. The results show that if the rapid ion nitriding by the thermal cycling
and the N potential cycling is controlled, the nitriding speed and nitrided layer thickness of materials can not only be enhanced
compared to the conventional ion nitriding technique, but also the alloy nitrides can be obviously increased. The precipitation
hardness phases of diffusion layer became more trivial and spread in all directions. It is very important to improve the quality
of the nitrided layer and to enhance the properties of nitrided parts. 相似文献
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Using a pulse low energy ion implantation with an electronic beam switch operating in the kHz regime, a more efficient nitriding process is possible than with either pulsed plasma immersion ion implantation (PIII) or continuous low energy ion implantation (LEII). Besides the pulsed mode, a fast and precise external heating system for controlling the substrate temperature is necessary. Using such an experimental setup, it is shown that the duty cycle itself does not influence the diffusion and phase formation, as long as the exact same substrate temperature is maintained, thus nitrogen uptake and diffusion are decoupled. Optimal nitriding efficiency was observed for a duty cycle between 20 and 35%. At lower duty cycles (below 15% duty cycle), not enough nitrogen was available to allow the formation of expanded austenite, while higher duty cycles led to a reduced layer thickness caused by higher sputtering induced by the increased ion bombardment itself. 相似文献
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为揭示活性屏等离子体源渗氮工艺特性(试样偏压电位和试样距屏高度)对AISI 316奥氏体不锈钢渗氮效果的影响规律,利用最小二乘法线性回归拟合了不同工艺条件下渗氮层厚度数据,绘制了活性屏等离子体源渗氮AISI 316奥氏体不锈钢的工艺特性图,以此确定其最佳工艺参数。并通过对金属网屏上溅射颗粒的化学成分和相结构分析,探讨了活性屏等离子体源渗氮的传质机制。结果表明:渗氮层厚度随试样距屏高度增大而降低,当适当降低渗氮气压或试样施加一定负偏压时,均有助于提高渗氮层的厚度,并且证实了"溅射-再沉积"模型是活性屏等离子体源渗氮重要的传质机制。 相似文献
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分别研究了在500、600、650和700 V阴极电压条件下采用连续供气抽真空和间歇供氮闭炉的方式进行纯氮离子渗氮的工艺及机理.通过对间歇供氮闭炉离子渗氮层显微组织、相组成和硬度梯度的测定与分析,计算和验证了该工艺中N2分子临界离解能.结果表明,纯氮离子渗氮的活性氮原子来自于经阴极位降区加速的高能N 2与中性N2分子间的非弹性碰撞,离解N2分子的N 2离子临界能为48.64 eV,相应的阴极电压门槛值为650 V.纯氮离子渗氮工艺除要求阴极电压高于650 V外,间歇供气闭炉渗氮也是必备条件,在一定温度和足够高的阴极电压下,只有采用间歇供氮闭炉方式进行离子渗氮,从N2分子才能离解出足够多的活性氮原子,使试样表面产生明显的渗氮效果. 相似文献
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Y. D. Zhu M. F. Yan Y. X. Zhang C. S. Zhang 《Journal of Materials Engineering and Performance》2018,27(3):961-969
In the present work, a copper-titanium film of gradient composition was firstly fabricated by the dual magnetron sputtering through power control and plasma nitriding of the film was then conducted to modify C17200 Cu alloy. The results showed that the prepared gradient Cu-Ti film by magnetron sputtering was amorphous. After plasma nitriding at 650 °C, crystalline Cu-Ti intermetallics appeared in the multi-phase coating, including CuTi2, Cu3Ti, Cu3Ti2 and CuTi. Moreover, even though the plasma nitriding duration of the gradient Cu-Ti film was only 0.5 h, the mechanical properties of the modified Cu surface were obviously improved, with the surface hardness enhanced to be 417 HV0.01, the wear rate to be 0.32 × 10?14 m3/Nm and the friction coefficient to be 0.075 at the load of 10 N, which are all more excellent than the C17200 Cu alloy. In addition, the wear mechanism also changed from adhesion wear for C17200 Cu substrate to abrasive wear for the modified surface. 相似文献
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高功率脉冲磁控溅射技术(HIPIMS)是一门新兴的高离化率磁控溅射技术.概述了HIPIMS的技术优势,包括高膜层致密度和平滑度、高膜基界面结合强度以及复杂形状工件表面膜层厚度均匀性好等.同时归纳了HIPIMS存在的问题,包括沉积速率及低溅射率金属靶材离化率低等.在此基础上,重点综述了近年来复合HIPIMS技术的研究进展,其中复合其他物理气相沉积技术的HIPIMS,包括复合直流磁控溅射增强HIPIMS、复合射频磁控溅射增强HIPIMS、复合中频磁控溅射增强HIPIMS、复合等离子体源离子注入与沉积增强HIPIMS等;增加辅助设备或装置的HIPIMS,包括增加感应耦合等离子体装置增强HIPIMS、增加电子回旋共振装置增强HIPIMS,以及增加外部磁场增强HIPIMS等.针对各种形式的复合HIPIMS技术,分别从复合HIPIMS技术的放电行为、离子输运特性,及制备膜层的结构与性能等方面进行了归纳.最后展望了复合HIPIMS技术的发展方向. 相似文献