共查询到18条相似文献,搜索用时 62 毫秒
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本文对纯铁进行了硼、氮离子注入试验,利用透射电镜和x射线衍射仪分析了纯铁注入层的组织结构,而且对纯铁注入层的硬度和耐蚀性进行了测试。结果表明:纯铁注入硼离子后表层形成了弥散的FeB相,晶界处形成了较粗大的Fe2B相;注入硼离子后再注入氮离子进一步形成了Fe2N和Fe3N相。硼、氮离子注入明显提高表层的硬度,显著地提高纯铁表层的耐蚀性。 相似文献
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本文应用透射电镜(TEM)等方法对纯Fe中注入Ni+、Mo+、B+及Ni++Mo++B+引起表面层微观结构变化进行了研究,同时对不同注入条件进行了计算机模拟计算。结果表明,离子注入后纯Fe表面层微观结构有明显变化,较高剂量离子注入可使表面晶粒细化,并能形成表面非晶层,注入Ni+后,注入层内出现以Fe为主的hcp碳化物,部分α-Fe转变为γ-Fe,并呈现微孪晶形貌 相似文献
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离子注入纯Fe表面微观结构研究 总被引:7,自引:0,他引:7
本文应用透射电镜等方法对纯Fe中注入Ni^+,Mo^+,B^+及Ni^++Mo^++B^+起表面层微观结构变化进行了研究,同时对不同注入条件进行了计算机模拟计算。 相似文献
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为了探究纯铁在天然海水中的腐蚀机理以及流速对其腐蚀行为的影响,进而对铁合金腐蚀研究提供理论基础,采用自行制造的水槽式流体流动装置,模拟流动海水对纯铁的腐蚀状况,利用电化学测试手段(自腐蚀电位监测,动电位极化)并结合表面与截面形貌分析,研究了纯铁在静止和选取流速(0.2,0.3,0.4 m/s)下的海水中的腐蚀行为.结果表明:纯铁在流动海水中的耐蚀性比静止时差,且流速越大耐蚀性越差,其腐蚀过程仍主要受阴极氧扩散控制;纯铁在海水中的自腐蚀电位随流速的提高而负移.纯铁在静止海水中的腐蚀产生突起状形貌,在流动海水中腐蚀产生具有明显方向性的腐蚀坑. 相似文献
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为了提高纯钛材的表面硬度及耐蚀性,使之更适应人体环境,对铸态纯钛材表面进行离子渗氮。利用能谱仪、X射线衍射仪、扫描电镜及显微硬度计研究了渗氮钛材的成分、相结构、形貌及硬度,利用动电位极化曲线及交流阻抗谱对比研究了纯钛材及离子渗氮钛材在37℃的Hank’s人工模拟体液中的电化学行为。结果表明:经过650℃渗氮处理后,铸态纯钛材表面形成了17μm的梯度渗氮层,其相组成为α-Ti(N),Ti2N,TiN;表面显微硬度约为(650±20)HV,为铸态纯钛材的2.3倍;离子渗氮钛材的耐蚀性明显提高。 相似文献
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通过干涉条纹分析,研究了65Nb模具钢经表面N^+注入强化处理后的磨损行为,提出了磨损性能最佳的N+注入工艺,该工艺用于65Nb模具钢十字头光冲模具,其寿命显著提高。 相似文献
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医用NiTi形状记忆合金的腐蚀特性 总被引:2,自引:0,他引:2
研究了0.9%NaCl生理液、Hank's模拟体液和Tyrode's模拟血液的pH值和Cl-离子浓度对医用NiTi形状记忆合金Ni离子腐蚀溶出的影响.结果表明,三种模拟体液的氧化还原电位不同,使Ni离子释放呈现出差异,Tyrode's模拟血液中Ni离子释放量较高;随着pH值的增大Ni的Flade电位降低,从而使Ni离子释放量降低;随着Cl-浓度增加,Ni离子释放量增大,呈现出较强的Ni选择性腐蚀行为,而Ti的腐蚀微弱,点蚀是其主要的腐蚀形式. 相似文献
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以AZ80A市售镁合金为参照,研究了镁基纳米复合材料镁,即:碳纳米管(Mg/CNT)复合材料及氧化镁(Mg/MgO)纳米复合材料在模拟体液中的腐蚀行为.浸泡过程中测量溶液的pH值变化,在浸泡1、4、8、10、20和30d后计算其腐蚀速率,并通过XRD分析腐蚀产物成分.结果显示:Mg/MgO纳米复合材料比Mg/CNT复合材料耐腐蚀,Mg/CNT复合材料在4d时已经腐蚀完,AZSOA型镁舍金最耐腐蚀。三者的腐蚀产物成分基本相同,均为Mg2CI(0H)3-4H2O及少量的MgCl2. 相似文献
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In this paper the corrosion behavior of NiTi thin films fabricated by sputtering from Ni and Ti targets has been studied by cyclic potentiodynamic polarization tests in Hank's and Ringer's solution at 310 K. For comparison, bulk NiTi Shape Memory Alloy (SMA) has also been studied to elucidate the different corrosion behavior of bulk and thin film material. The electrochemical experiments reveal that thin film NiTi SMA has comparable corrosion current density (icorr), much higher pitting corrosion potentials and wider passive range than the bulk NiTi. We show that NiTi SMA vapour deposited thin films are less susceptible to pitting corrosion than the bulk. 相似文献
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The chemical and physical processes of magnesium in simulated body fluid (SBF) were investigated. The corrosion rate of magnesium was measured after 3, 5, 7, 14 and 21 days of immersion, respectively. It was found that the corrosion rate decreased with increasing immersion time, while the pH of SBF changed inversely. Network-like cracks and pits were the main damages resulting from corrosion, and the localized buildup of chloride ions was the major cause of pit formation. 相似文献
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研究了两种钙含量相同、锌含量(质量分数)不同的镁合金(Mg-1.0%Ca-0.3%Zn和Mg-1.0%Ca-1.0%Zn)在模拟体液(Simulated body fluid,SBF)中的腐蚀行为.通过三电极体系动电位法、析氢法、pH计和扫描电子显微镜对合金在SBF中的极化曲线、浸泡过程中析出氢气量、SBF的pH值变化以及浸泡后的合金形貌进行分析和研究.结果表明:两种合金的耐腐蚀性均好于纯镁,其中合金Mg-1.0%Ca-1.0%Zn较合金Mg-1.0%Ca-0.3%Zn在SBF中极化阻力大,析出氢气量减少,在1~48 h内SBF溶液的pH值增加较快,SBF溶液的碱化较快;浸泡后合金Mg-1.0%Ca-1.0%Zn表面较平整,合金的耐腐蚀性较好,腐蚀速率能基本满足作为体内植入生物材料的要求,且在SBF中日离子溶出量不超过人体耐受量的前提下,其体内植入物制品表面积上限可达179 cm2,具有较大的实用性. 相似文献
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Lijun Liu Yao Meng Chaofang Dong Yu Yan Alex A. Volinsky Lu-Ning Wang 《材料科学技术学报》2018,34(12):2271-2282
Zinc was recently suggested to be a potential candidate material for degradable coronary artery stent. The corrosion behavior of pure zinc exposed to r-SBF up to 336?h was investigated by electrochemical measurements and immersion tests. The morphology and chemical composites of the corrosion products were investigated by scanning electron microscope, grazing-incidence X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectrometer. The results demonstrate that the initial corrosion products on the pure zinc mainly consist of zinc oxide/hydroxide and zinc/calcium phosphate compounds. The pure Zn encounters uniform corrosion with an estimated corrosion rate of 0.02–0.07?mm?y?1 during the immersion, which suggests the suitability of pure Zn for biomedical applications. 相似文献
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《Materials at High Temperatures》2013,30(3-4):185-193
Abstractα-iron samples, with a 4 to 6 nm oxide layer on top of the surface due to preparation, were oxidised in situ within a scanning electron microscopy equipped with electron back-scatter diffraction. At 773 and 973 K, two different growth mechanisms during the initial stage of iron oxide formation could be observed, layer-by-layer growth at 773K and island growth at 973 K. The growth mechanism at 973K is correlated to the formation of a thin layer of Fe1–XO (wüstite) prior to Fe3O4 (magnetite) crystallisation whereas at 773K only magnetite was found as newly grown oxide. Magnetite showed a strong epitaxial relationship to α-iron with its {111} plane growing preferentially on the {110} plane of iron. 相似文献