Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: Effect of pre-treatment processes including acid pickling and acid pickling plus alkaline cleaning on the corrosion resistance of achromium-free zirconate-titanate based conversion coating on AZ91D magnesium alloy was systematically investigated. The results indicated that the acid pickling could induce the preferential dissolution of α phase and thereby increase the surface roughness of AZ91D magnesium alloy, but which was not conductive to the enhancement of the corrosion resistance of the conversion coating. However, the acid pickling plus alkaline cleaning could appropriately modulate the surface chemical state of AZ91D magnesium alloy, and therefore effectively improve the corrosion resistance of the zirconate-titanate based conversion coating.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《材料研究学报》
Abstract: The effect of nanocrystallization on the adsorption of Cl- on Fe20Cr alloy in [Cl-] =0.1 mol/L borate buffer solution was investigated by means of X-ray photoelectron spectrum(XPS) and calculations per the first-principles. The results show that the influence of Cr on Cl- adsorption behavior could be described as the following two aspects : the one, in view of the calculation per the first-principles, is that the adsorption energy decrease with the increasing Cr content at the interface of passive film/alloy, which is conducive to the adsorption of Cl-; the other is that the Cr enrichment may also facilitate the formation of passivation film, which inhibit the Cl- adsorption. Nanocrystallization may enhance the diffusivity of Cr, which leads to the enrichment of Cr within the passive fil as well as at the interface of passive film/alloy. Thus, nanocrystallization can inhibit the adsorption and the inward migration of Cl- , and finally enhance the corrosion resistance of the alloy.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract: The waterborne epoxy coatings with polyaniline/vermiculite (PANI/VMT) as pigment were prepared. For the sake of identifying the functional groups of PANI/VMT, FT-IR measurement was performed. The thermal behavior of the pigments was characterized by thermal gravimetric analysis (TGA). The anticorrosion performance of waterborne epoxy coatings with different mass ratio of PANI/VMT was evaluated by electrochemical impedance spectroscopy (EIS) and salt spray test. The results show that a proper combination of the anodic protection ability of polyaniline and barrier property of vermiculite results in better performance of the PANI/VMT modified waterborne epoxy coating, for example, a coating with addition of 0.5% of PANI/VMT could provide a long- lasting anticorrosion protection for steel substrate.
Subjects: Materials Science >> Materials Science (General) submitted time 2017-11-21 Cooperative journals: 《金属学报》
Abstract:以K444镍基高温合金为基体,采用多弧离子镀法制备了NiCrAlY涂层、喷涂-烧结法制备了搪瓷基复合涂层,并对比研究了2种涂层的抗热震性能。热震实验高温段温度为900 ℃。高温段保温1.5 h后经水或空气冷却为一个热震循环。结果表明NiCrAlY涂层的抗热震性能较差。当冷却介质为水时,水淬热震50个循环后,涂层表面氧化膜开裂明显,且有个别裂纹已穿透氧化膜,扩展至涂层内部;而搪瓷基复合涂层的抗热震性能非常优异。热震后,涂层表面及内部均未发现裂纹,涂层和基体界面结合良好。经分析,其优良的抗热震性能源于(1)搪瓷釉热膨胀系数与高温合金基体匹配度高;(2)纳米Ni和NiCrAlY金属颗粒的加入进一步增大涂层的热膨胀系数的同时,还提高了搪瓷的韧塑性
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-14 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:本文采用双极性脉冲电源,在一定的阳极电流密度(ja)下,改变制备过程中阴极电流密度(jc)的大小,在LY12铝合金表面制备微弧氧化膜。采用扫描电镜(SEM)、电化学阻抗谱(EIS)以及中性盐雾试验研究微弧氧化膜的表面微观形貌、致密性以及实际服役性能的变化,进而分析阴极电流密度jc的变化对LY12铝合金微弧氧化膜致密性的影响。结果表明:阴极电流密度的大小对于微弧氧化膜的致密性具有至关重要的影响,施加适当的阴极电流密度可以制备致密性较好的氧化膜;当阴极电流密度较低或较高时,微等离子体在基体表面放电火花分布不均,无法获得致密性氧化膜;当ja=5A/dm2,ja/jc=1:1时,获得的LY12铝合金微弧氧化膜的致密性最佳。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-14 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:将3种含氧有机物(山梨醇、葡萄糖和抗坏血酸)分别与十二烷基苯磺酸钠 (SDBS) 进行复配, 利用线性极化、动电位扫描和电化学阻抗技术, 在 3.5% NaCl 饱和 Ca(OH)2 溶液中研究了不同比例复配物对钢筋的缓蚀性能, 基于量化计算结果和软硬酸碱理论 (HSAB), 分析探讨了复配物对钢筋的缓蚀机理, 以及化合物间的缓蚀协同效应。结果表明, 碱性氯离子溶液中3种含氧化合物对钢筋的缓蚀性能依次为山梨醇<葡萄糖<抗坏血酸, 且缓蚀效率与化合物作为路易斯碱的硬度呈正相关。与 SDBS 复配后均表现出一定的缓蚀协同效应, 其中以山梨醇与SDBS复配后协同效应最好。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-12 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:本文初步回顾了近年来电化学噪声分析方法的若干研究工作,举例介绍了电化学噪声数据直流漂移、电化学噪声时-频分析、非线性分析和模式识别等分析方法的优缺点,并对电化学噪声分析方法的发展方向进行了展望。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-12 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:从氧化动力学、氧化膜相组成和微观结构方面,研究了两种表面状态的Super 304H钢在700-900 oC纯水蒸汽中的氧化行为。研究表明:Super 304H钢的氧化动力学近似遵从抛物线规律,但是抛物线速率常数和氧化膜结构与氧化温度及试样表面状态密切相关。升高温度和抛光处理都显著增大了抛物线速率常数,促进了Fe氧化物瘤及其下方向内氧化区的生长。
Subjects: Materials Science >> Materials Science (General) Subjects: Geosciences >> Marine Sciences submitted time 2016-11-12 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:钢筋混凝土结构在海洋环境下因钢筋腐蚀而破坏,糖苷 (PG)阻锈剂的加入可有效改善钢筋表面钝化膜的性能,抑制钢筋的腐蚀。本文利用动电位极化和表面形貌观察方法,在 3.5% NaCl 饱和 Ca(OH)2 溶液中研究了糖苷对钢筋表面钝化膜的性能影响,运用肖特基图来研究混凝土中阻绣剂对钢筋钝化膜的半导体特性的影响。极化曲线结果表明,糖苷阻绣剂的加入可有效地促进钢筋表面的钝化和屏蔽氯离子对基体金属的侵蚀;Mott-Schottky检测结果和钝化膜致密性分析表明,钢筋表面钝化膜遵循正线性,且具有n型半导体特性,随糖苷浓度增大,钢筋表面钝化膜稳定性和致密性增强,耐蚀性提高;经表面观察表明加入阻绣剂后,钢筋表面钝化膜腐蚀程度明显减轻,说明阻绣剂抑制了钢筋表面钝化膜在含氯碱性溶液中的腐蚀。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-09 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:本文从氧化动力学、氧化膜相组成及微观结构方面,研究了晶粒尺寸对18Cr-8Ni耐热钢在700 oC下的高温水蒸汽中的氧化行为的影响。研究表明:(1)晶粒细化提高了耐热钢的抗水蒸汽氧化性能,降低了其氧化增重,推迟了失稳氧化的发生;(2)晶粒细化改变了耐热钢的氧化膜的微观结构,减小了“弹坑”区的尺寸且促进了“弹坑”区与合金界面上富Cr氧化物层的形成;(3)晶粒细化对耐热钢的抗水蒸汽氧化性能的改善主要归因于其对氧化物的形核和Cr向氧化膜/合金界面的扩散的促进作用。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-08 Cooperative journals: 《腐蚀科学与防护技术》
Abstract:本文系统研究了酸洗以及酸洗+碱洗前处理工艺对AZ91D镁合金无铬、无裂纹、低能耗钛/锆转化膜耐蚀性能的影响。研究结果表明,单独的酸洗前处理使得AZ91D镁合金表面的α相优先溶解,合金表面粗糙度增加,不利于钛/锆转化膜耐蚀性能的增加。合理地利用酸洗+碱洗调整AZ91D镁合金表面化学状态能够有效提高钛/锆化学转化膜的耐蚀性能。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-04 Cooperative journals: 《金属学报》
Abstract:在镍基铸造高温合金K38G上采用脉冲电镀的方法沉积Pt镀层,通过分步加热粉末包埋渗铝处理后,获得表层为单相PtAl2、内层为β-NiAl的铂铝涂层。分别对单相PtAl2涂层进行1100 °C恒温氧化及循环氧化测试,并分析涂层在两种氧化条件下的氧化行为及失效机制。结果表明:单相PtAl2涂层展现出良好的抗恒温氧化能力,初期快速增重主要来自于θ-Al2O3的生成,很快θ-Al2O3转变为α-Al2O3且增重趋于平缓;但是,单相PtAl2涂层的抗循环氧化能力较差,循环氧化过程中产生的热应力会导致部分区域PtAl2层剥离或脱落,继而引发涂层过早失效。因此,单相PtAl2涂层不适用于高温负载服役环境中,其在循环氧化过程中的失效和退化主要来自于PtAl2层剥落以及剥落区附近β-NiAl层Al元素的快速消耗。