AZ31镁合金表面单宁酸转化膜的组织结构与耐腐蚀性能

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AZ31镁合金组织性能的影响分析

摘要挤压变形AZ31镁合金组织以绝热剪切条纹和细小的α再结晶等轴晶为基本特征。

挤压变形可显著地细化镁合金晶粒并提高镁合金的力学性能。

随挤压比的增大,晶粒细化程度增加,晶粒尺寸由铸态的d400μm减小到挤压态的d12μm(min);强度、硬度随挤压比的增大而增大,延伸率在挤压比大于16时呈单调减的趋势。

轧制变形使板材晶粒明显细化,硬度提高。

AZ31合金中添加Ce,其铸态组织中能够形成棒状Al4Ce相,并能改善合金退火态组织和力学性能;添加Ce可以改善AZ31的综合力学性能。

关键词:AZ31变形镁合金;强化机制；组织；性能绪论20世纪90年代以来,作为最轻金属结构材料的镁合金的用量急剧增长,在交通、计算机、通讯、消费类电子产品、国防军工等诸多领域的应用前景极为广阔,被誉为“21世纪绿色工程材料”,许多发达国家已将镁合金列为研究开发的重点。

大多数镁合金产品主要是通过铸造生产方式获得,变形镁合金产品则较少。

但与铸造镁合金产品相比,变形镁合金产品消除了铸造缺陷,组织细密,综合力学性能大大提高,同时生产成本更低,是未来空中运输、陆上交通和军工领域的重要结构材料。

目前，AZ31镁合金的应用十分广泛,尤其用于制作3C产品外壳、汽车车身外覆盖件等冲压产品的前景被看好,正成为结构镁合金材料领域的研究热点而受到广泛重视。

第1章挤压变形对AZ31镁合金组织和性能的影响1.1 挤压变形组织特征及挤压比的影响作用图1-1为动态挤压变形过程中的组织变化。

动态变形过程大致分为3个区域:初始区、变形区和稳态区，分别对应着不同的组织。

图1-1a为初始区挤压变形前的铸态棒料组织。

由粗大的α-Mg树枝晶和分布其间的α-Mg+Mg17Al12共晶体组成,枝晶形态十分发达，具有典型的铸造组织特征。

晶粒尺寸为112~400μm。

图1-1b为变形区近稳态区组织。

图中存在大量无序流线,流线弯曲度大、方向不定且长短不一，显然这种组织特征是在挤压力作用下破碎的树枝晶晶臂(α固溶体)发生滑移、转动的结果。

AZ31镁合金基Cu-MOF-SA超疏水膜的制备及其耐腐蚀性能研究

AZ31镁合金基Cu-MOF-SA超疏水膜的制备及其耐腐蚀性能研究王世颖;康丰;吴敏娴;陈艳丽;陈智栋【期刊名称】《材料保护》【年(卷),期】2024(57)1【摘要】腐蚀是影响镁及其合金大规模应用的关键技术难题之一,因可有效隔离金属基底与腐蚀介质的直接接触,从而降低腐蚀速率,制备超疏水表面成为提高镁合金耐蚀性的有效途径。

通过一步电沉积方法,在AZ31镁合金基底上成功制备了铜-金属有机骨架-硬脂酸(Cu-MOF-SA)超疏水膜,并对超疏水膜的耐腐蚀性、化学稳定性和耐热性进行了综合研究。

结果表明,表面的水接触角可达158°,超疏水膜覆盖的试样在3.5%NaCl溶液中表现出良好的耐腐蚀性能,相比AZ31镁合金基底,其腐蚀电位正移了0.24 V,腐蚀电流密度降低了1个数量级。

在pH值为1~14的溶液中浸润24 h后,超疏水膜的水接触角仍可达135°以上,浸泡在pH=1的溶液24 h的超疏水膜的腐蚀电位比AZ31镁合金基底高0.21 V。

在20~90℃空气中保温24 h 后,超疏水膜的水接触角仍保持在154°以上,80℃下保温24 h后其腐蚀电位比AZ31镁合金基底的高0.22 V,腐蚀电流密度比AZ31镁合金基底的小1个数量级。

结果表明,本研究制备的Cu-MOF-SA疏水膜具有良好的超疏水性和耐腐蚀性。

【总页数】9页(P148-155)【作者】王世颖;康丰;吴敏娴;陈艳丽;陈智栋【作者单位】常州大学材料科学与工程学院;常州大学石油化工学院【正文语种】中文【中图分类】TG174.4【相关文献】1.Mg-Mn-Ce镁合金表面超疏水复合膜层的制备及耐腐蚀性能2.铜离子与植酸作用制备镁合金超疏水表面及耐腐蚀性能研究3.镁合金表面超疏水复合膜层制备及其耐腐蚀、自清洁性能研究4.AZ31镁合金表面含纳米SiC氟化镁膜层的制备及耐腐蚀性能因版权原因，仅展示原文概要，查看原文内容请购买。

变形镁合金AZ31的织构演变与力学性能

变形镁合金AZ31的织构演变与力学性能镁合金作为一种新型轻质金属结构材料,在汽车制造、通讯电子、航空航天等工业领域具有广阔的应用前景。

由于镁是密排六方（HCP）结构材料,其塑性变形在室温下仅限于基面{0001}<11（?）0>滑移及锥面{10（?）2}<1011>孪生,因此,镁合金的室温塑性加工能力较差。

目前大多数镁合金制品的加工局限于铸造,特别是压铸成型,然而,铸件的力学性能不够理想且容易产生组织缺陷,极大地限制了镁合金的应用范围。

变形镁合金在铸造后往往通过热变形方式（如挤压、轧制等）细化晶粒、改善合金的组织结构来提高合金的力学性能。

与铸造镁合金相比,变形镁合金的综合力学性能优异;但常规变形镁合金在热变形后一般会产生强烈的{0002}基面织构,而该织构的存在是导致变形镁合金低的室温塑性和高的各向异性的主要原因。

良好的室温塑性是变形镁合金广泛应用的前提之一,而如何通过织构控制及晶粒细化法有效地改善和提高镁合金的室温塑性成为变形镁合金工业发展中的重要方向。

针对上述问题,本论文开展了如下研究工作:（1）铸态纯镁热轧变形过程中{0002}基面织构的演变规律;（2）异步轧制AZ31镁合金板材的形变织构及退火织构;（3）非对称热挤压AZ31镁合金板材的显微组织、织构特征及力学性能;（4）晶粒尺寸及织构对AZ31镁合金室温压缩变形行为的影响。

主要结论如下:铸态纯镁在400℃热轧过程中发生了明显的动态再结晶,伴随晶粒细化和{0001}基面织构的形成。

随着轧制道次的增加,晶粒逐渐细化,晶粒大小趋于均匀,孪晶数量减少;织构由初始态的无规则取向逐渐转化为{0002}基面织构,且基面织构的强度随着热轧变形量的增加而增加。

经多道次热轧后（ε=78%）,纯镁板材内部形成均匀的等轴晶组织和较强的{0002}基面织构。

热轧纯镁中动态再结晶的形核机制主要为基于孪生的动态再结晶形核机制。

AZ31D镁合金固溶处理组织的耐蚀性

AZ31D镁合金固溶处理组织的耐蚀性马伯江;李冲;朱华东【摘要】用金相显微镜(OM)、扫描电镜(SEM)、能量分散谱仪(EDS)和X射线衍射仪(XRD)研究了AZ31D镁合金铸态和固溶组织的特征.为了揭示其腐蚀特征和机理,在NaCl溶液中进行了浸泡试验和极化腐蚀试验.结果显示:由于铸态组织成分不均匀和第二相晶界集中析出,在NaCl溶液中形成了梅花状腐蚀花纹;固溶组织在NaCl溶液中虽具点蚀特征,但耐蚀性仍优于铸态组织.%Theas-cast AZ31D magnesium alloy and its solution-treated microstructure were examinedby optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray Diffraction (XRD).The immersion testing of AZ31D magnesium alloys exposed to NaCl solution and electrochemical measurement were carried out to seek their corrosion characteristics and corrosion mechanisms.The results show that clubs-like patterns form on the surface of the as-cast sample in NaCl solution on account of uneven composition and the second phase precipitation at grain boundary;although pitting corrosion may form on the surface of the solution-treated sample, the self-corrosion current density of the solution-treated sample is far lower than that of the as-cast one in mass ratio of 3.5% NaCl solution saturated with Mg(OH)2.【期刊名称】《青岛科技大学学报（自然科学版）》【年(卷),期】2016(037)005【总页数】5页(P512-516)【关键词】AZ31D镁合金;铸态;固溶处理;耐蚀性;NaCl溶液【作者】马伯江;李冲;朱华东【作者单位】青岛科技大学机电工程学院,山东青岛 266061;青岛科技大学机电工程学院,山东青岛 266061;青岛科技大学机电工程学院,山东青岛 266061【正文语种】中文【中图分类】TG146.2作为一种轻金属，镁及镁合金有许多优良性能，其在运输车辆上已经有着广泛的应用。

变形镁合金AZ31的织构演变与力学性能共3篇

变形镁合金AZ31的织构演变与力学性能共3篇变形镁合金AZ31的织构演变与力学性能1变形镁合金AZ31是一种广泛应用于航空、汽车、电子、医疗等领域的轻金属材料。

其具有轻质、高比强度、高耐腐蚀性等突出特点，逐渐成为各个领域中的热门材料。

然而，AZ31合金在加工过程中存在明显的异方性，其机械性能受到材料的组织结构影响较大。

因此，对于AZ31合金织构演变对力学性能的影响进行深入研究，有助于提高这种合金材料的使用性能。

AZ31合金的织构演变与力学性能1. AZ31合金的结构特点AZ31合金属于Mg-Al-Zn系列，由镁、铝、锌组成，其中镁含量最高，达到90%以上。

该合金的强度和塑性取决于其织构和显微结构。

AZ31合金虽然密度较低，但其非球形晶粒结构导致其劣异性强，机械性能较差。

而AZ31合金加工过程中的塑性变形，会导致晶体的取向趋向于某些方向，进而改变其结构和性能。

2. AZ31合金的织构演变材料的织构是指其晶体结构的方向取向分布情况。

AZ31合金材料经过加工后，其晶体取向会出现明显的变化。

织构演变主要表现为以下几个方面：(1) 轧制织构AZ31合金在轧制过程中，由于强制变形而出现滑移活动和晶胞旋转，引起晶体取向转移。

随着轧制次数的增加，合金的织构也发生了显著变化。

初始材料晶粒的织构为强烈的(0001)取向，随着轧制次数的增加，晶胞几乎沿着轧制方向旋转。

在轧制后5次，(0001)织构逐渐消失，取向随机化趋势增强。

(2) 拉伸织构AZ31合金在拉伸过程中，晶粒沿着应力方向伸展。

拉伸应变随机化使得AZ31合金中的(0001)取向被破坏，取向随机性增强。

此外，拉伸过程中晶粒的滑移和旋转也会影响其织构。

(3) 桶形拉伸织构桶形拉伸是一种在不一致模式下进行的拉伸，能够产生高度逆变形，有利于产生组织细化和显着的织构改善。

桶形拉伸后，(0001)取向分布更为均匀，且滞后角度明显减小。

3.织构演变对AZ31合金力学性能的影响材料的力学性能受到其组织结构的影响。

AZ31镁合金表面锡酸盐化学转化膜的研究

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、
性能好等优点，在汽车、机械、空航天领域以及便携航式电子仪表、计算机等领域得到日益广泛的应用。但镁自身的标准电极电位只有一．７［化学、２３Ｖ１，电化学活性高，耐蚀性很差，为制约其发挥眭能优势的一个主要成
的涂装保护提供良好基底。
１试验条件及方法
试验所用材料为经轧制的Ａ３形镁合金，Ｚ１变试
样尺寸为１ｍｌｍｍｘ００ｍｘ０ｌｍｍ，选用Ｎ２ｎ３３２ａＯ・ＨＯ、Ｓ
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。
ＢＭ。１）（ｇ７相是Ｍｇ与Ａ组成的化合物相，Ａ３Ａ：ｌ在Ｚ１
镁合金组织中，相电位最负，（ｇ相电位最大，仅１３ｏＭ）ｔ（＋Ｂ电位介于二者之问，）三者的电位不同，存在电位差，
收稿１：００１— ３３期２１ — ０１
文章编号：００１１２１— ５
图１轧制态Ａ３合金显微组织Ｚ１
由图１可见，Ｚ１合金组织主要由ｏＭｇ相、Ａ３镁ｔ）（（＋）晶体和少量的点状１ＭｇＡ。相组成。由于ａ１共３３１）（，组成不同，ｒＭｇ相是以Ｍｇ为基溶有Ａ的固溶体【Ｏ（）．ｌ３一

AZ31镁合金表面聚吡咯的化学氧化合成及其耐蚀性能

能，腐蚀电位较镁合金裸样正移了１０ｍ、电流密度减小了约２个数量级．使１／ ’
关键词：聚吡咯：Ａ３镁合金：硅烷：耐蚀性Ｚ１中图分类号：０６７４
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（Ｐ）采用傅里叶变换￣＃（ＴＲ）Ｐｙ膜．ｆＦＩ光谱分析了镁合金表面聚吡咯膜结构，－通过电化学极化曲线、电化学阻抗谱（）究了其耐蚀性能，日Ｓ研通过扫描电子显微镜（Ｅ、ＳＭ）Ｘ射线能量散射谱（Ｄ分析了表面形貌和成分．ＥＳ）和镁
合金裸样相比，吡咯膜对镁合金腐蚀有一定的抑制作用．烷预处理改善了镁合金／吡咯体系的耐腐蚀性聚硅聚

AZ31镁合金板材在热处理中组织和性能的演变

（ＣｏｌｅｅｏｆＭａｅｉｌｉｎｃｎｇｉｅｉｇ，ＴａｙｕｎＵｎｉｒｉｙｏｅｈｎｏｏｌｇｔｒａｓＳｃｅｅａｄＥｎｎｅｒｎｉａｖｅｓｔｆＴｃｌｇｙ，Ｔａｙｎ０３０２４，Ｃｈｎｉｕａ０ｉａ）ＡｂｔａｔＴｈｅｅｆｃｓｏｅｔｔｅｔｅｈｅｍｉｒｔｕｔｅ，ｍｅｈａｉａｎｄｆｍｉｇｒｓｒｃ：ｆｅｔｆｈａ — ｒａｍｎｔｏｎｔｅｏｓｒｅｕｒｃｎｃｌａｏｒｎｐｏｐｅｔｅｏＺ３１ａｅｓｕｒｉｓｆＡｍｇｎｉｍ
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ＡＺ合金板材在热处理中组织和性能的演变＊３１镁
王自启，晓卿，继祥，黎忱，里波曹郭李万
（原理工大学材料科学与工程学院，太山西太原００２）３０４
摘要：究了热处理对ＡＺ１合金轧制板材显微组织、研３镁室温力学性能和成形性能的影响。热处理
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AZ31镁合金表微孤氧化聚合物涂层的结构与耐蚀性能的开题报告

AZ31镁合金表微孤氧化聚合物涂层的结构与耐蚀性
能的开题报告
题目：AZ31镁合金表微孤氧化聚合物涂层的结构与耐蚀性能研究
一、研究背景
AZ31镁合金因其轻质、高强度、良好的电导率和塑性等优良性能而广泛应用于汽车、航空航天、电子等领域。

然而，其在湿、酸、碱等环境中容易发生腐蚀，极大地限制了其应用范围。

因此，针对AZ31镁合金的耐蚀性进行研究，开发出具有良好耐蚀性的表面涂层具有重要的现实意义。

微孤氧化聚合物涂层是一种基于氧化膜的涂层技术，可以提高材料的表面硬度、耐磨性、耐腐蚀性等性能。

由于其制备简单、成本低、可扩展性好等优点，近年来受到了广泛的研究关注。

二、研究内容和方法
1. 研究内容
本研究将采用微孤氧化聚合物涂层技术制备AZ31镁合金表面涂层，通过扫描电镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)等手段分析其表面结构与组成，通过电化学测试、盐雾试验等方法研究其耐蚀性能，并比较不同制备条件下涂层的差异。

2. 研究方法
(1) AZ31镁合金表面的机械抛光和清洗处理
(2) 采用微孤技术在AZ31镁合金表面制备孤氧化膜
(3) 在孤氧化膜基础上采用阳极氧化技术制备聚合物涂层
(4) 通过SEM、EDS、XRD等方法分析涂层表面的结构和组成
(5) 采用电化学测试、盐雾试验等方法研究涂层的耐蚀性能
三、预期成果
本研究旨在制备出具有良好耐蚀性能的AZ31镁合金表面微孤氧化聚合物涂层，并深入探究其结构与耐蚀性能之间的关系。

通过本研究，可以为AZ31镁合金的应用提供新的解决方案和思路，同时也可以为微孤化学涂层在材料表面改性领域的应用提供理论和实验基础。

AZ31镁合金两种表面处理膜层的组织及其耐蚀性

第３期收稿日期：２０１８－１１－１３基金项目：南京工程学院大学生科技创新基金项目（ＴＢ２０１８０２０４８，ＴＢ２０１８０２０２３）作者简介：黄　杰（１９９７—），男，江苏人，本科，主要从事材料加工技术研究。

ＡＺ３１镁合金两种表面处理膜层的组织及其耐蚀性黄　杰，金建港，杨之琪，袁　野，王立阳，缪元昊（南京工程学院材料工程学院，江苏南京　２１１１６７）摘要：采用微弧氧化法和表面热扩散液相渗铝法在镁合金表面制备两种膜层。

通过扫描电镜和ＸＲＤ分析以及氯化钠溶液浸泡试验，对这两种膜层的组织及其耐腐蚀性能进行了研究和比较。

关键词：镁合金；微弧氧化；扩散渗铝；耐蚀性中图分类号：ＴＧ１７４．４文献标识码：Ａ文章编号：１００８－０２１Ｘ（２０１９）０３－００１９－０２ＭｉｃｒｏｓｔｒｕｃｔｕｒｅａｎｄＣｏｒｒｏｓｉｏｎＲｅｓｉｓｔａｎｃｅｏｆＡＺ３１ＭａｇｎｅｓｉｕｍＡｌｌｏｙｗｉｔｈＴｗｏＳｕｒｆａｃｅＴｒｅａｔｍｅｎｔｓＨｕａｎｇＪｉｅ，ＪｉｎＪｉａｎｇａｎｇ，ＹａｎｇＺｈｉｑｉ，ＹｕａｎＹｅ，ＷａｎｇＬｉｙａｎｇ，ＭｉａｏＹｕａｎｈａｏ（ＳｃｈｏｏｌｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，ＮａｎｊｉｎｇＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｎａｎｊｉｎｇ　２１１１６７，Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ：Ｔｗｏｓｕｒｆａｃｅｃｏａｔｉｎｇｌａｙｅｒｓｏｆｍａｇｎｅｓｉｕｍａｌｌｏｙｗｅｒｅｐｒｅｐａｒｅｄｗｉｔｈｍｉｃｒｏａｒｃｏｘｉｄａｔｉｏｎｍｅｔｈｏｄａｎｄｌｉｑｕｉｄａｌｕｍｉｌｉｕｍｄｉｆｆｕｓｉｏｎｔｅｃｈｎｏｉｏｇｙ．ＢｙＳＥＭｏｂｓｅｒｖａｔｉｏｎ，ＸＲＤａｎａｌｙｉｎｇａｎｄｓｏａｋｉｎｇｃｏｒｒｏｓｉｏｎｔｅｓｔｉｎｓｏｄｉｕｍｃｈｌｏｒｉｄｅｓｏｌｕｔｉｏｎ，ｔｈｅｓｔｒｕｃｔｕｒｅｏｆｔｈｅｓｅｌａｙｅｒｓｏｆｍａｇｎｅｓｉｕｍａｌｌｏｙａｎｄｔｈｅｉｒｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅｗｅｒｅｉｎｖｅｓｔｉｇａｔｅｄａｎｄｃｏｍｐａｒｅｄ．Ｋｅｙｗｏｒｄｓ：ｍａｇｎｅｓｉｕｍａｌｌｏｙ；ｍｉｃｒｏａｒｃｏｘｉｄａｔｉｏｎ；ｄｉｆｆｕｓｉｏｎａｌｕｍｉｌｉｚｉｎｇ；ｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅ表面处理是提高镁合金耐蚀性的有效方法［１－２］。

植酸转换膜对AZ31镁合金电化学腐蚀性能的影响

植酸转换膜对AZ31镁合金电化学腐蚀性能的影响张兆贵【摘要】镁合金的耐腐蚀性能不理想,从而严重阻碍了镁合金大规模的商业应用.在商用AZ31镁合金表面制备了植酸转换膜,采用扫描电镜、能谱仪、电化学工作站等进行了合金电化学腐蚀性能的检测.结果表明,表面制备的植酸转换膜显著改善了商用AZ31镁合金的电化学腐蚀性能;与未经表面处理的商用AZ31镁合金相比,制备了植酸转换膜的AZ31镁合金在20℃电解液中的开路电位和腐蚀电位分别正移185mV、238 mV;在质量分数为5％的KOH电解液中的开路电位和腐蚀电位分别正移221 mV、218 mV.【期刊名称】《轻合金加工技术》【年(卷),期】2015(043)003【总页数】4页(P53-56)【关键词】AZ31镁合金;电化学腐蚀性能;植酸转换膜;表面处理【作者】张兆贵【作者单位】潍坊工程职业学院应用化学与生物工程学院,山东青州262500【正文语种】中文【中图分类】TB304密度小、比强度高、减震降噪效果好、回收性好等优点使得镁合金成为最具应用前景的轻金属之一。

目前镁合金在汽车、摩托车、轮船、手持工具、航空航天等领域已经得到成功的应用。

但是，镁合金的耐腐蚀性能较差限制了镁合金的大规模应用，如何提高镁合金的耐腐蚀性一直是一个重点技术问题，也是一个极具挑战性的技术难题［1-2］。

为此，众多的科研人员和工程技术人员进行了较多的研究，也取得了较多的应用成果［3-5］。

植酸(肌醇六磷酸脂，分子式为C6H18P6O24)是一种具有优异环境友好型的有机物，它在金属表面处理研究过程中逐渐受到人们的青睐。

因此，本试验通过在AZ31镁合金表面制备植酸转换膜，研究了植酸转换膜对AZ31镁合金电化学腐蚀性能的影响。

1 试验材料与方法1.1 试验材料本试验选用商用AZ31镁合金，采用SEA-1000A型能量色散X射线荧光光谱仪对其进行化学成分分析，结果如表1所示。

然后利用碱性水溶液中AZ31镁合金的表面羟基化作用，在受热情况下与植酸分子间脱水形成酯键，从而在AZ31镁合金表面制备出植酸转化膜。

AZ31镁合金磷酸镁转化膜的腐蚀性能

Trans.Nonferrous Met.Soc.China 27(2017)1087−1095Enhanced corrosion performance ofmagnesium phosphate conversion coating on AZ31magnesium alloyNguyen Van PHUONG 1,Manoj GUPTA 2,Sungmo MOON 1,31.Korea Institute of Materials Science,Gyeongnam 51508,Korea;2.Department of Mechanical Engineering,National University of Singapore 119260,Singapore;3.Korea University of Science and Technology,Daejeon 34113,KoreaReceived 7April 2016;accepted 6September 2016Abstract:Magnesium phosphate conversion coating (MPCC)was fabricated on AZ31magnesium alloy for corrosion protection byimmersion treatment in a simple MPCC solution containing Mg 2+and 34PO -ions.The MPCC on AZ31Mg alloy showed micro-cracks structure and a uniform thickness with the thickness of about 2.5µm after 20min of phosphating treatment.The composition analyzed by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy revealed that the coating consisted of magnesium phosphate and magnesium hydroxide/oxide compounds.The MPCC showed a significant protective effect on AZ31Mg alloy.The corrosion current of MPCC was reduced to about 3%of that of the uncoated surface and the time for the deterioration process during immersion in 0.5mol/L NaCl solution improved from about 10min to about 24h.Key words:magnesium alloy;AZ31alloy;magnesium phosphate;conversion coating;corrosion protection1IntroductionMagnesium alloys are very attractive materials for a number of applications in the automotive,aeronautic,electronic and recreational industries,owing to their low density,high specific strength,good castability,machinability and weldability [1].However,one of the main challenges in the use of Mg alloys,particularly for outdoor applications,is its poor corrosion resistance [2−4].The standard reduction potential of Mgis 20Mg /Mg+ϕ=−2.356V (vs SHE)at 25°C [3],which is the lowest among industrial engineering metals.Attempts have been made to improve the corrosion resistance of Mg alloys using chemical treatment,anodizing,plating,metal coatings and organic coating [5−7].Among them,chemical conversion coatings (CCCs)are regarded as one of the most effective and cheapest ways to enhance the corrosion resistance of Mg Cs are formed by precipitation of corrosion inhibiting chemicals onto the metal substrate from chemical conversion coating solution,which can protect the substrate by acting as a barrier between the metal surface and the environment [5,6].The conventional CCCs are based on treatmentsolutions containing chromium compounds that have been shown to be highly toxic and carcinogens,and are now being restricted in the industry.Many types of CCCs have been reported as the potential replacements for conventional chromate conversion coatings on Mg alloys,including zinc phosphate,stannate,phosphate/phosphate–manganese,titanate,calcium phosphate,fluoride,rare-earth metal salt (RE),Mg−Al hydrotalcite,ionic liquid,molten salt,vanadium,hexafluorozirconic acid,stearic acid [8−42].Among potential chromate replacements,phosphate conversion coatings have attracted significantly attention due to their low toxicity,insolubility in neutral pH solution and chemical stability [5−8].Zinc phosphate conversion coatings have been successfully used as a primer coating on steels and aluminum alloys in automotive industries for many years due to the simplicity in operation,low-cost and low environmental impact.However,for Mg alloys,due to their high electrochemical activity,the zinc phosphate conversion coatings are limited in corrosion protection and still cannot satisfy modern industrial requirements.Other phosphate coating systems on Mg alloys have also been reported in a review by CHEN et al [8].However,they own limitations in corrosion resistance,operations and cost,and still cannot satisfy for practical use.Corresponding author:Sungmo MOON;Tel:+82-55-2803549;E-mail:Sungmo@kims.re.kr DOI:10.1016/S1003-6326(17)60127-4Nguyen Van PHUONG,et al/Trans.Nonferrous Met.Soc.China 27(2017)1087−10951088Therefore,further investigation for the development of better,simpler,cheaper and environmentally friendly chemical conversion coating solution for Mg alloys is still needed.Magnesium phosphate compounds such as Mg 3(PO 4)2and MgHPO 4·3H 2O are insoluble in water and chemically stable.These compounds have been reported to be present as an inner layer of zinc,calcium or manganese phosphates conversion coating on Mg alloys [29−34].The formation of the magnesium phosphate compounds has been explained by theprecipitation reactions between Mg 2+and 34PO -ions at the near alloy surface during the conversion coating process.Therefore,this suggests that to improve the corrosion resistance of Mg alloys,a coating should contain magnesium phosphate compounds,which can be formed from the chemical conversion coating solutioncontaining Mg 2+and 34PO -ions,so-called magnesium phosphate conversion coating (MPCC)solution.At present,MPCC has been considered as a novel chemical conversion coating method on carbon steels [43−46].The former MPCC mainly consists of newberyite (MgHPO 4·3H 2O)with a thickness of about 30µm which is about three times thicker than that of zinc phosphate conversion coating and provides two times longer stability under salt-spray conditions [45,46].PHUONG and MOON [47]and ZHAO et al [48]have investigated MPCC on AZ31Mg alloy and found that the corrosion resistance of MPCC was much better than that of zinc phosphate conversion coating,and about 20times better than that of the bare surface.However,these studies are limited in the preparation process of MPCC and simply investigating the corrosion behavior using potentiodynamic polarization test.Thus,further work is required to fully understand the composition and corrosion behavior of MPCC on AZ31Mg alloy.Accordingly,in this work,MPCC was prepared in a chemical conversion coating solution containing Mg 2+and 34PO -ions.The coating was characterized by observation of surface and cross-sectional morphologies,and analyzing compositions using energy dispersive X-ray spectroscopy (EDS)and X-ray photoelectron spectrometer (XPS).The corrosion behavior of MPCC was studied by the open-circuit potential (OCP)measurement,potentiodynamic polarization analysis,electrochemical impedance spectroscopy (EIS)measure-ments and also,immersion test in NaCl solution.2ExperimentalAZ31Mg alloy (Posco,Korea)with composition of Al 2.9%,Zn 0.8%,Mn 0.3%,Si<0.1%,Fe<0.005%,Cu<0.05%,Ni<0.005%(mass fraction).And Mg balance,was used in this work.The samples of 50mm ×50mm ×2mm were cut from a rolled AZ31sheet.The samples were ground in ethanol up to 4000grit SiC abrasive papers and then rinsed with ethanol.MPCC was applied on AZ31by immersion treatment of samples for 20min in the solution containing 0.1mol/L of Mg(OH)2and 0.24mol/L of H 3PO 4at 45°C.The formation and growth of MPCC on AZ31were studied by open circuit potential (OCP)measurement during the phosphating process.Surface morphology,cross-sectional morphology and analysis using energy dispersive X-ray spectroscopy (EDS)were performed using scanning electron microscope (SEM)(Jeol,Japan),operated at an acceleration voltage of 20kV.X-ray photoelectron spectroscopy (XPS)analysis was carried out on a MultiLab 2000spectrometer (Thermo Scientific,US)equipped with Al K αX-ray source,operated at 300W.The spectra of Mg 2p and O 1s were recorded.The binding energies were referred to the C 1s binding energy at 285.01eV.Electrochemical measurements were performed using a computer-controlled potentiostat and a conventional three-electrode cell (Zahner,Germany)with an exposed working electrode area of 1cm 2,using a saturated calomel electrode (SCE)and a platinum sheet as the reference and counter electrodes,respectively.Electrochemical experiments were carried out in 0.1mol/L NaCl at 25°C.Potentiodynamic polarization tests were performed at a scan rate of 1mV/s on the bare and the MPCC sample after 1h of exposure to 0.1mol/L NaCl solution.EIS measurements were measured separately and carried out at the open circuit potential in the frequency range of 100kHz to 10mHz with 5points/decade with an applied sinusoidal signal of 5mV.A parameter indicative of corrosion resistance,R corr ,was fitted from the spectra using a complex non-linear least squares fitting program (Thales Z2.12,Germany).The immersion test was conducted in 0.5mol/L NaCl solution at (25±1)°C.3Results and discussion3.1Formation of MPCCThe formation of MPCC from selected MPCC solution can be explained by using the thermodynamic stability diagram,which shows [Mg 2+]and pH levels for precipitation of magnesium phosphate/hydroxide compounds (Fig.1).The selected MPCC solution at [Mg 2+]=0.1mol/L (or lg[Mg 2+]=−1)and pH 3.2is indicated by asterisk (*),suggesting that it will existprimarily in the form of soluble 24MgH PO +ions.The immersion of the AZ31sample in the acidic MPCC solution induces spontaneous Mg ionization (reaction 1)and hydrogen evolution (reaction 2)on the alloy surface,by which magnesium ions and hydrogen gas bubbles areNguyen Van PHUONG,et al/Trans.Nonferrous Met.Soc.China 27(2017)1087−10951089produced,respectively.Mg →Mg 2+(aq)+2e (1)2H ++2e →H 2(g)(2)The generation of Mg 2+and the consumption of H +ions increase both Mg 2+concentration and pH at the near metal surface.As seen in Fig.1,with increasing Mg 2+concentration and pH,several magnesium compounds such as MgHPO 4·3H 2O,Mg 3(PO 4)2and Mg(OH)2/MgO can be formed (reactions (3−6)).24MgH PO ++OH –+2H 2O →MgHPO 4·3H 2O(s)(3)243MgH PO ++4OH –→Mg 3(PO 4)2(s)+24H PO -+4H 2O (4)24MgH PO ++4OH –→Mg(OH)2(c)+24H PO -+2H 2O(5)Mg(OH)2→MgO+H 2O(6)Fig.1Thermodynamic stability diagram showing [Mg 2+]and pH levels for precipitation of magnesium phosphate compounds,calculated using MEDUSA software package [49]at 34[PO ]-=0.24mol/L,[Mg 2+]from 10−4to 1mol/L and pH from 0to 12Figure 2shows the OCP transient of the AZ31Mg alloy immersed in the MPCC solution for 20min.The shifting of OCP towards a more positive value indicates that the formation process of coating occurs and the coating formed is more thermodynamically stable than the original surface.The OCP transient can be divided into two stages,as indicated in Fig.2.In the first stage up to 3min of immersion time,the OCP was rapidly increased from an initial value of approximately −1.92V to about −1.45V (vs SCE),which indicated the precipitation and rapid growing process of the coating on the surface.During the second stage,after 3min of immersion time,the OCP slightly increased,which suggests that the thickness of the MPCC is being further developed.Some potential fluctuations observed in the second stage are associated with the processes of dissolution and repassivation at some parts of the coating during the conversion coatingprocess.Fig.2OCP transient of AZ31Mg alloy in MPCC solution at 45°C3.2Surface characterization of MPCCFigures 3(a)and (b)show SEM images of the surface and cross-sectional morphologies of MPCC coated AZ31after 20min of treatment time.The MPCC on AZ31exhibited micro-cracked structure.The micro-cracked structure is commonly seen on the surface of chemical conversion coated Mg alloys such as with chromium,permanganate and cerium conversion coatings [5,10−13].Cracks are likely due to the lower molar volume of MPCC resulting from dehydration during the immersion treatment.The coating was otherwise smooth and exhibited a uniform thickness of about 2.5µm after 20min of phosphating treatment.Figure 3(c)shows the EDS area analyses of the MPCC on AZ31.It was found that the coating consists of Mg (62.11%),O (31.73%),P (3.21%),Al (2.68%)and Zn (0.27%).Thus,this result suggests that the coating was mainly composed of MgO/Mg(OH)2and Mg−PO 4compounds.To provide better understanding of the chemical composition of MPCC on AZ31,XPS was used to study the surface bonding of the coating (Fig.4).XPS survey spectrum of coating found that the main constituents of the coating surface included magnesium,aluminum,zinc,oxygen and phosphorous species (Fig.4(a)).High-resolution XPS scan (Fig.4(b))further shows the Mg 2p binding energies appearing at approximately peaks of 50.19,51.16and 52.13eV,which correspond with the bonding of MgO,Mg(OH)2and Mg−PO 4,respectively.For the O 1s binding energy (Fig.4(c)),three peaks at binding energies of 531.16,532.39and 533.67eV were fitted,which correspond with the bonding of metal oxide (MgO),hydroxide (Mg(OH)2)and phosphate (PO 4)compounds,respectively.Thus,both EDS and XPS analyses indicated that the MPCC on AZ31was composed of MgO/Mg(OH)2and Mg−PO 4compounds,such as MgHPO 4·3H 2O and Mg 3(PO 4)2.Nguyen Van PHUONG,et al/Trans.Nonferrous Met.Soc.China27(2017)1087−10951090Fig.3SEM images of surface(a)and cross-sectional morphologies(b),and EDS area analysis(c)of MPCC on AZ31after20min treatment time in MPCC solution at45°C 3.3Corrosion studiesFigure5shows the OCPs of bare and MPCC coated AZ31as a function of time immersed in0.1mol/L NaCl solution at25°C.The measurement of OCP transients is typically used to study some aspects of the chemical stability and corrosion processes of the surface layers on Mg alloys.It is the most rapid and sensitive way of detecting deterioration processes of the film,and the localized corrosion of Mg alloys in a corrosive solution. Localized corrosion of Mg alloys in an electrolyte containing chloride ions is characterized by the appearance of roughly circular blackened regions (pits),which expand radially with time and vigorously evolve hydrogen[3,4].The corrosion reaction of Mg alloys in aqueous environments generally progressesby Fig.4XPS analyses of MPCC coated AZ31:(a)Survey;high resolution of Mg2p(b)and O1s(c) electrochemical reaction with water to produce hydrogen gas and magnesium hydroxide(reactions(7−10))[3−6]:Mg(s)→Mg2+(aq)+2e(anodic reaction)(7)2H2O+2e→H2+2OH–(aq)(cathodic reaction)(8) Mg2+(aq)+2OH–(aq)→Mg(OH)2(s)(product formation)(9) Mg+2H2O→Mg(OH)2(s)+H2(overall reaction)(10) The hydroxide film formed on Mg alloys is much less stable than the passive films formed on aluminumNguyen Van PHUONG,et al/Trans.Nonferrous Met.Soc.China27(2017)1087−10951091and stainless steels[3−6].Therefore,Mg alloys show poor corrosionresistance.Fig.5OCPs of bare and MPCC coated AZ31with immersion time immersed in0.1mol/L NaCl solution at25°C(Inserted figure was OCP of MPCC sample with immersion time of20to 30h)The OCP transient of bare AZ31in0.1mol/L NaCl solution disclosed two stages.In the first stage,within 1h of immersion,the OCP increased from an initial negative value(about−1.6V(vs SCE))towards a more positive value(about−1.38V(vs SCE)),indicating the formation and growth process of Mg(OH)2film on the AZ31surface[3,4].In the second stage,after1h of immersion,the OCP dropped suddenly from−1.38V(vs SCE)to about−1.4V(vs SCE),indicating the deterioration of the hydroxide film on the surface, leading to a localized corrosion reaction.In contrast,the OCP transient of the MPCC sample was divided into three stages:a rapid increase from−1.5 to−1.36V(vs SCE)within2h;a slight increase between 2h and24h,dropped to a stable value of about−1.35V (vs SCE)after about24h.In the first stage,the increased OCP indicates the decreased chemical activity on the MPCC AZ31surface.This can be explained by the sealing effect produced by the MPCC during immersion in the NaCl solution.Since the MPCC on the AZ31 included micro-cracks(Fig.3),the electrolyte could reach the substrate to react with the Mg alloy.The corroded product Mg(OH)2(reaction(9))is formed,and it can seal the cracks which resulted in the rapid increase of OCP during the first2h of immersion(Fig.5).In the second stage,the slow increase in OCP suggested that a dynamic equilibrium between the formation and dissolution of the film was reached.In the third stage,the OCP suddenly dropped,indicating that the film had damaged and the continuous corrosion reaction occurred on the surface.Thus,the initial pitting corrosion of MPCC was24h,which is much longer than that of the bare surface(about1h).Figure6shows the potentiodynamic polarization curves of bare and MPCC on AZ31obtained after1h exposure to0.1mol/L NaCl solution at25°C.The bare AZ31surface had a more negative corrosion potential (φcorr=−1.61V(vs SCE))than that of the MPCC sample (φcorr=−1.41V(vs SCE)).The corrosion current density (J corr)of MPCC sample was6.9×10–3mA/cm2,which was reduced to about3%of the bare surface (J corr=2.23×10–1mA/cm2).Compared to zinc phosphate conversion coatings,MPCC showed more negative corrosion potential and had a little higher corrosion current density,but the MPCC was much more stable than zinc phosphate conversion coatings against corrosion under the salt-spray conditions,due to its compact coating[47].Fig.6Potentiodynamic polarization curves of bare and MPCC coated AZ31samples at scan rate of1mV/s in0.1mol/L NaCl (MPCC was prepared by20min treatment in MPCC solution at 45°C)To further understand the corrosion behavior and the associated deterioration process of the bare and MPCC on AZ31,EIS was employed.Figure7(a)shows the Nyquist plots of the bare AZ31obtained after0min, 20min,1h,3h,10h and20h exposure to0.1mol/L NaCl solution at25°C.EIS experiments of the bare AZ31showed two capacitive loops at the high and middle frequencies(HF and MF)in combination with an inductive loop at low frequencies(LF).HF capacitive loops are usually attributed to both charge transfer and surface film effect[50,51].MF capacitive loops are attributed to the relaxation of mass transport in the growing solid oxide phase.LF inductive loops are attributed to the phenomena of adsorption and desorption of Mg+species on the surface of the Mg substrate, suggesting the slow corrosion reaction at the interface of AZ31[11,14,50,51].The typical EIS experiments of MPCC coated AZ31consisted of two capacitive loops at HF and MF.According to SEM surface and cross-sectional morphologies,the MPCC on AZ31consisted ofNguyen Van PHUONG,et al/Trans.Nonferrous Met.Soc.China27(2017)1087−1095 1092cracks,which reach deeply to the metal surface(Fig.3). The cracks can be sealed by the corrosion product during immersion in the NaCl solution to form layers:a sealed layer and an unsealed layer.Thus,these two layers correspond to the two capacitive loops of the EIS experiment.The appearance of an inductive loop in the LF region after24h immersion is attributed to the localized corrosion of AZ31due to the deterioration process of the MPCC[52].Fig.7Nyquist plots of bare(a)and MPCC coated(b)AZ31 samples after different immersion time in0.1mol/L NaCl solution at(25±1)°C(MPCC was prepared by20min treatment in MPCC solution at45°C)Based on the impedance plots,the microstructure of MPCC,and the EIS studies of bare Mg alloy[50−52], two appropriate equivalent circuits were proposed for fitting these plots,as shown in Fig.8.The equivalent circuits consist of two R/CPE components in series with R s,with or without inductive loop(R/L).The equivalent circuit presented in Fig.8(a)was used to fit the EIS spectrum of the bare AZ31.The element R s was the solution resistance,the R1/CPE1and R2/CPE2pairs were suggested to represent two capacitive loops at HF and MF as explained above.The R3/L pair was suggested to represent inductive loops.The equivalent circuit presented in Fig.8(b)was used to fit the EIS spectra of the MPCC coated AZ31.The R f1/CPE f1and R f2/CPE f2 pairs were suggested to represent the two layers of MPCC during immersion in NaCl solution.The model presented in Fig.8(a)with an inductive loop was also used to fit the EIS spectra of MPCC on AZ31with immersion time24h due to the occurrence of the localized corrosion process.The fittings were performed by using the Thales Z2.12software and the fitted results are drawn as solid lines,together with experimental data, in Fig.7.Fig.8Equivalent circuit models for simulation of Nyquist plots Considering the protective film formed on the bare and MPCC coated AZ31,the magnitudes of R1,R2,R f1 and R f2were plotted with immersion time and shown in Fig.9.For AZ31,the film resistance(R1)is much larger than the mass transport resistance(R2).The increase of R1during the first1h immersion indicates the growth of hydroxide film on AZ31.However,after an immersion time longer than1h,the rapid decrease of R1indicates the process of deterioration of the hydroxide film,where the localized corrosion occurs on the surface.The slight increase of R1with immersion time up to20h indicates that the surface of the AZ31was completely covered by the corrosionproduct.Fig.9Resistances of bare and MPCC coated AZ31resulted from fitting on EIS spectrum by equivalent circuit models in Fig.8Nguyen Van PHUONG,et al/Trans.Nonferrous Met.Soc.China 27(2017)1087−10951093Fig.10Photographs of (a)bare and (b)MPCC coated AZ31for 20min with immersion time in 0.5mol/L NaCl solution at (25±1)°CIn contrast to bare AZ31,both R f1and R f2of the MPCC coated AZ31rapidly increased to much higher value with increasing the immersion time from 0to 3h in 0.1mol/L NaCl solution.As explained before,the corrosion product can be formed and seal the cracks of MPCC to increase the coating resistance.The sealing effect occurred strongly during the first 3h of immersion in the NaCl solution,and became stabilized with immersion time longer than 3h.After 24h immersion,the sudden decreases of both R f1and R f2indicate the deterioration of MPCC and the initiation of localized corrosion on the surface.This result is in good agreement with OCP measurement (Fig.5),where,OCP is rapidly increased within the first 3h,and then,dropped after 24h of immersion.Figure 10shows photographs of bare and MPCC coated AZ31with immersion time in 0.5mol/L NaCl solution at 25°C.The bare AZ31showed pitting corrosion with a pit initiation time of about 10min.The corroded sites rapidly expanded to the entire surface within 3h immersion.In contrast,the MPCC coated AZ31showed a filiform corrosion with a much longer pit initiation time of about 24h.Thus,the immersion test again revealed that the MPCC can significantly increase the deterioration process of AZ31magnesium alloy in NaCl solution.4Conclusions1)Magnesium phosphate conversion coating can be successfully applied on AZ31using a solution containingMg 2+and 34POions.2)The results of characterization studies show that the coating consists of magnesium phosphate and magnesium hydroxide/oxide compounds with a thickness of about 2.5µm after 20min of phosphating treatment.Cracks observed can be sealed by corrosion products during immersion in NaCl solution.3)The coating shows a significant protective effect.The corrosion current measured by potentiodynamicpolarization curve is reduced to about 3%of that of the bare surface.During the immersion test in 0.5mol/L NaCl solution,the pitting corrosion was observed after about 24h for MPCC,which is much longer than that of the bare surface (about 10min).AcknowledgementsThis research was financially supported by a research grant from Korea Institute of Materials Science (PNK4652).References[1]FRIEDRICH H 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Z31镁合金激光焊件的力学性能和应力腐蚀开裂行为

AZ31镁合金激光焊件的力学性能和应力腐蚀开裂行为摘要：采用Nd-YAG激光对AZ31 HP镁合金进行激光束焊接，并使用填料AZ61。

显微组织分析表明，使用或不使用填料(焊料)AZ61镁合金得到的激光焊接接头的平均晶粒尺寸大约为12μm，显微硬度和拉伸强度与母材相近。

然而，慢应变速率拉伸表明，在ASTM D1384溶液中两种焊接接头的抗应力腐蚀性能比母材略差。

可观察到应力腐蚀裂纹在焊缝金属中萌生并向热影区（HAZ）扩展。

然而，在以AZ61镁合金为填料(焊料)获得的焊接接头中，观察到裂纹起源及扩展出现在热影区（HAZ）。

在慢应变速率拉伸试验中，由于试样表而暴露在腐蚀环境中，在氢氧化/镁氧化镁层形成局部损伤，从而导致应力腐蚀裂纹的生成。

关键词：镁合金；激光焊接；显微组织；力学性能；慢应变速率拉伸；应力腐蚀裂纹；断面分析1 简介汽车和飞机应用需要重量轻，HP的材料，在这些工业中，锻造镁合金正逐渐替代钢材和铝合金［１］。

在一般情况下，镁合金具有优良的铸造性和稳定的成形性，因此，很多部件用铸造和锻造镁合金制成。

虽然可以用气体钨极氩弧焊完成镁合金的焊接［２－４］，但最近，激光束焊接（LBW），电子束焊（EBW）和摩擦搅拌焊接（FSW）工艺被广泛用于这些合金的链接［５－９］。

这是由于可控的能量束和FSW工艺减少了缺陷水平，并进而提高效率的结果。

但是FSW的工艺是一种固态的过程，不涉及任何填充材料，而激光束焊可以在用或不用额外的填充材料的情况下生产镁合金焊接件。

对于许多应用，除了在机械性能以外，材料的抗耐腐蚀能力也必须加以考虑。

镁合金材料一般都被视为是一种抗耐腐蚀性能力较弱的材料[10] 。

然而，一般来讲，当镁合金杂质水平在一定的范围之内时，其抗耐腐蚀性能被认为好于碳钢，这是将它们放在德州墨西哥湾海岸的大气中暴露２年的试验得出的结果。

杂质对镁合金腐蚀行为的影响是显著的，尤其是其表面上[12] 。

就焊接件的案例来说，除表面杂质为外，晶粒尺寸，焊接金属成分，微成分的分布和残余应力等也会影响其腐蚀行为。

AZ31镁合金表面防腐涂层的制备及耐蚀性研究的开题报告

AZ31镁合金表面防腐涂层的制备及耐蚀性研究的开题报告一、选题背景随着经济的快速发展，镁合金作为轻质高强度材料被广泛应用于航空、汽车、电子、医疗等领域。

但是，镁合金由于其极易被大气、水和土壤中的氧化物、盐类和化学物质腐蚀，导致其使用寿命受到了很大的限制。

因此，对于镁合金的防腐蚀研究成为了一个重要的研究方向。

在防腐蚀技术中，表面涂层技术是一种简单且有效的方法。

其中，无机涂层具有较高的防腐蚀性能，因此被广泛应用于镁合金的防腐蚀中。

二、研究内容本研究将以AZ31镁合金为研究对象，采用溶胶-凝胶法制备SiO2/ZrO2复合涂层，并研究其在不同条件下的制备过程、物理和化学性质以及防腐蚀性能。

具体内容包括：1、制备SiO2/ZrO2复合涂层，并考察所制备涂层的微观形貌、化学组成和结构特点。

2、采用扫描电镜、X射线衍射仪、红外光谱仪等手段，研究所制备涂层的表面形貌、物理化学性质以及结构组成。

3、采用腐蚀实验研究所制备涂层在3.5% NaCl溶液中的腐蚀行为及其对AZ31镁合金表面性能的影响。

4、对所制备涂层的防腐蚀性能进行评价，并探究其防腐蚀机理。

三、研究意义本研究将填补AZ31镁合金表面防腐涂层材料的研究空白，为未来的生产和应用提供有利的技术支持。

同时，本研究探究表面涂层对于防腐蚀机理的影响，在理论上具有较高的参考价值。

四、研究方法本研究将采用溶胶-凝胶法制备SiO2/ZrO2复合涂层，并采用扫描电镜、X射线衍射仪、红外光谱仪等手段，研究所制备涂层的表面形貌、物理化学性质以及结构组成。

采用电化学方法研究所制备涂层在3.5% NaCl溶液中的防腐蚀性能，并探究其防腐蚀机理。

五、研究进度安排第一年：完成对SiO2/ZrO2复合涂层的制备和表面形貌、物理化学性质的研究，并开始对防腐蚀性能的研究。

第二年：完成对SiO2/ZrO2复合涂层的防腐蚀性能研究，分析其防腐蚀机理，并撰写研究报告。

第三年：完成论文的修改和完善，准备论文答辩。

AZ31镁合金钕基转化膜工艺与耐蚀性能研究

AZ31镁合金钕基转化膜工艺与耐蚀性能研究∗赵丁藏;张丁非;孙静;余大亮;潘复生【期刊名称】《功能材料》【年(卷),期】2015(000)019【摘要】研究了 AZ31镁合金钕基转化膜的制备工艺,并对膜层形貌、化学组成和耐腐蚀性能进行了分析.通过正交优化得到了钕基转化膜的4个工艺条件的最佳水平组合为 Nd(NO 3)3浓度为5 g/L,H 2 O 2浓度为5 mL/L,成膜时间9 min,成膜温度40℃.结果表明,采用最佳工艺得到的钕基转化膜层均匀且致密,其主要成分是Nd2 O 3和少量 MgO.通过动电位极化曲线和析氢实验研究了钕基转化膜层对AZ31镁合金在3．5％(质量分数)NaCl 溶液中耐蚀性能的影响,结果表明,钕基转化膜可以大大降低 AZ31镁合金的腐蚀速率,当 Nd(NO 3)3浓度为5 g/L 时,钕基转化膜的腐蚀电流密度最小,耐腐蚀性能最好.【总页数】5页(P19110-19114)【作者】赵丁藏;张丁非;孙静;余大亮;潘复生【作者单位】重庆大学材料科学与工程学院，重庆 400045;重庆大学材料科学与工程学院，重庆 400045; 重庆大学国家镁合金材料工程技术研究中心，重庆400044;重庆大学材料科学与工程学院，重庆 400045;重庆大学材料科学与工程学院，重庆 400045;重庆大学材料科学与工程学院，重庆 400045; 重庆大学国家镁合金材料工程技术研究中心，重庆 400044【正文语种】中文【中图分类】TG174【相关文献】1.抑制铝金属基复合材料Al6061/SiCp腐蚀的三价铈转化膜工艺及性能的研究 [J], 于兴文2.AZ31镁合金表面钼酸盐转化膜的制备与耐蚀性能 [J], 刘俊瑶;李锟;雷霆3.AZ31镁合金钼酸盐转化膜制备及性能研究 [J], 周游;姚颖悟;吴锋;刘伟星;赵春梅4.AZ31镁合金磷酸盐化学转化膜的研究 [J], 崔建红;吴志生;弓晓圆5.转化膜致密化及耐蚀性能提升工艺优化进展 [J], 卢勇;冯辉霞因版权原因，仅展示原文概要，查看原文内容请购买。

AZ31镁合金表面钼酸盐转化膜的制备与耐蚀性能

AZ31镁合金表面钼酸盐转化膜的制备与耐蚀性能刘俊瑶;李锟;雷霆【摘要】以Na2MoO4为主盐,与氧化剂H2O2、成膜促进剂NaF和Na2SiO3一起组成化学转化液,在AZ31镁合金表面制备钼酸盐转化膜,利用扫描电镜和X线光电子能谱仪分析转化膜的形貌和组成,通过电化学阻抗测试研究转化膜在3.5%NaCl溶液中的腐蚀行为,并讨论成膜机理,研究转化液中Na2MoO4浓度与pH以及成膜温度和时间对薄膜结构与耐腐蚀性能的影响.结果表明:转化液的优化组成为0.2 mol/L Na2MoO4+0.12 mol/L NaF+0.014 mol/L Na2SiO3+0.012 mol/L H2O2;优化工艺条件为pH=5,温度60℃,转化时间30 min;转化膜为黄棕色,主要由MgMoO4,MgF2,MoO2,MoO3和MgSiO3组成,转化膜宏观上完整均匀,存在网状微裂纹;钼酸盐转化膜能有效提高AZ31镁合金的耐腐蚀性能,对基体合金有一定的保护作用.【期刊名称】《粉末冶金材料科学与工程》【年(卷),期】2016(021)001【总页数】9页(P137-145)【关键词】镁合金;钼酸盐;化学转化膜;耐蚀性能;硅酸盐【作者】刘俊瑶;李锟;雷霆【作者单位】中南大学粉末冶金国家重点实验室,长沙 410083;中南大学粉末冶金国家重点实验室,长沙 410083;中南大学粉末冶金国家重点实验室,长沙 410083【正文语种】中文【中图分类】TG178为了提高镁合金的耐腐蚀性能，通常采用阳极氧化、化学镀、化学转化膜等方法进行表面处理，其中化学转化处理方法凭借成本低、易操作的优势得到广泛运用[1−3]。

铬酸盐转化法是目前应用最多、最有效的方法[4]，但由于六价铬毒性很强，其应用受到很大局限。

因此，锡酸盐、稀土盐及磷酸−高锰酸盐等作为环境友好的转化体系应运而生[5−7]。

钼酸盐是一种低毒低污染物质，并且钼酸盐转化膜具有良好的导电性能，为镁合金的进一步后处理提供了良好的导电基础。

AZ 31镁合金稀土转化成膜及其耐蚀性能的研究

AZ 31镁合金稀土转化成膜及其耐蚀性能的研究杨潇薇;王桂香;董国君;张密林;龚凡【期刊名称】《电镀与环保》【年(卷),期】2008(28)2【摘要】对AZ 31镁合金表面稀土转化处理的成膜工艺进行了初步研览.分析了不同的成膜工艺参数(稀土盐的质量浓度、成膜时间、成膜温度)对稀土转化膜的形成以及耐蚀性能的影响.扫描电镜分析不同成膜工艺形成的稀土转化膜表面形貌;用极化曲线研究转化膜的电化学腐蚀行为.结果表明:当转化液中铈的质量浓度为21.7 g/L时,膜的耐蚀性最好;成膜时间、成膜温度对膜的耐蚀性也有不同程度的影响.在本文研究的时闻范围内,处理时间长能获得更好的耐蚀性.【总页数】4页(P31-34)【作者】杨潇薇;王桂香;董国君;张密林;龚凡【作者单位】哈尔滨工程大学,材料科学与化学工程学院,超轻材料与表面工程教育部重点实验室,黑龙江,哈尔滨,150001;哈尔滨工程大学,材料科学与化学工程学院,超轻材料与表面工程教育部重点实验室,黑龙江,哈尔滨,150001;哈尔滨工程大学,材料科学与化学工程学院,超轻材料与表面工程教育部重点实验室,黑龙江,哈尔滨,150001;哈尔滨工程大学,材料科学与化学工程学院,超轻材料与表面工程教育部重点实验室,黑龙江,哈尔滨,150001;哈尔滨工程大学,材料科学与化学工程学院,超轻材料与表面工程教育部重点实验室,黑龙江,哈尔滨,150001【正文语种】中文【中图分类】TG174【相关文献】1.AZ31镁合金钕基转化膜工艺与耐蚀性能研究∗ [J], 赵丁藏;张丁非;孙静;余大亮;潘复生2.AZ31镁合金稀土转化成膜工艺研究 [J], 曹大勇3.AZ91镁合金表面稀土转化膜的制备及耐蚀性能研究 [J], 许越;陈湘;吕祖舜;李英杰4.稀土Gd对AZ31镁合金耐蚀性能的影响 [J], 刘军;张金玲;渠治波;于彦冲;许并社;王社斌5.稀土Ce和Nd对AZ31镁合金耐蚀性能的影响 [J], 余琨;黎文献;王日初;巢国辉因版权原因，仅展示原文概要，查看原文内容请购买。

生物医用AZ31B镁合金表面改性及性能研究

生物医用AZ31B镁合金表面改性及性能研究不锈钢,钛和铬基合金,作为生物硬组织植入材料,已经被应用于临床。

但是,这些金属生物材料因在植入人体内发生体液腐蚀而释放出有毒的离子,而导致炎症发生,降低了生物相容性并且导致组织损坏。

另外,金属基生物材料的弹性模量与人骨组织相差过大,会产生应力遮挡效应。

不利于新骨的生长和重塑,易导致二次骨折。

随着对生物医用植入材料不断深入研究,开发具有良好力学性能和生物相容性,又可在体内安全降解的新型植入材料具有重要意义。

与已应用于临床的金属基植入材料相比,镁合金具有多方面的优点:(1)镁是人体中的必需元素;(2)良好的生物相容性、优异的生物活性;(3)更接近骨组织的力学性能;(4)与骨组织更为接近的密度;(6)原材料成本低。

因此镁合金作为一种新型可降解植入材料而受到了广泛关注。

然而,作为生物医用材料,镁合金降解速度过快,这将造成植入部位局部碱化,氢气释放过快,形成皮下气肿,影响其在临床上的应用。

本文选择AZ31B镁合金作为基体材料,在其表面制备一层含Mg2SiO4和SiO2的陶瓷涂层,以控制镁合金基体的降解速度,并对涂层的制备工艺、微观形貌、相组成、涂层形成机理、降解性能等进行了系统研究。

在此基础上,本文选择硅涂层作为重点研究对象,对其在体外的降解性能和降解过程中的生物相容性进行了深入研究。

本文主要的研究结论如下:(1)采用正交实验方法确定了涂层的最佳工艺:NaOH的质量-体积浓度40g/L时,Na2SiO3·9H2O的质量-体积浓度为40g/L、以及处理时间为7h,处理温度100℃。

(2)所制备的涂层表面致密均匀光滑,肉眼观察呈金黄色,扫描电镜下可见由球状晶体组成,厚约为1.9μm。

XPS结果表明,涂层主要由Mg2SiO4、MgO和少量SiO2组成。

(3)浸泡实验表明,涂层有效降低了镁合金基体的降解速度,尤其在在浸泡初期效果更明显,表面改性前后的AZ31B镁合金在不同的模拟体液中显示了不同的降解规律。