纳米晶镍脉冲电沉积层在NaCl和NaOH溶液中的腐蚀性能

目前,对纳米材料耐腐蚀性研究的结论不尽相同,对其腐蚀机制的见解也不统一.通过脉冲电沉积方法制备了纳米晶Ni沉积层.采用浸泡法和电化学方法研究了纳米晶Ni沉积层在3.5%NaCl(质量分数)以及10.0%NaOH(质量分数)溶液中的腐蚀行为.结果表明:在3.5%NaCl溶液中,纳米晶Ni沉积层具有较低的自腐蚀电位和较宽的钝化区,其耐腐蚀性能随着晶粒尺寸的减小而降低;在10.0%NaOH溶液中,纳米晶Ni沉积层的阳极极化曲线有较宽的钝化区,其耐腐蚀性能随着晶粒尺寸的减小而提高.     

Ce对铝青铜合金粉体材料涂层在5.0% H2SO4溶液中腐蚀行为的影响

利用等离子喷焊技术,将自主研究开发的多元铜合金粉末(含Ce和不含Ce)涂覆在45#钢表面,通过静态浸泡腐蚀实验、电化学实验,采用X射线衍射、表面EDS、EPMA等分析手段,研究Ce对多元铝青铜粉末熔覆层在5.0%H2SO4溶液中耐腐蚀性能及腐蚀行为的影响。结果表明,在5.0%H2SO4溶液中,合金粉体涂层发生了选择性脱成分腐蚀,稀土元素Ce能改善铝青铜合金粉体涂层的自腐蚀电位,提高该涂层的耐腐蚀性能。     

WC-10Co-4Cr涂层在不同温度酸与NaCl溶液中的耐腐蚀性能

为提高1Cr18Ni9Ti不锈钢在NaCl和酸溶液环境中的耐磨损性能,利用等离子喷涂制备两种晶粒WC-10Co-4Cr涂层,研究其在3.5%(质量分数,下同)NaCl溶液与酸溶液(pH=5.0)中的耐腐蚀性能。结果表明:涂层中含有WC,W_2C,W以及η相(Co_xW_xC)。两种涂层在3.5%NaCl溶液中的腐蚀电位均高于1Cr18Ni9Ti基体的腐蚀电位。在不同温度酸溶液(pH=5.0)中,纳米WC-10Co-4Cr涂层的电位差随温度的变化最小。涂层在NaCl和酸溶液中腐蚀机制分别为:WC-10Co-4Cr涂层表面吸附氧粒子与涂层中的Co和WC在3.5%NaCl溶液中形成电偶;在酸溶液中(pH=5.0),涂层中的Co溶解形成Co²⁺离子,和WC相直接形成电偶腐蚀,导致涂层表面出现孤立的WC颗粒。     

铸态和挤压态 AZ31 镁合金在 3.5%的 NaCl 溶液中的腐蚀性能比较

目的研究铸态和挤压态AZ31镁合金在3.5%NaCl溶液中的腐蚀性能。方法采用光学显微镜和X射线衍射分析了铸态AZ31镁合金挤压前后的显微组织。利用静态浸泡失重实验和电化学实验研究了铸态和挤压态AZ31镁合金在3.5%NaCl溶液中的腐蚀性能。结果热挤压可有效细化AZ31合金的晶粒,铸态试样的平均晶粒大小约为111μm,挤压态试样的平均晶粒大小约为9μm。AZ31镁合金在3.5%NaCl溶液中的腐蚀初期,合金表面没有发生钝化。挤压后合金的自腐蚀电位从铸态的-1.55 V提高到-1.52 V。浸泡72 h后,铸态试样的腐蚀速率为4.293 mm/a,挤压态试样的腐蚀速率为2.957 mm/a。结论挤压提高了AZ31镁合金在3.5%NaCl溶液中的腐蚀性能。     

Ni/SiC复合镀层腐蚀行为研究

研究了Ni/SiC复合镀层在3.5%NaCl溶液中的腐蚀行为.测定了Ni/SiC镀层在NaCl溶液中的失重曲线,利用solartron恒电位仪测定其极化曲线,借助扫描电镜对镀层表面形貌进行了观察.结果表明,随着腐蚀时间的延长,腐蚀失重逐渐增加,但腐蚀速率逐渐降低;Ni/SiC复合镀层与纯Ni镀层耐盐水腐蚀能力基本相当;Ni/SiC复合镀层在3.5%NaCl溶液中的开路电位要高于纯Ni镀层的开路电位;在3.5%NaCl H2O2溶液中,两种镀层的开路电位均明显正移,且Ni/SiC复合镀层自腐蚀电流降低,说明复合镀层耐盐水腐蚀能力有所提高.镀Ni层中引入SiC颗粒能使其组织细化,并促进复合镀层在3.5%NaCl溶液中发生钝化,可能是Ni/SiC镀层在盐水中耐蚀性能提高的主要原因.     

Al-Si涂层对不锈钢电化学腐蚀行为的影响

Al-Si涂层能提高不锈钢的耐蚀性,但目前对其缺乏深入研究。采用料浆法与真空扩散相结合的方法在1Cr18Ni9Ti不锈钢表面制备Al-Si、Al-Si-Cr、Al-Si-Y涂层,测试了各涂层在3.5%(质量分数)NaCl溶液和0.05mol/L H_2SO_4+0.25 mol/L Na_2SO_4溶液中的电化学腐蚀性能以及其在6.0%FeCl_3溶液中的浸泡失重速率,并观察腐蚀形貌。结果表明:涂层试样的电化学腐蚀性能优于不锈钢基材的,Al-Si、Al-Si-Cr及Al-Si-Y涂层试样在6.0%FeCl_3溶液中的腐蚀失重依次降低,在3.5%NaCl溶液中的腐蚀孔径依次减小,在0.05 mol/L H_2SO_4+0.25 mol/L Na_2SO_4溶液中的腐蚀孔径先减小后增大;涂层使不锈钢耐腐蚀性能有了很大的提高,这是由于涂层表面形成了更为致密的钝化膜。     

海水环境下老化周期对T800碳纤维/环氧树脂复合材料的影响EI北大核心CSCD

研究T800碳纤维/环氧树脂基复合材料在海水环境中进行湿热腐蚀老化,将制备好的试件放置在人工制备70℃,3.5%NaCl溶液中腐蚀30,60,90 d,通过质量变化、老化前后表面形貌、红外光谱、动态力学性能、压缩实验和层间剪切实验分析材料的力学性能变化。结果表明:T800碳纤维/环氧树脂复合材料在3.5%NaCl溶液中吸湿率分别为0.39%,0.47%,0.53%;未老化试样纤维与基体之间黏结良好,在3.5%NaCl溶液老化后纤维与基体界面破坏随时间的增加老化更加严重;玻璃化转变温度T_(g)下降,分别在老化30,60,90 d后从189.16℃下降到177.54,171.88,168.06℃;经3.5%NaCl溶液老化后,老化30,60,90 d试样的最大破坏载荷分别降低3.2%,8.4%,15.3%,压缩强度分别降低3.0%,8.2%,15.9%;层间剪切最大破坏载荷分别降低3.0%,9.2%,14.9%,剪切强度分别降低3.0%,9.7%,16.4%。     

28CrMo钢表面磁控溅射TiN涂层的组织结构及耐腐蚀性能

为了提高28CrMo钢表面的致密性和耐腐蚀性能,采用磁控溅射技术在28CrMo钢表面制备TiN涂层,通过光学显微镜、X射线衍射仪(XRD)、电化学测试等手段分析了TiN涂层的显微结构及其在3.5%NaCl溶液中的耐腐蚀性能。结果表明:采用磁控溅射技术在28CrMo钢表面制备了厚约0.5μm的TiN涂层,涂层与基体结合良好,没有出现明显的裂纹,涂层表面N的原子分数明显高于Ti;电化学Nyquist谱得到高频区的容抗弧可能是由电荷转移电阻引起和膜层引起,中频区的容抗弧由基体金属溶解时的传质弛豫引起,低频区的感抗弧由基体表面吸附物的弛豫过程引起;3.5%NaCl溶液中腐蚀96 h后TiN涂层表面有蚀坑,吸附有白色疏松的腐蚀产物,并出现大小不一的腐蚀坑;TiN涂层能够明显改善基体的耐蚀性能,对改进高铬钢表面特性具有重要的作用。     

Al-SiC-TiO_2陶瓷涂层对304不锈钢基体的防腐研究

为了提高硅酸盐基陶瓷涂层对金属基体的腐蚀防护性能,在304不锈钢表面制备了4种不同Al含量的硅酸盐基陶瓷涂层(简记为S1—S4)。运用扫描电子显微镜对涂层在3.5%NaCl溶液中浸泡后的微观形貌进行分析,并分别研究了涂层试样腐蚀前后单位面积上的质量变化情况以及涂层的电化学腐蚀行为。结果表明,S3涂层经400h腐蚀液浸泡后基本保持表面平整,相同腐蚀条件下,S3涂层的单位面积质量损失最小,经800℃熔烧,S3涂层能形成较为稳定的钝化区间,表现出最佳的耐腐蚀性能。     

Al元素对Mn-Cu基阻尼合金耐蚀性能的影响

用干湿循环增重法、极化实验研究了Al含量对Mn-Cu基阻尼合金在0.5%NaCl溶液中耐腐蚀性能的影响,并利用SEM、EDS、XRD等手段对Al元素的影响机理进行了分析。结果表明,Al元素的添加使材料的自腐蚀电位(Ecorr)提高,腐蚀电流密度(Icorr)降低,合金的耐蚀性增加;另一方面,含Al元素的Mn-Cu合金腐蚀产物中Al2O3与Cu2O、Mn3O4、Mn2O3协同作用,使腐蚀层结构致密化,有效阻碍了Cl-向基体的扩散,使材料的耐腐蚀性能提高。     

Characterization and corrosion behavior of NiTi-Ti2Ni-Ni3Ti multiphase intermetallics produced by vacuum sintering

An in-situ synthesis method was employed to produce NiTi-Ti₂Ni-Ni₃Ti multiphase intermetallics. In this regard, the amorphous/nanocrystalline Ni-Ti powders were sintered at 1300 °C for 2 hrs to obtain Ni-Ti alloys with dense structure. Tafel polarization tests were employed to study corrosion behavior of multiphase materials in 3.5% NaCl and 0.1 M H₂SO₄ corrosive media. The results indicated that the microstructure of sintered samples consists of NiTi(Fe) and Ti₂Ni/Ti₄Ni₂O_x phases embedded in a Ni₃Ti matrix. The synthesized multiphase materials had microhardness up to 873 HV1 kg.Further investigations showed the corrosion performance of multiphase samples in 3.5% NaCl solution was inferior to that of wrought NiTi alloy. In contrast, the corrosion resistance of multiphase samples in 0.1 M H₂SO₄ solution was comparable to that of wrought NiTi alloy.     

Characterization and corrosion behavior of NiTi–Ti2Ni–Ni3Ti multiphase intermetallics produced by vacuum sintering

An in-situ synthesis method was employed to produce NiTi–Ti₂Ni–Ni₃Ti multiphase intermetallics. In this regard, the amorphous/nanocrystalline Ni–Ti powders were sintered at 1300 °C for 2 hrs to obtain Ni–Ti alloys with dense structure. Tafel polarization tests were employed to study corrosion behavior of multiphase materials in 3.5% NaCl and 0.1 M H₂SO₄ corrosive media. The results indicated that the microstructure of sintered samples consists of NiTi(Fe) and Ti₂Ni/Ti₄Ni₂O_x phases embedded in a Ni₃Ti matrix. The synthesized multiphase materials had microhardness up to 873 HV1 kg.Further investigations showed the corrosion performance of multiphase samples in 3.5% NaCl solution was inferior to that of wrought NiTi alloy. In contrast, the corrosion resistance of multiphase samples in 0.1 M H₂SO₄ solution was comparable to that of wrought NiTi alloy.     

Corrosion Behavior and Protection Efficiency of 2024Al and SiCp／2024Al Metal Matrix Composite

The corrosion resistance of 2024 Al and SiC particle reinforced 2024 Al metal matrix composite(SiCp/2024Al MMC) in 3.5% NaCl solution was investigated with electrochemical method and immersion test, and the corrosion protection of sulfuric acid anodized coatings on both materials was evaluated by electrochemical impedance spectroscopy.The results showed that the SiCp/2024AlMMC is more susceptible to corrosion than its matrix alloy in 3.5% NaCl.For 2024Al,the anodized coating provides excellent corrosion resistance to 3.5%NaCl.The anodized coating on the SiCp/2024Al provides satisfactory corrosion protection,but it is not as effective as that for 2024Al because the structure of the anodized layer is affected by the SiC particulates.     

Ce3+掺杂聚苯胺中空微球/环氧涂层防腐蚀研究

聚苯胺作为一种新型的防腐蚀材料,在钢铁防腐蚀领域具有良好的应用前景.通过自组装法在聚(2-丙烯酰胺基-2-甲基丙磺酸)(PAMPS)水溶液中制备了聚苯胺(PANI)中空微球,将稀土Ce~(3+)掺杂到聚苯胺中空微球表面制备了一种新型的Ce~(3+)掺杂修饰的聚苯胺中空微球(PANI-Ce~(3+)).以PANI-Ce~(3+)中空微球为防腐填料添加到环氧树脂(EP)中,制备Ce~(3+)掺杂修饰的聚苯胺中空微球/环氧(PANI-Ce~(3+)/EP)防腐涂层.采用FT-IR、UV-Vis、SEM、XRD等对PANI-Ce~(3+)中空微球进行表征,通过动电位极化法、交流阻抗测试探究PANI-Ce~(3+)/EP涂层的防腐蚀性能.结果表明:PANI-Ce~(3+)/EP涂层具有较高的腐蚀电压(Ecorr=-0.414 V)和较小的腐蚀电流密度(I_(corr)=0.676×10~(-5)μA/cm~2);PANI-Ce~(3+)/EP涂层低频区阻抗模量随浸泡时间呈现先减小后增大的变化趋势,在质量分数3.5%的NaCl水溶液中经过1 680 h腐蚀后,阻抗模量保持在106.6Ω·cm~2;表面有划伤的PANI-Ce~(3+)/EP涂层在质量分数3.5%的Na Cl水溶液进行1 680 h腐蚀实验后,涂层表面不起泡,仅在划痕处有少量铁锈.PANI-Ce~(3+)/EP涂层表现出优异的耐腐蚀性能.     

Preparation of Ni–Co alloy coating on sintered NdFeB magnet by potentiodynamic electrodeposition

A protective Ni–Co alloy coating was successfully prepared on sintered neodymium–iron–boron (NdFeB) magnet via potentiodynamic electrodeposition in this paper. The microstructure and surface morphology analysis of Ni–Co alloy coating showed that the surface morphologies were quite compact and more uniform than that prepared by direct current (DC) electrodeposition; significantly, the chemical composition analysis indicated that the content of Co in the alloy coatings amounted to 33–34?wt-%. Potentiodynamic polarisation and long term immersion test results revealed that the Ni–Co alloy coating could supply excellent corrosion protection for NdFeB substrate in 3.5?wt-% NaCl solution. Overall, the Ni–Co alloy coating with higher Co content prepared by potentiodynamic electrodeposition exhibited better corrosion protection for sintered NdFeB magnet compared with that prepared by DC electrodeposition.     

Sn,Al对船用铜管耐蚀性的影响

研究了铜及Cu-2.80%Sn-1.06%Al合金在3.0%NaCl溶液及流动海水中腐蚀性能,利用金相、扫描电镜及电化学特征分析了它们的耐蚀特性。结果表明,纯铜在21mV时发生阳极溶解,在海水冲刷作用下保护膜很快遭到破坏,腐蚀速度大,Cu-2.80%Sn-1.06%Al合金由于其表面形成的Cu、Sn和Al的混合氧化物保护膜均匀、致密、质硬、在流动海水冲刷、摩擦作用下,保护膜稳定性好,腐蚀速度小。     

Corrosion protection and formation mechanism of anodic coating on SiCp/Al metal matrix composite

The corrosion protection from sulfuric acid anodized coatings on 2024 aluminum and SiC particle reinforced 2024 aluminum metal matrix composite (SiC_p/2024Al MMC) in 3.5 wt.% NaCl aqueous solution was investigated using electrochemical methods. The results show that the anodized coating on 2024Al provides good corrosion protection to 3.5 wt.% NaCl, and the anodized coating on the SiC_p/2024Al MMC provides some corrosion protection, but it is not as effective as for 2024Al because non-uniformity in thickness and cavities present are associated with the SiC particulates. Cavities above SiC particles are the reason that the anodized coating on the MMC cannot be completely sealed by hot water as with anodic Al alloy. SiC particle anodizes at a significantly reduced rate compared with the adjacent Al matrix. This gives rise to alumina film encroachment beneath the particle and occlusion of the partly anodized particle in the coating. It was found that the barrier layer of anodized Al MMC is not continuous, and it is composed primarily of the barrier layer of anodized Al matrix and a barrier-type SiO₂ film on occluded SiC particles in the coating. A new formation mechanism of coating growth during anodizing of a SiC_p/2024Al MMC was proposed.     

2024铝合金阳极氧化膜的结构和耐蚀性能

为促进2024铝合金的进一步应用,用动电位阳极极化和电化学阻抗方法研究了2024 Al合金阳极氧化膜的结构及其在3.5% NaCl水溶液中的耐蚀性.结果表明,经硫酸阳极氧化的2024 Al合金较未处理基体的腐蚀速度降低了2个数量级以上,表现出相当好的保护性能;用光学显微镜、扫描电镜和透射电镜对阳极氧化膜的形貌观察发现,氧化膜表面平整,孔隙分布均匀,每个孔隙周围多含6个孔隙,也有5和7个孔隙结构,其孔隙尺寸细小,大小在10～30 nm之间.