Mg-3.0Nd-0.2Zn-0.4Zr镁合金表面电沉积Cu镀层及其耐腐蚀性能

研究Mg-3.0Nd-0.2Zn-0.4Zr（NZ30K）镁合金上电沉积Cu镀层的前处理过程及耐腐蚀行为。研究结果表明：活化膜和浸锌层均优先在Mg12Nd共晶相表面沉积。Cu镀层能够为镁基体提供长达60 h的防护作用,这主要归因于其致密的镀层结构及浸泡过程中形成较稳定的钝化膜。热震试验证明镀层具有良好的结合力。     

化学处理液中的La及BTA 对铜合金表面性能的影响

为了提高铜及其合金的耐蚀性能,研究了稀土La盐与BTA对铜合金缓蚀的协同作用,化学处理后的铜合金表面耐蚀性能得到改善。利用扫描电镜及XRD,对铜合金处理后的表面形貌及结构进行了分析;通过阳极极化、交流阻抗等电化学测试方法分析了La盐与BTA对铜合金表面性能的影响。结果表明:稀土La盐与BTA的加入使铜合金表面形成了均匀、致密的转化膜,从而提高了铜合金表面的耐蚀性能。     

AZ91D镁合金微弧氧化膜的腐蚀行为研究

利用双向全波脉冲电源对AZ91D镁合金在硅酸盐体系中进行了微弧氧化处理,通过电化学阻抗谱(EIS)测试、极化曲线分析并结合XRD和SEM等分析方法对微弧氧化处理的镁合金腐蚀行为进行了研究.结果表明,微弧氧化膜表面分布着几微米的微孔,微弧氧化膜中主要含有MgF2,Mg2SiO4和Al2O3.AZ91D镁合金经过微弧氧化处理之后,耐蚀性能明显提高,自腐蚀电流密度降低3个数量级,自腐蚀电位高出约300 mV,阻抗值高出3个数量级,研制的微弧氧化膜对镁合金具有很好的防腐保护性能.     

冷喷涂铬锆铜涂层在海水中的耐蚀性能

采用冷喷涂技术在普通碳钢基体上制备了厚度为300μm的铬锆铜涂层,用扫描电子显微镜(SEM)观察涂层的组织形貌。用开路电位（OCP）、电化学阻抗谱和动电位极化曲线等电化学方法研究冷喷涂铬锆铜涂层在天然海水中的耐蚀性能。研究表明,铬锆铜涂层组织致密,在海水环境中,涂层表面形成一层致密的腐蚀产物膜,能有效阻止腐蚀介质向涂层内部渗透,对基体起到良好的保护作用。     

SiO2微球负载BTA缓蚀剂型自修复耐蚀涂层的制备及性能研究

目的研究由负载缓蚀剂多孔Si O2微球和7537聚氨酯(PU)所制备的自修复涂层的耐蚀性能和防腐机理。方法利用负压-浸渍法将苯并三氮唑(BTA)负载到Si O2微球中,利用X射线衍射(XRD)、扫描电子显微镜(SEM)、热重分析(TGA)分别对Si O2的形貌与BTA负载含量进行分析检测,并利用划痕浸泡试验、电化学极化曲线及交流阻抗技术,研究Si O2、BTA以及负载有BTA的多孔Si O2微球(Si O2/BTA)对涂层耐蚀性能的影响。结果 SEM图像分析表明Si O2微球粒径约为1μm,热重分析试验表明BTA的负载含量为32.38%(质量分数)。划痕试验表明在浸泡过程中除了PU+Si O2/BTA coating试样外,其他试样的划痕处都出现了宏观腐蚀现象。电化学极化曲线和交流阻抗结果表明PU+Si O2/BTA coating试样始终具有最低的电流密度和较高的阻抗值。结论涂层中的多孔Si O2一方面可以储存BTA,当该涂层产生缺陷时,Si O2中的BTA被释放出来并在基体的缺陷处吸附成膜,从而使该涂层对微观缺陷具有一定的自修复功能;另一方面提高了涂层的致密性;两方面协同作用使PU+Si O2/BTA coating试样具有最好的耐蚀性能和一定的自修复功能。     

高硅对不锈钢耐高温浓硫酸腐蚀行为的影响

用失重法、动电位阳极极化、XRD、SEM及EPMA等多种实验方法研究了四种硅含量对不锈钢在高温浓硫酸中的腐蚀行为,结果表明:高硅的加入使不锈钢的耐酸性能显著提高。认为其主要原因是硅的加入促进了不锈钢的钝化,并使其表面形成外层以SiO2、内层以Cr2O3为主的钝化膜。     

不同镁合金支架材料MAO/PLLA复合膜研究

两种系列的镁合金WE42与AM20微弧氧化(MAO)后用浸渍法对微弧氧化膜进行聚乳酸(PLLA)封孔处理制备复合涂层,通过扫描电镜(SEM)分析微弧氧化膜及聚乳酸封孔膜的表面形貌及结构,X射线衍射(XRD)分析微弧氧化膜的主要成分为MgSiO3和SiO2,通过腐蚀失重测定试样的失重率.在37℃的hank's模拟体液中测...     

Sn含量对镁合金电镀Sn-Ni合金镀层性能的影响

采用阴极电沉积法在AZ3lB镁合金表面上制备了不同Sn含量的Sn-Ni合金镀层.利用x射线荧光光谱仪(XRF)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、动电位极化曲线(Tafel)、电化学阻抗谱(EIS)和硬度仪研究了不同Sn含量时镀层的结构、表面形貌、耐蚀性及硬度.结果表明,镀层中Sn含量对镀层各种性能的影...     

溶液温度对医用Mg-Li—Ca合金表面锌钙系磷酸盐转化膜耐蚀性能的影响

考察不同磷化液温度对Mg-Li-Ca合金表面锌钙磷酸盐转化膜质量和耐蚀性能的影响。利用扫描电子显微镜、电子探针、能谱仪、X射线衍射和傅里叶红外光谱研究转化膜的表面形貌、化学成分和物相,采用析氢腐蚀实验和动电位电化学技术以及电化学阻抗研究磷化液温度对 Mg-Li-Ca 合金表面磷酸盐转化膜耐蚀性能的影响。结果表明：当溶液温度低于45℃时,膜层主要由Zn和ZnO组成,而当温度高于50℃时,膜层的主要相为Zn3（PO4）2·4H2O、少量的Zn和ZnO;在55℃温度下制备的磷酸盐转化膜的耐蚀性能最好;在40~50℃下制备的膜,由于镁基体与锌之间形成的电偶腐蚀而加快了其析氢速率。     

Environmentally friendly anodization on AZ31 magnesium alloy

A novel anodization which is environmentally friendly,low voltage and low energy consumption was developed to improve corrosion resistance of AZ31 magnesium alloy.The corrosion resistance of the anodic films was studied by electrochemical impcdance spectroscopy(EIS) and potentiodynamic polarization techniques.The microstructure and compositions of films were examined by SEM,XPS and XRD.A new kind of organic additive used in the electrolyte is friendly to the environment.The compact, intact and uniform co...     

在优化Na2SiO3电解液制备的镁合金陶瓷膜的防护性能

    优化镁合金微弧氧化常用的Na₂SiO₃电解液并制备了白色陶瓷质微弧氧化膜,采用动电位极化曲线和电化学交流阻抗(EIS)等方法研究其防护性能.结果表明,与常用的Na₂SiO₃电解液制备的试样相比,优化的Na₂SiO₃电解液所制备试样的自腐蚀电流降低了3个数量级,并表现出较高的阻抗值;在3.5% NaCl溶液中浸泡发生点蚀的时间从24 h延长到240 h.SEM和XRD分析结果表明,在优化的Na₂SiO₃电解液中制备的AZ91D的陶瓷膜层孔隙减少,孔径也较小,且增加了低溶解度的Mg₅F₂(SiO₄)₂相和起钝化作用的MgAl₂O₄相.     

Anodization of AZ91 magnesium alloy in alkaline solution containing silicate and corrosion properties of anodized films

The anodization of AZ91 magnesium alloy in an alkaline electrolyte of 100g/L NaOH 20g/L Na2B4O7·10H2O 50g/L C6H5Na3O7·2H2O 60g/L Na2SiO3·9H2O was studied.The corrosion resistance of the anodized films was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques.The microstructure of the films was examined with scanning electronic microscope (SEM) and X-ray diffractometer (XRD).The results show that,under the experimental conditions,the optimum anodizing time and the optimum anodizing current density are 40min and 20mA/cm2 respectively for obtaining the anodic film with high corrosion resistance.The XRD pattern shows that the components of the anodized film consist of MgO and Mg2 (SiO4).     

Microwave-assisted synthesis of lanthanum conversion coating on Mg–Li alloy and its corrosion resistance

Lanthanum-based conversion coating on Mg–Li alloy has been prepared by a microwave-assisted method. X-ray diffractions (XRD) indicate that the intermetallic compounds of lanthanum are formed on Mg–Li alloy surface. Scanning electron microscopy (SEM) images show that the coating has different morphologies and special structures. The corrosion resistance was assessed by means of potentiodynamic polarization curves and electrochemical impedance spectra (EIS). The results indicate that this coating significantly reduces the corrosion rate of Mg–Li alloy in NaCl solution. A comparing experiment indicates that the coating prepared by microwave-assisted process has superior corrosion resistance to the coating obtained at room temperature.     

HEPJet多元铝青铜合金涂层在3.5%的NaCl溶液中的腐蚀性能

采用超音速等离子喷涂(HEPJet)技术将新型多元铝青铜合金粉体喷涂在45号钢基体上。通过失重法、极化曲线法、X射线衍射分析(XRD)、扫描电镜(SEM)、能谱(EDS)和电子探针(EPMA-1600)等方法研究多元铝青铜合金涂层在3.5%的NaCl溶液中的腐蚀性能。结果表明,在3.5%的NaCl溶液中,多元铝青铜合金涂层具有良好的耐蚀性能,该涂层的腐蚀速率为0.0636mm/a。腐蚀后试样表面Al元素的含量明显下降,Cu的含量明显增加,可见,涂层发生的主要是脱铝腐蚀。     

硅酸钠对5083铝合金点蚀性能的影响研究

通过循环阳极极化曲线、电化学阻抗谱的测试以及浸泡腐蚀试验,研究了硅酸钠对5083铝合金在3.5%氯化钠溶液中的点蚀性能的影响。极化曲线结果表明,硅酸钠的加入使得5083铝合金在3.5%氯化钠溶液中的点蚀电位正移。通过EIS试验和浸泡腐蚀试验可进一步得出:体系中硅酸钠水解使得溶液中OH-浓度增加,铝合金表面钝化膜和Al2(SiO3)3沉淀膜增厚,从而较好地抑制了铝合金表面的点蚀,基体得到保护。     

Corrosion mechanism of NiCrBSi coatings deposited by HVOF

NiCrBSi alloy powders were coated on a low carbon steel substrate using high-velocity oxygen fuel (HVOF) thermal spraying, and corrosion tests were carried out by immersing the specimens in 3.5% NaCl with pH adjusted to 3 by addition of acetic acid. Techniques such as scanning electron microscope (SEM), spectral analysis, electron probe microanalysis (EPMA) and X-ray diffraction (XRD) were employed to study the mechanistic process of corrosion of the coating surface. It was found that the corrosion of the NiCrBSi coating first occurred around the particles that had not melted during spraying and the defects such as pores, inclusions and microcracks, then followed by the development along the paths formed by pores, microcracks and lamellar structure, resulting in exfoliation or laminar peeling off. Adjusting the thermal spraying parameters to reduce the electrochemical unevenness or sealing the pores can improve the corrosion resistance of the coating.     

Characterization of anodic films formed on AZ91D magnesium alloy

Anodization of die-casted AZ91D magnesium alloy was performed in 3 M KOH+0.21 M Na₃PO₄+0.6 M KF base electrolyte with and without Al(NO₃)₃ addition. The anodic film was characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the various anodized alloys was then evaluated in 3.5 wt % NaCl solution using electrochemical impedance spectroscopy (EIS) and immersion testing. The results showed that the anodic film was mainly composed of MgO. The addition of Al(NO₃)₃ into the base electrolyte results in the formation of Al₂O₃ and Al(OH)₃ in the anodic film. The maximum amount of Al₂O₃ was found in the anodic film when the alloy was anodized in the electrolyte containing 0.15 M Al(NO₃)₃. The results of EIS analysis and morphological examination showed that the MgO anodic film modified with Al₂O₃ exhibited the superior corrosiom resistance for AZ91D Mg alloy.     

The long-term corrosion performance and adhesion properties of 7B04 aluminum alloy/anodic film/epoxy primer system in acidic NaCl solution

The deterioration process and corrosion protective effect of 7B04 aluminum alloy/anodic film/epoxy primer system in acidic NaCl solution for 3024 h were investigated by optical/electron microscopes, electrochemical impedance spectroscopy (EIS), scanning Kelvin probe (SKP), and pull-off adhesion test. The results showed that the protective system of anodic film and epoxy primer can protect aluminum alloy from pitting corrosion after immersion for 2352 h. According to the response characteristics of EIS and SKP, different stages of the failure process could be identified. During the first 100 h of immersion, the water transport in the coating followed Fickian law, and the water diffusion coefficient was 2.03 × 10^?11 cm²/s, which demonstrated that the coating has good impermeability. Anodizing and coating treatment improved the open circuit potential and impedance of 7B04 aluminum alloy and made the distribution of Volta potential more uniform. The decreasing rate of wet adhesion strength was first fast and then slow, which was similar to the variation rule of coating resistance. The anodic film enhanced the adhesion between epoxy primer and substrate so that the failure nature of the adhesion test was mainly the cohesive failure of the epoxy primer.     

镁锂合金表面锌锰磷化膜的制备与性能表征

采用化学转化法在镁锂合金表面制备了外观深灰色、结构均匀致密、耐蚀性能良好的锌锰磷酸盐转化膜,并研究了磷化温度对磷化膜性能的影响。采用扫描电子显微镜(SEM)、能谱(EDS)仪、X射线光电子能谱(XPS)和X射线衍射(XRD)仪对膜层的表面形貌、化学组成及结构进行了表征。采用动电位极化曲线、电化学交流阻抗(EIS)和腐蚀失重实验对磷化膜的耐蚀性进行了研究。结果表明,锌锰磷化膜主要由Zn、Zn3(PO4)2、MnHPO4、Mn3(PO4)2组成。锌锰磷酸化膜起到了保护镁锂合金的作用,提高了镁锂合金的耐蚀性,当磷化温度为45℃时,磷化膜的腐蚀电流密度最低,腐蚀速率最小,耐蚀性能最好。     

镁牺牲阳极法制备羟基磷灰石涂层的电化学性能

羟基磷灰石(HA)作为一种最重要的生物材料被成功采用镁牺牲阳极法在Ti6Al4V合金表面合成,以提高该复合材料的电化学抗腐蚀性能。使用电子能谱(EDX)、电子探针(EPMA)、傅里叶红外变换图谱(FTIR)和X射线衍射(XRD)对HA涂层进行分析。结果表明,涂层主要由针状羟基磷灰石晶体组成,Ca/P比为1.4063。浸泡30 d后,HA涂层在汉克氏溶液中晶体变大,在林格氏溶液和台氏溶液中针状晶体分别转变为片状和柱状。通过测试在3 种模拟体液和人血中的开路电位、极化曲线和交流阻抗图谱表明,有HA涂层的Ti6Al4V合金比未涂层的Ti6Al4V合金具有更好的电化学性能