热喷涂锌铝复合涂层的耐硫化物的应力腐蚀行为

对热喷涂底锌面铝复合涂层与铝涂层做了耐硫化物应力腐蚀的对比试验．试验结果表明：锌铝复合涂层并没有保持锌、铝的各自优点,改善原来的不足;相反,在底锌面铝复合涂层中,由于腐蚀介质渗透到底锌层,使锌层优先溶解,导致面铝层开裂脱落,进而使整个涂层失效．同时,探讨了锌铝复合涂层在ＮＡＣＥ的标准饱和Ｈ２Ｓ水溶液的应力腐蚀失效过程,指出了热喷涂锌铝复合层设计的不合理性．     

Ti_3Al合金的电化学腐蚀研究及涂层防护

利用电化学工作系统,分析了Ti_3Al合金的电化学腐蚀行为。在Ti_3Al基体上制备防护涂层,分析涂层对合金的电化学腐蚀影响。采用电化学工作站三电极系统分别在25%Na_2SO_4+75%K_2SO_4、3.5%NaCl溶液中进行电化学腐蚀实验,利用动电位扫描方式获取Tafel曲线对材料的腐蚀行为进行表征。Ti_3Al合金在室温硫酸盐体系中腐蚀速度较快,添加涂层后,在同样的环境下呈现分级钝化现象,腐蚀速度有所减缓;Ti_3Al合金在室温NaCl体系中阳极快速溶解,添加涂层后,在同样的环境下呈现钝化现象,腐蚀速度有所减缓;升高温度,在70℃的硫酸盐和NaCl体系中,Ti_3Al合金阳极溶解速度更快,添加涂层后同样出现阳极溶解现象。Ti_3Al合金的抗硫酸盐和氯化钠的电化学腐蚀能力较弱,添加涂层后,耐蚀能力有所提高。     

可控气氛喷涂钛涂层及涂层电化学性能

为了研究在低度真空环境中所获得的钛涂层的组织和性能,以氩气为载气,在压力为0.4MPa、载气温度为室温、不同的喷涂条件下,用热喷涂方法在Q235钢基体上制备了钛金属涂层.经扫描电子显微镜（SEM）观察,发现在真空中用氩气为载气喷涂的钛涂层组织致密,缺陷与孔隙相对较少.x 射线衍射分析仪（XRD）分析表明,在空气中喷涂的钛涂层有较多的氧化物和氮化物;在真空中喷涂的钛涂层基本上没有氧化物和氮化物,其衍射图谱与纯钛十分接近;在空气中用氩气为载气喷涂的钛涂层含有一些氧化物,涂层中的缺陷和孔隙数量介于前两种状态之间.采用动电位极化法研究了在不同条件下热喷涂钛涂层的电化学腐蚀行为,并与纯钛试样进行比较.结果表明：在真空条件下喷涂的钛涂层腐蚀电位高于在空气中喷涂的钛涂层和在空气中用氩气为载气喷涂的钛涂层,但略低于纯钛的腐蚀电位.     

镁合金AM60表面改性及其在Hank's溶液中的腐蚀

采用等离子喷涂TiO2对镁合金AM60进行表面改性,利用扫描电子显微镜和能谱发现分别观察了涂层结构,分析了其化学成分,通过表面纳米划痕实验研究了涂层的力学性能,用动电位电化学方法测量镁合金及其涂层的腐蚀性能.研究表明:AM60镁合金表面等离子热喷涂TiO2涂层具有多孔的陶瓷结构,存在鳞片状和菜花状/珊瑚状2种形貌,涂层鳞片状部位氧含量要高于菜花状部位的氧含量,涂层的显微硬度的平均值为886 HV,划痕实验表明涂层与基体结合良好,封闭后的涂层明显地提高了镁合金在Hank's溶液中的耐蚀性能.     

Q345E钢在模拟海水溶液中的腐蚀行为

采用失重法及电化学方法研究了Q345E钢在模拟海水溶液（3．5％NaCl）中的腐蚀行为．结果表明：Q345E钢自腐蚀电位前期急剧下降,实验后期逐渐趋于稳定;腐蚀初期腐蚀介质充足且发生吸氧腐蚀使Q345E钢的腐蚀速率较大,随着浸泡腐蚀时间的延长及腐蚀产物的附着,腐蚀速率逐渐减小,在腐蚀后期因附着产物脱落而增大．     

镁合金AMSO表面改性及其在Hank’s溶液中的腐蚀

采用等离子喷涂TiO2对镁合金AM60进行表面改性，利用扫描电子显微镜和能谱发现分别观察了涂层结构，分析了其化学成分，通过表面纳米划痕实验研究了涂层的力学性能，用动电位电化学方法测量镁合金及其涂层的腐蚀性能．研究表明：AM60镁合金表面等离子热喷涂蜀晓涂层具有多孔的陶瓷结构，存在鳞片状和菜花状／珊瑚状2种形貌，涂层鳞片状部位氧含量要高于菜花状部位的氧含量，涂层的显微硬度的平均值为886HV，划痕实验表明涂层与基体结合良好，封闭后的涂层明显地提高了镁合金在Hank’S溶液中的耐蚀性能．     

碳钢在亚硫酸铵制浆蒸煮过程中的电化学特性

用电化学方法研究了碳钢在亚硫酸铵法制浆蒸煮过程中的腐蚀行为．结果发现，在蒸煮前期温度较低时，碳钢表面呈活化状态；在蒸煮后期温度较高时，碳钢表面呈自钝化状态．电化学研究结果表明，对亚铵法蒸球不能应用外加电流阳极保护法．失重试验证实了电化学研究结果     

Nb质量分数对Al⁃15Si⁃xNb涂层组织与耐蚀性能的影响

以Al?15Si?xNb涂层为研究对象,探究了Nb质量分数对涂层显微组织结构和耐蚀性能的影响规律。采用金相显微镜观察涂层的组织形貌,运用XRD分析涂层的物相组成,应用电化学实验方法（包括开路电位、阻抗谱、极化曲线）表征并讨论了涂层在质量分数为3.5%的NaCl溶液中的腐蚀行为。结果表明,Al?15Si?xNb涂层主要由α?Al、初生Si、共晶Si组成,在涂层中加入Nb元素后生成少量的NbAl₃相和Nb₅Si₃相;Nb元素的加入促进异质形核,较明显地改变涂层的组织分布;Al?15Si?10Nb涂层中的组织更细小且分布更均匀,均匀分布的α?Al、初生Si和共晶Si构成众多均匀分布的腐蚀微电池,促进α?Al阳极反应,使涂层表面生成的Al₂O₃氧化膜更加连续;Al?15Si?xNb涂层的极化曲线具有类钝化特征,其中Nb质量分数为10%时涂层的自腐蚀电位和点蚀电位较高,产物膜电阻较大,维钝电流密度较低,具有更好的耐腐蚀性能。     

铝电解预焙阳极原料配方对阳极过电位的影响

铝电解碳素阳极过电位高达400－600mV，导致吨铝电耗和原铝的生成成本增加，作者通过不同原料配方（沥青量和残极添加量）工业试验预焙阳极取样，在实验室用“改进断电流法”进行阳极过电位测试，考察了铝用碳素阳极生产中粘结剂沥青含量和残有添加量对阳极过电位的影响，研究结果表明：随着沥青量的增加，试验阳极的过电位变化不大，但略有降低；添加残极时带的Na3AlF6,AlF3,Al2O3和NaF等杂质，可加速阳极过程的电化学和表面转化步骤，从而降低阳极过电位，阳极孔隙度过高可导致阳极过电位增大。     

不锈钢在NaCl溶液和海水中的腐蚀行为

用动电位扫描法测定了几种不锈钢在３．５％ＮａＣｌ溶液和海水中的阳极极化曲线，研究了Ａ７２５Ｍ０２Ｔｉ及Ｒ１系列的不锈钢在二种腐蚀介质中的电化学腐蚀行为，并与含ＣＬ＾－和Ｈ３ＰＯ４溶液中几种不锈钢的腐蚀特征进行了比较。     

New pattern Zn-Al-Mg-RE coating technics for steel structure sustainable design

Based on the advanced integrated technology of materials preparation and formation, a new pattern ZnAl-Mg-RE anti-corrosion coating for steel structure sustainable design was manufactured by cored wires and high velocity arc spraying (HVAS) technologies. The developments of thermally sprayed coatings for steel structure protection were described. Based on Al, Zn, Zn-Al and Zn-Al-Mg coatings, the anti-corrosion properties of new-pattern Zn-Al-Mg-RE coating were evaluated through electrochemical methods including electrochemical polarization and electrochemical impedance spectroscopy (EIS) coupled with SEM and XRD. The models of Zn-Al-Mg-RE coating undergoing corrosion with the initial pinhole defect and the latter with accelerated products were also discussed. The results show that Zn-Al-Mg-RE coating exhibites excellent corrosion resistance for long-term immersion, which is helpful for the sustainable design of steel structure in aggressive corrosion conditions. And the corrosion products seem to possess certain self-sealing function.     

Effect of Salt Spray Corrosion on Tribological Properties of HVOF Sprayed NiCr-Cr_3C_2 Coating with Intermediate Layer

The objective of the present work was to determine the influence of the neutral salt spray corrosion on the wear resistance of HVOF sprayed NiCr-Cr_3C_2 coating with intermediate layer. Ni-Zn-Al_2O_3 coatings as interlayers were prepared by low pressure cold spray(LPCS) between NiCr-Cr_3C_2 cermet coatings to form a sandwich structure to enhance the corrosion resistance properties. The tribological properties were examined using the UMT-3 fricition and wear tester by line-contact reciprocating sliding under dry and salt spray one week corrosion. The morphology, element distribution, and phase compositions of the coating and worn sufaces were analyzed by using scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction respectively. The corrosion behavior of the coating was studied by the open-circuit potential, the electrochemical impedance spectroscopy, potentiodynamic polarization, and salt spray corrosion methods. It is found that the sandwich structured coating has better corrosion resistance than the single layer coating. The results show that under dry wear conditions, the wear mechanism is abrasive and adhesive wear, whereas under salt spray corrosion conditions it becomes corrosion wear. The friction coefficient of the sandwich structured coating after salt spray corrosion is slightly lower than the dry friction coefficient, but the weight of the wear loss is lower than that under dry condition.     

AZ91D镁合金表面等离子喷涂Al_2O_3-TiO_2陶瓷涂层的微观组织及防护性能

采用大气等离子喷涂技术在AZ91D镁合金表面制备Al2O3-TiO2陶瓷涂层。对涂层的显微组织、化学成分、相组成及显微硬度进行表征,并对涂层的耐磨损和耐电化学腐蚀防护性能进行研究。结果表明,Al2O3-TiO2陶瓷涂层的组织呈现层状结构,主要组成相为α-Al2O3、γ-Al2O3和金红石TiO2。涂层平均硬度654.2HV,涂层具有良好的抗磨损和抗电化学腐蚀防护性能。     

New pattern Zn-Al-Mg-RE coating technics for steel structure sustainable design

Based on the advanced integrated technology of materials preparation and formation, a new pattern Zn-Al-Mg-RE anti-corrosion coating for steel structure sustainable design was manufactured by cored wires and high velocity arc spraying (HVAS) technologies. The developments of thermally sprayed coatings for steel structure protection were described. Based on Al, Zn, Zn-Al and Zn-Al-Mg coatings, the anti-corrosion properties of new-pattern Zn-Al-Mg-RE coating were evaluated through electrochemical methods including electrochemical polarization and electrochemical impedance spectroscopy (EIS) coupled with SEM and XRD. The models of Zn-Al-Mg-RE coating undergoing corrosion with the initial pinhole defect and the latter with accelerated products were also discussed. The results show that Zn-Al-Mg-RE coating exhibites excellent corrosion resistance for long-term immersion, which is helpful for the sustainable design of steel structure in aggressive corrosion conditions. And the corrosion products seem to possess certain self-sealing function. Foundation item: Project (50235030) supported by the National Natural Science Foundation of China     

Effect of laser remelting on the microstructure and corrosion resistance of plasma sprayed Fe-based coating

Fe-based amorphous and nanocrystalline coatings were fabricated by air plasma spraying. The coatings were further treated by laser remelting process to improve their microstructure and properties. The corrosion resistance of the as-sprayed and laser-remelted coatings in 3.5wt% NaCl and 1 mol/L HCl solutions was evaluated by electrochemical polarization analysis. It was found that laser-remelted coating appeared much denser than the as-sprayed coating. However, laser-remelted coating contains much more nanocrystalline grains than the as-sprayed coatings, resulting from the lower cooling rate in laser remelting process compared with plasma spraying process. Electrochemical polarization results indicated that the laser-remelted coating has great corrosion resistance than the as-sprayed coating because of its dense structure.     

Effect of salt spray corrosion on tribological properties of HVOF sprayed NiCr-Cr<Subscript>3</Subscript>C<Subscript>2</Subscript> coating with intermediate layer

The objective of the present work was to determine the influence of the neutral salt spray corrosion on the wear resistance of HVOF sprayed NiCr-Cr₃C₂ coating with intermediate layer. Ni-Zn-Al₂O₃ coatings as interlayers were prepared by low pressure cold spray (LPCS) between NiCr-Cr₃C₂ cermet coatings to form a sandwich structure to enhance the corrosion resistance properties. The tribological properties were examined using the UMT-3 fricition and wear tester by line-contact reciprocating sliding under dry and salt spray one week corrosion. The morphology, element distribution, and phase compositions of the coating and worn sufaces were analyzed by using scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction respectively. The corrosion behavior of the coating was studied by the open-circuit potential, the electrochemical impedance spectroscopy, potentiodynamic polarization, and salt spray corrosion methods. It is found that the sandwich structured coating has better corrosion resistance than the single layer coating. The results show that under dry wear conditions, the wear mechanism is abrasive and adhesive wear, whereas under salt spray corrosion conditions it becomes corrosion wear. The friction coefficient of the sandwich structured coating after salt spray corrosion is slightly lower than the dry friction coefficient, but the weight of the wear loss is lower than that under dry condition.     

Al-Ce-TM（Fe,Co,Ni）非晶铝合金在NaCl溶液中的耐腐蚀性

使用单辊旋淬技术制备非晶态Al88Ce6TM6（Fe,Co,Ni）薄带,并研究了非晶态铝合金Al88Ce6TM6（Fe,Co,Ni）在中性NaCl溶液的电化学腐蚀行为.采用XRD和TEM对非晶合金的微观结构进行表征.使用直流和交流的电化学分析方法研究非晶态合金在中性0.6M NaCl溶液中的耐腐蚀性,并与纯Al进行比较.结果发现：使用单辊旋淬技术制备的铝基合金Al88Ce6TM6（Fe,Co,Ni）为完全非晶结构,铝基非晶合金在阳极活化过程中均发生了明显的钝化现象,在中性NaCl溶液中铝基非晶合金Al88Ce6TM6（Fe,Co,Ni）均发生点蚀.与纯Al相比,3种非晶合金有更高的抗腐蚀能力和抗点蚀能力.3种铝基非晶合金中Al88Ce6Fe6的耐蚀性最好.     

Corrosion resistance of plasma sprayed NiCrAl (ZrO_2 Y_2O_3) thermal barrier coating on 18-8 steel surface

1INTRODUCTION Austeniticstainlesssteelisdevelopedtocom pensateforpoorcorrosionresistanceofmartensite stainlesssteelandoverlargebrittlenessofferrite stainlesssteel.Basicconstituentsofitstypicalal loyare18%Crand8%Ni(massfraction),which isusuallycalledas188s…     

Electrochemical corrosion behavior of arc sprayed Zn and Zn15Al coatings in simulated salina soil and neutral meadow soil solutions

Arc sprayed Zn and Zn15Al coatings were chosen to protect the metal ends of prestressed high-strength concrete (PHC) pipe piles against corrosion of salina soil in northern china and neutral meadow soil in northeast China. The corrosion behavior of the coated Q235 steel samples in two simulated soil solutions were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. The experimental results show that the corrosion of the matrix Q235 steel in both simulated solutions is remarkably inhibited by Zn and Zn15Al coatings. The corrosion products on Zn and Zn15Al are thick, compact, firm and protective. The corrosion current density icorr of both Zn and Zn15Al-coated samples is decreased evidently with corrosion time, and the charge transfer resistance Rct is increased greatly. The corrosion resistance indexes of Zn and Zn15Al in simulated neutral meadow soil solution are more outstanding than those in salina soil. The corrosion resistance of Zn15Al in salina soil is slightly superior to that of Zn. When the sprayed coatings are sealed with epoxy resin, the corrosion resistance of the coatings is further enhanced markedly.