低阴极沉积电位对铝合金表面硅烷膜层的影响

在低阴极沉积电位条件下,使用表面活性剂改性硅烷溶液,实现了双-1,2-[γ(三乙氧基)硅丙基]四硫化物(BTSPS)在铝合金电极表面的电化学沉积,新的临界沉积电位(NCCP)约为-1.6 V.研究表明,在低阴极沉积电位下铝合金表面能得到更厚、更致密的硅烷膜层,并且在改性后溶液中制备的膜层具有较高的极化阻力.表面活性剂的加入可以降低沉积时析氢的影响,提高硅烷沉积性能.临界沉积电位的降低,使得硅烷覆盖的铝合金电极比临界沉积电位(-0.8 V)下的电极具有更好的抗腐蚀性能.     

硅烷膜的阴极电化学辅助沉积及其防护性能

采用电化学辅助技术在LY12铝合金表面沉积了两种防护性硅烷膜（1，2-二-（三乙氧基硅基）乙烷（BTSE）膜与十二烷基三甲氧基硅烷（DTMS）膜），电化学阻抗谱测试结果显示，经硅烷化处理后铝合金的耐蚀性能得到大幅度提高，并且发现在阴极电位下沉积所得硅烷膜的耐蚀性能较常规“浸涂法”有明显提高；两种硅烷膜均存在一个最佳的“临界阴极电位”（-0．8V），在此电位下制得的膜耐蚀性最佳，扫描电镜观察显示临界电位下所得硅烷膜最为完整致密，电位过正不利于成膜，而电位继续变负膜表面呈现多孔形貌，可能与氢气的生成并溢出破坏表面有关．由于在硅烷分子中含有疏水性较强的十二烷基长链，DTMS膜具有更好的耐蚀性．     

6061铝合金上硅烷膜的制备与性能

采用浸涂技术,在6061铝合金表面制备了γ-氨丙基三甲氧基硅烷膜。采用电化学方法和SEM研究了其在3.5%NaCl溶液中的耐蚀性及形貌。结果表明,当硅烷浓度为3%(体积分数),溶液pH为12,室温下水解时间72h形成的硅烷溶液具有较好的稳定性;铝合金试样在硅烷溶液中浸涂3min,固化温度180℃,固化时间120min,其表面形成的硅烷膜的耐蚀性最佳,表现为腐蚀电流密度降低和腐蚀电位的升高。     

AA6061-T6铝合金表面纳米Y_2O_3改性硅烷膜的耐蚀性

采用动电位极化曲线,电化学阻抗谱(EIS)和中性盐雾试验(NSS)研究了溶液中加入不同含量纳米Y2O3对铝合金AA6061-T6表面硅烷膜耐蚀性的影响,采用扫描电镜(SEM)对其形貌进行了观察。结果表明,在1,2-双-三乙氧基硅烷(BTSE)溶液中加入少量纳米Y2O3可提高硅烷膜在3.5%NaCl溶液中的耐蚀性。硅烷膜对铝合金的保护只起到物理屏障作用。纳米Y2O3抑制了电化学腐蚀过程中阴极还原反应的发生,但不影响电极反应的动力特征。SEM表明在BTSE硅烷溶液中添加10~20mg/L的纳米Y2O3后,硅烷膜表面变得平滑致密。     

高温合金表面锌镍沉积层的电化学制备及结构性能分析

采用电化学沉积法在GH3230高温合金基底上制备了锌镍合金沉积层,研究了沉积电位、沉积时间和溶液质量浓度对沉积层组成和结构的影响规律。结果表明：沉积电位负移、延长沉积时间和提高溶液质量浓度能有效提高沉积层结晶程度。当在沉积电位-1.2 V、沉积时间30 min、采用配制的沉积溶液S-2时,制得的沉积层表面致密平整,与基底之间的结合力良好,并具有优良的耐蚀性。     

Si-69应用于2024铝合金表面硅烷化防腐蚀处理的工艺研究

采用正交试验探索硅烷偶联剂Si-69的水解工艺条件,研究了Si-69用量、水解pH值、水解时间等水解因素和老化成膜条件(温度、时间)对硅烷成膜试样耐蚀性的影响,确定了最佳水解工艺和老化成膜工艺.经电化学测试表明,硅烷膜的生成使2024铝合金基体表面的多孔性降低,有效阻止了腐蚀介质所参与的阴极活性点还原反应,极大地提高了...     

脉冲阴极电沉积羟基磷灰石涂层

对脉冲阴极电沉积与恒电位阴极电沉积制备的羟基磷灰石涂层膜进行了对比实验.结果表明:由于脉冲电沉积的一个关断时间使离子得以从溶液本体向电极表面扩散,在下一脉冲来临时浓差极化的减小有利于HAP的生长;在一定的导通时间下,关断时间的延长有利于羟基磷灰石的沉积,但时间的过度延长不利于羟基磷灰石的沉积;当通电时间为5 s时,其最佳关断时间为2 s;沉积时阴极极化的增强虽有利于膜的生长,但极化过于强烈(阴极电位为-1.0 V(vs SCE)时,涂层易脱落.     

镀锌钢板表面硅烷膜的制备及性能研究

目的提高镀锌钢板的耐腐蚀性能。方法在镀锌钢表面制备双-[γ-(三乙氧基硅)丙基]四硫化物(BTESPT)和乙烯基三乙氧基硅烷(VTES)单一硅烷膜和双硅烷膜,并掺杂缓蚀剂和稀土盐改性制备复合膜,用动电位极化曲线测试研究各种硅烷膜在3.5%Na Cl溶液中对镀锌钢的腐蚀防护性能。结果 VTES硅烷膜的最佳工艺条件为:V(VTES):V(乙醇):V(水)=7:30:70,p H=4.5,水解2 d,成膜时间20 min,固化温度100℃,固化时间30 min,VTES硅烷膜耐蚀性比BTESPT硅烷膜略差,但更经济。双层硅烷膜能够提高物理屏障作用,可以进一步增加耐蚀性。当铈盐和硅烷混合水解再成膜时,硅烷膜的耐蚀性最好。在硅烷水解溶液中加入0.01 mol/L的吡咯,可以制得耐蚀性优良的缓蚀剂掺杂硅烷摸。结论铈盐和吡咯改性硅烷膜对镀锌钢具有良好的保护作用。     

氨络合物体系电积锌的阴极过程

采用CHI650电化学工作站测定了在锌氨络合物体系中锌电沉积的稳态阴极极化曲线及电流-时间暂态曲线.结果表明:锌的阴极电结晶过程是以瞬时成核方式进行的,随外加电位负移,晶体的向外生长速率增大;添加剂的加入不会改变锌阴极电沉积的成核方式,但将大大减小晶体的向外生长速率.通过对不同NH3浓度下测得的阴极极化曲线的分析,可获得各条件下的平衡电位,以及阴极过程动力学参数(交换电流密度J°、传递系数α),进而推导出溶液中存在的主要离子为Zn(NH3)2 4,在阴极直接放电的络离子为Zn(NH3)22 .     

Studies on Silane-based Anti-corrosion Surface Treatment of Aluminum Allov 2024

采用正交试验探索硅烷偶联剂Si-69的水解工艺条件,研究了Si-69用量、水解pH值、水解时间等水解因素和老化成膜条件(温度、时间)对硅烷成膜试样耐蚀性的影响,确定了最佳水解工艺和老化成膜工艺.经电化学测试表明,硅烷膜的生成使2024铝合金基体表面的多孔性降低,有效阻止了腐蚀介质所参与的阴极活性点还原反应,极大地提高了基体的耐蚀性.     

Normal and anomalous electrodeposition of tin–copper alloys from methanesulphonic acid bath containing perfluorinated cationic surfactant

Abstract

Sn–Cu alloys were deposited from a 12˙5 vol.-% (1˙93 mol dm^–3) methanesulphonic acid bath containing a perfluorinated, cationic surfactant at 296 K. Electrodeposition was carried out under controlled flow conditions, using rotating disc, rotating cylinder and rotating cylinder Hull cell electrodes. The influences of deposition current and potential, rotation speed, cupric ion concentration, stannous ion level and surfactant concentration on the deposited alloy composition have been investigated. The presence of surfactant resulted in a shift in the Cu deposition potential compared to that of Sn deposition. Both 'normal' deposition (Cu deposited at a more positive potential than Sn) and 'anomalous' deposition (Sn deposited at a more positive potential than Cu) could be achieved. A series of Sn–Cu alloys was electrodeposited over a wide range of operating conditions to produce matte grey through golden yellow to light brown, surface finishes. Golden yellow coloured bronze deposits, containing 70–80 wt-% Cu and 20–30 wt-%Sn could be obtained. When Sn was deposited preferentially, the Cu content of the alloy was typically in the range 3–9 wt-% along the cathode of the rotating cylinder Hull cell.     

INVESTIGATION ON DEPOSITIONS AND HARDNESS CHARACTERISTICS OF a SiC:H FILMS

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Corrosion protection of electroplated nickel using silane coupling agent

Abstract

Electroplated nickel was chemically modified using an aminosilane coupling agent (as an alternative to chromate) in order to improve its corrosion performance. Infrared spectroscopy revealed that the silane bonded to the metal satisfactorily. The corrosion behaviour of a nickel electroplated steel workpiece was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy to optimise the silane deposition conditions. These data confirm that the most effective conditions are dipping in the silane coupling agent solution for 30 s and then curing at 100°C for 40 min.     

Process Conditions and Microstructures of Ceramic Coatings by Gas Phase Deposition Based on Plasma Spraying

Plasma spraying at very low pressure (50-200 Pa) is significantly different from atmospheric plasma conditions (APS). By applying powder feedstock, it is possible to fragment the particles into very small clusters or even to evaporate the material. As a consequence, the deposition mechanisms and the resulting coating microstructures could be quite different compared to conventional APS liquid splat deposition. Thin and dense ceramic coatings as well as columnar-structured strain-tolerant coatings with low thermal conductivity can be achieved offering new possibilities for application in energy systems. To exploit the potential of such a gas phase deposition from plasma spray-based processes, the deposition mechanisms and their dependency on process conditions must be better understood. Thus, plasma conditions were investigated by optical emission spectroscopy. Coating experiments were performed, partially at extreme conditions. Based on the observed microstructures, a phenomenological model is developed to identify basic growth mechanisms.     

表面活性剂对Ni-Si3N4复合镀层的影响

通过分析3种典型表面活性剂对Si3N4微粒在镀液中悬浮性的影响,研究各表面活性剂对Ni-Si3N4复合层中微粒含量、沉积速率和镀层硬度的影响及作用机理。结果表明,阳离子表面活性剂十六烷基三甲基溴化铵可提高复合镀层中Si3N4微粒含量和镀层硬度,有利于Ni-Si3N4的沉积;非离子表面活性剂甲酰胺对Ni-Si3N4镀层的影响不显著。选择适当的阴离子表面活性剂和阳离子活性剂的混和比例,可以获得较好的Ni-Si3N4镀层。     

Electrochemical study of modified non-functional bis-silane layers on Al alloy 2024-T3

In the last few years great efforts have been made in order to find and to develop environmentally friendly substitutes for Cr⁶⁺ pre-treatments applied on aluminium alloys used in the aircraft industry. Among the potential substitutes, silane layers have attracted considerable interest from researchers and from the industry. The present work investigates the anti-corrosion behaviour of (bis-1, 2-(triethoxysilyl) ethane (BTSE)) silane layers modified with Ce ions and/or silica nanoparticles applied on Al alloy 2024-T3 substrates. The corrosion behaviour was investigated in 0.1 M NaCl solution via d.c. polarization and electrochemical impedance spectroscopy (EIS). Contact angle measurements and XPS were used to assess information on the chemistry of the silane pre-treated surfaces. The results have shown that the introduction of additives improves the corrosion protection properties of the silane layer.     

镀锌钢表面硅烷膜的耐蚀性能研究

采用浸涂技术,在热镀锌（HDG）钢板表面制备3-氨丙基甲基二乙氧基硅烷膜。通过电化学方法研究硅烷膜在3．50％的氯化钠溶液中的耐蚀性能,并用SEM研究存在硅烷膜的镀锌钢在腐蚀前后的形貌变化。结果表明,形成硅烷膜的镀锌钢在3．50％的氯化钠溶液中的自腐蚀电流密度下降到2．434×10^-8A·cm^-1自腐蚀电位正移。经SEM测试表明,硅烷膜在腐蚀前后的形貌几乎不变,耐蚀性能明显优于空白样镀锌钢。     

表面活性剂对镀Ti金刚石-Ni复合电沉积行为的影响

研究了阴离子表面活性剂十二烷基硫酸钠(SDS,sodium dodecyl sulfate)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB,cetyl trimethyl ammonium bromide)对镀Ti金刚石-Ni复合电沉积的影响,并结合循环伏安、交流阻抗等电化学方法研究了镀Ti金刚石-Ni镀液中Ni电沉积过程。结果表明:与未镀覆金刚石相比,镀Ti金刚石与Ni层浸润性得到提高。浓度为0.05 g/L的SDS对Ni电结晶过程有抑制作用,而浓度为0.05 g/L的CTAB能促进Ni~(2+)离子转移并加快Ni的电沉积过程。SDS和CTAB都能促进电沉积过程中氢气的析出并细化Ni镀层,同时减少镀层针孔和凹痕。     

生物约束成型与化学沉积制备Cu微米杆材料

采用微生物法和化学沉积法在直径为0.4-0.6μm的诺卡氏(Nocadia)菌体表面成功沉积了厚度约为200 nm、晶粒尺寸约为20 nm的Cu镀层,制备出新型Cu微米杆材料.在相同条件下,十二烷基苯磺酸钠对菌体的分散效果好于焦磷酸钠.在表面活性剂十二烷基苯磺酸钠和机械搅拌联合分散下,菌体均匀分散在前处理溶液和镀铜液中.施镀过程中,菌体保持原有形状,得到了纳米Cu晶粒组成的微米级杆状金属材料.