盐酸基溶液中铁离子对铁素体不锈钢腐蚀行为的影响

通过腐蚀失重测试、宏观形貌观察、微观形貌分析、自腐蚀电位测定、极化曲线以及交流阻抗图谱测试等试验检测方法,考察了盐酸溶液中铁离子对热轧抛丸后铁素体不锈钢表面氧化层去除过程的影响。结果表明:不锈钢酸洗过程中Fe~(2+)的累积使溶液氧化还原电位降低,同时降低酸洗效率;Fe~(3+)的累积使溶液氧化还原电位提升,同时提升酸洗效率。在3 mol/L盐酸浓度的溶液中,加入0.5 mol/L的Fe~(3+)或Fe~(2+),不锈钢的酸洗失重率由0.22%分别增至1.23%或降至0.14%。随着溶液中Fe~(3+)同Fe~(2+)摩尔浓度比(C_(Fe~(3+))/C_(Fe~(2+)))的增大,不锈钢的酸洗失重率逐渐增大。在盐酸浓度为1.37 mol/L、全铁浓度为1.79 mol/L的溶液体系中,当C_(Fe~(3+))/C_(Fe~(2+))≥2时,不锈钢的酸洗失重率较不含铁离子的溶液体系提高7.2倍以上。在盐酸溶液中,Fe~(3+)通过直接参与阴极反应提升反应速率,Fe~(2+)通过替换不锈钢表面吸附的H~+从而降低反应速率。     

铜箔表面硅烷化处理及其耐腐蚀性能

采用动电位极化与交流阻抗谱方法, 研究了电解铜箔经不同剂量的硅烷偶联剂γ-APT表面硅烷化处理后在3.5 % NaCl溶液中的腐蚀防护效果.实验通过改变硅烷与乙醇、水为溶剂配比以及溶液pH值、固化温度、固化时间等因素,探索自组装形成的有机膜对铜箔影响效果.结果表明:γ-APT自组装膜具有良好的耐腐蚀性能,其中含量为2.0 %,pH值为5的γ-APT硅烷液涂覆铜箔经100 ℃固化1 h自组装形成的有机膜防腐效果较优.      

304不锈钢在稀硫酸溶液中的腐蚀行为探讨

采用动电位极化曲线、电化学阻抗谱和全浸试验研究了304不锈钢在硫酸溶液中的腐蚀行为。试验结果表明:在浓度5%的硫酸溶液中,304不锈钢出现3个自腐蚀电位,分别为-0.38V、-0.14V和0.0V,为不稳定体系;电化学阻抗谱中钝化膜电阻为228.7Ω·cm2,表明不锈钢耐蚀性主要由表面钝化膜提供;浸泡试验发现在低于50%的硫酸浓度下,不锈钢的腐蚀速率随着硫酸浓度的增加而增大。     

十八烷硫醇在斯特林银合金表面自组装膜抗变色性能的研究

自组装膜可有效防止环境介质对基底材料的破坏,采用十八烷硫醇溶液在斯特林银合金表面形成一种自组装膜,通过量化变色试验分析讨论了十八烷硫醇自组装膜自组装时间对斯特林银合金表面抗变色性能的影响,并与十六烷硫醇自组装膜抗变色性能进行对比。试验结果表明,十八烷硫醇浓度0.05 mol/L,温度50℃,自组装时间120 min条件下,斯特林银合金表面形成的自组装膜抗变色性能最佳;十八烷硫醇自组装膜和十六烷硫醇自组装膜对斯特林银合金表面均有明显的抗变色效果,但后者略差。     

ACF/CNT复合材料的制备及其对Cr(Ⅵ)的吸附性能

以硝酸镍为催化剂前驱体,C2H2为碳源,H2为还原气,N2为载气,采用化学气相沉积法(CVD)在活性炭纤维(ACFs)毡体的纤维表面催化生长碳纳米管(CNTs),制备ACF/CNT复合材料。经测定,所制复合材料比表面积可达62.56 m2/g;扫描电镜分析表明,CNTs在ACFs表面分布均匀而致密,经过表面修饰可以作为1种良好的吸附材料。选择低浓度的六价铬(Cr(Ⅵ))溶液进行吸附研究,考察振荡时间、溶液pH值以及溶液的初始浓度等因素对吸附行为的影响。实验结果表明,初始Cr(Ⅵ)浓度为1 mg/L,在25℃时,随着振荡时间的增长溶液中Cr(Ⅵ)的脱除率逐渐增加,在150 min时达到最大值49.48%。溶液中Cr(Ⅵ)的脱除率随着pH的减小而增大,当pH值为2.0时脱除率达91.50%,对Cr(Ⅵ)的吸附量随着溶液初始浓度的增加而增大,但是当初始浓度到达5.0 mg/L时,脱除效率到达最大值后开始降低。并对ACF/CNT复合材料的吸附机制进行了探讨。     

表面状态对核级316LN不锈钢电化学腐蚀行为的影响

表征了打磨态和机械抛光态316LN不锈钢表面的粗糙度、表面残余应变和表面电子功函数的分布,并研究了打磨态和机械抛光态样品在硼酸盐溶液中电化学腐蚀行为的差异.与机械抛光态316LN不锈钢相比,打磨处理后样品表面较为粗糙,且表面的微观残余应变较大,近表面产生约50μm的加工硬化层.表面粗糙度和微观应变的增加引起打磨态表面电化学活性的增大,从而促进316LN不锈钢在硼酸盐溶液中腐蚀.机械抛光处理降低了表面钝化膜的载流子密度(供体和受体),并增大了钝化膜的阻抗,提高了钝化膜的致密性和保护性,能够有效抑制金属的进一步腐蚀.      

化学镀铜表面烷基膦酸自组装单分子膜的制备及表征

通过脉冲恒电位强化技术,在新生的化学镀铜样品表面上制备了烷基膦酸自组装单分子膜,测试了自组装单分子膜的电化学和谱学特性,以及润湿性变化规律。结果表明在1%烷基膦酸溶液,脉冲恒电位强化制备的自组装膜腐蚀电流较空白样品下降了98.4%,反应阻抗值相应增加,其自组装膜抑制了铜电极腐蚀反应的阳极过程,使得控制步骤由氧的扩散转变为界面电荷转移;FT-IR检测证实了样品表面成功组装了烷基膦酸单分子膜,脉冲恒电位强化处理的对应吸收峰相对较大;接触角测试间接印证了烷基膦酸已组装成膜,样品表面的润湿性由亲水性转为疏水性,脉冲恒电位强化处理后自组装单分子膜的接触角θ增加了39°,说明脉冲恒电位强化使组装膜更为致密。      

不锈钢表面电镀Cu-Mn_3O_4复合涂层

铁素体不锈钢的热膨胀系数与固体氧化物燃料电池(SOFC)的组元相近,成本低廉,具有良好的抗氧化性,已被广泛用作SOFC电池堆的金属连接体材料.但是表面Cr2O3膜的挥发会导致SOFC阴极Cr中毒,缩短SOFC的服役寿命.为解决这一问题,本文利用电镀的方法在铁素体不锈钢(SUS 430)连接体表面沉积CuMn3O4复合涂层,研究了复合电镀Cu-Mn3O4涂层的电镀工艺,结果表明:复合电镀的适宜工艺参数为:溶液pH值为3,阴极电流密度为2.12 A/dm2,镀液温度为35℃,溶液中Mn3O4粉末添加量为20 g/L.并研究了涂覆不锈钢在800℃空气中的氧化行为及氧化膜的导电性能.涂覆Cu-Mn3O4不锈钢氧化后表面生成CuO、(Mn,Cu)3O4和(Fe,Cu)3O4尖晶石氧化物,表面氧化物的导电性良好,并能有效阻止Cr向外迁移和扩散.     

外加拉应力对13Cr马氏体不锈钢的腐蚀行为影响

采用电化学测试手段(开路电位、交流阻抗谱及动电位极化曲线测试), 结合接触角测试及体视显微镜微观形貌观察探究在80 g·L-1 NaCl溶液中拉应力对L80-13Cr马氏体不锈钢钝化膜溶解与再修复机制的影响.结果表明, 拉应力大小与L80-13Cr的钝化特性存在正相关关系.随着外加拉应力的增大, L80-13Cr马氏体不锈钢的开路电位负移, 电子转移电阻减小, 线性极化电阻减小, 反应速率随着拉应力的增大而增大.而L80-13Cr马氏体不锈钢在高电位下再钝化形成的钝化区会缩短, 自腐蚀电位降低, 维钝电流密度增加.接触角测试和体视显微镜微观形貌观察发现, 拉应力使得表面接触角减小, 不锈钢表面容易发生点蚀.外加拉应力使得L80-13Cr马氏体不锈钢的表面能增加, 促进钝化膜的溶解, 并且抑制钝化膜的再生, 导致材料耐蚀性降低.      

离子膜电解法制备La(OH)3

利用阴离子交换膜电解方法制备了La(OH)3。研究了电极材料、电流密度、反应介质对La(OH)3的影响。使用不锈钢材料作阴极,在电流密度低于300 A.m-2时,La(OH)3质量随电解时间线性增大。较佳工艺条件为:电流密度300 A.m-2,LaCl3浓度为0.2 mol.L-1,添加剂浓度为15%。循环伏安曲线表明,电解过程中不锈钢表面氧化膜和H 的还原均有一个电流阶跃,两个阶跃间有一个相对平缓的电流区域。相同电压时,无添加剂的0.2 mol.L-1LaCl3溶液电流最大,含15%添加剂时的电流下降,0.6 mol.L-1NaCl空白溶液的电流最小。La(OH)3的生成使析氢电位正移。     

A Comparison Study on Corrosion Resistance of 430 Stainless Steel Surfaces Modified by Alkylsilane and Fluoroalkylsilane SAMs

The self-assembly monolayers (SAMs) of n-dodecyltriethoxysilane (DTES) and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDS) on the surface of the 430 stainless steel (430SS) were prepared and their corrosion protection performance was investigated by potentiodynamic polarization, Fourier transform infrared spectroscopy (FTIR) -attenuated total reflection (ATR), static contact angle and atomic force microscopy (AFM). The results showed that the alkali pretreatment and the water added into the self-assembly solution could generate more hydroxyls on the 430SS surface, and then enhanced the adsorption of the SAMs. A suitable temperature of the self-assembly solution is important for the formation of the SAMs. The silane SAMs were chemically adsorbed on the 430SS substrates by Fe-O-Si bonds. In all cases tested, PFDS has a better inhibition effect compared with DTES, and the difference in inhibition effect is most marked at the lowest concentration of 1 mmol/L.     

Adsorption and Corrosion Inhibition Performances of 1-Tetradecylphosphonic Acid Self-Assembled Monolayers on 430 Stainless Steel Surface

The self-assembled monolayers (SAMs) of 1-tetradecylphosphonic acid (TDPA) formed on the 130 stainless steel (SS430) were studied. Surface and morphological characterizations were studied by Fourier transformed infrared spectroscopy (FTIR), water contact angle measurement and atomic force microscopy (AFM). And the electrochemical study on the corrosion inhibition of the SAMs was performed by polarization curve and electrochemical impedance spectroscopy (EIS) for evaluating the corrosion protection of the SAMs. The results show that TDPA was able to form a film spontaneously on the SS430 surface and the hydrophobic SAMs could protect SS430 from corrosion effectively. In addition, the oxide surface formed by the heat pretreatment could accelerate the rate of adsorption, but had little effect on improving the inhibition efficiency.     

Pitting Corrosion Behavior of Stainless Steel 304 in Carbon Dioxide Environments

The pitting corrosion behavior of stainless steel (SS) 304 in aqueous CO2-H2S-CI-environment was investigated by potentiodynamic cyclic anodic polarization and electron probemicroanalysis (EPMA). The experimental results show that the pitting corrosion susceptivityof SS 304 increases with the increase of temperature. Chlorine ion is the prerequisite for pittingcorrosion of SS 304 in H2S-CO2 environments. There is a linear relatiotxship between the pittingcorrosion potential (Eb-100) and chlorine ion concentration, and Eb-00 becomes noble with in-creasing pH value of the solution with or without H2S. pH value has little effect on the protec-tion potential with the presence of Hz S. H2S increases strongly the pitting corrosion susceptivi-ty and deteriorates the pitting corrosion resistance of SS 304 in CO2 environments. The obser-vations by EPMA show that SS 304 in CO2-saturated NaCI solution (3%) with H2S sufferspitting corrosion accompanied with intergranular corrosion.     

Green Approach to Corrosion Inhibition of Mild Steel by Lignin Sulfonate in Acidic Media

The inhibition effect of lignin sulfonate against corrosion for mild steel in acidic solution has been examined by means of FTIR(fourier transform infrared spectroscopy),FAA(flame atomic absorption)spectroscopy,SEM(scanning electron microscope),EDS(energy dispersive X-ray spectroscopy),and mass loss techniques.The results revealed that lignin is a beneficial inhibitor for mild steel corrosion in acidic medium.It has been further found that Langmuir adsorption isotherm is obeyed by the tested lignin′s adsorption over the surface of mild steel.The range of inhibition efficiency(IE)in 2mol·L~(-1) HCl was found to be 75.88%-87.88%for Reax 88 A,40.72%-60.32%for Reax 88 B,and 54.32%-63.03%for Reax 100 M,after immersed at 298 Kfor 24htime.     

Effects of Different Oxidants on HCl-based Pickling Process of 430 Stainless Steel

To shorten the time required for the pickling process and to enhance the quality of ferritic stainless steel plates,the effects of oxidants including hydrogen peroxide(H2O2),potassium permanganate(KMnO4),and potassium chlorate(KClO3)on the pickling behavior in HCl-based electrolyte as well as the surface quality of hot-rolled and blasted 430 stainless steel(430-SS)were studied.Experiments were conducted using mass-loss tests,microstructure analyses,potentiodynamic polarization curves,and electrochemical impedance spectroscopy measurements.The results showed that the addition of oxidants substantially accelerated the pickling process of 430-SS by enhancing the cathodic reaction rate and reducing the charge transfer resistance.In electrolytes comprising 5-8mass% HCl at a temperature of 40-60 ℃ and at the same concentration within the range from 0to 2mass%,H2O2 was demonstrated to be superior to KMnO4 and KClO3in accelerating the pickling process.The surface quality of 430-SS pickled in the presence of H2O2 was better than those of specimens pickled in the presence of KMnO4 and KClO3 when the removal of the oxide layer,intergranular corrosion,and surface roughness were collectively considered.When 1mass% H2O2 was added,the mass loss rate of 430-SS was increased by 629%and no residual oxide layer or intergranular corrosion was observed on the surface of the steel;in addition,the roughness was only 1.7μm.H2O2 was determined to be a better oxidant than KMnO4 and KClO3 when the pickling process,surface quality,solution recycling,and environment protection were considered as a whole.     

咪唑啉缓蚀剂在NaCl溶液中对2099Al-Li合金的缓蚀行为

采用极化曲线、交流电化学阻抗谱（EIS）和扫描电化学显微镜（SECM）技术研究了咪唑啉在3 %（指质量分数，下同）NaCl溶液中对2099 Al-Li合金的缓蚀行为.结果表明:咪唑啉有很好的缓蚀效果.极化曲线测试和交流阻抗测试都验证了咪唑啉浓度达到0.01 mmol/L时，缓蚀效率达77 %以上的准确性.采用扫描电化学显微镜技术（SECM）研究0.01 mmol/L咪唑啉缓蚀剂在3 % NaCl+5 mmol/LKI溶液中对2099铝锂合金的缓蚀行为.结果表明:在缓蚀剂条件下，合金表面电流峰数量减少，强度减弱.      

Influence of Marine Aerobic Biofilms on Corrosion of 316L Stainless Steel

The influence of marine aerobic biofilms on the corrosion of 316 L stainless steel(SS) in aerated and deaerated seawater was studied by electrochemical impedance spectroscopy(EIS), potentiodynamic polarisation curves, current-potential curves and scanning electron microscopy with energy-dispersive spectroscopy(SEM-EDS). EIS and SEM-EDS results showed that the aerobic biofilms inhibited 316 L SS corrosion within the test duration. Comparison of results under aerated and deaerated conditions revealed that O2 enhanced the inhibition efficiency of the aerobic biofilms. This result indicated that living cells were necessary for the aerobic biofilms to inhibit the corrosion of 316 L SS. Polarization curves indicated that the biofilms mainly inhibited anode action. Current-potential curves under deaerated conditions showed that electron transfer processes occurred between microorganisms and electrodes. Moreover, 316 L SS as an electron acceptor was protected from corrosion.     

The Enhanced Even and Pitting Corrosion Resistances of Bulk Nanocrystalline Steel in HCl Solution

We studied the corrosion properties of bulk nanocrystalline 304 stainless steel (BN‐SS304) produced by severe rolling technique and conventional polycrystalline 304 stainless steel (CP‐SS304) with immersion test, X‐ray photoelectron spectroscopy, ultra‐violet photoelectron spectroscopy, inductively coupled plasma emission spectrometer, and scanning electron microscope. Immersion test was carried out in 0.5 mol L^?1 HCl solution for 30 days immersion interval at room temperature. It is well known that the pitting corrosion of stainless steel could be inevitable in solution containing Cl^?. However, BN‐SS304 can scarcely suffer from pitting corrosion with the compact oxide film on its corrosion surface and less corrosion rate in comparison with CP‐SS304. The less corrosion rate of BN‐SS304 was attributed to the stronger O₂ adsorption and compact oxide film on its corrosion surface, its less weight of 4s–4s valence electrons and its larger work function in comparison with CP‐SS304. The improved pitting corrosion resistance of BN‐SS304 resulted from the compact oxide film, weaker Cl^? adsorption and less Cl^? chemical activity on its corrosion surface.     

硼含量对低碳钢耐蚀性的影响

 为考察不同硼含量低碳钢的腐蚀规律,利用盐雾腐蚀试验研究了不同硼含量低碳钢的腐蚀行为,结合X射线衍射（XRD）和傅里叶红外光谱（FTIR）对腐蚀产物进行了分析。试验结果表明：含硼低碳钢腐蚀速率与硼质量分数有关,硼质量分数0.002%试验钢腐蚀速率低于无硼钢,硼质量分数高于0.002%的试验钢腐蚀速率超过无硼钢,并且随硼含量增加,试验钢的腐蚀速率逐渐增加;阐述了硼的腐蚀机制。