采用失重法、表面分析技术和电化学测试技术研究了45钢在硫杆菌和假单胞菌协同作用下的腐蚀行为。结果表明,与单种菌相比,腐蚀初期两种菌混合作用下45钢平均腐蚀速率受到明显抑制。随浸泡时间延长,30 d时混菌体系中电极电化学阻抗值较单菌体系减小,腐蚀电位降低,腐蚀电流密度增大,混菌逐渐加速了金属腐蚀。扫描电镜 (SEM) 分析结果表明,混合菌体系中45钢腐蚀产物膜存在大量裂纹且金属表面点蚀现象更为严重。
Abstrsct: The microbe-induced corrosion of 45 steel in tropic seawaters was investigated in the presence of thiobacillus thiooxidans and pseudomonas sp. by means of mass loss method, surface analysis techniques and electrochemical measurement technology. The results showed that in comparison with the seawaters containing only one of the two bacterial species, the corrosion of 45 steel was evidently prohibited in seawaters with the presence of the two bacterial species at the initial stage, however after 30 d immersion 45 steel showed relatively smaller impedance, lower corrosion potential and higher corrosion current density. With the prolonging of immersion time, synergism of thiobacillus thiooxidans and pseudomonas sp. accelerated the corrosion of 45 steel, while a large numbers of cracks were observed in the corrosion product film formed on the surface of 45 steel and the pitting corrosion was rather severe.
The oxidation behavior of binary Fe-10Si and Fe-22Si alloys beneath KCl-ZnCl2 deposits in air was investigated at 600~700 ℃. Experimental results indicated that in air and without salt deposits on the surface, Fe-22Si exhibited excellent oxidation resistance, while Fe-10Si formed a double layered structure, an outer layer of Fe oxides and an inner layer of Fe and Si mixed oxides. In the contrast, in air and with salt deposits on the surface, the two alloys suffered from accelerated corrosion characterized by the growth of porous oxides plus internal corrosion, particularly the degradation of the protective scales on Fe-22Si alloy. The corrosion rate decreased with increasing Si content. The accelerated corrosion was mainly caused by the reaction between the oxide scales and chloride containing salts. The thermodynamic phase diagram was calculated to estimate the possible chemical reactions, and to discuss the corrosion mechanism and the effect of Si element.
通过现场暴晒实验研究碳钢在吐鲁番干热大气环境中的腐蚀行为和机理。Q235和Q450钢在吐鲁番干热大气环境中经过1 a暴露后,Q235钢的腐蚀速率大于Q450钢。结合扫描电镜 (SEM)、能谱分析 (EDS)、X射线衍射 (XRD) 等分析测试手段,研究了两种碳钢表面的腐蚀产物,两者的腐蚀产物主要为α-FeOOH,γ-FeOOH和Fe3O4。Q235钢中γ-FeOOH与α-FeOOH含量的比值较高,其腐蚀产物疏松,耐蚀性较差。而Q450钢中γ-FeOOH与α-FeOOH含量的比值较低,其腐蚀产物相对致密,耐蚀性较好。去除腐蚀产物后,通过体视学显微镜观察发现,Q235钢的表面产生大量密集腐蚀坑,且腐蚀坑深度和体积都大于Q450钢表面腐蚀坑。
The corrosion behavior and the relevant mechanism of carbon steels Q235 and Q450 exposed for 1 a in the hot and dry atmosphere environment at Turpan area was studied by weight lose test, scanning electron microscopy (SEM), energy dispersive spectra (EDS), X-ray diffraction (XRD) and stereological microscope. The results showed that the corrosion rate of carbon steel Q235 was greater than carbon steel Q450. The corrosion products on the surface of the carbon steels were consisted of α-FeOOH,γ-FeOOH and Fe3O4. The corrosion product of carbon steel Q235 was relatively loose for its rather low ratio of γ-FeOOH to α-FeOOH, whilst the corrosion product of carbon steel Q450 was dense for its higher ratio of γ-FeOOH to α-FeOOH. After removal of corrosion products, it could be observed that the depth and volume of corrosion pits of carbon steel Q235 was larger than those of carbon steel Q450.
在青岛和海南进行40CrNi2Si2MoVA超高强度钢的大气暴露实验,对暴露后的材料性能以及腐蚀形貌进行了研究。结果表明,40CrNi2Si2MoVA钢在海洋性大气环境中,腐蚀以均匀腐蚀为主,随环境不同和腐蚀发展的变化,腐蚀产物成分和结构不同,主要成分是Fe3O4,Fe2O3,γ-FeOOH和α-FeOOH。腐蚀失重与时间的关系可用幂函数w=at b(b<1) 回归。40CrNi2Si2MoVA钢在海洋性大气环境下具有较高的应力腐蚀敏感性,应力腐蚀为沿晶开裂模式,裂纹起源于表面产生腐蚀的部位,并向内部扩展。40CrNi2Si2MoVA钢在海南万宁的腐蚀速率以及应力腐蚀敏感性明显高于在青岛团岛的。由于环境腐蚀对材料的影响,导致其抗拉强度的损失,从而使其抗应力能力降低,在更低的强度水平和更短的时间内产生断裂。
Outdoor exposure tests in marine atmosphere of 40CrNi2Si2MoVA high strength steel were carried out in Qingdao (on the east coast of Shandong facing the East China Sea) and Wanning (on the east coast of Hainan Island facing the South China Sea) respectively. The test samples include plate sample, samples for tensile and various stress corrosion cracking (SCC) test. The corrosion behavior of the steel was examined by means of mass loss measurement, SEM, as well as the change of mechanical property and SCC susceptibility. The results show that general corrosion occurs on the surface of 40CrNi2Si2MoVA steel, corrosion products are mainly Fe3O4、Fe2O3、γ-FeOOH and α-FeOOH; the mass losses vary at w=atb(b<1). The steel exhibited high SCC sensitivity in marine environment with typical intergranular cracking, and the crack initiated from corrosion pits in the surface and developed inwards. Higher corrosion rate and higher SCC sensitivity were observed in Hainan rather than in Qingdao. The decrease of tensile strength is result from corrosion inducing premature fracture in a short term.
利用称重法对一种环氧粉末涂层在不同溶液种类 (NaCl,KCl,CaCl2和蒸馏水),不同温度 (20,40,60和80 ℃),不同浓度NaCl溶液中的吸水性进行了研究。结果表明,水在环氧粉末涂层中的扩散基本符合Fick第二定律,饱和吸水量和水在涂层中的扩散系数与溶液温度和水活性有关,并计算得到不同溶液中水在环氧粉末涂层自由膜中扩散的活化能；涂层浸泡过程中填料会有溶出,不同溶液溶出行为不一致；一次结合水和二次结合水含量随温度的升高而增大；80 ℃蒸馏水中涂层结构发生松弛导致吸水量不断增加。
The water absorption characteristics of a kind of epoxy powder coating in different type of solutions (NaCl, KCl, CaCl2, distilled water) at temperatures (20, 40, 60 and 80 ℃) were studied by mass gain measurement. Results showed that the diffusion of water in epoxy powder coating obeys the second Fick's law, while the saturated quantity of water absorption and diffusion coefficient of water in the coating is related with the solution temperature and water activity, fillers of the coating will be dissolved out during immersion,however the amount of the dissolved filler varies with the type of solution; the amount of the primary- and secondary-bound water increases with the rise of temperature. In the distilled water at 80 ℃ relaxation of the coating occurred leading to the enhancement of water absorption. Besides, the activation energy of water diffusion in epoxy powder coating was also calculated for different solutions.
采用电化学方法、电偶实验、EPMA和ICP-MS对不同Fe含量的Al-Zn-In-Mg-Ti-Si牺牲阳极在海水中的电化学性能进行了研究。结果表明,铝合金牺牲阳极随着Fe含量的增加,Fe的析出相随之增多。Fe主要富集在晶界处,少数呈点状在晶内弥散分布。Al-5Zn-0.02In-1Mg-0.05Ti-0.12Si-0.1Fe合金的阳极表面溶解均匀,工作电位处于-1.047~-1.068 V之间,电流效率达到93%以上,耦合电位较负且稳定,耦合电流较高,2 h时的Al和Zn溶解量为2.2×10-8和3.8×10-9 g/L,48 h时的扫描电流峰值为36 mA,增加了溶解活性点,铝合金的溶解均匀性得到增强。而Fe含量超过0.1%后,会限制In的活化作用,活性溶解阻力逐渐增大,电流效率明显下降。Fe含量为0.1%的Al-Zn-In-Mg-Ti-Si合金具有较好的阳极性能。
The electrochemical performance of Al-Zn-In-Mg-Ti-Si sacrificial anodes with different Fe content was studied by electrochemical method, galvanic corrosion, EPMA and ICP-MS in seawater. The results show that along with the increase of Fe content, the amount of Fe cantaining precipitates also increases. Fe is mainly gathering in the grain boundaries and few Fe distributes in the interior of grains. The Al-5Zn-0.02In-1Mg-0.05Ti-0.12Si-0.1Fe sacrificial anode dissolves uniformly. Its working potential is between -1.047~-1.068 V and current efficiency reaches 93%. The coupling potential is negative and stable. The coupling current is higher. The dissolved amount of Al and Zn are 2.2×10-8 and 3.8×10-9 g/L at 2 h. The value of current peak by 48 h is 36 mA. It means that the number of active points and dissolution uniformity of the aluminum alloy are enhanced. When Fe content exceeds 0.1%, the resistance of active dissolution increases gradually, which indicates that the activation of In is suppressed and the anode current efficiency decreases obviously. It is found that Al-Zn-In-Mg-Ti-Si alloy owns better anodic performance with 0.1%Fe.
利用腐蚀失重法探讨了X60管线钢在不同温度、流速、压力条件下原油中的失重规律,进一步利用 (SEM)、能谱分析 (EDS) 分析腐蚀产物膜的成分。结果表明,随着温度的升高,X60管线钢在原油中的腐蚀速率先增大后减小。动态原油比静态原油更具腐蚀性,且随着流速的增大X60管线钢的腐蚀速率随之增大。压力对输油管线在原油中的腐蚀影响较小。EDS分析结果表明,腐蚀产物主要由Fe,O,S,C和Cl组成。
The factors on the corrosion of crude oil, corrosion rate of X60 pipeline steel was investigated by the mass loss method in crude oil with different temperature, flow velocity, pressure. Meanwhile, the technology of SEM and EDS were used to analysis the corrosion product scale. The results showed that with the increase of temperature, the corrosion rate of X60 pipeline steel showed the tendency of increase-decrease. Dynamic oil had more corrosive compared to static oil, and the corrosion rate of X60 pipeline steel increasing with the increasing of flow velocity. Pressure had an small affection on the corrosion of crude oil. The result of EDS analysis indicated that the corrosion product scale was mainly composed of iron, oxygen, sulfide, carbon, chlorine element.
To improve the heterogeneous dispersion of nano materials in epoxy resin, sodium dodecyl benzene sulfonate (SDBS) was used to modify the surface of home-made nano-ZrO2 powders. The modified nano-ZrO2 particles were characterized by transformation infrared (FTIR) and X-ray diffraction (XRD), and the dispersion effect of the modified nano-ZrO2 in epoxy coating was observed by scanning electron microscope with energy dispersive X-ray spectroscopy (SEM/EDS). In addition, protectiveness of the nano-ZrO2/epoxy coating on Q235 steel in 3.5%NaCl solution was examined by electrochemical impendence spectroscopy (EIS). Results indicated that SDBS was proved to graft onto the surface of nano-ZrO2, so that the dispersion effect of nano-ZrO2 was improved in epoxy coating. The adhesive strength of the epoxy coating decreased with the increase of nano-ZrO2 content. The nano-ZrO2/epoxy coating containing 1% (mass fraction) nano-ZrO2 exhibited a high impermeability and electric resistance, therewith an excellent protectiveness for Q235 steel.
研究了粉末渗锌涂层钢在3.5%NaCl溶液、人工海水 (ASW) 和天然海水 (NSW) 中的腐蚀行为。结果表明,渗锌层主要成分为Zn-Fe合金。渗锌涂层在3.5%NaCl溶液中的腐蚀速率要大于ASW和NSW。这可能是由于两种介质中含有的成分能够与Zn反应,生成更难溶的物质堆积于涂层表面,导致腐蚀速率降低。
Corrosion behavior of sherardized carbon steel was studied by electrochemical measurements in 3.5%NaCl solutions, artificial seawater (ASW) and natural seawater (NSW) respectively. The results show that the sherardized surface layer consisted of Fe4Zn9, Zn and others; the corrosion rate of sherardized steel in 3.5%NaCl solutions is larger than that in ASW and NSW. This is because the corrosion products generated on the sherardized steel surface in ASW and NSW was difficult to dissolve compared with that in 3.5%NaCl solutions, hence acted as a better corrosion barrier.
采用电化学阻抗谱 (EIS) 和动电位扫描研究了紫铜在酸性和碱性土壤浸出液中的腐蚀行为,并用频率调制 (EFM) 方法测量了紫铜的腐蚀电流密度Icorr。结果表明：紫铜在腐蚀过程中表面生成了钝化膜,溶液中Cl-,NO3-和SO42-等离子会延长钝化膜的生长期；在酸性介质中,靠近溶液侧的钝化膜会转化成结构疏松的外层,膜层的转化使钝化膜的保护作用减弱；腐蚀20 d后,碱性介质中紫铜的Icorr为4 μA/cm2左右,酸性介质中Icorr约为25 μA/cm2,紫铜耐酸蚀性较差。
The electrochemical corrosion behavior of copper was studied by EIS, potentiodynamic and EFM measurements in acid and alkaline soil extract solutions. The result shows that a passive film was formed on the surface of copper during the corrosion, growth period of the passive film could be extended due to the existence of ions like Cl-,NO3- and SO42-. In the acid soil extract solution, the outer portion of the passive film transformed into a loose layer, therewith its protectiveness would be lowered. After 20 d corrosion, the icorr of copper in alkaline soil extract is about 4 μA/cm2, while 25 μA/cm2 in acid extract. In other words, the corrosion resistance of copper in acid soil solution is low.
Corrosion inhibition of fluconazole on cupper in 3.5%NaCl solution was studied by means of electrochemical measurements and surface morphology observation. The results show that fluconazole exhibited good performance as corrosion inhibitor for copper and its effectiveness increases with the increasing concentrations of fluconazole in NaCl solution; while, its inhibition efficiency decreases with the increasing temperature. The results of electrochemical measurements indicate that fluconazole is a mixed type inhibitor for the corrosion inhibition of copper in NaCl solution. Analysis of surface morphology also confirms that fluconazole has good inhibition effect on copper corrosion in NaCl solution.
通过电化学测试方法研究了Q235钢在1-甲基-3-(4-磺酸基丁基) 咪唑硫酸氢盐[(CH2)4SO3HMIm][HSO4](IL1)、N-(4-磺酸基丁基) 吡啶硫酸氢盐[(CH2)4SO3HPy][HSO4](IL2)、N-(4-磺酸基丁基) 三乙基铵硫酸氢盐[(CH2)4SO3HTEA][HSO4](IL3) 等3种Br?nsted酸离子液体中的腐蚀行为,通过扫描电镜 (SEM) 观察了实验后Q235钢的表面腐蚀形貌及产物的元素组成,分析了Q235钢在3种离子液体中的腐蚀机理。结果表明,Q235钢在这3种不同离子液体中的耐腐蚀性从强到弱的顺序为：IL3>IL2>IL1。同时,升高温度,Q235钢的腐蚀速率随之增加。
The corrosion behavior of Q235 steel in three proton acid ionic liquids with different cations, i.e. 3-methyl-l-(4-sulfonic acid) butyl imidazolium hydrogen sulfate [(CH2)4SO3HMIm][HSO4](IL1), N-(4-sulfonic acid) butylpyridinium hydrogen sulfate [ (CH2) 4SO3HPy][HSO4] (IL2) and N-(4-sulfonic acid) butyl triethylammonium hydrogen sulfate) [(CH2)4SO3HTEA][HSO4] (IL3) were studied. The surface morphology and compositions of the corrosion products were examined by scanning electron microscopy (SEM). The results revealed that the Q235 steel exhibited rather good resistance to these liquids and its corrosion rates increased with the increasing temperature. Corrosion resistance of Q235 steel in the three ionic liquids decreases according to an order as follows: IL3>IL23>IL1, and finally the electrochemical corrosion mechanism is also proposed.
采用室温溶胶-凝胶法在热镀锌板表面成功制备得到了锌锆复合物纳米膜,采用扫描电镜 (SEM),原子力显微镜 (AFM),X光电子能谱 (XPS) 及辉光光谱 (GDOES) 等手段对所得薄膜的微观形貌、结构进行分析；同时采用电化学手段对锌锆复合物纳米膜的耐蚀性进行评价。结果证实,现有条件下所得薄膜致密、均匀地附着于热镀锌板表面；除含有一定数量的结构水外,膜主要成分为Zn及Zr的复合物。此外,电化学结果证实,与热镀锌板基材相比,涂覆锌锆复合物纳米膜有效提高了材料在腐蚀介质中的耐蚀性能。
Nano scale zinc-zirconia composition film was successfully fabricated on the galvanized (GI) sheets using sol-gel method under room temperature, the micromorphology and structure of such film was characterized by SEM, AFM, XPS and GDOES; meanwhile, the anti-corrosion property of the as-prepared nano scale zinc-zirconia composition film was evaluated by electrochemical method. Results indicated that the film coated on the GI sheets was uniform and compact; meanwhile, the nano scale zinc-zirconia composition film is composed of Zn, Zr and O elements. The electrochemical results indicated that, the nano scale zinc-zirconia composition film improved the anti-corrosion property of the GI sheets in the corrosion medium.
在DZ38G高温合金表面制备了NiCr-CrAl、Co-Al、Al-Si和Al-Ti 4种改性的铝化物涂层,对比研究了4种涂层的组织结构和在900 ℃下的涂盐 (25%NaCl+75%Na2SO4) 热腐蚀行为。结果表明：在4种涂层中,Ti-Al涂层表面腐蚀产物连续致密,而且与基体结合紧密,表现出最优异的抗热腐蚀性能。