通过在环氧涂层中加入镁粉、三聚磷酸铝和氧化铈,制备了对AZ91D镁合金具有优良保护效果的耐蚀涂层,利用Machu测试、电化学阻抗 (EIS) 和扫描电镜 (SEM) 等方法研究了三聚磷酸铝和氧化铈对涂层保护性能的影响。结果表明,含50%Mg的环氧富镁涂层经过约2000 h浸泡后基体发生腐蚀,涂层失效,而添加10%三聚磷酸铝、0.25%氧化铈的40%Mg富镁涂层经过4488 h浸泡后基体仍然未发生明显腐蚀。三聚磷酸铝和氧化铈在富镁涂层中能够显著抑制Mg颗粒的活性,延长镁粉对镁合金基体的保护作用时间,同时也能一定程度上提高涂层的致密性,改善涂层的屏蔽性能,二者的作用相互叠加,有效提高了涂层的综合保护性能。
A corrosion resistant coating for AZ91D magnesium alloy was prepared by adding pure magnesium particles, aluminium triphosphate (SAP) and ceria in an epoxy coating. The performance of the coating in 3%NaCl solution was studied with methods of Machu test, electrochemical impedance measurement and scanning electron microscope. The results show that the Mg-rich epoxy coating failed and the magnesium substrate was corroded after immersion for about 2000 h, while no corrosion was observed beneath the coating with SAP and ceria addition after immersion for 4448 h . Distinctly the added SAP and ceria can decrease the activity of magnesium particles in the Mg-rich epoxy and thereby prolong the life time of the coating. On the other hand, the compactness and the barrier property of the coating are improved as well.
利用扫描电镜 (SEM)、能谱、X射线衍射仪 (XRD) 和超景深三维立体显微镜等表面分析手段,调查研究油田污水集输管线材料的腐蚀和结垢行为。实验结果表明,暴露在没有添加杀菌剂的污水中30 d的试样表面形成了大量的垢状沉淀物,局部放大可以发现以胞外聚合物为主的生物膜覆盖在试样表面,此时生物膜的厚度高达169.6 μm,生物膜中含碳酸盐垢和细菌代谢产物硫铁化合物,且膜下基体材料局部腐蚀孔深度达到23.96 μm。在连续添加100 mg/L有机胍类杀菌剂1个月后,试样表面覆盖物中以无机矿物为主,且膜层厚度较未添加的薄,厚度为48.6 μm,膜下腐蚀较均匀,局部腐蚀轻微。硫酸盐还原菌参与的生物作用是管线局部腐蚀穿孔的主要原因之一。
The situatuion concering corrosion and scaling of the inner wall of sewage gathering pipelines in oil field was investigated by means of scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), X-ray diffracmeter (XRD) and three-dimensional stereoscopic microscopy. The results indicated that after exposure to the sewage for 30 d a scale of deposits ca 169.6 μm in thickness could be observed on the surface of test samples, which consisted maily of extracellular polymeric substance with iron sulfides, the product of sulfate reducing bacteria metabolism, while beneath the scale the pipeline steel suffered from pitting corrosion with a maximum pit depth 23.96 μm; however after exposure for the same period in the same medium but with continuously adding organic guanidine bactericide of a dose 100 mg/L, the thickness of corrosion products scale was lowed to only ca 48.6 μm, besides, the corrosion of the substrate beneath the scale was light. It may be concluded that one of the reasons responsible to the localized perforation of pipelines was the SRB induced corrosion.
The surface morphology of rust converter coating was firstly studied using scanning electron microscopy (SEM) in conjunction with atomic force microscopy (AFM). Then, the conversion of Fe3+ in rust-converting coating, which was induced by rust converter, was investigated by XPS technology. Finally, the key compositions of rust converter were characterized by energy dispersive spectrum technology (EDS) and Fourier transform infrared spectroscopy (FTIR) in order to study the converting mechanism of rust converter. It was found that some chemical reactions occurred in rust converter coating after rust layer had been coated with rust converter. After 72 h, the rust converter coating has eventually developed into homogeneous phase, and surface roughness decreased. During this conversion, parts of Fe3+ transformed into Fe2+, forming stably inorganic salt film composed of iron phosphate, zinc phosphate and ferrous oxides. At the same time, some organic compounds, for example tannic acid, can complex with Fe3+, and mixed with inorganic salt film, forming stably protective film.
研究了核电站蒸汽发生器传热管用合金材料在模拟压水堆一回路水环境中形成的腐蚀氧化膜,首次获得了原位振动光谱。Inconel 600合金的拉曼谱中存在3个峰,540 和610 cm-1拉曼峰源自于表面生成的Cr2O3氧化膜,670 cm-1峰对应于表面生成的FeCr2O4尖晶石产物,随着电位的增加,670 cm-1峰的相对强度显著增强。Inconel 690合金的表面氧化膜由Cr2O3构成,不含NiO或尖晶石成份。Inconel 600合金发生应力腐蚀开裂 (SCC) 的敏感性与其表面氧化膜的变化存在关联性。Inconel 690合金尚未发现SCC现象,这与其表面生成的稳定的氧化膜有关。
In this study, we have acquired in-situ vibrational spectra of oxides formed on inconel alloys of steam generator tube in simulated primary water (PW) of pressurized water reactor (PWR). There are three Raman peaks for the oxidized Inconel 600. The peaks at 540 and 610 cm-1 are attributed to a formation of Cr2O3, and 670 cm-1 peak is corresponding to FeCr2O4 spinel. As the potential increases, the relative intensity of 670 cm-1 peak increases. The surface film of Inconel 690 consisted of Cr2O3 solely. Stress corrosion cracking (SCC) of Inconel 600 is correlating with the changing of its surface film. A stable surface film formed on Inconel 690 might be responsible for its excellent SCC resistance.
The corrosion behavior of tungsten-aluminum alloy in NaCl solutions was studied by electrochemical impendence spectroscopy (EIS) and potentiodynamic scanning (PDS). The results show that the corrosion rate of tungsten-aluminum alloy increases with the increase of salinity of the solutions and its corrosion resistance drops along with the increase of temperature. The corrosion rate of the alloy goes up with the increase of acidity of solutions, in other words, the alloy shows better anti corrosion performance in neutral NaCl solution.
Effect of corrosive fluid flow on the performance of an inhibitor film on carbon steel is studied by means of electrochemical impedance spectroscopy (EIS) in a laboratory simulated environment, which aims to simulate the service condition of pipelines for oil and gas gathering and transferring. While the morphology of the inhibitor film was also characterized by SEM. Experimental results show that the thickness of the inhibitor film on the carbon steel 45 decreased and become much porous with the increasing fluid flow rate and temperature. Therefore, the effectiveness of this corrosion inhibitor is reduced due to the action of surface shear stress and bubble impact of the fluid flow.
采用盐水浸泡实验探讨了0.4,0.9,1.2和1.7 g/m2 4种涂油量对冷轧钢板腐蚀行为的影响。结果表明,在5%NaCl溶液中浸泡4 h时,涂油量为1.7 g/m2的钢板保护效率最高,为52.13%,涂油量为0.4 g/m2的钢板保护效率则最低,只有29.2%；浸泡20 h时,1.2和1.7 g/m2两个涂油量的钢板锈蚀等级能保持B级。EIS和Mott-Schottky数据表明,在同一浸泡时间下,涂油量越大的试样其电荷转移电阻越小,载流子密度越大,耐蚀性更好。
Salt solution immersion test was employed to examine the effect of four amounts of the coated antirust oil i.e. 0.4, 0.9, 1.2 and 1.7 g/m2 respectively on the corrosion performance of cold-rolled steel. The results showed that after immersed in 5%NaCl solution for 4 h, the 1.7 g/m2 oil-coated steel exhibited the highest protective efficacy 52.13%, the 0.4 g/m2 oil-coated steel exhibited the lowest protective efficacy only 29.2%. After immersion for 20 h, only those coated with 1.2 and 1.7 g/m2 antirust oil can reach the B rusting grade. The data of EIS and Mott-Schottky tests for the same immersion time showed that the larger amount of the coated oil on the steel had, the smaller the charge transfer resistance and the bigger the carrier density are, which indicated a better corrosion resistance.
利用扫描电镜 (SEM) 结合能谱分析 (EDS)、X射线衍射 (XRD)、腐蚀失重实验、电化学极化曲线等方法,研究了0.1%,0.4%,0.7%和1.0%的Sm对AZ91D合金的微观组织和腐蚀性能的影响,并对其腐蚀机理进行分析。结果表明：随着Sm含量的增加,合金中粗大的枝状第二相 (β-Mg17Al12) 逐渐断裂变小,其体积分数下降,因为Sm会结合Al形成颗粒状的Al2Sm和杆状的Al3Sm,从而减少晶界处第二相的数量,使第二相呈不连续分布；AZ91D的耐腐蚀性随着Sm加入量的增多,先增加后降低；当Sm加入量为1.0%时,合金的耐腐蚀性与不添加Sm的AZ91D接近；Sm的最佳添加量为0.4%。
The influence of 0.1%, 0.4%, 0.7% and 1.0% Sm addition on microstructure and corrosion property of AZ91D alloy was studied by means of SEM with EDS, XRD, corrosion weight loss test and electrochemical polarization curve etc. The results show that with the increasing Sm content, the bulky dendritic second phase (β-Mg17Al12) in the alloy becomes finer and the volume fraction of which decreases gradually, whilst Sm may combine with Al to form granular Al2Sm and rod-shaped Al3Sm, thereby, cutting down the number of the second phase in grain boundaries, leading to the second phase discontinuous distribute; Sm can improve the corrosion resistance of alloy, but the corrosion resistance firstly increases and later decreases with the increasing Sm content. The corrosion resistance of the alloy with 1.0% Sm is close to the bare AZ91D. The optimum addition amount is 0.4% Sm for the highest corrosion resistance.
通过对Ni-Cr2O3复合镀层620 ℃部分渗铝制备了δ-Ni2Al3-Cr2O3/Ni-Cr2O3涂层体系。Cr2O3颗粒在渗铝的过程中和Al反应生成更为稳定的Al2O3。1000 ℃恒温氧化20 h后发现,铝化物涂层和复合镀层内掺杂的Cr2O3颗粒完全转化为Al2O3,并在铝化物涂层/Ni镀层界面自发形成了一层Al2O3富集层,该富集层起扩散障作用,阻碍铝化物涂层因互扩散所致的退化。
A δ-Ni2Al3-Cr2O3/Ni-Cr2O3 coating system was prepared by aluminizing partially a pre-electrodeposited Ni-Cr2O3 film on pure Ni by means of a conventional pack cementation process at 620 ℃, during which a part of Cr2O3 particles reacted with Al to form more stable oxide of Al2O3. After oxidation at 1000 ℃ for 20 h, Cr2O3 particles in the aluminide coating and the rest electrodeposited composite film all transformed into Al2O3 particles, therewith at the interface aluminide/Ni, an Al2O3-rich layer might form and then act as a diffusion barrier to mitigate the inter diffusion between the aluminide coating and the Ni-substrate.
将不同比例的装载缓蚀剂蒙脱土和环氧树脂混合制备出纳米复合环氧涂层。根据电化学阻抗谱 (EIS) 和盐雾实验对涂层的耐蚀性进行表征。结果表明,3%装载蒙脱土环氧涂层的水扩散系数为9.89×10-11 cm2/s,孔隙率为2.22×10-8,整个浸泡过程中阻抗值在109 Ωcm2以上,表现出最佳的耐蚀性。
Nanocomposite epoxy coatings were prepared with different proportion of epoxy resin and inhibitor-grafted montmorillonite. The effect of the inhibitor-grafted montmorillonite on the corrosion resistance of epoxy coating on hot dip galvanized steel sheet was investigated by using salt spray tests and electrochemical impedance spectroscopy (EIS). The results show that among the coatings tested, the one with 3% of the inhibitor-grafted MMT exhibits the most superior corrosion resistance with water diffusion coefficient of 9.89×10-11 cm2/s and porosity of 2.22×10-8 respectively; while its impedance values is above 109 Ωcm2 during the whole immersion times.
采用扫描电镜 (SEM)、能谱 (EDS) 和X 射线衍射 (XRD) 等技术对红壤中变电站接地网服役长达13 a的镀锌扁钢进行了形貌分析和腐蚀产物分析。结果表明,该镀锌扁钢受到严重腐蚀,腐蚀产物主要由FeOOH,Fe3O4和Fe2O3等组成,腐蚀产物分层的原因是新生成的腐蚀产物沉积在金属/腐蚀产物层界面或腐蚀产物开裂处,同时S和Cl对内层腐蚀产物具有较大的影响。Tafel测试结果表明,在腐蚀电流峰值附近,SO42-与Cl-的百分比为1∶2时,两者对镀锌Q235碳钢在该红壤中的腐蚀性影响具有等效作用。通过室内加速实验模拟镀锌Q235碳钢在该红壤中的腐蚀发现,镀锌Q235碳钢的腐蚀速率呈现先增大后减小的规律,该加速实验在未改变镀锌Q235碳钢腐蚀机理的同时具有较好的加速效果。
Macroscopic analysis and corrosion product analysis of galvanized flat steel which had been in service for 13 a in substation grounding grid were made by scanning electron microscopy (SEM), energy spectrum (EDS) and X-ray diffraction (XRD). The result shows that galvanized flat steel suffered serious corrosion and corrosion products are mainly composed of FeOOH, Fe3O4, Fe2O3 and etc. The cause of the corrosion product layer is the new production of corrosion products deposition on the metal/corrosion product layer interface or the cracking. At the same time, S and Cl have great influence on the inner corrosion products. Tafel test results show that the percentage of SO42- and Cl- is 1∶2 and they have equivalent effect on the corrosion influence of galvanized Q235 carbon steel near the corrosion current peak. Result of the accelerated corrosion experiment shows that corrosion rate of galvanized Q235 carbon steel in red soil increase first and then decrease,meanwhile,the corrosion mechanism of galvanized Q235 carbon steel in this acceleration that had a good speedup was unchanged.
无机消毒剂ClO2和有机消毒剂季铵盐 (苯扎溴铵) 作为常用的再生水消毒剂对循环冷却水系统具有一定的腐蚀性。通过两种消毒剂的对比,发现消毒后残留的Cl-和氨氮分别是两种消毒剂对316L不锈钢产生腐蚀的主要因素。此外,采用响应面分析法 (RSM) 和中心组合设计 (CCD) 分析了温度和流速对316L不锈钢腐蚀速率的作用。结果表明,在低温和低流速的情况下,瞬时腐蚀速率变化较小,产生腐蚀的主要原因还是电化学腐蚀。
As common disinfectant inorganic ClO2 and organic quaternary ammonium salt (benzalkonium bromide) exhibits certain corrosivity for the facilities of the circulating cooling water system. Through a contrast test for the two kinds of disinfectant, it is found that Cl- and ammonia nitrogen respectively are the main factors responsible to the corrosion of 316L stainless. In addition, the influence of temperature and water flow velocity on the corrosion rate of 316L stainless steel was analyzed by means of response surface method (RSM) and central composite design (CCD). It follows that the instantaneous corrosion rate changes little at low temperature and low water flow velocity. And the main cause for corrosion is electrochemical corrosion.
Corrosion rates of carbon steel electrodes in resistance reducing agents (RRA) were measured by means of methods of electrochemical linear polarization and inductance probe respectively. The acquired data were compared with those measured by mass loss methods by the same test condition. The results indicate that the accurate corrosion rate can be acquired by electrochemical means only when the measurement was performed at a time after the entire cure of the RRA, otherwise the given corrosion rate would be higher; both methods of the electrochemical linear polarization and inductance probe are effective and fast means to evaluate the corrosivity of RRA in the practice.
模拟高温高压CO2腐蚀实验,通过失重法,结合扫描电镜 (SEM)、能谱分析 (EDS) 和X射线衍射 (XRD) 等分析技术,研究了原油含水率对N80油套管钢和D级抽油杆 (25CrMnVA) 钢的超临界CO2腐蚀形态、腐蚀速率和腐蚀产物膜特征的影响规律。结果表明：在超临界CO2腐蚀环境中,材质对腐蚀速率具有重要影响。平均腐蚀速率转变的临界含水率,N80钢为75%,25CrMnVA钢为50%。腐蚀形态由全面腐蚀向局部腐蚀转变的临界含水率为50%,含水率在50%~75%范围内发生点蚀,含水率高于75%,主要发生台地腐蚀。
Effect of water content of crude oil on CO2 induced corrosion behavior of N80 steel and 25CrMnVA steel was investigated in a simulated high temperature and high pressured oil field environment. The corrosion rates of the steels were measured by mass loss method. SEM, EDS and XRD were employed to analyze the morphologies and characteristics of corrosion scales on the steels. The results indicate that the critical water content 75% corresponds to the abrupt change of average corrosion rate of N80 steel, but 50% to that of 25CrMnVA steel. The critical water content 50% may correspond to the transformation from uniform corrosion into local corrosion for the two steels. When the water content within a range 50%~75% pitting corrosion is the dominant mechanism of corrosion for the steels. However, the steels are suffered from the mesa-type localized attack when the water content higher than 75%.
介绍了糠醛精制装置设备腐蚀部位及腐蚀情况,对设备造成严重腐蚀的原因进行分析,从腐蚀机理和装置的特点出发阐明了装置的腐蚀机理为糠酸、相变涡流腐蚀及糠醛结焦引起的腐蚀,找出了原料脱气、糠醛氧化、设备材质等影响腐蚀的因素。结合装置的现状提出了采用减少带入系统的氧气、控制好脱气塔操作和加热炉出口温度、材质升级等物理措施以及加注缓蚀剂等化学防腐措施。实践证明, 装置腐蚀得到了有效控制, 装置大修周期延长。
硅烷掺杂 (改性) 防护性聚合物涂层是制备新型环保涂层的一种新方法。这种“超级涂层”摒弃了传统涂层的环境毒性和高成本而具有重要现实意义。本文较详细地介绍了“超级涂层”的制备方法及硅烷促进聚合物涂层抗蚀性能的作用原理。