采用新型环保均一化前处理工艺在AZ91D镁合金表面制备了化学镀Ni-P镀层。利用扫描电镜 (SEM)、能谱仪 (EDS) 和X射线衍射仪 (XRD) 研究了镀层的微观形貌、成分和相结构。通过电化学方法和热震实验评价了镀层的电化学腐蚀行为和结合力。结果表明，经前处理后基体表面的β相 (Mg17Al12) 被选择性去除，表面组织均一化，从而得到了均匀致密的浸Zn层。Ni-P镀层均匀致密，P含量为7.0%，具有非晶结构。与AZ91D基体相比，Ni-P镀层的自腐蚀电位正移了1.136 V，自腐蚀电流密度降低了两个数量级，表明镀层具有优良的耐腐蚀性能。热震实验表明镀层与基体之间结合良好。
A new environment-friendly homogenization pretreatment process was adopted for the electroless nickel plating on AZ91D magnesium alloy. Then, the morphologies, chemical composition and microstructure of the pretreated layer and the formed Ni-P coating were studied using scanning electronic microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD). It was indicated that a dense Zn film formed on the substrate surface after the homogenization pretreatment, due to the selective removal of β phase during the processing. As the result, the subsequently formed Ni-P coating was uniform, compact and defect-free with P content around 7.0%, which was characterized as an amorphous matter by XRD. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests revealed that the Ni-P coating could significantly improve the corrosion resistance of AZ91D magnesium alloy with an obvious positive shifting of corrosion potential by 1.136 V and a dramatic reduce of corrosion current density by two orders of magnitude. Furthermore the obtained Ni-P coating showed excellent adhesion to AZ91D substrate.
The corrosion behavior of Zn and 55%Al-Zn alloy coatings was studied by salt spray test which is designed to simulate the practical service situation, coupling with measurments of polarization curves and electrochemical impedance spectroscopy (EIS) as well. While corrosion products were characterized by XRD. The results show that the corrosion rate of two coatings exhibited different trends during the test. Compared with Zn coating, 55%Al-Zn alloy coating had better corrosion resistance,which may be related to the different composition and microstructure of coatings and corrosion products formed at different test stages.
利用扫描电镜 (SEM)、X射线衍射 (XRD) 和腐蚀电化学测试研究了镀液中SiC含量对化学镀Ni-P-SiC复合镀层结构和耐蚀性能的影响。结果表明，随着镀液中SiC含量的增加，镀层沉积速率和镀层中SiC共沉积量呈现先增加后降低的趋势，镀层中P含量和沉积胞状颗粒尺寸逐渐降低。电化学测试结果表明，镀层中SiC共沉积量的变化不影响镀层腐蚀反应机理，但是镀层耐蚀性随SiC共沉积量的增加而降低。结构分析显示，Ni-P-SiC镀层致密性良好，基本完全覆盖了镁合金基体。
The effect of SiC content in plating bath on the surface morphology and corrosion resistance of electroless plated Ni-P-SiC composite coatings on AZ91D magnesium alloy was investigated by means of SEM, XRD and electrochemical corrosion measurements. The results indicate that the deposition rate and SiC content in the Ni-P-SiC composite coatings increase firstly and then decrease afterwards with the increase of SiC content in the plating bath. The P content and grain size of the composite coatings decrease with the increase of SiC content in the plating bath. The effect of the codeposited SiC on the corrosion process of Ni-P-SiC composite coatings in 3.5%NaCl solution is found negligible, however the corrosion resistance of the Ni-P-SiC composite coatings decreases with the increase of SiC content in the coatings.
以某酸性气田集输管道工况为研究背景，通过实验模拟研究L360抗硫钢在S沉积环境的3.5%NaCl (质量分数) 溶液中的腐蚀行为，结果表明：S的沉积导致L360钢发生了均匀腐蚀和小孔腐蚀；S使L360钢的均匀腐蚀速率增加约50倍；金属的腐蚀行为与S沉积厚度有关，但当S厚度超过临界厚度后，金属的腐蚀速率不再随S的厚度增加而变化；在3.5%NaCl溶液中，含S与不含S条件下L360钢的腐蚀行为明显不同，由于存在明显的腐蚀电位差，S沉积导致了电偶腐蚀的发生。
Corrosion behavior of L360 mild steel in 3.5%NaCl solution in the presence of elemental sulfur was investigated in laboratory aiming to simulate the service environment of a sour gas gathering pipeline. The results showed that severe uniform corrosion and pitting corrosion were observed for L360 mild steel in 3.5%NaCl solution in the presence of elemental sulfur, and the uniform corrosion rate was increased by about 50 times. The corrosion behavior of L360 steel was affected by the thickness of elemental sulfur, but its corrosion rate was not further changed with the increasing thickness of elemental sulfur deposits when the thickness exceeded a critical value. The corrosion behavior of L360 steel in 3.5%NaCl solution in the presence and absence of elemental sulfur was different, an obvious corrosion potential difference was observed, which indicated that the deposition of elemental sulfur in the gathering pipeline caused galvanic corrosion.
对不同Mn含量的Al-Ga-Mg-Sn-Mn阳极合金的组织和腐蚀形貌进行了观察和分析，并测试了该系列合金在4 mol/L NaOH溶液中的析氢速率、开路电位、电化学阻抗谱、放电曲线等，研究了Mn对Al-Ga-Mg-Sn阳极合金组织和电化学性能的影响。结果表明：在Al-0.1Ga-1Mg-0.1Sn基础上添加0.05%~0.15% (质量分数) Mn后，合金中第二相数目明显增多，Al阳极进一步活化，开路电位和工作电位负移,但同时造成自腐蚀析氢速率增大，Al-0.1Ga-1Mg-0.1Sn-0.1Mn合金具有较好的综合性能。
The influence of Mn content on the microstructure and electrochemical performance of Al-Ga-Mg-Sn-Mn anode alloys in 4 mol/L NaOH solutions were investigated by SEM examination, as well as by measurements of hydrogen evolution rate, open circuit potential, Ac impedance spectroscopy and discharge curve etc. Experimental results indicate that the addition of 0.05%~0.15% Mn into Al-0.1Ga-1Mg-0.1Sn alloy results in that the amount of second phase in the alloys increased obviously, as a consequence which further activated the aluminum anode, therewith the open circuit potential and working potential shifted negatively, but at the same time the hydrogen evolution rate increased. Among the tested alloys, the Al-0.1Ga-1Mg-0.1Sn-0.1Mn alloy has good comprehensive performance.
Two kinds of conversion coating KH560-chitosan and KH560-chitosan- cerium salt were prepared on galvanized sheet. Of which the corrosion performance was examined in NaCl solution while monitoring their electrochemical ac impedance. Then the surface morphology of the corroded samples was observed with VHX-900 microscope and the composition of the passive film was characterized by infrared spectra. The results indicated the KH560-chitosan-cerium salt exhibits stronger self-healing ability rather than the KH560-chitosan coating and the silane modification significantly enhances the corrosion resistance of the chitosan.
The inhibition performance of alkyl triazole was studied by mass loss and electrochemical testing methods. While the surface morphology of carbon steel before and after corrosion in hydrochloric acid with and without the corrosion inhibitor was examined by scanning electron microscopy. In the meantime, the adsorption pattern of corrosion inhibitor molecules on the surface of the steel was studied in terms of the adsorption regulations and the calculation of the relevant fitting parameters. The results showed that the alkyl triazole is a cathodic inhibitor and its adsorption model belongs to Langmuir isotherm. The analysis of the molecular structure and the surface of carbon steel status indicate a typical single molecular layer adsorption of the inhibitor. Weight loss method results also show that alkyl triazole possess high corrosion inhibition efficiency and excellent temperature resistance.
采用溶胶-凝胶法，以正硅酸乙酯 (TEOS) 和乙烯基三乙氧基硅烷 (KH151) 作为水解前驱体制备杂化溶胶，掺杂1.5×10-3 mol/L Ce(NO3)3，通过浸渍法在蒸发器铝管表面制备了耐蚀性膜层。CuSO4点滴实验、中性盐雾实验和电化学测试结果表明，掺杂改性杂化膜的耐蚀性能优于铬酸盐钝化膜。红外光谱分析表明，膜层中存在不同类型的Si—O—Si共价键，有机官能团C=C共价键增强了膜层的疏水性。从SEM像可看出，杂化膜均匀、致密、平整。
A hybrid sol was prepared by sol-gel technique with precursors of ethylsilicate (TEOS) and vinyltriethoxysilane (KH151), and which then was further doped with 1.5×10-3 mol/L Ce(NO3)3 to get a Ce-doped hybrid sol. A coating of this Ce-doped hybrid sol was prepared on aluminum tube by dipping method. Results of bluestone drips test, neutral salt spray test and electrochemical measurement showed that the coating doping modified hybrid film possessed superior corrosion performance rather than the conventional chromate passivation film. The infrared spectrum of the coating revealed that there existed different types of Si—O—Si covalent bonds and organic functional groups C=C covalent bonds, which might enhance the hydrophobicity of the coating. Finally SEM examination showed that the formed coating was dense, uniform and smooth.
以磷化氟碳丙烯酸酯 (磷化氟丙) 乳液为成膜物质，制备不同填料的防腐蚀涂料。利用扫描电镜 (SEM) 观察涂料的表面形貌，用极化曲线、电化学阻抗 (EIS)、开路电位 (OCP) 等电化学手段研究成膜物质及填料对涂料防腐蚀性能的影响。结果表明：当选用磷化氟丙乳液为成膜物质，在填料中添加蒙脱土时，制备的涂料表面致密，涂层具有良好的防腐蚀性能。
A series of anticorrosion coatings were prepared of phosphate-fluorocarbon acrylate emulsion with different kinds of pigments. The morphology and anticorrosion performance of the coatings were characterized by scanning electron microscopy (SEM) as well as polarization curves, electrochemical impedance spectroscopy (EIS) and open-circuit potential (OCP). The results showedthat the coatings consisted of phosphate-fluorocarbon acrylate emulsion as film-forming substances and montmorillonite as pigments had good anticorrosion performance.
通过高温循环氧化实验，研究了3种镍基合金在1095和1150 ℃的高温抗氧化行为，并采用扫描电镜 (SEM)和能谱分析 (EDS) 研究了氧化膜表面形貌、氧化膜厚度及成分。结果表明： BSTMUF601合金的抗氧化性能优于Inconel601合金和Incoloy800H合金，Incoloy800H合金抗氧化性能最差。1095 ℃下合金的氧化动力学曲线呈抛物线规律，1150 ℃下Incoloy800H合金抗氧化性显著降低，试样氧化极为严重，温度低于1150 ℃时合金均体现出良好的抗高温氧化能力。BSTMUF601和Inconel601合金氧化后表面生成一层致密的氧化膜，经分析主要是Cr和Al的氧化物，且氧化膜外层以Cr的氧化物为主，氧化膜厚度接近50 μm，Incoloy800H合金表面氧化层中以Fe的不同结构氧化产物为主。
The oxidation behavior of three nickel-based superalloys had been investigated systematically at the temperature 1095 and 1150 ℃ by a serial of high temperature cyclic oxidation experiments. The characteristic of oxidation film surface topography, component as well as oxidation film thickness were analyzed by using SEM and EDS. The results show that: oxidation resistance of BSTMUF601 alloy superior to oxidation resistance of Inconel601 alloy and Incoloy800H alloy, and the oxidation resistance of Incoloy800H alloy is worst; oxidation kinetics curves of three superalloys at 1095 ℃ basically obey parabolic law and the alloys antioxidation are advanced except Incoloy800H at 1150 ℃ which has broken after oxidation 25 h; a dense oxidation layer generated on BSTMUF601 and Inconel601 alloy surface after cyclic oxidation, in which the main oxides are Cr2O3 and Al2O3 and the outside of oxide film is Cr2O3, making the oxidation film thickness up to 50 μm, while ferrum oxides are checked out in Incoloy800H oxidation film.
Influence of solution treatment and cool rolling deformation on the microstructure and electrochemical performance of the Al-Ga-Mg-Mn-Bi anode alloy was investigated by measuring the impedance spectroscopy, polarization curve, free-corrosion rate, etc. The results show that: in comparison with the cast alloy, the quantity of the second phase, the free-corrosion rate and the hydrogen evolution rate of the solution-treated alloy were greatly reduced, while the amount and size of corrosion pits were also reduced with a negative shift of its potential of constant-current discharge; after cool rolling deformation the alloy exhibits a rather uniform corrosion morphology with small pits and also a negative shift of its potential of constant-current discharge.
The change of compressive strength and the bonding strength to spheroidal graphite cast iron of the slag cement mortar lining, as well as the change of its morphology before and after spray corrosion test with 10%Na2SO4 salt were investigated by means of compressive and tensile tests, and XRD, XRF and SEM respectively. The results show that hydration hardening time of slag cement mortar is longer than sulfate resistance mortar and Portland mortar. The compressive strength and bonding strength to spheroidal graphite cast iron for the slag cement mortar are more or less the same as that of the sulfate resistance mortar, but higher than that of the Portland mortar. The hydration reaction products of active ore powders together with water may act as a barrier to suppress the permeation of SO42-, and also the formation of CaSO42H2O and AFt. Due to the formed rod-like gypsum accumulated at the interface of sulfate hydration, thereby which may cause mortar surface cracking when filtration sulfate reaches a certain level.
按照现有的ISO 9223大气环境腐蚀性分类分级标准，在进行实际腐蚀数据应用时对于大气环境和腐蚀等级之间关系的判别过程中，部分腐蚀等级分类具有不确定性。针对上述问题，提出了一种新的大气环境与碳钢腐蚀等级的量化关系挖掘方法，并进行实际腐蚀数据分析。结果表明，挖掘出的量化关系能够比ISO 9223标准更精确的以概率的方式反映大气环境与碳钢腐蚀等级之间的相关性。因此，该方法能够促进大气环境腐蚀性分类分级工作的进一步研究。