Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: The corrosion behavior of pure aluminum A1060 in tropic marine environment was simulated by cyclic immersion test, while the correlation of the corresponding results of indoor cyclic immersion test and outdoor marine atmospheric corrosion test of A1060 was comparatively studied in terms of its corrosion morphology, corrosion products and corrosion kinetics by means of weight loss measurement scanning, electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results showed that the corrosion morphologies and phase constituents compositions of corrosion products after cyclic immersion test agreed fairly well with those after the real atmospheric test. Thereafter, a prediction model for the C corrosion prediction model of aluminum 1060 in two kinds of marine atmospheric environments, which aims to simulate the atmospheric environments at Wanning and Xisha areas in the South China Sea, was estab-lished built combined with Grey correlation method, while the corresponding arithmetic expressions could be described as follows i.e. TWN=146.7t 1.29 and TXS=862.3t 0.85 respectively.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: Corrosion behavior of E36 and E690 steel in simulated seawater was comparatively studied by means of mass loss method, electrochemical measurements, morphology observation and analysis of corrosion products. The results showed that the two steels exhibited similar electrochemical behavior with characteristics of activation dissolution and very low corrosion current density; the two steels presented a homogeneous corrosion morphology with a low corrosion rate, which declined with time; during the first week immersion the two steels exhibited nearly the same corrosion rate and while the average corrosion rate of E690 gradually fell behind that of E36 after four weeks.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: none
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: none
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: The effect of alloyed Cr on the corrosion behavior of a corrosion-resistant rebar 5Cr steel in simulated concrete pore solutions (saturated Ca(OH)2 solution) with various Cl- contents was investigated. The results showed that the corrosion resistance of 5Cr steel is much better than HRB400 steel, and which may be attributed to the following reasons: the addition of 5%Cr enabled the microstructure of the steel to be refined as bainites dispersed uniformly on ferrites; the passive film formed on 5Cr steel to be modified to exhibita nobler pitting potential in simulated concrete pore solution and to possess a higher content of α-FeOOH in the rust scales, which all lead to the corrosion resistance of 5Cr steel superior to HRB400 steel.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: Corrosion behavior of electrogalvanized steel plate exposed to atmospheres at Qingdao located at the East coast of China and Xishuangbanna, an area of tropical rainforest climate, located at Yunnan province respectively for 2 a was investigated by means of weight- loss measurement, macro-morphology observation, SEM and XRD etc. The electrochemical behavior of the plate in solutions with different chloride concentration was studied by electrochemical impedance spectroscopy. The results showed that the corrosion rates of the steel exposed to the atmospheres at Qingdao and Xishuangbanna are 0.76 and 0.1935 μm/a respectively. Local red rust was observed on the surface of the steel plate exposed to Qingdao atmosphere, which consists of Zn5(OH)8Cl2H2O, ZnO and Zn(OH)2. In the atmosphere at Xishuangbanna, the main corrosion products are 2ZnCO3·3Zn(OH)2, ZnO and Zn(OH)2. Inhomogeneous general corrosion occurs in the two test areas and the electrogalvanized steel plate suffered more severely from corrosion in the atmosphere at Qingdao because of the influence of Cl-.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: Corrosion behavior of the Cr modified HRB400 carbon steel rebar in 2%NaCl solution was investigated by means of dry/wet cyclic corrosion test, potentiodynamic polarization and electrochemical impedance spectroscopy. Results show that the open circuit potential moved to higher value in positive direction; the corrosion current density decreased; the polarization resistance increased and the corrosion rate declined for the Cr modified steel in comparison to HRB400 steel. After dry/wet cyclic corrosion test for 72 h, the HRB400 steel exhibited an uniform corrosion morphology, however the Cr modified steel rebar exhibited features of local corrosion. Anyhow, the addition of Cr can significantly reduce the uniform corrosion rate of HRB400 steel rebar.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: Serious corrosion problem could be found in the vicinity of the interface sea-water/seamud (VISS) for marine structures of steels. The corrosion of carbon steel in an artificial environment as a simulation of the above VISS was studied by means of wire beam electrode (WBE) technique, linear polarization (LP) technique, electrochemical impedance spectroscopy (EIS) and corrosion morphology examination etc. For the simulated VISS, the sea- water and sea- mud were taken directly from Zhanjiang bay of the South China sea. The galvanic current between one electrode and another electrode among the rest 99 electrodes was successively measured by WBE technique, and the change of the cathode area and anode area was acquired from the results of the measurement of galvanic current. The Ecorr and Icorr of the electrodes of carbon steel, which were perpendicular to the interface of sea-water/sea-mud (ISS), were obtained by the linear polarization technique. Then the corrosion morphology of the tested electrodes was observed by stereo microscope. The results show that the portion under ISS of an immersed electrode of carbon steel acts as anode, and that above ISS acts as cathode. The corrosion of carbon steel in the VISS was controlled by the potential difference, the dissolve oxygen concentration and the sea-mud impedance. The areas both of where near by the ISS on the anode portion and where far from the ISS on the cathode portion were the serious corrosion areas. Correspondingly of which the formed corrosion product on the former was fluffy and low adhesive, while that on the later was compact and strongly adhesive.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: none
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: The corrosion behavior of a commercial carbon steel Q235, and two new steels A1 and A2 in an artificial soil, which consisted of diatomite and appropriate acid solution to simulate a typical acidic soil at Southern China was studied by mean of corrosion weight loss measurement, and then the corrosion morphology and products were characterized by SEM and XRD. The results showed that the corrosion rate of Q235, A1 and A2 steel in the simulated acidic soil was 0.48, 0.14 and 0.097 mm/a respectively after 300 h corrosion; the tendency to micro-cell corrosion of a steel can be lowered as the carbon content of the steel has been reduced; an appropriate addition of Cr can shift positively the corrosion potential of the matrix; the enrichment of Cr in the inner portion of the rust scale can improve its compactness, and change the propagation mode of corrosion pits; the corrosion products of Q235, A1 and A2 steel were mainly consisted of α-FeOOH, γ-FeOOH and Fe3O4, however, the corrosion products of A1 and A2 steels possess a ratio of α-FeOOH to γ-FeOOH ca 10 times higher than that of Q235 steel, which implying a better protectiveness of the rust layers for the two new steels.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: 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 coldrolled steel. The results showed that after immersed in 5%NaCl solution for 4 h, the 1.7 g/m2 oilcoated 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.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《材料研究学报》
Abstract: In order to investigate the corrosion resistance of ocean platform steel E690 in sea water, the corrosion induced by oxygen-concentration cell of E690 steel in 3.5%NaCl with oxygen concentration within a range of 0.3 to 8 mg/L was investigated by means of electrochemical measurement techniques, scanning electron microscopy and Raman spectroscopy. The influence of the difference in dissolved oxygen, the ratio of cathode area to anode area and the corrosion product on the corrosion behavior of E690 steel was examined respectively. It was found that: when the ratio of cathode area to anode area was less than four (Sc/a≤4), the cathode and these ratios would be the main factor that influenced the oxygenconcentration cell corrosion; when Sc/a>4, the dissolved oxygen would be the main factor that influenced the oxygen-concentration cell corrosion; How the corrosion product influenced the oxygen-concentration cell corrosion depends on the dissloved oxygen. When the rusted metal under an oxygen-deficient condition, the rust layer would prevent the substrate from corrosion; when the rusted metal was immersed in an aerated condition, the corrosion product would participate in the cathodic reaction process, which would accelerate the anode dissolution and resulted in localized corrosion, such as pitting.
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-04 Cooperative journals: 《金属学报》
Abstract:采用电化学阻抗谱(EIS)和扫描Kelvin探针技术(SKP)研究了热风整平无铅喷锡处理印制电路板(PCB-HASL)在模拟电解质0.1 mol/L NaHSO3以及不同pH值的0.1 mol/L NaHSO3/Na2SO3溶液中的腐蚀行为与机理,探讨了浸泡时间和pH值对其腐蚀机理转变的影响,通过OM, SEM结合EDS对PCB-HASL表面上腐蚀产物形核和扩展行为进行了观察和分析。结果表明:PCB-HASL试样在酸性NaHSO3/Na2SO3溶液体系中的腐蚀形式类似点蚀,浸泡前期腐蚀坑加速扩展,腐蚀产物主要为Sn的氧化物和硫酸盐。NaHSO3溶液能够活化PCB-HASL试样表面,且腐蚀坑形核仅发生在浸泡初期。而在中性或碱性NaHSO3/Na2SO3溶液体系中,PCB-HASL试样表面腐蚀坑形成受到抑制,电解质溶液通过氧化膜向电极界面的传输过程限制了电极反应速率。