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: The short-term corrosion behavior of X70 steel and Q235 steel buried for 1 a in soil of a select site at Singapore were investigated in terms of characterizing the corrosion products by means of scanning electron microscopy and X-ray diffraction, as well as the physical and chemical parameters of the soil, and measuring the corrosion mass lass. It was found that the soil at the select site was an acidic soil; where the average corrosion rate of Q235 steel was higher than that of X70 steel; the two steels all suffered form local corrosion, while that of Q235 steel was more serious; the corrosion products of these two steels were similar and mainly composed of Fe2O3, Fe3O4, FeOOH and FeOCl, the surface of products were rough and there were some cracks in the products scale, which seemed harmful to its protectiveness.
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: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract:对无定河流域野外考察,在其下游苏家坛蛇( SJGT)地点发现夹有古洪水滞流沉积物(swD)的全新世剖面。古洪水SWD厚度30 cm,具有平行微薄层理特征,且直接覆盖在东汉文化层之上。室内分析结果表明古洪水SWD有着与2012年洪水SWD相似的沉积学特征,以粗粉沙为主,分选良好,磁化率和烧失量较小,说明它记录了一次无定河下游的大洪水事件。文化层光释光( OSL)测年结果显示该次古洪水事件发生在1 900一1 700 a BP。古洪水洪峰水位和洪峰流量分别为765. 9 m和10 530 m3 " s -'。同时利用2012年洪水洪痕水位验证,在同一断面用相同参数恢复洪峰流量为1 030 m3 " s -',实测洪峰流量为1 000 m3 " s -',误差为3. 09%,说明古洪水洪峰流量恢复结果合理可靠。研究结果延长了无定河下游洪水数据序列,对水资源、水能源的开发利用提供了科学依据。
Subjects: Materials Science >> Materials Science (General) submitted time 2017-03-31 Cooperative journals: 《金属学报》
Abstract:通过数据采集、电化学测试、浸泡实验和表面分析技术研究了交流电对X80钢在近中性环境中的腐蚀行为的影响。结果表明:交流电干扰下,随着交流电密度的增大,交流腐蚀形态发生变化,由全面腐蚀转变为局部腐蚀,且试样表面产生较多的点蚀坑。全波交流电正负半波交替干扰下,X80钢发生阴阳极极化,导致铁的局部溶解和氢的析出;负半波交流干扰下会导致析氢而发生氢致阳极溶解,产生的点蚀坑均较尖锐;正半波干扰下,只发生阳极溶解,产生的点蚀坑呈现凹行,且比较平滑。不同波形交流干扰下,X80钢表面产生的腐蚀产物不一致。全波和正半波干扰下,腐蚀产物较疏松而且腐蚀产物发生龟裂,腐蚀产物不存在α-FeOOH;负半波交流干扰下,X80钢表面腐蚀产物较致密,腐蚀产物存在α-FeOOH对基体具有一定的保护作用。
Subjects: Materials Science >> Materials Science (General) submitted time 2017-03-31 Cooperative journals: 《金属学报》
Abstract:采用慢应变速率拉伸(SSRT)实验、动电位极化技术和SEM观察等方法,研究了X90钢基体和焊缝在近中性土壤模拟溶液中不同阴极保护电位下的应力腐蚀行为。结果表明:X90管线钢及其焊缝组织在近中性土壤模拟溶液中均具有一定的应力腐蚀敏感性,裂纹扩展为穿晶腐蚀裂纹;应力腐蚀开裂(SCC)的裂纹萌生与扩展与外加保护电位有关。在OCP~-1000mV的电位范围内,X90钢的SCC机制均为阳极溶解(AD)+氢脆(HE)的混合机制,在OCP下由于AD作用较强从而SCC敏感性较明显,在-800mV下由于AD和HE作用均较弱而导致SCC敏感性最低,而在-900mV时由于HE作用明显增强而具有最高的SCC敏感性;在相同电位条件下,焊缝的SCC敏感性高于母材。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-14 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:通过现场试验(1年),并结合腐蚀形貌宏观观察、SEM、XRD及失重法对纯铜和铜包钢在大港土壤环境中的腐蚀行为进行了研究。研究表明: 现场埋样1年的纯铜、电镀铜包钢和连铸铜包钢的平均腐蚀速率分别为1.01 g/dm2?a、1.05 g/dm2?a和1.07 g/dm2?a,其平均腐蚀速率接近,纯铜的腐蚀速率略小;腐蚀特征均表现为非均匀的全面腐蚀,腐蚀程度有所差异;腐蚀产物均主要由Cu2O、Cu(OH)2组成。
Subjects: Materials Science >> Materials Science (General) Subjects: Energy Science >> Energy Science (General) submitted time 2016-11-14 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:利用高压下的电化学实验及U型弯浸泡实验结合微观分析手段,研究了13Cr不锈钢在不同H2S分压下CO2驱驻井环空环境模拟液中的电化学特征及应力腐蚀规律。结果表明:油套管钢的刺漏现象以及环境中硫酸盐还原菌的存在使得环空环境成为复杂的高压H2S-CO2-Cl-环境,13Cr钢在该种环境下具有明显的应力腐蚀敏感性。随着H2S分压的升高,13Cr不锈钢击破电位下降,应力腐蚀敏感性增强,这主要因为H2S分压的增大对不锈钢表面膜(钝化膜及腐蚀产物膜)的破坏作用加强。当H2S分压达到0.2MPa时,13Cr不锈钢发生明显的应力腐蚀,断口由沿晶应力腐蚀裂纹(IGSCC)和穿晶应力腐蚀裂纹(TGSCC)组成的混合断口,应力腐蚀受阳极溶解和氢致开裂共同控制。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-12 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:通过实海暴露实验,研究了N6纯镍和Monel400镍合金在中国南海海域800米和1200米深海环境下的长周期(3年)腐蚀行为。采用SEM,EDS和XRD技术,分别进行了腐蚀形貌观察,腐蚀产物成分和相组成分析。结果表明:在深海环境下,Monel400镍合金的耐局部腐蚀能力要优于N6纯镍。N6纯镍在绿色腐蚀产物膜(由NiCl2?6H2O组成,还覆盖有少量的CaCO3、MgCO3等无机盐类)下面发生了很严重的隧道腐蚀,甚至出现了局部穿孔现象。Monel400镍合金表面生成了宽浅型的点蚀坑,点蚀坑上覆盖有由(CuNi)2Cl(OH)3组成的腐蚀产物。将本文中的实验结果与文献中同种合金的实验结果对比作图,表明N6纯镍和Monel400镍合金的最大点蚀坑深度均随水深的增加而降低。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-11 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:采用高压釜模拟海底集输环境,通过电化学测试技术,浸泡实验,扫描电镜(SEM)及X射线衍射(XRD)分析技术研究了H2S浓度和pH值对X65钢焊接接头腐蚀行为的影响。结果表明, X65钢焊接接头中热影响区的开路电位最负,焊缝最正,母材介于两者之间,腐蚀电流密度从大到小的顺序为热影响区、母材和焊缝;焊接接头平均腐蚀速率在0.1-0.25mm/a之间,硫化物浓度增加、pH降低均可导致腐蚀速率增加; X65钢海管焊接接头在模拟现场工况条件下以均匀腐蚀为主,焊缝腐蚀程度低于热影响区。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-11 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:通过电化学测试、浸泡实验和表面分析技术研究了交流电频率(50-400Hz)对X80钢在鹰潭酸性土壤模拟溶液中腐蚀行为的影响。研究结果表明随交流电频率增加,X80钢的腐蚀速率逐渐减小,腐蚀程度减弱。交流电作用下X80钢生成的腐蚀产物疏松,裂纹多,对基体的保护性很差。X80钢的腐蚀电位偏移量随交流电频率增加而减小。随交流电频率的增大,阴阳极极化曲线的振荡幅度逐渐减弱。交流电的施加不仅使阴阳极的电流密度增大,还使阴极反应由混合控制逐渐向活化控制转变。
Subjects: Materials Science >> Materials Science (General) submitted time 2016-11-11 Cooperative journals: 《中国腐蚀与防护学报》
Abstract:在实验室模拟的条件下,采用失重法及电化学等方法和手段并结合腐蚀形貌的显微镜观察,研究了X65钢焊接接头在浅海和深海(1000米)环境中短期腐蚀行为及其机理。结果表明,X65钢焊接接头在浅海环境下的腐蚀速率大于深海环境下的腐蚀速率,浅海环境下以点蚀为主,深海环境下只在熔合线附近腐蚀相对较快,焊缝区腐蚀不明显;在模拟浅海和深海环境下,HAZ的腐蚀电位均低于焊缝和母材区,导致焊缝区域存在电偶效应,加速了HAZ腐蚀,使热影响区腐蚀产物膜较厚,Rt值较大。