温度、溶解氧对Q235B钢在脱硫液中腐蚀行为的影响

为了给Q235B钢管道防腐蚀设计与工艺参数设置提供依据,采用挂片试验、SEM、动电位极化曲线和交流阻抗谱,研究了Q235B钢在不同温度、溶解氧脱硫液中的腐蚀行为。结果表明:由失重法计算出的Q235B钢的腐蚀速率随温度的升高而升高,并在45℃达到峰值,之后开始减小;随氧含量升高,腐蚀速率加大。极化曲线和交流阻抗测定中,脱硫液温度、溶解氧变化时,Q235B钢的极化曲线上均未出现钝化区,自腐蚀电位随温度的升高先负移后正移,但随溶解氧含量的升高变化不大。Nyquist谱均由高频区的容抗弧和低频区的感抗弧组成,容抗弧半径随温度升高先减小后增大,随溶解氧含量的升高而减小。扫描电镜形貌显示,温度升高时,Q235B钢表面的絮状腐蚀产物变成球状,堆积紧密;脱硫液中氧含量升高,腐蚀产物出现球状。脱硫液温度和溶解氧含量升高时,都能加速阴极反应,使Q235B钢的腐蚀加剧;而溶解氧含量升高会促进腐蚀反应,并且使得产物层的致密性降低,腐蚀速率显著增大。     

凝汽器铜管氨腐蚀的研究

研究了影响凝汽器铜管氨腐蚀的因素与规律,以确定防止凝汽器氨腐蚀的途径.将HAl77-2A铜管管样在10种氨浓度、两种溶解氧浓度的溶液中浸泡45d,测定溶液的溶解氧变化情况,用失重法、原子吸收法测定铜管管样腐蚀速率;在6种温度、两种溶解氧、4种氨浓度条件下研究温度对铜管腐蚀速率的影响.氨液浓度小于800mg/L时,铜管氨腐蚀轻微,氨液浓度为800～1000mg/L时铜管腐蚀速率明显增大,且随氨液浓度的增大而增加;开口状态下铜管腐蚀速率比闭口时大,温度升高时同一氨液浓度下铜管腐蚀速率增大.凝汽器铜管氨腐蚀主要影响因素是溶解氧与氨液浓度,氨液浓度超过800mg/L后,腐蚀速率随氨浓度、氧含量、温度的增加而增大;用失重法与原子吸收法测定铜管腐蚀速率基本一致.     

碱液输储装置用12Cr13钢的热浓碱液腐蚀行为

目前对12Cr13钢在碱液中的腐蚀行为未见研究报道.采用浸泡试验通过调整流速、碱液浓度、浸泡时间等参数研究了12Cr13钢在热浓碱液中的腐蚀行为,以明确不同因素影响碱液腐蚀的规律及碱液腐蚀机理.结果表明:试验范围内12Cr13钢静态下的腐蚀速率大于动态下的,流速增大加速了试样的腐蚀及钝化膜的修复,促进了材料表面钝化膜的生成,降低了腐蚀速率.碱液浓度低(0～20％)时12Cr13钢以钝化为主,腐蚀速率较低,碱液浓度高(＞20％)时由于过钝化溶解,使腐蚀速率显著增大;在45％碱液中12Cr13钢经历着钝化膜的生成、过钝化溶解及钝化膜的修复过程,腐蚀速率随时间增大呈先增大后降低趋势,浸泡7d出现最大腐蚀速率;动态条件下这些过程被加速,腐蚀速率减小,约是静态下的1/2.     

H2S薄层液膜下16Mn钢腐蚀的电化学研究

利用自行设计的测量金属在薄层液膜下腐蚀的三电极电化学电池,通过极化曲线和交流阻抗技术(EIS)研究了16Mn钢在含H2S薄层液膜下的电化学行为,并与之在大量H2S电解质溶液中的电化学行为进行了比较.结果表明:H2S促进了16Mn钢腐蚀的阴阳极过程;随着H2S浓度的升高,16Mn钢的自腐蚀电位(Ecorr)正移,腐蚀速率逐渐增加,但C(H2S)＞2 mmol/L后腐蚀速率不再增加;随薄层液膜酸度增加,Ecorr负移,自腐蚀电流(Jcorr)增大,但pH＜4.4后腐蚀速度与酸度无关.16Mn钢在H2S薄层液膜下与在全浸状态下的腐蚀机理可能不同.     

含氯融雪盐对汽车用镀锌钢腐蚀行为的影响

目前,对热镀锌钢板在含氯融雪盐雪水溶液中的腐蚀行为研究不多。为此,采用浸泡和电化学方法研究了汽车用镀锌钢板及裸钢在不同氯离子含量的模拟融雪盐雪水溶液中的腐蚀行为。结果表明:含氯融雪盐的雪水溶液比纯雪水具有更强的腐蚀性,随着融雪盐含量的增加,汽车用镀锌钢腐蚀速率增加缓慢,腐蚀速率较祼钢降低了约1倍,耐蚀性显著提高。汽车用镀锌钢在含1%Cl-的雪水中发生腐蚀,表面沉积一层由Zn(OH)2和ZnO组成的二次腐蚀产物膜,对镀锌层的溶解起到一定的阻碍作用,但融雪盐中的Cl-破坏了膜的稳定性,使镀锌钢在成膜-破坏-再成膜-再破坏的反复中发生腐蚀。     

温度对注气井P110油管钢耐蚀性能的影响

目前,对于注气工况下井筒存在的氧腐蚀问题及其影响因素研究较少。利用高温高压反应釜进行腐蚀模拟试验,辅以失重法、SEM、EDS、XRD等测试手段,研究含氧工况下温度对P110油管钢耐蚀性能的影响。结果表明:温度通过改变溶液中的氧含量、电化学反应速率、溶解氧的扩散作用以及表面产物层而影响P110钢耐蚀性能。温度升高,电化学反应加速,溶解氧扩散加快,CaCO_3垢层脱落,腐蚀速率增大;溶解氧含量下降,又会导致腐蚀速率下降。温度的双重作用导致P110腐蚀速率先增大后减小,100℃时最大,且会发生局部腐蚀。     

土壤中阴离子对X70钢微生物腐蚀的影响

本文主要通过改变含有SRB的土壤模拟溶液中主要的阴离子含量,采用电化学测量,研究SRB在不同阴离子含量的土壤模拟溶液中对X70钢的腐蚀行为的影响。以便研究SRB对输油管道的外腐蚀。结果表明:在土壤模拟溶液中,当增加C1-的浓度时,SRB对X70管线钢的腐蚀速率先减小后增大,而当增加的浓度时,SRB对X70钢的腐蚀速率先增大后减小。     

库尔勒土壤中溶解氧含量对X80钢及其焊缝腐蚀行为的影响

目前,有关实际土壤中环境因素对埋地X80管线钢电化学腐蚀行为的研究较少。制备了库尔勒土壤模拟溶液,利用动电位极化曲线、交流阻抗谱(EIS)研究了模拟液中溶解氧(DO)含量对X80管线钢及其焊缝腐蚀行为的影响,采用金相显微镜观察材料的组织形貌。结果表明:随着土壤中溶解氧含量的降低,X80钢及其焊缝的腐蚀电流密度均明显减小,腐蚀产物膜的致密性逐渐提高,试样的腐蚀速率显著下降;相同溶解氧含量下,X80钢焊缝处的腐蚀程度明显高于母材。     

含Cr钢的CO_2腐蚀行为及成膜动力学研究

目前对含Cr钢CO_2腐蚀中的产物膜生长动力学过程研究不多。为此,采用高温高压反应釜、动电位极化、电化学阻抗谱、光电子能谱、高分辨拉曼光谱等方法研究了不同Cr含量钢在模拟油井下环境中的CO_2腐蚀行为及成膜动力学。结果表明:Cr含量的升高会明显降低含Cr钢在模拟CO_2腐蚀环境中的腐蚀速率,其中3Cr钢和5Cr钢的腐蚀速率相近,腐蚀速率高于3 mm/a; 6Cr钢和7Cr钢的腐蚀速率明显低于3Cr和5Cr钢,腐蚀速率低于1mm/a;腐蚀产物膜成膜过程可以分为2个阶段,阶段1为Cr(OH)3的生长过程,成膜电流I和时间t取对数后满足线性关系;阶段2中随着腐蚀时间的增加,腐蚀电流逐渐增大;产物膜在成膜初期以直接成膜的Cr(OH)3为主,随着腐蚀时间的延长,Cr(OH)_3发生溶解,留下的位置被FeCO_3沉淀填充。     

X80钢在伊川土壤模拟溶液中的腐蚀行为

采用失重法、阳极极化曲线、光学显微镜、扫描电镜(SEM)及X射线衍射(XRD)等方法研究了X80钢在伊川土壤模拟溶液中的腐蚀行为.结果表明,X80钢在模拟溶液中的腐蚀行为与HCO3-、CO32-、SO42-和Cl-离子的浓度有关.随HCO3-或CO32-浓度增加,X80钢的阳极溶解电流密度都呈现出先增加后减小的趋势;X80钢钝化的临界HCO3-或CO32-浓度分别为0.008 mol/L或0.005 mol/L.在低于临界HCO3-或CO32-浓度下,SO42-和Cl-浓度的增加都促进了X80钢的阳极活性溶解;而在高于临界HCO3-或CO32-浓度下,X80钢的钝化性能随SO42-或Cl-浓度的增加而减弱.在90 d浸泡期内,X80钢在模拟溶液中的腐蚀形态为全面腐蚀;其腐蚀速率随浸泡时间的增加而呈逐渐增大的趋势.     

AZ31镁合金表面气相沉积不锈钢薄膜的实验研究

利用真空蒸发镀膜技术在镁合金表面沉积不锈钢薄膜是提高镁合金防腐性能的新尝试.本研究利用该技术在AZ31上成功制备了不锈钢薄膜.通过在5%NaCl溶液中的浸入实验和极化实验考察了腐蚀性能,发现镀膜后耐蚀性显著降低.另外,镀膜后的显微硬度也未有明显提高.利用AFM,SEM,EDX等分析手段对薄膜进行了观察和检测,发现耐蚀性变差的原因主要是薄膜表面存在贯穿性的微米级孔洞和Cr元素分布不均匀造成的.     

Study of the characteristics and corrosion behavior for the Zr-based metallic glass thin film fabricated by pulse magnetron sputtering process

Two sets of source target which consist of ZrCuAlNiV and ZrTiAlNiV, respectively were selected as the target materials for preparing a series of thin film coatings on the 304 stainless steel substrate by DC pulse magnetron sputtering process. The microstructures of these as-prepared ZrCuAlNiV and ZrTiAlNiV thin films were examined by X-ray diffraction and TEM observation. In parallel, the characteristic analysis of these ZrCuAlNiV and ZrTiAlNiV alloy thin films including surface roughness, and corrosion resistance were analyzed by atomic force microscopy (AFM), and tested by electrochemical method as well as salt spray testing, respectively. The results showed that the ZrCuAlNiV thin film exhibits a typical amorphous microstructure and smooth surface with average roughness about 1 nm. The ZrCuAlNiV thin film performs similar corrosion resistance to 304 stainless steel according to the result of salt spray testing in 5% NaCl solution. Additionally, the AC impedance value of ZrCuAlNiV is 20 times than 316L stainless steel and 4 times than ZrTiAlNiV, implying that the ZrCuAlNiV thin film has better corrosion resistance than the others owing to its amorphous state.     

Temperature and NaCl deposition dependent corrosion of SAC305 solder alloy in simulated marine atmosphere

The stable operation of electronic devices in marine atmospheric environment is affected by the corrosion deterioration of solder joints,and the effects by atmosphere temperature and chloride deposition are critical.In this work,NaCl deposition and temperature dependent corrosion of Pb-free SAC305 solder in simulated marine atmosphere has been investigated.The results indicate that higher NaCl deposition prolongs the surface wetting time and leads to the final thicker saturated electrolyte film for further corrosion.Higher temperature accelerates the evaporation and contributes to the final thinner saturated NaCl electrolyte film.Besides,the corrosion control process varies under the initially covered thicker NaCl electrolyte layer and under the final saturated much thinner NaCl electrolyte film as the evaporation proceeds.Moreover,the ready oxygen availability through the final thinner saturated NaCl electrolyte film facilitates the formation of corrosion product layer mainly of electrochemically stable SnO2,but higher temperature leads to the final corrosion product layer with smaller crystal size and large cracks.The findings clearly demonstrate the effects of NaCl deposition and temperature on corrosion evolution of SAC305 solder joints and are critical to the daily maintenance of electronic devices for longer service life in marine atmosphere.     

镀锌层表面KH-560硅烷膜耐蚀性能研究

利用正交实验研究了硅烷偶联剂在镀锌板上的钝化工艺,采用KH-560对热镀锌板进行钝化处理.比较钝化膜与空白试样在5%NaCl溶液中的极化曲线、电化学交流阻抗谱,并通过盐水浸泡实验进一步验证了硅烷膜的耐蚀性能.结果表明:经硅烷钝化处理后的镀锌板,其腐蚀电流密度下降,极化电阻升高,硅烷膜抑制了镀锌板的腐蚀过程,其耐蚀性能优于空白试样,接近铬酸盐钝化膜的耐蚀性.     

乙烯基硅烷处理的Q235钢在3．5％NaCl中腐蚀性的阻抗谱分析

从阻抗谱方面研究Q235钢硅烷处理的防腐蚀效果和成膜机理的报道较少。以不同浓度（1％～7％）、不同pH值（3～5）的乙烯基三乙氧基硅烷（VTES）水解液对Q235钢进行处理,利用电化学阻抗谱（EIS）分析了硅烷膜对3．5％NaCl溶液中Q235钢的防护效果及机理,并用红外光谱与扫描电镜（SEM）分析了Q235钢表面VTES膜的分子结构及其在盐水中浸泡腐蚀后的形貌。结果表明：VTES膜能明显改善Q235钢的耐蚀性能;经5％硅烷,pH=4的水解液处理形成的VTES膜在3．5％NaCl溶液中的电荷转移电阻及膜孔电阻最大,耐蚀效果最好,在3．5％NaCl溶液中浸泡5d后仍未发生腐蚀;Q235钢表面形成的硅烷膜既存在金属表面与硅醇单体的缩合,也有硅醇单体的缩合,还有未发生交联的Si-OH基团。     

Evaluation of the Corrosion Protection Performance of Epoxy-Coated High Manganese Steel by SECM and EIS Techniques

The corrosion protection performances of epoxy-coated Mn steel and carbon steel were evaluated by electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) analysis. EIS was performed on coated Mn steel with a scratch in a 0.1 M NaCl solution after a wet/dry cyclic corrosion test. The charge transfer resistance (R _ct) and film resistance (R _f) of the coated Mn steel displayed a higher value than the coated carbon steel. The increase in the charge transfer resistance and film resistance of the coated steel is due to the presence Mn in steel. SECM was conducted to estimate the corrosion protection performance of the epoxy-coated Mn steel immersed in a 0.1 M NaCl solution. It was found that dissolution of Fe²⁺ was suppressed at the scratch on the coated Mn steel due to the higher resistance for anodic dissolution of the substrate. SEM/EDX analysis showed that Mn was enriched in corrosion products at a scratched area of the coated steel after corrosion testing. FIB-TEM analysis confirmed the presence of the nanoscale oxide layer of Mn in the rust of the steel, which had a beneficial effect on the corrosion resistance of the coated steel by forming protective corrosion products in the wet/dry cyclic test.     

含H2S的NaCl溶液中溶解氧对PH13-8Mo钢腐蚀性能的影响

为研究新型马氏体沉淀硬化不锈钢PH13-8Mo在含饱和H_2S的NaCl溶液中的腐蚀行为,利用极化曲线、电化学阻抗谱等电化学测试和浸泡实验相结合的方法,通过扫描电子显微镜(SEM)和X射线光电子能谱分析技术(XPS),观察了该高强钢在含H_2S的除氧和不除氧的NaCl溶液中的腐蚀形貌,并对其腐蚀产物的成分进行了分析.结果表明:在除氧的NaCl溶液中,阳极极化曲线的形状发生了明显的变化,电化学阻抗谱的容抗弧的幅值也较未除氧的溶液中变小;在除氧的NaCl溶液中浸泡7 d后,由于H_2S水解后的S~(2-)或HS~-离子侵入到钝化膜的内部,并与钝化膜或金属基体发生反应,使得试样表面发生全面腐蚀,腐蚀产物主要为Fe、Cr、Ni、Mo的氧化物和硫化物;而在未除氧的NaCl溶液中浸泡后,试样表面仅发生局部腐蚀.     

3Cr低合金钢在含饱和CO_2的NaCl溶液中的腐蚀电化学行为

研究了含饱和CO2的NaCl溶液pH值对3Cr低合金钢腐蚀及其电化学行为的影响。结果表明: 当NaCl溶液的pH值较低(2, 3.9)时, 腐蚀产物膜为单层结构, 呈龟裂状; 当pH值较高(6.5)时, 腐蚀产物具有三层结构, 外层腐蚀产物为颗粒状, 内层仍呈龟裂状。NaCl溶液的pH值对3Cr低合金钢的腐蚀电化学行为也有显著影响。 NaCl溶液的pH值升高能改变电极过程中的主要阴极反应, 使腐蚀电位逐渐负移, 且电荷转移电阻的增大使腐蚀电流密度减小。     

Demanding applications in harsh environment – FeCrMnNiC amorphous equiatomic alloy thin film

An amorphous equiatomic FeCrMnNiC alloy thin film was synthesised on silica and silicon substrates by ion beam sputter deposition. Scanning electron microscopy energy-dispersive X-ray spectroscopy, X-ray diffraction, selected area electron diffraction and nano indentation were used to investigate the material. The produced film is amorphous and uniform on the atomic level without any detectable element segregation. The corrosion properties were assessed in 3.5% NaCl solution. The FeCrMnNiC alloy has corrosion resistance better than corrosion resistance of 304 SS. The thin film has hardness at around 12.3?±?0.5?GPa and reduced Young’s modulus at around 222?±?12?GPa.