低碳镍钼合金的析出相及其对合金腐蚀的影响

采用金相显微镜、Ｘ射线衍射、电子探针和透射式电子显微镜相结合的方法,研究Ｎｉ－Ｍｏ型铸造镍基合金的组织、析出相形态、种类、成分、结构及形成条件,并研究了他们对均匀腐蚀、晶间腐蚀和电化学腐蚀性能的影响。研究结果表明,Ｎｉ－Ｍｏ型铸造合金在８００～１１００℃温度范围内均有不同程度的Ｎｉ－Ｍｏ金属间化合物和Ｍ６Ｃ型碳化物析出。合金经１１５０℃～１１８０℃固溶处理后,在５０℃浓盐酸介质中,仍具有良好的耐蚀性能。并具有较好的抗晶间腐蚀与电化学腐蚀行为。     

Effect of inorganic inhibitors on the corrosion behavior of 1018 carbon steel in the LiBr + ethylene glycol + H2O mixture

The effect of inorganic inhibitors on the corrosion behavior of 1018 carbon steel in the mixture LiBr (55%) + ethylene glycol + H₂O at room temperature has been evaluated. Used inhibitors included LiNO₃ (Lithium Nitrate), Li₂MoO₄ (Lithium Molybdate) and Li₂CrO₄ (Lithium Chromate) at concentrations of 5, 20 and 50 ppm. Electrochemical techniques included potentiodynamic polarization curves, electrochemical noise resistance (EN) and electrochemical impedance spectroscopy (EIS) measurements. Additionally, adsorption isotherms were calculated. The results obtained showed that both, the corrosion rate and the passive current density decreased with inhibitors, and, in general terms, inhibitors efficiency increased with inhibitor concentration, except in the case of Li₂CrO_4, where the highest efficiency was obtained with 20 ppm of inhibitor. Pitting potential with 5 ppm of inhibitor, regardless its chemical composition, was more active than in absence of inhibitor, increased at 20 ppm, especially with Li₂CrO₄, and remained unaltered with 50 ppm. EN measurements showed that at 5 ppm of inhibitor, the number of film rupture/repassivation events was higher than that obtained at 20 or 50 ppm. Adsorption isotherms suggested a different adsorption mechanism for each inhibitor, whereas EIS results suggested that the corrosion process when nitrates were added was under charge transfer control, but in the case of molybdates or chromates was under diffusion control.     

淬火介质及工艺对Al-Zn-Mg-Cu合金腐蚀性能的影响

采用晶间腐蚀、剥落腐蚀、扫描电镜、透射电镜等方法,研究了不同的淬火方式对Al-6.5Zn-2.65Mg-2.2Cu-0.3Sc-0.13Zr锻造态铝合金的腐蚀性能及显微组织的影响。结果表明,空气中自然冷却淬火严重降低了T6时效态合金的抗腐蚀性能。而采用室温水淬的T6时效态合金比室温油淬的时效态合金具有更好的抗剥落腐蚀性能。当预先采用80℃×30s水淬或80℃×30s油淬再室温水淬时,相应T6时效态合金的抗腐蚀性能得到明显改善。预先80℃淬火能提高时效态合金的抗剥落腐蚀性能的主要原因是晶界析出相的大小与分布发生了明显的改变。     

硫酸泵用钢的腐蚀行为研究

在温度为60℃、浓度为60％的H_2SO_4苛刻介质条件下,对7种铸造不锈钢进行了耐蚀试验。均匀腐蚀、晶间腐蚀和电化学腐蚀的试验结果表明,除316钢外,其余各试验钢均具有良好的抗硫酸腐蚀性能,可根据用户的要求选择使用。     

建筑用6063铝合金型材的腐蚀行为

以建筑用6063铝合金型材为研究对象,通过硬度测试、晶间腐蚀、全浸泡腐蚀和电化学腐蚀方法,研究了不同时效制度下6063合金的腐蚀行为并探讨了其作用机理。结果表明,随着时效温度升高,出现局部晶间腐蚀和均匀晶间腐蚀的时间提前,且最大腐蚀深度逐渐降低;不同时效热处理制度下的6063合金的动电位极化曲线测试结果与晶间腐蚀和全浸泡腐蚀测试结果保持一致,即130、175和210℃时效,峰时效时间下的合金最容易腐蚀,其次为过时效状态,而欠时效状态下合金的耐腐蚀性能较高。     

工业腐蚀监测的发展及其食品的智能化

综述了腐蚀监测技术的发展,归纳了工业应用中主要的腐蚀监测方法及仪器,并对仪器的智能化、便携式的应用发展趋势作了探讨。     

Zirconia primers for corrosion resistant coatings

The recent restriction in the use of chromium VI gave a new impulse in the field of anti-corrosion treatment for an alternative solution.A promising route seems to be the deposition of a thin ceramic layer on the metallic surface. In this study, four zirconia primers have been deposited on 1050 aluminium sheets by sol-gel process. Sol preparation was obtained starting from two different precursors and two curing temperatures were tested.Surface microstructure and chemical composition were determined by AFM and XPS for all samples. Electrochemical Noise Analysis (ENA) was used in Harrison's solution to evaluate the corrosion resistant features of the samples. Tests have been also performed on samples protected by polyester topcoat deposited on the aforesaid primers.AFM analysis revealed that, for all the samples, covering and structure of the coating were uniform. XPS depth profiling allowed concluding that film thickness was in the range from 18 to 30 nm and that chemical composition was constant through primer thickness.Corrosion tests demonstrated that zirconia primers showed good performances in terms of corrosion resistance, comparable to chromate and fluotitanate layers industrially prepared.Topcoated samples gave an optimal corrosion resistance.     

回归时间对7150铝合金力学和晶间腐蚀性能的影响

通过维氏硬度、电导率和室温拉伸、晶间腐蚀等试验,分析比较T6态和回归再时效处理（RRA）态7150铝合金的性能。借助光学显微镜和透射电镜,研究回归时间对RRA态7150铝合金微观组织的影响。结果表明,T6态的7150铝合金强度很高,但抗晶间腐蚀性很差。RRA态的7150合金随回归时间延长,抗晶间腐蚀性能增强,强度先升高后降低。当回归时间为1h时,晶内组织主要析出相为GP区,并伴有细小沉淀相η′,η′相分布较为均匀,约几个nm,晶界处析出相粗大且分布不连续,有明显无沉淀析出带。T6+185℃×1h+T6处理的7150铝合金既具有较高的强度,又具有较好的抗晶间腐蚀性,表现出最佳的综合性能。     

Corrosion behavior of thermal-sprayed WC cermet coatings in SO4 2− environment

A series of the electrochemical and long-term corrosion tests was carried out in a 3.5 wt% Na2SO4 solution on thermal-sprayed WC-17Co and WC-10Co-4Cr cermet coatings in order to examine the effect of composition of binder materials on the corrosion behavior. The results reveal that the overall corrosion resistance of the WC-17Co coating is inferior to that of the WC–Co–Cr coatings due to the corrosion of binder materials which induce WC particles to fall off. CoO and WO3 oxide films form on the surface of WC-17Co coating in Na2SO4 solution electrochemical corrosion process, which will protect the coating in the process of corrosion. Cr2O3 oxide film formed on the WC-10Co-4Cr coating surface has a strong hindered role to corrosion. The corrosion mechanism of WC-17Co coating in Na2SO4 solution is entire corrosion of Co matrix, while it is film-hole corrosion mechanism for WC-10Co-4Cr coating.     

Detection of corrosion degradation using electrochemical noise (EN): review of signal processing methods for identifying corrosion forms

Electrochemical noise (EN), as one of the most promising in situ electrochemical methods in corrosion and electrochemical science, has been developing rapidly in recent years with the advancements in instrumentation and signal processing methods. One advantage of EN is its application in long-term or early stage corrosion process monitoring because it instantly detects corrosion rate and corrosion forms. Investigators have applied various mathematical methods to extract characteristic parameters from EN. In this paper, identifying corrosion forms using parameters obtained from time domain, frequency domain and time–frequency domain is reviewed, and the correlation between parameters and corrosion forms is discussed. Finally, other in situ techniques are recommended to be employed synchronously with EN measurement in order to obtain reliable analyses.     

钢筋混凝土腐蚀与防护的技术发展动态

总结,分析并阐述了在腐蚀环境条件下,混凝土中钢筋腐蚀发生和发展的原因,腐蚀性组分从环境透过作为多相电解质的混凝土到达钢筋表面,破坏了钢筋的印态,是钢筋腐蚀的主要原因。     

Assessment of intergranular corrosion (IGC) in 316(N) stainless steel using electrochemical noise (EN) technique

In the present work, an attempt was made to demonstrate the use of electrochemical noise (EN) technique in assessment of intergranular corrosion (IGC) in 316(N) stainless steel (SS). Degree of sensitization (DOS) in the specimens aged at 923 K for 24, 40, 50 and 100 h was determined using double loop electrochemical potentiodynamic reactivation (DLEPR) technique. Immediately after applying a prior preconditioning treatment, current and potential noise measurements were made. The DOS was determined from standard deviation of current noise (σ_I) versus time plot and it was found to bear a good correlation with the values obtained by DLEPR. Shot noise analysis of the EN data confirmed the above results.     

高铝锌基合金的耐腐蚀性研究

在质量分数为3．5％的NaCl溶液介质中，用电化学测量系统测定了Al的质量分数为30％～50％，Cu的质量分数为1．0％～2．5％的Zn-Al合金的塔菲尔参数、线性极化电阻、自腐蚀电位等电化学参数。并在三维视频显微镜下观察了合金的腐蚀形貌。结果表明，Zn-Al合金的耐蚀性随Al含量的增加和Cu含量的减少而下降。在试验合金中Al的质量分数为30％、Cu的质量分数为2．5％的Zn-Al合金耐腐蚀较好。     

电化学方法应用于电力设备腐蚀与防护的研究

从双水内冷发电机空芯铜导线的腐蚀行为研究,电厂凝汽器铜管耐蚀性的评定以及热力设备停用保护用十八烷基胺的成膜研究等方面介绍了电化学方法在电力设备腐蚀与 也护研究中的应用。     

固溶温度对Al-Zn-Mg-RE合金电化学性能的影响

对Al-5Zn-0.03In-1Mg-0.05Ti-0.5RE合金进行510、550℃保温10h的固溶处理。测试了合金在人造海水中的电流效率。通过电化学阻抗方法研究了合金在3%的NaCl溶液中的电化学性能。结果表明,固溶处理使Al-Zn-In-Mg-Ti-RE合金的电流效率下降,开路电位和工作电位降低,溶解加速。     

Quantitative evaluation of general corrosion of Type 304 stainless steel in subcritical and supercritical aqueous solutions via electrochemical noise analysis

Electrochemical noise (EN) sensors have been developed to measure the corrosion rate of Type 304 stainless steel (SS) in subcritical and supercritical environments. The EN sensors were tested in flowing aqueous solutions containing NaCl and HCl at temperatures from 150°C to 390°C, a pressure of 25 MPa, and flow rates from 0.375 to 1.00 ml/min. The potential and coupling current noise were recorded simultaneously and the noise resistance (R_n) was calculated from the standard deviations in the potential and current records. We found that the inverse noise resistance correlated very well with the corrosion rate evaluated from separate mass loss experiments, and that both the inverse noise resistance and the average corrosion rate were functions of temperature and flow rate. In the temperature range from 200°C to 390°C, the corrosion rate was found to be proportional to the inverse noise resistance and hence the Stern-Geary relationship can be used to evaluate the corrosion rate. However, at 150°C, the relation between inverse noise resistance and corrosion rate significantly deviated from the Stern-Geary relationship. It was found that the deviation was related to the low corrosion rate of Type 304 SS and 150°C.     

类金刚石(DLC)膜对2Crl3不锈钢耐蚀性能的影响

采用失重法、极化曲线法和金相显微分析等方法研究了类金刚石(DLC)膜对2Cr13不锈钢耐蚀行为的影响.失重试验结果表明:DLC膜较薄时对2Crl3不锈钢在中性NaCI溶液中耐全面腐蚀的影响不明显,而膜较厚时能显著降低2Crl3不锈钢的腐蚀速度;失重试验和电化学试验均表明DLC膜降低了2Crl3不锈钢在酸性介质中的腐蚀速度;动电位扫描曲线和金相显微分析说明DLC膜明显改善了2Crl3不锈钢基体抗点蚀、晶间腐蚀等局部腐蚀的能力.     

Ni-Cr-Mo-Cu合金耐晶间腐蚀及点蚀性能研究

在Cr、Mo成分一定的情况下,通过改变铜的质量分数(1％～5％),制备新型Ni-Cr-Mo-Cu耐蚀合金.利用化学浸泡法、电化学法(极化曲线法、循环伏安法)对其耐晶间腐蚀以及耐点蚀能力进行分析研究.实验结果表明,w(cu)=1％～5％的Ni-Cr-Mo-Cu合金具有优良的耐晶间腐蚀以及点蚀性能,相对而言w(cu)=2％的镍基合金耐晶间腐蚀以及点蚀性能较差,因此说明合适的铜含量可以提高镍基合金的耐晶间腐蚀和点蚀性能;并且试验合金晶间腐蚀与点蚀的电化学行为和特征与其浸泡腐蚀的结果是吻合的.     

BFe10-1-1和B7-2-2铜管的耐腐蚀性比较

用电化学测试方法评定了加缓蚀剂BTA前后BFe10-1-1和镍含量约7%的B7-2-2铜镍合金冷凝管在模拟冷却水中的耐蚀性能。结果表明,不加BTA,B7-2-2的耐蚀性不如BFe10-1-1;添加BTA能有效抑制脱镍,使管样的耐蚀性比不加BTA提高约4倍,且BTA对B7-2-2的缓蚀效果优于BFe10-1-1。