316L不锈钢在西沙海洋大气环境下的腐蚀行为评估

采用循环阳极极化、电化学阻抗谱(EIS)和扫描Kelvin探针技术(SKP)评估了在西沙群岛苛刻海洋大气环境下,316L不锈钢经过不同时间暴露后的腐蚀行为。研究结果表明,暴露时间的长短对316L不锈钢的钝化行为没有显著影响。在极化曲线上均表现为阳极活化溶解特征,钝化膜失去保护作用,且暴露时间越长,不锈钢表面破损越多。同时随着暴露时间的延长,不锈钢表面微区的Kelvin电位整体分布下降,且趋向于不均匀分布,电位波动逐渐增大,这可能是由于钝化膜发生破裂进而发生点蚀以及腐蚀产物积累造成的。     

Martensite transformation induced by deformation and its phase electrochemical behavior for stainless steels AISI 304 and 316L

The martensite transformation induced by tensile elongation and its effect on the behavior or phase electrochemistry of AISI 304 and 316L in 3.5% NaCl solution were studied.The results show that the content of α′-martensite in stainless steel 304 increases with the true strain,As α′-martensite content increased.freee corrosion potential and pitting potential of stainless steel 304 in 3.5% NaCl solution appeared the change trend of a minimum.It was also found that pitting nucleated preferentially at the phase interfaces between martensite and austenits,There exsted apparent differnece between electrochemical properties of austenite and of martensite for stainless steel 304 and 316L in 3.5% NaCl solution.     

模拟冷却水中几种缓蚀剂对不锈钢耐蚀性的影响

采用极化曲线、Mott-Schottky图和交流阻抗谱研究了不同缓蚀剂对316L不锈钢的缓蚀效果.极化曲线结果显示,模拟水中不锈钢的耐蚀性能随着温度的升高而不断降低,不锈钢的点蚀倾向增大.缓蚀剂可以提高不锈钢的点蚀电位,从Mott-Schottky图分析,缓蚀剂的加入降低了不锈钢表面钝化膜的载流子浓度.用于实验的6种缓蚀剂中,TB5和TB7显示出了较好的缓蚀性能.     

氮含量和环境温度对316L不锈钢耐腐蚀性的影响

研究低温条件下腐蚀溶液温度以及钢中氮含量对316L奥氏体不锈钢耐腐蚀性能的影响,在1mol／L H2SO4＋0．5mol／L NaCl的腐蚀液中,对氮含量为0．0095％～0．5575％的316L奥氏体不锈钢进行阳极极化曲线及电化学阻抗测量。结果表明,提高氮含量,316L奥氏体不锈钢耐蚀性增强;腐蚀液温度升高,316L奥氏体不锈钢耐蚀性减弱。     

三种不锈钢在含Cl^—衣康酸介质中的腐蚀行为

研究了３种不锈钢在衣康酸／氯化钠水溶液中的腐蚀和电化学特性并探讨了介质组成和温度的影响。结果表明,在一定范围内,随衣康酸浓度,氯化钠浓度和温芳的提高,不锈钢的腐蚀速率、致钝电流密度和维钝电流密度也有所增大,不锈钢的点蚀电位与衣康酸介质中Ｃｌ＾－浓度的对数间存在线性关系;     

Study on pitting process of 316L stainless steel by means of staircase potential electrochemical impedance spectroscopy

Pitting corrosion of 316L stainless steel in NaCl solution was investigated by means of staircase potential electrochemical impedance spectroscopy(SPEIS).The investigation focused on the transition of stainless steel from the passive state to pitting corrosion.Based on the evolution of electrical parameters of the equivalent electrical circuit,it is suggested that the most probable mechanism of pit creation is the film breaking model.The result demonstrates that staircase potential electrochemical impedance...     

Passivation method of 317L stainless steel used in medicine

The electrochemical performance of 317L stainless steel used in medicine under different conditions of passivation(Different conternts of HNO3 solution,different passivation time and different passivation temperatures)was studied.The results show that the pitting potential of 317L stainless steel used in medicine can reach about 1.0V(SCE) when electrochemically tested in 0.9% NaCl solution after the steel was passivated in 30% HNO3 solution at 35℃for 6h,which indicates that the passivation film has a relatively strong resistance to corrosion,The results also show that the corrosion resistance of the passivation film on the surface of 317SS can be increased after suitable amount of K2Cr2O7 is added into NHO3 passivation solution.     

Electrochemical Method for Evaluating the Passivated State of Medical Stainless Steel 317L

The electrochemical behavior of the medical Stainless steel 317L which is used as in vivo fixation materials has been investigated at different passivated states in several candidate-testing solutions. The potentiodynamic scanning polarizaion technique was employed to measure the polarizaion curves of 317L in 0.9%NaCl solution at 37℃. The results showed that the electrochemical behaviorin 0.9% NaCl solution at 37℃ and in 2% NaCl solotion at 30℃ can be better used to detect and evaluate passivated states and corrosionresistance of 317L. In addition,the pitting potential Eb can be used as a criterion and itS lower limit could be 0.85 V(SEC) for this system.     

Pitting corrosion and crevice corrosion behaviors of high nitrogen austenitic stainless steels

Pitting corrosion and crevice corrosion behaviors of high nitrogen austenitic stainless steels(HNSS) were investigated by electrochemical and immersion testing methods in chloride solution,respectively.The chemical constitution and composition in the depth of passive films formed on HNSS were analyzed by X-ray photoelectron spectrum(XPS).HNSS has excellent pitting and crevice corrosion resistance compared to 316L stainless steel.With increasing the nitrogen content in steels,pitting potentials and critical ...     

Physico-chemical properties and microstructure of hydroxyapatite-316L stainless steel biomaterials

Sintering shrinkage, compressive strength, bending strength, metallurgical morphology, microstructure and chemical composition diffusion of hydroxyapatite-316L stainless steel(HA-316L SS) composites were investiga-ted. The results show that the sintering shrinkage of HA-316L SS composites decreases from 27.38O/6o to 8.87% for cylinder sample or from 27.18% to 8.62% for cuboid sample with decreasing the volume ratio of HA to 316L SS,which leads to higher sintering activity of HA compared with that of 316L SS. The compressive strength of HA-316L SS composites changes just like parabolic curve (245.3→126.3→202.8 MPa) with reducing the volume ratio of HA to 316L SS. Bending strength increases from 86.3MPa to 124. 2 MPa with increasing the content of 316L SS. Furthermore, comprehensive mechanical properties of 1.0：3.0 (volume ratio of HA to 316L SS) composite are optimal with compressive strength and bending strength equal to 202. 8 MPa and 124. 2 MPa, respectively. The microstructure and metallurgical structure vary regularly with the volume ratio of HA to 316L SS. Some chemical reaction takes place at the interface of the composites during sintering.     

硼酸铝晶须增强铝复合材料的电化学腐蚀行为

通过对不同扫描速率下电化学极化曲线的测试,研究了3种晶须体积分数的硼酸铝晶须增强纯铝基复合材料在3.5%NaCl溶液中的电化学腐蚀行为,并利用扫描电子显微镜观察了经极化处理后,复合材料表面的微观组织形貌.研究结果表明,随晶须体积分数的增加,复合材料阳极钝化区域逐渐减小,且相应复合材料表面被腐蚀程度也显著增加,即随体积分数的增加,复合材料发生腐蚀的敏感性逐渐增加.对同种晶须体积分数的复合材料而言,随扫描速率的提高,复合材料阳极极化曲线中钝化区域明显增大,从而表明在较高的腐蚀速率下,复合材料更易于钝化.     

3O4不锈钢在Cl~- NO_3~-介质中孔蚀引发特性的研究

测量了304不锈钢在0.5mol／LHCl＋0．5mol／LNaCl＋Xmol／LNaNO3（X=0001，0．01，0．05，0.2）溶液中的极化曲线，得到腐蚀电位Ec和击破电位Eb和NO-3浓度之间关系。结果表明，Ec和Eb都随NO-3浓度增加而正移。同时，将不锈钢记片在各试验溶液中作定时浸泡腐蚀试验，比较不锈钢孔蚀引发及早期发展之特性；低浓度NO-3介质中比高浓度NO-3介质中的孔蚀更为严重；蚀孔的扫描电镜观察表明，孔蚀易于在晶界，夹杂物等高能区引发。     

Corrosion behavior of Al-Zn-Sn-Ga alloy in NaCl solution

The corrosion behavior of Al-Zn-Sn-Ga alloy in 3.5% NaCl solution was investigated by corrosion morphology observation and electrochemical testing. The experimental results show that there exist three stages during the course of corrosion. At the initial stage, pitting occurs surrounding the precipitates, which is driven by the galvanic couple effect. At the middle stage, pitting rapidly extends toward the horizontal direction, forming the shallow circular structure caused by the deposition of Ga ions around Sn. At the final stage, the new active sites led to the continuous corrosion of the alloy.     

碘化钾对铝合金表面化学镀镍耐蚀性的影响

通过扫描电子显微镜考察了碘化钾(KI)对2024铝合金表面化学镀Ni-P层表面形貌的影响,采用 浸泡法和动电位极化以及交流阻抗等电化学方法,研究了KI对Ni-P镀层在质量分数为3.5%的NaCl溶液中腐蚀 行为的影响。实验结果表明,KI减少了Ni-P镀层中表面缺陷的数量,细化了晶粒,镀层更加平整致密,表面质量得 到改善。同时,KI也增加了镀层中磷的质量分数。这两个原因使Ni-P镀层的耐蚀性进一步提高。     

Passivation Mechanism of 316L Stainless Steel in Oxidizing Acid Solution

The compositions and the chemical valence states of elements of 316L stainless steel passive film formed in the oxidizing acid solution were studied by X-ray Photoelectron Spectroscopic (XPS) analysis. The electrochemical polarization curve was measured. The passivation process in the oxidizing acid solution was studied by AC impedance technology. The results indicated that the stable compounds layer was formed on the surface of the sample and the adsorption was the main step in the nitrite solution during passivation process. The catalysis passivation mechanism was put forward according to the experimental results. During passivation process, the water molecule was adsorbed on the surface of the sample at first in the oxidizing acid solution. The oxidizer in the solution played a role as catalyst. The oxide and hydroxide, which could be changed each other and finally formed stable passive film, were generated from adsorbing intermediate under the catalytic action. The mathematical models for predicting the steady polarization curve and the AC impedance spectra at certain conditions have been obtained. The passivation mechanism of 316L stainless steel in the oxidizing acid solution can be interpreted by the catalysis passivation mechanism.     

Corrosion Fatigue Behavior of Duplex Stainless Steel in 3.5% Sodium Chloride Solution

The corrosion fatigue behavior of duplex stainless steel (DSS) was studied at different cyclic stress levels in 3.5%NaCl (mass fraction, so as the follows) solution (pH = 7) at 50℃. The results showed that DSS was susceptible to pitting Corrosion and Corrosion fa- tigue. Both Intergranluar Corrosion cracking and transgranlular corrosion cracking initiated at the bottom of pitting holes. Furthermore, the corrosion fatigue properties of DSS in 3.5%NaCl solution may be relatived to complex electrochemical and mechanical coupling effects between the three phases (austenite, ferrite and medensite), where martensite and ferrite were anodic in the corrosion cell and could be prone to cracking under certain condition.     

Electrochemical behavior of Mg-Al-Pb alloy in 3.5% NaCl solution

An investigation on electrochemical behavior of Mg-5%Pb alloy, Mg-6%Al alloy and Mg-6%Al-5%Pb alloy(mass fraction) in 3.5% Na Cl(mass fraction) solution was conducted using electrochemical measurements and corroded morphology observation, in which solid solution and the as-aged state of each alloy were compared to discuss the influence mechanism of lead and aluminium on the electrochemical properties of alloys. The X-ray diffraction(XRD) analysis was performed to make microstructure characterization. The electrochemical results indicate that the corrosion of Mg-5%Pb alloy is predominated by homogeneous pitting and dissolution of PbCl_2 film due to Cl ions attack, while corrosion crevice propagates along grain boundaries in solid solution of Mg-6%Al alloy and the micro galvanic corrosion also plays vital role in Mg_(17)Al_(12) phase containing experimental alloys. The co-existence of lead and aluminium in magnesium alloy increases corrosion current density and electrochemical activity as well. The comparison between solid solution and the as-aged state demonstrates that Mg_2 Pb and Mg_(17)Al_(12) somewhat increase corrosion resistance but lighten anodic polarization by facilitating corrosion product flaking off.     

Susceptibility of two types of low-alloy hull steels to pit initiation

Four low-alloy hull steels with different alloy elements were selected. Their susceptibility to pitting corrosion was compared by means of electrochemical polarization test. The inclusions in the steels and their pitting corrosion characteristics were studied by an electron probe micro-analyzer (EPMA). The results indicate that some inclusions are the main sources of pitting corrosion. The susceptibility of nickel-chromium steel to pit initiation is less than that of manganese steel. Under the same conditions, nickelchromium steel is easier to passivate than manganese steel, and the passive films on nickel-chromium steel surface are more stable than that on manganese steel. In low-alloy steels, the higher the contents of nickel and chromium, the lower the critical passive pH value. In the same kind of steel, multi-phase inclusions containing sulfide are easier to initiate pitting corrosion than other inclusions.     

Nb质量分数对Al⁃15Si⁃xNb涂层组织与耐蚀性能的影响

以Al?15Si?xNb涂层为研究对象,探究了Nb质量分数对涂层显微组织结构和耐蚀性能的影响规律。采用金相显微镜观察涂层的组织形貌,运用XRD分析涂层的物相组成,应用电化学实验方法（包括开路电位、阻抗谱、极化曲线）表征并讨论了涂层在质量分数为3.5%的NaCl溶液中的腐蚀行为。结果表明,Al?15Si?xNb涂层主要由α?Al、初生Si、共晶Si组成,在涂层中加入Nb元素后生成少量的NbAl₃相和Nb₅Si₃相;Nb元素的加入促进异质形核,较明显地改变涂层的组织分布;Al?15Si?10Nb涂层中的组织更细小且分布更均匀,均匀分布的α?Al、初生Si和共晶Si构成众多均匀分布的腐蚀微电池,促进α?Al阳极反应,使涂层表面生成的Al₂O₃氧化膜更加连续;Al?15Si?xNb涂层的极化曲线具有类钝化特征,其中Nb质量分数为10%时涂层的自腐蚀电位和点蚀电位较高,产物膜电阻较大,维钝电流密度较低,具有更好的耐腐蚀性能。     

Galvanic corrosion behavior of die cast AZ91D magnesium alloy in chloride solution

The galvanic corrosion behavior of die cast AZ91D magnesium alloy coupled with H62 brass, 316L stainless steel, A3steel and LY12 aluminum alloy of different areas in 3.5% NaC1 solution was studied. The free corrosion potentials, galvanic potentials and currents of these galvanic couples were measured. The galvanic effects were determined by the mass loss and regression method using three points. The results show that: (1) In these four kinds of couples AZ91D acts as the anode, whose galvanic corrosion behavior is mainly controlled by the cathodic polarization; (2) The free corrosion potentials of these four kinds of couples change a liffle with time and cathodic/anodic area ratio (CAAR); (3) The galvanic potential of AZ91D/LY12 moves positively with the increase of time and CAAR; (4) The galvanic currents increase with CAAR, but there is difference in the current change between different couples; (5) The anodic dissolution rate of the magnesium alloy increases by 2-3 orders after being coupled with these four kinds of metals and the galvanic effects of these couples have such a relation as γH62＞γ316LS.S＞γLY12 ＞γA3.