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.     

氯离子对2205双相不锈钢抗氢氟酸腐蚀性能的影响

采用浸泡失重、动电位极化和电化学阻抗等方法,研究了2205双相不锈钢在含有不同浓度氯化钠（NaCl）的氢氟酸（HF）介质中的腐蚀行为。结果表明,当HF溶液中加入浓度为0.015～0.030 mol/L的NaCl时,随着NaCl浓度的逐渐增加,2205双相不锈钢在该溶液中的腐蚀电位逐渐变负,自腐蚀电流密度逐渐增大,平均腐蚀速率逐渐升高。这主要是因为NaCl降低HF溶液的pH所致。     

Pitting corrosion of 316L stainless steel under low stress below yield strength

Pitting corrosion of 316L stainless steel(316L SS)under various stress was studied by potentiodynamic polarization,electrochemical impedance spectroscopy(EIS)and Mott-Schottky(M-S)analysis in 3.5% NaCl solution.The results of polarization curves show that,with the increase of the stress,the pitting potentials and the passive current density markedly decrease firstly(180 MPa),and then increase greatly(200 MPa).The corresponding surface morphologies of the samples after the polarization test well correspond to the results.Mott-Schottky analysis proved the least Cl-adsorbed to the surface of passive film with more positive flat potential,indicating that a moderate stress could increase the pitting corrosion resistance of 316L SS in 3.5% NaCl solution.     

中温SOFC复合阴极材料BSCN0.6-30%GDC的表征

通过固相反应法制备了钙钛矿氧化物Ba0.6Sr0.4Co0.9Nb0.1O3-δ(简称BSCN0.6),采用XRD对BSCN0.6与Gd0.1Ce0.9O1.95(简称GDC)电解质间的高温化学相容性进行表征。结果表明,BSCN0.6与GDC高温煅烧后存在微弱的固溶反应,但并未对阴极性能造成不利影响。将BSCN0.6与质量分数为30%的GDC复合(简称BSCN0.6-30%GDC)后作SOFC阴极,采用四电极法测电导、热膨胀测试等手段对复合阴极进行表征。结果表明,BSCN0.6与GDC复合降低了材料的电导率,同时也降低了材料的热膨胀系数,提高了阴极与GDC电解质间的热匹配性。以BSCN0.6-30%GDC复合材料作电极,700~800℃时对称电池BSCN0.6-30%GDC//GDC的极化阻抗为0.047~0.012Ω·cm2。因此,BSCN0.6-30%GDC复合材料有望作IT-SOFC的低极化阻抗的阴极材料。     

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.     

NaCl 溶液中回收AZ31 镁合金的腐蚀和电化学特性

利用熔炼工艺,将回收镁合金型材(RMA)进行了制备。在回收过程中,添加适量的Al、MnCl_2,最终得到合金AZ31,其中各元素质量分数如下:Al 3.31%、Zn 0.82%、Mn 0.27%、Fe 0.002%、Cu 0.004%、Ni 0.000 7%,剩余为Mg。研究了RMA的结构、在NaCl溶液中的腐蚀和电化学特性,并与商业化镁合金(CMA)进行了对比。X射线衍射仪和金相显微镜表明, RMA和CMA主要由镁基底组成,另外还有少量的Mg_(17)Al_(12)第二相。在NaCl溶液中进行的腐蚀试验和电化学特性研究表明, RMA抗腐蚀特性差于CMA,这可能与RMA中有更多的第二相有关。将两种合金作为镁电池原型器件的负极材料,进行放电性能测试。结果表明, RMA的放电时间和放电容量优于CMA。当NaCl电解质溶液浓度从0.6 mol/L增加至0.9 mol/L时,两种合金材料的放电时间和放电容量都得到了增加。     

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。     

Intergranular corrosion behavior of high nitrogen austenitic stainless steel

The intergranular corrosion (IGC) behavior of high nitrogen austenitic stainless steel(HNSS) sensitization treated at 650-950℃ was investigated by the double loop electrochemical potentiodynamic reactivation(DL-EPR) method.The effects of the electrolytes,scan rate,sensitizing temperature on the susceptibility to IGC of HNSS were examined. The results show that the addition of NaCl is an effective way to improve the formation of the cracking of a passive film in chromium-depleted zones during the reactivation scan. Decreasing the scan rate exhibits an obvious effect on the breakdown of the passive film. A solution with 2 mol/L H2_SO_4+1 mol/L NaCl+0.01 mol/L KSCN is suitable to check the susceptibility to IGC of HNSS at a sensitizing temperature of 650-950℃ at a suitable scan rate of 1.667 mV/s. Chromium depletion of HNSS is attributed to the precipitation of Cr_2N which results in the susceptibility to IGC. The synergistic effect of Mo and N is suggested to play an important role in stabilizing the passive film to prevent the attack of IGC.     

表面活性剂对镁合金基体上的非铬化镀镍涂层的腐蚀特性的作用

在镁合金AZ91D化学沉积了镍涂层,研究了非铬化预处理及表面活性物质对涂层腐蚀特性的影响。通过盐水试验(1mol/L HCl)和电化学极化试验(3.5%NaCl)检测了腐蚀性能。试验表明:化镀镍溶液中添加的表面活性剂可提高镁合金镍涂层上的抗腐蚀能力。此外,表面平整均匀的纳米和非晶相涂层提高了其抗腐蚀能力。极化试验表明,其腐蚀电位向正方转移,且腐蚀电流密度减低。浸泡试验和电化学极化试验都表明阳离子表面活化剂具有更好的提高抗腐蚀性能的作用。     

904L不锈钢在5g/L H_2SO_4溶液中的腐蚀行为

为了研究904L不锈钢在5 g/L H2SO4溶液中的腐蚀行为,采用动电位极化测试、电化学阻抗测试(EIS)和X射线光电子能谱(XPS)研究其腐蚀行为,并分析其钝化膜的组成.结果表明,904L不锈钢极化后会发生自钝化,钝化区间为-0.2~0.6 V,电荷传递电阻为4 801Ω/cm2,表明904L不锈钢具有较强的耐蚀性能.X射线光电子能谱(XPS)研究表明,钝化膜主要成分为Cr2O3、Cr OOH、Cr(OH)3等化合物.因而904L不锈钢在5 g/L H2SO4溶液中可以表现出良好的耐蚀性能.     

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.     

两种邻苯二胺类席夫碱缓蚀剂缓蚀性能研究

运用分子自组装技术在铜电极表面分别制备了双水杨醛缩邻苯二胺（简称A）和双邻香兰素缩邻苯二胺（简称B）两种席夫碱缓蚀膜。采用电化学方法研究了两种席夫碱自组装单分子层膜在质量分数3.5%的NaCl溶液中对铜的缓蚀行为。在25 ℃下,席夫碱A溶液浓度为10 mmol/L,组装时间为4 h时缓蚀效果最佳,席夫碱B溶液浓度为15 mmol/L,组装时间为6 h时缓蚀效果最佳,A、B的缓蚀效率分别达到94.06%和96.62%。结果表明,两种缓蚀剂对铜具有很好的缓蚀性能,且缓蚀效果B>A。     

生物医用T42NG铁合金腐蚀性能研究

对生物医用的T42NG经3Cr13不锈钢复合构成的T42NG钛合金"双金属材料",在常温常常压下3 5%的NaCl水溶液中,采用"三电极体系"实验装置运用恒电位法测定其阳极稳态极化曲线,对其电化学腐蚀行为进行了系统地研究。结果表明:经3Cr13不锈钢复合后的T42NG钛合金,其电极过程的阳极稳态极化曲线几乎只有纯化区和析氧区,不易发生腐蚀。     

带锈层NSB钢在模拟海水中的电化学腐蚀行为

采用极化曲线测试和电化学阻抗测试(EIS)方法研究带锈层NSB钢在3种温度(0,15,30℃)下、质量分数为3.5%的NaCl溶液(模拟海水)中全浸20 d后的电化学腐蚀特征,利用扫描电子显微镜观察试样腐蚀形貌,并对锈层的组成进行X射线衍射分析。结果表明:随着温度的升高,试样的腐蚀电流密度显著增加而电荷转移电阻降低;30℃全浸试样腐蚀锈层较0℃的疏松多孔,锈层对基体的保护作用减弱;全浸试样锈层由γ-FeOOH,α-FeOOH和Fe3O4三相组成,温度越高,锈层中具有良导电性的Fe3O4含量越高,导致试样耐蚀性下降。     

T6处理对真空压铸AM50镁合金腐蚀行为的影响

为了研究不同时效工艺对真空压铸AM50镁合金耐蚀性的影响,通过静态失重实验和电化学实验研究了T6处理后AM50镁合金在Na Cl溶液中的腐蚀行为.结果表明,合金经过170和230℃时效处理后腐蚀速率的变化情况基本类似,均为先降低后升高,最后达到一个稳定值.但经过230℃时效处理后合金的耐蚀性远差于经过170℃时效处理后的情况,且达到腐蚀速率最低点所需时间更长.不同时效处理后的合金具有相似的电化学腐蚀行为,腐蚀电位无明显变化规律,而腐蚀电流密度与腐蚀速率的变化趋势近乎一致.腐蚀速率随腐蚀时间的延长而下降,并最终保持一个较为稳定的数值.此外,合金腐蚀速率的理论值和实测值相吻合.     

黄原胶/AMPS/膨润土制备油田堵水剂的研究

通过水溶液法制备了一种黄原胶/2-丙烯酰胺基-2-甲基丙磺酸（AMPS）/膨润土三元复合型油田堵水剂,考察了2-丙烯酰胺基-2-甲基丙磺酸、膨润土、交联剂以及引发剂质量分数等因素对堵水剂吸水率的影响,测试了不同温度下堵水剂的吸水倍率和保水值,研究了堵水剂对不同质量分数NaCl溶液的吸水性能。结果表明,最佳的制备工艺：膨润土的质量分数为15%,AMPS的质量分数为3%,交联剂的的质量分数为2%,引发剂的质量分数为2.5%,在60℃的温度下反应4h,在最佳工艺下,环境温度20℃时,堵水剂的吸去离子水的倍率最高达到1 677g/g,吸质量分数0.9%NaCl溶液的倍率为165g/g;环境温度80℃的高温下仍保持着1 590g/g的吸水倍率,12h后仍能保水20%以上,具有良好的热稳定性和耐盐性。     

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.     

2A12铝合金电化学腐蚀行为研究

采取正交试验方法,利用极化曲线和电化学阻抗谱(EIS)等电化学方法研究了2A12铝合金在不同溶液浓度、pH值以及温度的NaCl溶液中的腐蚀行为。试验结果表明,溶液浓度、pH值以及温度对2A12铝合金在NaCl溶液中耐腐蚀行为的影响依次为：pH值、温度、溶液浓度。2A12铝合金的耐腐蚀性能随着NaCl溶液浓度的增加而变差;NaCl溶液温度越高,腐蚀电流密度Icorr越大,合金耐腐蚀性能下降;溶液中性条件下,合金耐腐蚀性能最强,碱性条件下耐腐蚀性能最差;酸性条件下腐蚀电流密度Icorr随pH值的降低而增大,合金耐腐蚀性能减弱。     

Air electrode supported manganese electrocatalysts for neutral electrolyte magnesium air cell

The catalysts of air electrode were prepared by sintering the active carbon loaded with manganese nitrate and potassium permanganate at 360 °C The air electrode was made up of a catalyst layer, a waterproof and gas-permeable layer, a current collecting substrate and a second waterproof and gas-permeable layer. The cell was assembled by the air electrode, pure magnesium anode and 10% NaCl solution used as electrolyte. The microstructures of air electrodes before and after discharging were characterized by SEM. The electrochemical behaviors of the air electrodes were determined by means of polarization curves, volt-ampere curves and constant current discharge curves. The polarization voltage of air electrode is—173 mV (vs SCE) at the current density of 50 mA/cm². The air electrodes exhibits good activity and stability in neutral electrolyte. The magnesium-air cell could work at 5 W for more than 7 h.     

Synergistic Corrosion Inhibition Effect of Molybdate and Phosphate Ions for Anodic Oxidation Film Formed on 2024 Aluminum Alloy

In order to effectively improve the corrosion resistance of aluminum alloys, anodic oxidation technique was used to generate the oxide film. We investigated the influences of two inorganic corrosion inhibitors(ammonium dihydrogen phosphate and sodium molybdate) on the corrosion resistance of anodic oxidation films on 2024 aluminum alloy, and studied the synergistic effect of two corrosion inhibitors. The corrosion resistance of anodic oxidation film in 3.5 wt% NaCl solution was evaluated by electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization curves. Results show that, after adding the single ammonium dihydrogen phosphate or sodium molybdate of 0.01 M to oxalic acid electrolyte, inhibition efficiencies of the anodized samples are 10% and 47%, respectively. However, in the presence of two inhibitors with the same concentration of 0.01 M, inhibition efficiency can be as high as 92%. Therefore, we observed the significantly synergistic corrosion inhibition effect of molybdate and phosphate ions for anodic oxidation film formed on 2024 aluminum alloy.