316L不锈钢在硫酸盐还原菌与铁氧化菌溶液中的腐蚀及电化学行为

1 INTRODUCTION Type 316L stainless steel has good corrosion re- sistance and has been used increasingly for cooling water service in the chemical, petrochemical and power utility industries. However stainless steel is susceptible to localized corrosion by chloride ions and reduced sulfur compounds[1]. The presence of micro- organisms on a metal surface often leads to highly localized damages in the concentration of the electro- lyte constituents, pH and oxygen levels[2]. These mi- croorg…     

应变和氯离子浓度对304不锈钢点蚀敏感性的影响

The effects of strain and chloride concentration on pitting susceptibility for type 304 stainless steel were studied in situ using the electrochemical technology under constant strain. The impact factor fc was brought forward to value the effect of strain on pitting. The pitting behaviors of type 304 stainless steel in various chloride concentrations under the strain levels 0%, 10%, and 30% were investigated. Potentiostatic polarization technology was used to study how the chloride concentration affected corrosion current density. The results indicated that fc increased substantially and pitting potential varied remarkably when chloride concentration was over 90 mg.L . Under the three levels of strain mentioned above, when chloride concentration was below 463 mg.L^-1,121 mg.L^-1, and 98 mg.L^-1 respectively, the pitting potential shifted towards positivity and, the passive film became more stable. When the strain was below 10%, the pitting susceptibility of type 304 stainless steel varied greatly as strain increased, whereas the susceptibility only changed a little when the strain was over 10%.     

PE膜表面接枝间苯二酚

Low density polyethylene film surface-grafted process. Firstly, acrylic acid was grafted to the surface grafting. Secondly, the carboxylic groups in poly （acrylic resorcinol was prepared by a sequential of low density polyethylene by UV photoacid） chains were transferred to acyl chloride groups by the reaction of carboxylic groups with thionyl chloride. The stability of acyl chloride groups in several solvents （alcohol, water, acetone, aqueous NaOH and in N2 atmosphere） was investigated, and N2 atmosphere and acetone were appropriate media to protect acyl chloride groups from side reaction. Finally, resorcinol monomer reacted with acyl chloride to append to the poly（acrylic acid） chains at room temperature. FT-IR ATR was used to characterize the change of carbonyl groups during each step of the grafting process. Furthermore, by the experimental data of gravimetric analysis the grafted resorcinol monomer on the surface of low density polyethylene film was verified to have undergone condensation with acetone further in the resorcinol/acetone solution at 56℃, which might be a useful feature for synthesizing a thermoplastic/thermosetting composition.     

在NaOH-烯丙基氯-DMSO体系中合成烯丙基蔗糖的新方法

Allylsucrose has been prepared by reaction of sucrose with allyl chloride in the NaOH-DMSO system. DS^↑- （average degree of substitution） of allylsucrose calculated by elemental analysis was 6.7, and the efficiency of allyl chloride was 83.7%. The mechanism of the reaction was based on the acceleration of base-catalyzed reactions in dipolar aprotic solvents. The novel method is facile and suitable for large-scale preparation.     

利用市售不锈钢箔制备氮化硼纳米线

Chemical vapor deposition growth of one-dimensional nanomaterials usually demands substrates that have been coated with a layer of catalyst film. In this study, a green process to synthesize boron nitfide （BN） nanowires directly on commercial stainless steel foils was proposed by heating boron and zinc oxide powders under a mixture gas flow of N2 arid 15% H2 at 1100℃, and a large quantities of pure h-BN nanowires have been produced directly on commercial stainless steel foil. The stainless steel foils not only acted as the substrate but also the catalyst for the nanowire growth. The synthesized BN nanowires were characterized by X-ray diffraction, scanning and transmission electron microscopes, X-ray energy dispersive spectrometer and photoluminescence spectroscopy, The nanowires also possess strong PL emission bands at 515, 535, and 728 nm.     

Influence of Deformation-Induced Martensite on Stress Corrosion Cracking of AISI 321 Stainless Steel

Specimens of AISI 321 stainless steel(0Cr18Ni9Ti)of various martensite contents were prepared bythe low temperature(-70℃)elongation method.X-ray diffraction(XRD)and transmission electron micrograph(TEM)techniques were used to study the phase transition process and its structure.The relationshio betweendeformation-induced martensite and stress corrosion cracking(SCC)susceptibility of the steel in 42%(boiling)MgCl_2 solution was investigated using the constant load SCC test with the normalized threshold values.The re-sults reveal that when the α'-martensite content is less than 5% and also in the range of 15%-24%,the SCCsusceptibility of this material decreases with the increase of α'-martensite content.However when the α' martenstiecontent is in the rang of 5%-15% and more than 24%,the SCC susceptibillty of this material increases withthe increase of the α'-martensite content.The SCC fracture surface of the specimens exhibits a stepped fracturesurface and transgranular stress corrosion fracture surf     

利用DMO-M离子交换树脂除去稀溶液中的汞

A mercaptan-containing resin, DMO-M, with high redox capacity- 6.00 mequiv/g, prepared by reacting mercaptoacetyl chloride with the aminophenol resin Duolite A-7 in free-base form has been used to remove mercury in dilute aqueous solution. The resin has high mercury removal capacity; 1200mg/g. Sodium chloride affects the equilibrium sorption of mercury on the resin. At lower pH values, below 1.76, mercury sorption of the resin was greatly reduced. The sorbed mercury is partially removed by 2 mol/L HCl solution containing 5% thiourea.     

Vacuum pressure swing adsorption process for coalbed methane enrichment

The enrichment of low concentration coalbed methane using adsorption process with activated carbon adsorbent was studied in this work.Adsorption isotherms of methane,nitrogen and carbon dioxide on activated carbon were measured by volumetric method,meanwhile a series of breakthrough tests with single component,binary components and three components feed mixture has been performed for exploring dynamic adsorption behaviors.Moreover,a rigorous mathematical model of adsorption bed containing mass,energy,and momentum conservation equation as well as dual-site Langmuir model with the Linear driving force model for gas-solid phase mass transfer has been proposed for numerical modeling and simulation of fixed bed breakthrough process and vacuum pressure swing adsorption process.Furthermore,the lumped mass transfer coefficient of methane,nitrogen and carbon dioxide on activated carbon adsorbent has been determined to be 0.3 s~(-1),1.0 s~(-1) and 0.06 s~(-1) by fitting the breakthrough curves using numerical calculation.Additionally,a six bed VPSA process with twelve step cycle sequence has been proposed and investigated for low concentration coalbed methane enrichment.Results demonstrated that the methane molar fraction in feed mixture ranged from 10% to 50% could be enriched to 32.15% to 88.75% methane in heavy product gas with a methane recovery higher than 83%under the adsorption pressure of 3 bar(1 bar=10~5 Pa) and desorption pressure of 0.1 bar.Energy consumption of this VPSA process was varied from 0.165 kW·h·m~(-3) CH_4 to 0.649 kW·h·m~(-3) CH_4.Finally,a dual-stage VPSA process has been successfully developed to upgrade a low concentration coalbed methane containing 20% methane to a target product gas with methane purity higher than 90%,meanwhile the total methane recovery was up to 98.71% with a total energy consumption of 0.504 kW·h·m~(-3) CH_4.     

明胶涂覆于亲水化改性的支撑层上以提高复合膜的结构稳定性和渗透蒸发性能简

The interfacial compatibility of composite membrane is an important factor to its structural stability, andseparation performance. In this study, poly （ether sulfone） （PES） support layer was first hydrophilically modified with poly（vinyl alcohol） （PVA） via surface segregation during the phase inversion process. Gelatin （GE） was then cast on the PVA-modified PES support layer as the active layer followed by crosslinking to fabricate composite membranes for ethanol dehydration. The enrichment of PVA on the surface of support layer improved interfacial compatibility of the as-prepared GE/PVA-PES composite membrane. The water contact angle measurement and X-ray photoelectron spectroscopy （XPS） data confirmed the surface segregation of PVA with a surface coverage density of -80%. T-peel test showed that the maxima/force to separate the support layer and the active layer was enhanced by 3 times compared with the GE/PES membrane. The effects of PVA content in the support layer, crosslinking of GE active layer and operating parameters on the pervaporative dehydration performance were investigated. The operational stability of the composite membrane was tested by immersing the membrane in ethanol aqueous solution for a period of time. Stable pervaporation performance for dehydration of 90% ethanol solution was obtained for GE/PVA-PES membrane with a separation factor of -60 and a permeation flux of -1910 g.m^-2.h1 without peeling over 28 days immersion.     

低温水相一步合成钛酸钡:热力学模型化及实验合成研究

A thermodynamic model has been developed to determine the reaction conditions favoring low temperature direct synthesis of barium titanate (BaTiO3). The method utilizes standard-state thermodynamic data for solid and aqueous species and a Debye-Hǔckel coefficients model to represent solution nonideality. The method has been used to generate phase stability diagrams that indicate the ranges of pH and reagent concentrations, for which various species predominate in the system at a given temperature. Also, yield diagrams have been constructed that indicate the concentration, pH and temperature conditions for which different yields of crystalline BaTiO3 can be obtained. The stability and yield diagrams have been used to predict the optimum synthesis conditions (e.g.,reagent concentrations, pH and temperature). Subsequently, these predictions have been experimentally verified.As a result, phase-pure perovskite BaTiO3 has been obtained at temperature ranging from 55 to 85℃ using BaCl2,TiCl4 as a source for Ba and Ti. and NaOH as a orecioitator.     

304不锈钢应力腐蚀的临界氯离子浓度

通过慢拉伸实验得出了304不锈钢应力腐蚀敏感性与溶液中Cl-浓度的关系,用扫描电镜对拉伸试样的断口形貌进行了分析,得出了304不锈钢发生应力腐蚀的临界氯离子浓度。采用自行设计的装置对304不锈钢试样施加拉应力,通过恒应变条件下的电化学原位测试研究了304不锈钢钝化膜破裂电位与氯离子浓度的关系。得出导致钝化膜破裂电位突变的Cl-浓度与发生应力腐蚀破裂的临界Cl-浓度是基本一致的结论。     

循环水中304不锈钢发生点蚀的Cl~-浓度阈值研究

采用电化学法研究了循环水中304不锈钢点蚀电位(Eb)、蚀孔深度、蚀孔数量与氯离子浓度的关系。结果表明,常温下304不锈钢的Eb总是随着氯离子浓度的增大而减小,当氯离子质量浓度小于800 mg/L时,增大氯离子浓度易导致点蚀敏感,而大于该值时增大氯离子浓度不会明显增大点蚀倾向;从蚀孔深度和表面蚀孔数量得出的304不锈钢点蚀倾向由大变小的氯离子质量浓度阈值为770 mg/L。     

土酸溶液中苯扎氯铵对不锈钢的缓蚀作用及吸附热力学研究

为了研究土酸介质中烷基季铵盐类阳离子表面活性剂对不锈钢的缓蚀及吸附作用,采用静态失重法在不同温度的10%土酸溶液中苯扎氯铵对304#不锈钢的缓蚀作用,应用吸附理论和Sek ine方法对静态挂片试验数据进行处理。结果表明,苯扎氯铵在不锈钢表面的定向吸附是产生缓蚀的主要原因,当其含量达到一定浓度后,缓蚀作用基本保持不变;在浓度为0~0.2%时,其在不锈钢表面的吸附服从Langmu ir吸附等温式,相关系数大于0.99;缓蚀率随浓度的增加和温度的升高而增大,是由吸附过程中表现为总熵增加的特点决定的;获得了吸附过程ΔHo、ΔSo和ΔGo等重要热力学参数。     

Investigations of the passive layer cracking by means of Dynamic Electrochemical Impedance Spectroscopy

The Dynamic Electrochemical Impedance Spectroscopy has been applied for stress corrosion cracking (SCC) investigations. The effect of applied potential and tensile stresses on the stress corrosion cracking behaviour of type 304L stainless steel (SS) immersed in 0.5 M NaCl solution of room temperature has been examined. This paper presents impedance spectra obtained for 304L stainless steel samples at the different potential values. The results obtained proved the possibility of providing new details about the dynamics of the initiation and propagation of the crack path compared to classical electrochemical techniques.     

氯离子对催化裂化分馏塔顶冷却系统腐蚀的研究

针对延安炼油厂年产量200万t催化裂化装置分馏塔顶空冷器内侧腐蚀问题,进行现场取样检测,配制模拟溶液,研究氯离子单一因素的变化对腐蚀结果的影响,选用了空冷管束常用的10钢、20钢和304不锈钢三种材料进行腐蚀试验。通过对试验的极化曲线和电化学阻抗的分析,得到氯离子对10#钢和20#钢的腐蚀机理相同;三种材料都会随着氯离子的加入,出现局部腐蚀点蚀,且随着氯离子浓度的增大都有腐蚀加剧的趋势;304钢随着氯离子浓度的变大,点蚀电位下降不明显,钝化膜变的不稳定。综合对比,304钢抗腐蚀性表现优于10#钢,10#钢优于20#钢,但10#钢对于氯离子变化更敏感。     

Pitting of AISI 304 stainless steel in bicarbonate and chloride solutions

Metastable and stable pitting on 304 stainless steel (SS304) in 0.1–0.5 m NaCl aqueous solution (pH ~8) has been investigated using a potentiodynamic, a potentiostatic and a weak anodic current galvanostatic techniques. The addition of bicarbonate (0.025–0.5 m) to the solution had an inhibiting effect, manifested by a shift of the pitting potentials to more positive values, a longer induction time for pitting and reduced pit nucleation. The pit nucleation frequency and growth, in the metastable and stable states, decrease as the NaHCO3/NaCl molar concentration increases and pitting is no longer observed for NaHCO3/NaCl molar ratios higher than 3 (four times larger % wt of NaHCO3). Pitting events never occurred at a potential below –0.1 V, fewer metastable events were observed at higher temperature (50°C) and none were observed in chloride free bicarbonate solutions. The inhibiting behaviour of oxyanions is discussed.     

Corrosion behaviour of innovative stainless steels in mortar

The main problem of the building sector is the limited durability of reinforcing concrete structures under highly aggressive environments due to the corrosion of reinforcements. In order to demonstrate that stainless steels are the adequate solution to avoid corrosion of reinforced concrete structures by contained chlorides, the corrosion behaviour of AISI 304 and AISI 316L stainless steels in mortar with two chloride doses is compared with the corrosion behaviour of three new stainless steels of low Ni content and reduced cost, and with the traditional carbon steel. The lowest chloride contamination (2% Cl⁻) has been used in this research to provoke corrosion in an active state of reinforcing carbon steel, whereas the highest one (5% Cl⁻) exceeds all expected levels found in the natural environment, including sea water. The new stainless steels remain in the passive state in mortar specimens with both chloride contents.     

Investigation of 304L stainless steel in a NaCl solution using a microcapillary electrochemical droplet cell: Comparison with conventional electrochemical techniques

In this work a comparison has been made between a localized (micro scale) and a conventional (large-scale) corrosion study of 304L stainless steel in a sodium chloride solution using Tafel plots and electrochemical impedance spectra. Results show the high ability of microelectrochemical techniques for the local investigation of corrosion procedures on solid surfaces, something which is not feasible with conventional large-scale techniques. In the second experiment the microelectrochemical behavior of a faulty copper layer on 304L stainless steel was investigated using linear sweep voltammetry. Glass capillaries touching only small areas of the surface were used and the copper coated surface of the steel sample was scanned in a 9 by 6 matrix (54 measurements) while acquiring data. The obtained corrosion potentials for both defect and intact areas were used to map the surface. The surface plot shows the exact position of the defect point in the coating layer.     

The tribocorrosion behaviour of YSZ coating deposited on stainless steel substrate in 3.5 wt% NaCl solution

The YSZ coating was applied to 304 stainless steel substrate by atmospheric plasma spraying technology, and its electrochemical and tribological properties in 3.5 wt% NaCl solution were studied. In electrochemistry, under the action of cathode and anode potential, observe the changes of corrosion current density and EIS before and after wear. The results show that the YSZ coating has a very low corrosion current density during wear and corrosion compared to 304 stainless steel, and after the condition of the anode potential is applied, the effect of friction on the electrochemical impedance of the YSZ coating is very low, while the 304 stainless steel Impedance performance decreases; In terms of tribology, the friction coefficient of 304 stainless steel in 3.5 wt% NaCl solution is easily affected by potential, and the friction coefficient of YSZ coating relative to 304 stainless steel only changes under high potential. As the potential increases, the material volume loss of 304 stainless steel and YSZ coating increases linearly. From the data, the volume loss caused by the corrosion and wear of 304 stainless steel is much higher than that of YSZ coating.