Effect of Chloride on Semiconducting Properties of Passive Films Formed on Supermartensitic Stainless Steel in NaHCO3 Solution

 The effects of chloride ion on the electrochemical behavior and the semiconducting properties of the passive film on supermartensitic stainless steel in 0. 5 mol/L NaHCO3 solution were investigated using potentiodynamic polarization, the potentiostatic current transients and Mott-Schottky analysis. The results indicated that chloride ion narrowed passivation region and improved pitting susceptibility. The steady state current densities were independent of film-formed potentials, which was in good agreement with the assumption of the point defect model (PDM). The capacitance results showed the fact that the passive films had a multilayer character. The defect density decreased with increasing passive film formation potential. The chloride ion induced changes of the acceptor densities and donor densities of the passive films.     

固溶处理温度对耐蚀马氏体时效钢力学性能的影响

 研究了固溶处理温度对耐蚀马氏体时效钢力学性能的影响。研究结果表明,800℃固溶处理后的组织遗传了锻态的晶粒形态、尺寸及高密度缺陷,使固溶处理后的马氏体也具有高的缺陷密度,并增加了组织中残余/逆转变奥氏体的含量,从而使材料具有较高的强韧性。较高温度固溶处理奥氏体发生回复和再结晶,其缺陷密度的降低使最终马氏体时效强化效应下降,而且残余/逆转变奥氏体量也下降,从而使材料的韧性水平下降。该试验钢固溶处理温度低于传统的马氏体时效不锈钢的固溶处理温度。     

硫酸浓度对多孔氧化铝膜的影响

在H2SO4电解液中对高纯铝箔进行阳极氧化,考察分析了电解液浓度对多孔阳极氧化铝膜的影响,结果表明:随硫酸电解液浓度的增加,纳米孔孔径逐渐增大,孔密度降低,孔的有序性先提高后降低;采用23 V直流电压进行阳极氧化,电解液浓度为0.6~1.0 mol/L时制得的氧化铝膜孔径均匀性及有序度均较好,尤其以0.8 mol/L H2SO4最佳;阳极氧化铝膜的厚度随电解液浓度的提高而增大;电解液浓度过高易于将铝箔快速击穿。     

硫酸厂浓酸泄漏事故原因分析及应急处理方法

在对硫酸中金属腐蚀机理分析的基础上,探讨了硫酸厂浓酸区域各种泄漏情况产生的原因,并且针对不同的泄漏情况,提供了相应的应急处理方法。     

烧结自制硫酸与工业硫酸酸洗不锈钢效果评定

以太钢产量较大的铁素体不锈钢430为试验原料,在实验室模拟现场酸洗工艺条件,采用烧结自制硫酸和现场用工业硫酸分别进行酸洗试验,对其性能进行了对比.试验表明,采用烧结自制硫酸酸洗喷丸后的430不锈钢比工业硫酸速率较慢,且试样颜色较白亮,但扫描电镜观察两种酸酸洗后试样的腐蚀形貌没有明显差异.     

氢对不锈钢钝化膜纳米力学性能的影响

利用电化学实验方法和纳米力学探针技术,通过测量载荷-位移关系曲线,研究了氢对不锈钢钝化膜纳米力学性能的影响。结果表明:随氢含量的增加,不锈钢钝化膜的临界破裂载荷降低,位移偏移量减小,氢导致钝化膜的径向抗拉强度(应力)和弹性模量降低,钝化膜随氢含量的增加而逐渐软化。

     

Corrosion Resistance and Semiconducting Properties of Passive Films Formed on 00Cr13Ni5Mo2 Supermartensitic Stainless Steel in Cl- Environment

The semiconducting properties of passive films grown on 00Crl3Ni5Mo2 supermartensitic stainless steel were investigated in comparison with conventional 2Cr13 martensitic stainless steel. Cyclic vohammetry and electro- chemical impedance spectroscopy （EIS） were used for the studies. 00Crl3NiSMo2 steel exhibited a good corrosion resistance performance, attributing to its passive capability. The results of Mott-Schottky analysis demonstrated n- type semiconductors for the passive films with doping densities of about 1020- 1021 cm -3, and the thickness of space- charge layers was also calculated. The experimental results confirmed that Mo plays an important role in improving the corrosion resistance of 00Crl3Ni5Mo2 steel due to its impact on the doping density.     

The Effect of Second Tempering on Hydrogen Embrittlement of Ultra-High-Strength Steel

The objective of the present study is to enhance the resistance of hydrogen embrittlement (HE) via second tempering at 250 °C for 30, 60 and 120 minutes. Although second tempering results in a higher saturated hydrogen content for the second tempering specimens during a slow strain rate test (SSRT), it effectively reduces HE susceptibility. As the second tempering time increases, dislocation density decreases. In contrast, the size of the cementite and Mo_yC_x precipitates increase slightly. The density of Mo_yC_x precipitates increases, whereas the density of cementite remains approximately the same as the second tempering time increases. Regarding second tempering specimens, the volume fraction’s increase in Mo_yC_x precipitates, which acts as a hydrogen trap with high binding energy, plays an important role in reducing the HE susceptibility, and the decrease in dislocation density can also improve HE resistance. In addition, the growth of the interface of the cementite and matrix disperses more hydrogen, which could enhance HE resistance. The result also reveals that the cementite and matrix interface is a type of low-binding-energy hydrogen trap without plastic deformation, whereas the strain interface with interfacial dislocations is a type of high binding energy hydrogen trap under plastic deformation.

     

Characterization of Passive Film Formed on AISI 316L Stainless Steel after Magnetoelectropolishing in a Broad Range of Polarization Parameters

The aim of the paper is to present the changes in the surface film composition on AISI 316L stainless steel (SS) after electropolishing (EP) and magnetoelectropolishing (MEP) in a broad range of the process conditions. The X‐ray photoelectron spectroscopy surface analyses were performed to reveal the effect of MEP. The EP process has been performed under natural convection (in a stagnant electrolyte), much above the polarization plateau. A series of experiments were carried out on AISI 316L SS samples in accordance with the five‐level composite rotary statistical plan with the variables being the magnetic field intensity B (mT), and the anodic current density i (A dm^?2). XP high resolution spectra have been obtained on AISI 316L SS surface concerning Fe 2p, Cr 2p, O 1s, S 2p, P 2p, and C 1s, respectively. The Cr:Fe ratio regarding both metallic M and compound X was also studied and calculated. At the end, the summary results of Cr/Fe = f(B, i) in relation to the corrosion potential, have been compared. The conclusions, concerning the selection of MEP process conditions, regarding the optimum Cr/Fe ratio and corrosion behavior, have been formulated. It was found the Cr:Fe ratio well correlates with the pitting corrosion potential. MEP process can modify not only the rate of dissolution to a determined extent, but also control the corrosion behavior and Cr:Fe ratio results.     

含钛硫酸浸出液的水解研究

制备了含钛硫酸浸出液,并通过单因素和正交试验考查了水解时间、水解温度和钛液浓度对水解率的影响。结果表明,影响二氧化钛水解率因素的主次顺序为:水解温度、钛液浓度和水解时间。较佳水解条件为:水解温度95℃、钛液浓度110g/L,水解时间210min,此时,水解率为97.12%,能满足工业生产要求。     

固溶温度对00Cr22Ni5Mo3N钢组织及耐点蚀性能的影响

 研究了固溶温度对00Cr22Ni5Mo3N钢相比例及耐点蚀性能的影响。结果表明,在1 000~1 300 ℃,随着固溶温度的提高,00Cr22Ni5Mo3N钢组织中的铁素体含量逐渐增加,钢的耐点蚀性能呈曲线变化。本试验条件下,在1 000~1 150 ℃固溶处理时,该钢具有较好的耐点蚀性能,这与其化学成分、相析出、相比例及化学元素在两相中的分配比有直接的关系。     

Ti35合金在沸腾硝酸中钝化膜及过渡层形成及组成分析

研究了Ti35合金在8 mol/L沸腾浓硝酸中腐蚀240 h后表面钝化膜及过渡层的相结构。采用扫描电子显微镜(SEM)、原子力显微镜(AFM)、X射线衍射(XRD)和X射线光电子能谱(XPS)对Ti35合金腐蚀后样品的钝化膜和过渡层形貌、相结构等进行分析。研究结果表明,Ta原子优先与硝酸反应,钝化膜最终产物Ti O2和Ta2O5是通过逐步的化学反应形成的,Ta元素的加入能有效改善钛合金的耐硝酸腐蚀性能。     

硫酸与氢氟酸混合溶液中白云母溶解行为

通过白云母在硫酸与氢氟酸混合溶液中的溶解试验,研究白云母中Al、Si及K的溶出行为,采用FTIR、XRD、SEM等手段考察白云母溶解过程中晶体结构变化规律。结果表明,与单一硫酸溶液体系相比,加入4%氢氟酸后,Al、Si和K的溶出率分别提高了23.12、44.51和11.00个百分点,说明氢氟酸有效破坏白云母晶体结构中Al-O八面体和Si-O四面体。随溶解时间延长,-OH、Si(AlIV)-O(Al)、Si-O-Si(AlIV)逐渐破坏,破坏晶面主要是(002)、(004)和(131)。     

硫磷混酸体系中钒的萃取实验研究

以某高磷钒矿直接活化硫酸浸出并经预净化的溶液作为研究对象,用N263进行萃取反萃后经过直接沉钒,制得V2O5产品.实验主要研究了水相平衡pH、萃取剂浓度、添加剂浓度、相比、逆流萃取及反萃级数对硫磷混酸体系中钒萃取率的影响.实验确定了N263最佳萃取工艺条件:有机相浓度取15%N263-5%仲辛醇-磺化煤油,O/A=1:3,常温振荡10 min,常温静置10 min,萃取平衡pH=2,经5级逆流萃取,钒的萃取率可达99.51%;最佳反萃工艺条件:反萃剂浓度取1 mol·L-1 NH4 OH4 mol·L-1 NaCl,O/A=3:1,常温振荡10 min,常温静置10 min,反萃平衡pH=8.5,经4级逆流反萃,钒的反萃率可达99.58%;经直接沉钒所得V2O5产品质量达到99.54%,符合GB3283-87V2O598质量要求.     

从石煤提钒酸浸液中萃取分离硫酸

采用萃取法从石煤高酸浸出液中优先萃取分离硫酸,考查还原剂用量、萃取剂浓度、萃取温度、萃取时间对硫酸萃取率的影响。结果表明,在还原剂亚硫酸钠用量2g/L、萃取剂三异辛胺浓度40%、萃取温度25℃、萃取时间2min、相比O/A=1/1的条件下,经4级萃取,浸出液中硫酸浓度由110g/L降低至5.25g/L,浸出液pH升高至2.3,可直接用于萃取钒。以60℃热水为反萃剂、O/A=1/3条件下,经5级反萃,99%以上的硫酸可被反萃出来。萃取过程无其它药剂消耗,有机相可循环使用,且回收的硫酸可再利用。     

固溶处理温度对D667钢性能的影响

研究了固溶温度对D667钢性能的影响。结果表明,D667钢固溶温度在1000℃以下时,其延伸率有所提高,但抗拉强度没有明显下降;固溶温度在1000℃～1060℃范围内,试验钢的抗拉强度呈下降趋势,延伸率也保持在高水平线上;固溶温度在1060℃以上,抗拉强度加速下降。D667钢固溶温度在1000℃～1060℃范围内时,可以获得较好的强度和韧性,满足技术要求和各项使用要求。     

6xxx系铝合金硫酸阳极氧化膜绝缘性研究

采用不同合金,通过控制电流密度以及改进封闭剂等方式,获得绝缘性能优异的阳极氧化膜,并使用金相显微镜、扫描电镜进行微观表征。试验结果表明,在相同铝合金的前提下,氧化电流密度控制在1.5A/dm 2~1.8A/dm^2,膜厚等级AA15,使用ZW1封闭剂可获得绝缘性能优异的阳极氧化膜。     

湿法冶金酸性溶液中游离硫酸测定方法的改进

针对测定含有Cu^2 、Fe^3 、Zn^2 、Co^2 等金属离子溶液中游离硫酸的影响因素，试验了用亚铁氰化钾沉淀分离干扰金属离子，消除其对游离硫酸测定的影响。试验取得了满意的结果，并拟定出了可靠的酸性溶液中游离硫酸测定方法。     

冶金工业废液中硫酸的回收

冶金工业产生大量的酸性废液,其中的无机酸和有价金属有很高的回收价值.综述了酸性废液中硫酸的回收方法,着重介绍了溶剂萃取法、离子交换法和膜分离回收硫酸的工艺原理、研究进展与应用现状,对比讨论了上述几种工艺的优势与不足之处.溶剂萃取和离子交换法反应速度快;膜分离回收硫酸的重点在于高性能膜的研发.     

不锈钢在贵冶烟气制酸中的应用

总结了贵溪冶炼厂烟气制酸工艺的发展及技术进步情况,并介绍了硫酸的腐蚀特性以及各类不锈钢材料在贵溪冶炼厂烟气制酸工艺中的应用情况。