ATA及其与PASP复配在3.5%NaCl溶液中对碳钢的缓蚀作用

为寻找新的缓蚀荆来解决碳钢的腐蚀问题,采用极化曲线和交流阻抗方法,研究了3-氨基-1,2,4-三氮唑(ATA)及其与聚天冬氨酸(PASP)复配在3.5%NaCl溶液中对碳钢的缓蚀作用,并对比观察了碳钢在未加和加入复配缓蚀荆的3.5%NaCl溶液中浸泡后的腐蚀形貌.结果表明:ATA在3.5%NaCl溶液中对碳钢具有缓蚀作用,属阳极型缓蚀剂,其添加量以25 mg/L为最好,此时的缓蚀效果最佳,缓蚀率可达93.51%;ATA和PASP复配在3.5%NaCl溶液中对碳钢具有缓蚀协同作用,且15 mg/L ATA和10 mg/L PASP复配时的缓蚀协同作用最好,缓蚀率高达99.89%.     

钨酸钠与十二烷基苯磺酸钠协同缓蚀作用研究

为了研究钨酸钠和十二烷基苯磺酸钠的协同缓蚀作用,采用浸泡法、失重法和极化曲线法研究环境友好型缓蚀剂钨酸钠和十二烷基苯磺酸钠复配而成的复合缓蚀剂对铸铁在3.5%NaCl溶液中的缓蚀效果.研究发现,该复合缓蚀剂具有很好的协同缓蚀作用且当缓蚀剂总的质量分数为0.3%,两种缓蚀剂的质量比为2:1时其缓蚀效果最好.     

双子表面活性剂对铜在氯化钠溶液中的缓蚀作用

缓蚀剂是阻止或延缓换热设备、石油开采及其他领域金属发生腐蚀,保护机械设备安全运行的一种行之有效、经济效益显著的技术手段。文中选用了一种新型季铵盐类双子表面活性剂作为缓蚀剂,运用失重实验、电化学实验、量子化学计算等多种方法测试了所选化合物在3.5%NaCl溶液中对铜的缓蚀性能,从理论上探讨了缓蚀剂分子与金属表面的作用方式。失重、电化学实验结果表明,缓蚀剂对铜有较好的缓蚀效果和较高的缓蚀效率,在100mg·L~(-1)时对铜的缓蚀效率达到93.9%。通过吸附模型以及量子化学模拟证明缓蚀剂符合Langmuir吸附等温模型,缓蚀剂分子的吸附机理为化学吸附。     

铜经MBT和HQ钝化处理后在3.5%NaCl溶液中的电化学行为

采用循环伏安曲线、极化曲线和交流阻抗谱研究铜经2-巯基苯并噻唑(MBT)和8-羟基喹啉(HQ)钝化处理后在3.5%NaCl溶液中的电化学行为,利用扫描电镜观察铜经缓蚀溶液处理前后在3.5%NaCl盐水中的腐蚀形貌。结果表明,MBT或HQ在铜表面形成的络合物膜能明显改善铜在3.5%NaCl溶液中的耐蚀能力;经0.5 mmol/L MBT+0.5 mmol/L HQ复配溶液处理后,其缓蚀率达90.3%;缓蚀剂的缓蚀效果由大到小的顺序为:MBT+HQ,MBT,HQ,Blank。分析了MBT与HQ两者具有缓蚀协同作用的机理。     

四元复合型缓蚀剂在中性NaCl溶液中对碳钢的缓蚀作用

通过正交试验研制了一种具有良好缓蚀效果的四元复合缓蚀剂HZY03。采用动态失重法、电化学方法、腐蚀形貌表征等手段研究了此复配缓蚀剂对3.5%NaCl溶液中碳钢的缓蚀效果。结果表明:HZY03的缓蚀效果随着缓蚀剂量的增大而提高,最佳质量浓度为150mg/L,此条件下,其在低温(45℃)和高温(80℃)试验溶液中对碳钢的缓蚀率分别为91.96%和91.02%。HZY03是一种阳极型缓蚀剂,可有效抑制金属在3.5%NaCl溶液中的腐蚀。     

低合金钢在添加缓蚀剂的NaCl溶液中的腐蚀行为

研究分别添加少量(1%)缓蚀剂乌洛托品、磷酸钠、硫脲时在3.5%NaCl溶液中对低合金钢的缓蚀作用。运用线性极化技术测定比较上述三种缓蚀剂的缓蚀效果,且用交流阻抗法测得的结果与线性极化的一致。通过Tafel曲线对缓蚀剂的缓蚀机理进行了初步探讨。研究结果表明缓蚀效果:磷酸钠>硫脲>乌洛托品。缓蚀剂的作用是在金属表面成膜,改变了金属表面状态,从而抑制金属的腐蚀。     

文摘辑要

AZ91D镁合金用复合缓蚀剂缓蚀行为的研究采用腐蚀试验、电化学极化曲线和交流阻抗谱对自主研发的用于抑制镁合金在3.5%NaCl中腐蚀的有机-无机复合缓蚀剂的缓蚀性能和缓蚀机理进行了研究。实验结果表明,在3.5%NaCl溶液中添加复合缓蚀剂的质量分数为3%时,其缓蚀效果最好,缓蚀效率高达91%,此时AZ91D镁合金的静态腐蚀速度小于20.06g/(m·h);复合缓蚀剂同时抑制了镁合金腐蚀的阴极和阳极过     

镧盐型缓蚀剂对Cu-Zn-Ni铜合金在3.5% NaCl溶液中的缓蚀作用

利用硝酸滴定试验、失重试验、动电位极化方法以及电化学阻抗谱技术,研究了Cu-Zn-Ni铜合金稀土镧盐型缓蚀剂,在3.5%NaCl溶液中的缓蚀作用。结果表明,协同型缓蚀剂BTA(苯并三氮唑)+TTA(甲基苯并三氮唑)和BTA+LaCl3能够很好地提高该铜合金在3.5%NaCl溶液中的耐腐蚀性能。当缓蚀剂中同时含有BTA、TTA、LaCl3(BTA:3g.L-1,TTA:14g.L-1,LaCl3:7g.L-1)时所表现出来的缓蚀效率最高。Cu-Zn-Ni合金经BTA+TTA+LaCl3缓蚀剂处理后,在NaCl溶液中室温下的腐蚀速率为2μm/a。     

苦丁茶提取物对N80钢的缓蚀作用

采用傅里叶变换红外光谱、气相色谱-质谱、电化学阻抗谱、极化曲线和扫描电子显微镜研究了苦丁茶(KDC)提取物在含3.5%NaCl(质量分数)和饱和CO_2溶液中对N80钢的缓蚀作用。结果表明:苦丁茶提取物属于混合型缓蚀剂;该缓蚀剂对N80钢在含3.5%NaCl和饱和CO_2溶液中具有一定的缓蚀作用,能够有效抑制N80钢的腐蚀;缓蚀率随着缓蚀剂含量的增大而提高,当加入4%(体积分数)苦丁茶缓蚀剂时,根据极化曲线和电化学阻抗谱计算得到的缓蚀率分别达到了92.47%和96.90%。     

光电化学方法现场监测模拟海水中铜腐蚀及缓蚀剂PTD的缓蚀行为

采用光电化学方法现场测量铜电极的开路光电压,研究铜在模拟海水3%NaCl溶液中的腐蚀行为及缓蚀剂PTD对铜的缓蚀行为.实验发现,在3%NaCl溶液中铜电极随浸泡时间的延长其开路光电压由正变负即光响应由p型光响应转变为n型光响应,这表明铜表面受到Cl-的严重侵蚀.加入缓蚀剂PTD后,当PTD的浓度小于6×10-5%时,铜电极的光响应转型时间较不加PTD时提前.当PTD的浓度大于6×10-5%时,铜电极的光响应不存在转型情况,表明PTD产生了良好的缓蚀作用.在本文条件下,PTD产生缓蚀作用的最佳浓度为1×10     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。