柚子皮提取物对C38的缓蚀作用

目的研究柚子皮提取物对C38钢在1 mol/L HCl中的缓蚀作用。方法通过索氏提取器从柚子皮中提取天然绿色缓蚀剂,进而与0.01 mol/L KI进行复配,采用失重法和电化学测试法分析柚子皮提取物的缓蚀作用机理。结果失重实验表明,柚子皮提取物对C38钢的缓蚀作用最高达93%,而与0.01mol/L KI复配使用后缓蚀效率最高达98%以上。同时表明其在碳钢表面的吸附符合Langmuir吸附等温式;Tafel极化曲线表明其能同时抑制碳钢腐蚀的阴、阳极过程;碳钢的阻抗值随着柚子皮提取物浓度的增加而增大。结论柚子皮提取物是很好的缓蚀剂,与卤素离子复配后效果更佳。     

豆粕提取物在盐酸中对Q235钢的缓蚀性能

采用失重法、极化曲线、电化学阻抗谱、扫描电子显微镜等方法研究了豆粕提取物(SME)作为植物缓蚀剂对Q235钢的缓蚀性能。结果表明,缓蚀剂在25～90℃范围内,随着温度升高,缓蚀效率先升高后降低。在温度为40℃,缓蚀剂浓度为0.8 g/L时,缓蚀效率达到92%。缓蚀剂对阳极和阴极都有抑制作用,属于混合型缓蚀剂。缓蚀剂分子在Q235钢表面的吸附符合Langmuir等温吸附模型,既有化学吸附也有物理吸附。     

樟树籽提取物在5%硫酸中对A3碳钢的缓蚀性能影响

采用失重法、极化曲线法、电化学阻抗谱研究了25℃时樟树籽提取物(CCSE)在5%H2SO4溶液中对A3碳钢的缓蚀性能。结果表明,樟树籽提取物为15g/L时,在25℃时缓蚀率达84.01%;因其在钢铁表面吸附起缓蚀作用,吸附模型符合Langmuir吸附等温式;运用相关公式,求出ΔG的值在-20~0kJ/mol之间,属于物理吸附;并讨论了缓蚀机理。极化曲线表明樟树籽提取物是一种混合型缓蚀剂。     

土酸溶液中苯扎溴铵对碳钢的缓蚀作用研究

采用失重法和电化学极化曲线研究了不同温度下苯扎溴铵对5%的土酸溶液中碳钢的缓蚀作用。实验结果表明,苯扎溴铵在碳钢表面产生单分子层吸附,并且满足Langmuir吸附规律;吸附过程为放热过程,随着温度的升高,吸附能力减弱,缓蚀效率下降;苯扎溴铵为混合型缓蚀剂。     

2-(4-吡啶基)苯并咪唑对碳钢的缓蚀行为

采用失重法、极化曲线和电化学阻抗谱(EIS)等方法对2-(4-吡啶基)苯并咪唑(PBI)在盐酸体系中对碳钢的缓蚀行为进行了研究。结果表明,PBI对碳钢的腐蚀具有优良的抑制作用,其缓蚀效率随着缓蚀剂浓度的增大而升高,随着温度升高和盐酸浓度增大而下降。PBI能够自发吸附在碳钢表面,其吸附遵循Langmuir吸附等温式。     

氨基磺酸溶液中烷基咪唑啉对碳钢的缓蚀作用

采用失重实验、电化学和扫描电镜等方法研究了2-十一烷基-N-羧甲基-N-羟乙基咪唑啉(UHCI) 在8 mass%氨基磺酸溶液中对碳钢的缓蚀行为。失重实验表明,该缓蚀剂在氨基磺酸溶液中能够有效地抑制碳钢腐蚀,当缓蚀剂的质量分数为0.4 mass%时,碳钢腐蚀速率为0.6370 g/(m²•h),缓蚀效率达到90.12%。极化曲线测试结果表明,该缓蚀剂为混合型缓蚀剂。该缓蚀剂的吸附行为符合Langmuir吸附等温式,吸附机理是一种物理-化学混合吸附。扫描电镜结果也证明 UHCI可有效地抑制氨基磺酸对碳钢的腐蚀。     

植物型缓蚀剂提取及灰色系统对其效果评价

研制了一种环保型酸洗缓蚀剂.采用索氏提取法从橙皮中提取酸洗缓蚀成分,用静态失重法确定酸洗缓蚀剂的最佳缓蚀条件:在研究范围内,腐蚀温度控制在35℃,腐蚀时间5小时20分钟,盐酸酸度为2%,缓蚀剂浓度为0.5%时,缓蚀效果最好;而与六亚甲基四胺复配使用后,缓蚀效果更佳,缓蚀效率达到96%.利用电化学极化曲线对其缓蚀机理进行探讨,发现其为阳极型缓蚀剂.通过考察温度对缓蚀效率的影响,得出缓蚀剂的加入使碳钢在盐酸中溶解反应的活化能升高的结论.通过Frumkin吸附等温式的拟合计算,得到缓蚀成分在碳钢上的吸附为单分子层吸附,且吸附分子间表现为斥力.运用灰色模型GM（1.1）对缓蚀效果进行评价和预测,也得到较理想的结果.     

除盐水中A106碳钢缓蚀剂的电化学试验比选

采用失重法和极化曲线法,试验对比了除盐水中几种缓蚀剂对A106碳钢的缓蚀作用,结果显示除盐水中在30~85℃间缓蚀剂A的缓蚀效果最好,缓蚀率在95%以上;在试验温度范围内,缓蚀剂A能够稳定地发挥缓蚀作用。     

土酸介质中1,4-丁炔二醇对碳钢的缓蚀作用研究

通过失重法和电化学极化曲线法研究了不同温度下1,4-丁炔二醇在5%的土酸介质中对碳钢的缓蚀作用。结果表明,1,4-丁炔二醇在碳钢表面产生单分子层吸附,并且满足Langmuir吸附规律;1,4-丁炔二醇为混合型缓蚀剂。     

吐温-40 与植酸复配对碳钢的缓蚀作用

目的提高0.5 mol/L HCl中植酸对热轧碳钢(HRCS)的缓蚀性能。方法用失重法和电化学阻抗法测试植酸、吐温-40以及复配缓蚀剂的缓蚀效率,从热力学和动力学方面分析复配缓蚀剂的作用机制。结果失重法测试表明,植酸和吐温均对热轧碳钢有一定缓蚀作用。当293 K,植酸质量浓度为0.3g/L时,缓蚀效率达到69.1%,在质量浓度为0.8 g/L时缓蚀效率下降为9.6%;吐温-40的缓蚀效率随着质量浓度的增大而增大,0.8 g/L时达到73.4%。在0.5 mol/L盐酸中加入0.05 g/L吐温-40后,复配缓蚀剂的缓蚀效率随着质量浓度的增加而增大,且优于植酸和吐温-40单独使用,表现出协同效应。电化学测试得到了相同的结论,表明复配缓蚀剂在碳钢表面产生自发的Langmuir吸附,使碳钢腐蚀反应的活化能增大,是熵减少的放热过程。结论吐温-40和植酸在盐酸中对热轧碳钢的腐蚀有缓蚀协同作用。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.