壳聚糖及衍生物掺杂聚苯胺在0.5mol·L~(-1)HCl溶液中对碳钢的缓蚀性能

采用化学氧化法合成了壳聚糖掺杂聚苯胺(CTS-PANI)、羟丙基壳聚糖掺杂聚苯胺(HPCS-PANI)及羧甲基壳聚糖掺杂聚苯胺(CMC-PANI);利用红外光谱法(FTIR)对合成产物进行表征,用腐蚀试验和电化学测试研究了掺杂态聚苯胺对Q235钢在0.5mol·L~(-1) HCl溶液中的缓蚀性能。结果表明:本征态聚苯胺及掺杂态聚苯胺的缓蚀率随缓蚀剂含量的增加先增大后减小,当缓蚀剂的质量浓度达到50mg·L~(-1)时缓蚀率最大;四种缓蚀剂对Q235碳钢在0.5mol·L~(-1) HCl溶液中的缓蚀率从大到小顺序为CMC-PANIHPCS-PANICTS-PANIPANI,羧甲基壳聚糖掺杂聚苯胺的缓蚀性能最好,缓蚀率可达91.9%。     

羟丙基壳聚糖及其复配的缓蚀性

合成了具有良好水溶性的羟丙基壳聚糖(HPCS),采用傅立叶红外光谱仪(FTIR)对合成产物进行表征,采用失重法、动电位极化和电化学阻抗技术研究HPCS、十二烷基苯磺酸钠(SDBS)和焦磷酸钠(TSPP)缓蚀剂单体及其复配对Q235钢在1mol·L-1 HCl溶液中的缓蚀性能。结果表明,单独添加HPCS、SDBS、TSPP时缓蚀效率较低;HPCS/SDBS、HPCS/TSPP分别以浓度比100∶70(mg·L-1)和100∶30(mg·L-1)复配,缓蚀效率分别提高到83.30%和82.54%;HPCS、SDBS、TSPP三者复合具有良好的协同缓蚀作用,当以浓度比50∶20∶10(mg·L-1)复配时,缓蚀率达到91.93%,且在60℃时仍维持在62.60%。     

模拟酸性海洋大气环境中锌缓蚀剂的研究

目的 针对锌在海洋大气环境中的腐蚀状况,筛选有效的缓蚀复配体系,进一步研究多聚磷酸钠和硫脲的缓蚀剂复配体系在模拟酸性海洋大气环境中对锌的腐蚀影响,探讨复配体系对锌的缓蚀机理。方法 利用失重法评价复配体系在不同温度、不同浓度下的缓蚀性能,并利用强极化曲线法、电化学阻抗法和X射线光电子能谱法(XPS)探讨其缓蚀机理。结果 在40 ℃时,pH=4、0.3 mol/L的NaCl 溶液中,质量比1∶4的多聚磷酸钠和硫脲复配缓蚀剂能够有效抑制锌和热镀锌的腐蚀,缓蚀率分别达到92.19%和91.39%。该复配缓蚀剂对锌在气相环境中的腐蚀同样具有良好的抑制作用。电化学测试结果表明,在25、40、60 ℃时,缓蚀率随浓度的升高而增加;在80 ℃时,缓蚀率随浓度的增大而减弱。通过表面成分分析发现,添加复配缓蚀剂后,在锌表面出现了N、S、P三种新元素。结论 多聚磷酸钠和硫脲的复配体系是混合抑制型缓蚀剂。复配缓蚀剂中的多聚磷酸钠能够在锌表面形成保护性薄膜。硫脲属于小分子有机物,容易吸附在锌的表面,所以它能填充膜的间隙,并与锌紧密地结合在一起。多聚磷酸钠和硫脲共同作用可以使锌表面形成更致密、更稳定的膜,从而增强对锌的保护作用。     

复配缓蚀剂在50%乙二醇冷却液中对AZ91D镁合金的缓蚀作用

采用电化学试验、表面形貌观察、腐蚀产物分析等方法研究了磷酸氢二钠(DSP)和D-葡糖酸钠(GS)两种物质复配后对镁合金在50%(体积分数,下同)乙二醇型冷却液中的缓蚀作用。结果表明:DSP对AZ91D镁合金在50%乙二醇冷却液中是一种混合抑制型缓蚀剂,GS对AZ91D镁合金在50%乙二醇冷却液中没有缓蚀作用;DSP和GS之间存在缓蚀协同效应,复配后的缓蚀剂是一种以抑制阳极过程为主的混合型缓蚀剂;GS的添加量存在极值,而DSP和GS的质量浓度比达到4∶1时,即复配缓蚀剂E,其缓蚀率趋于稳定;随着复配缓蚀剂E加入量的增大,缓蚀率增大,其加入量为2.5g/L时,缓蚀率高达90%以上;复配缓蚀剂E对AZ91D镁合金起到缓蚀作用主要表现为形成了MgHPO4沉淀物,通过GS络合在镁合金表面,从而抑制了镁合金在乙二醇冷却液中的腐蚀。     

十六烷基二甲基乙基溴化铵与 NH4 SCN 缓蚀协同效应

目的研究十六烷基二甲基乙基溴化铵(CDAB)与NH4SCN在硫酸介质中对Q235钢的缓蚀协同效应,并探讨其缓蚀机理和性能,以期为工业实际生产提供理论数据。方法运用失重法研究CDAB质量浓度与缓蚀率的关系,通过失重法、动电位极化曲线法和交流阻抗法分析CDAB与NH4SCN复配后的缓蚀率和缓蚀机理。结果仅添加CDAB时,缓蚀率随着CDAB质量浓度增大而增大,但缓蚀性能并不显著,当质量浓度为10 mg/L时缓蚀率仅为85.07%;当CDAB与30 mg/L的NH4SCN复配后,缓蚀率显著提高到96.73%,能有效抑制Q235钢在0.5 mol/L硫酸介质中的腐蚀。极化试验结果显示,该复配缓蚀剂是一种以控制阳极反应为主的混合型缓蚀剂,缓蚀率随CDAB质量浓度增大而增大,与交流阻抗法、失重法试验结果相一致。复配缓蚀剂在Q235钢表面的吸附服从Langmiur吸附等温模型,吸附吉布斯自由能ΔG0=-48.33 k J/mol,为自发吸附。结论 CDAB与NH4SCN在0.5 mol/L硫酸介质中具有优异缓蚀协同效应,能有效抑制腐蚀介质对Q235钢在的腐蚀,复配缓蚀剂具有较高的缓蚀率。     

水溶性壳聚糖及其磷酸酯在海水中对碳钢的缓蚀作用

对水溶性壳聚糖进行磷酸酯化改性。采用静态失重实验与电化学测试相结合,研究了水溶性壳聚糖及其磷酸酯对Q235低碳钢在海水中的腐蚀抑制作用,并探讨缓蚀机理。结果表明,水溶性壳聚糖对碳钢具有一定的缓蚀作用,随其浓度的增加缓蚀率升高;壳聚糖磷酸酯在300 mg/L时缓蚀率达到88.71%,高温下仍保持较高的缓蚀效率,且持久保持高效。壳聚糖磷酸酯为抑制阴极型缓蚀剂。     

盐酸体系不锈钢缓蚀剂的开发

采用失重法和扫描电镜法,测定了五种缓蚀剂对浸没于8%盐酸介质中不锈钢的缓蚀作用,确定了在盐酸体系中对不锈钢具有较好缓蚀性的单组分、二元和三元缓蚀剂配方.实验结果表明:咪唑啉,十六烷基三甲基溴化铵具有较好的缓蚀效果;十六烷基三甲基溴化胺在使用浓度为700 mg/L时,缓蚀率为90.0%;十六烷基三甲基溴化铵与三乙醇胺、咪唑啉及硫脲复配后,缓蚀剂各组分浓度为单组分最佳浓度一半的情况下,缓蚀率分别达到为91.8%、90.8%和89.7%,缓蚀剂的成本得以下降;三元复配缓蚀剂中,咪唑啉-硫脲-乌洛托品和咪唑啉-硫脲-三乙醇胺两种缓蚀剂的缓蚀率均高于90%,且使用成本低,是理想的盐酸体系不锈钢缓蚀剂.扫描电镜图像表明,添加了缓蚀剂的金属表面腐蚀轻微,表面光滑,且不存在明显的点蚀倾向,缓蚀剂对金属表面起到很好的保护作用.     

H2SO4中丙炔醇复配缓蚀剂对碳钢的缓蚀作用

目的探究不同温度下丙炔醇、KI及其复配对Q235碳钢和N80钢片在10%(质量分数)硫酸中的缓蚀性能。方法采用静态失重法和电化学方法,60℃下测定酸液中的单剂对Q235碳钢的缓蚀性,然后对二者进行复配研究。优化配比后升高实验温度,探究高温下不同配比在酸液中对N80钢片的缓蚀性能。根据吸附等温模型和腐蚀动力学对缓蚀机理进行初步探讨。结果失重法表明,60℃时单独使用丙炔醇、KI,当质量浓度分别为120、1000 mg/L时,对Q235碳钢的缓蚀率均达到90%,两者的使用浓度较高。复配后得到两个优选配比,配比A为丙炔醇18 mg/L+KI 250 mg/L,配比B为丙炔醇15 mg/L+KI 300 mg/L,配比A、B的缓蚀率均高达98%。配比A、B的缓蚀率均随温度升高而降低,配比A在80℃酸液中对N80的缓蚀率为93%,配比B在100℃酸液中的缓蚀率为73%。结论复配后缓蚀剂的使用量均降低,且在一定高温下具有良好的缓蚀性能,丙炔醇和KI有较好的协同作用。电化学的实验结果与失重法相一致,丙炔醇和复配剂为混合型缓蚀剂。缓蚀剂在金属表面的吸附为化学吸附,符合Langmuir吸附等温模型。     

固定化溶菌酶的缓蚀机理及性能

采用物理吸附方法将溶菌酶固定在MCM-41介孔分子筛上,并与化学缓蚀剂[氨基三亚甲基膦酸(ATMP)与聚天冬氨酸(PASP)]复配用作循环冷却水缓蚀剂。利用电化学法分析复配缓蚀剂的缓蚀机理,并用失重法所测得的复配缓蚀剂缓蚀性能为指标优化复配条件。结果表明:复配缓蚀剂为混合型缓蚀剂,可以同时抑制腐蚀过程的阴极反应与阳极反应,最佳复配方案为固定化溶菌酶投加量0.7g/L、ATMP质量浓度10mg/L、PASP质量浓度20mg/L,缓蚀率可达88.55%,循环冷却水对碳钢腐蚀速率降至0.017 3mm/a,作用时间为11~13d。     

高浓度氯离子溶液中Y112铝合金缓蚀剂的电化学研究

应用电化学测试技术研究了亚硝酸钠、钼酸钠和钼酸氨三种缓蚀剂浓度、温度对Y112铝合金在高浓度氯离子环境中腐蚀行为的影响,以及三种缓蚀剂与铜缓蚀剂BTA复配的缓蚀情况。结果表明:铝合金腐蚀电位和腐蚀速率与缓蚀剂浓度之间有一定关系;缓蚀剂复配削弱了原有缓蚀剂的缓蚀效果;铝合金在高浓度氯离子溶液中的腐蚀速率随温度的升高而加快,缓蚀剂的缓蚀效果随温度的升高而降低。     

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.