三氯化铝/盐酸三甲胺离子液体中电沉积制备Al-Ni合金镀层

目的研究离子液体中Ni~(2+)浓度对Al-Ni合金镀层结构和成分的影响,同时考察电流密度对镀层表面形貌和织构的影响。方法采用脉冲电流法,在含有不同浓度氯化镍的无水三氯化铝/盐酸三甲胺离子液体中,于不同电流密度下电沉积制备Al-Ni合金镀层。利用扫描电子显微镜、X射线衍射技术和能谱分析仪探究离子液体中Ni~(2+)的浓度对Al-Ni合金镀层结构和成分的影响,考察电流密度对镀层表面形貌和织构的影响。结果随着离子液体中Ni~(2+)浓度的增加,镀层中镍的含量增多,表面胞状颗粒逐渐变小,表面趋于均匀,当Ni~(2+)的浓度为0.2 mol/L时,形成铝镍金属间化合物。另外,随着电流密度的增加,镀层表面形貌由针状晶体变为棒状颗粒,并且颗粒逐渐增大。结论离子液体中Ni~(2+)的浓度和电流密度对Al-Ni合金镀层表面形貌、结构和成分有一定的影响。当溶液中Ni~(2+)的浓度为0.2 mol/L、电流密度为6 m A/cm~2时,电沉积4 h可制备得到厚度为10μm、由3μm大小晶粒组成、含有铝镍金属间化合物的合金镀层。     

AlCl3-BMIC离子液体中Na+含量对铝电沉积的影响

测定AlCl3-BMIC离子液体(摩尔比2:1)电导率与Na+含量的关系,采用循环伏安法研究不同Na+含量离子液体的电化学性能,并通过恒电流电沉积考察Na+含量对槽电压、电流效率、沉积层形貌及电沉积铝纯度的影响。结果表明:随着Na+含量增加,离子液体的电导率和铝电还原峰值电流密度降低,交换电流密度增加,传递系数基本保持不变;而且铝沉积的电流效率降低、能耗增加。此外,当离子液体中Na+含量低于0.2 g/L时,对铝沉积层形貌影响不大,当Na+含量增加到0.5 g/L时,沉积层变得平整致密,颗粒减小,但进一步增加Na+含量,颗粒又逐渐长大。离子液体中Na+的存在对铝沉积层的纯度影响很小,即使Na+含量高达2.0 g/L,铝沉积层中Na含量也非常低。     

基于阳离子型聚丙烯酰胺高聚物溶液的电化学沉积试验研究

以阳离子型聚丙烯酰胺(CPAM)高聚物为唯一添加剂,采用直流电源在超低电压下开展锌镀层电化学沉积试验,重点研究了CPAM离子度对锌镀层表面形貌、成分和电流密度的影响,考察了主盐Zn2+和CPAM的质量浓度对镀层微观形貌、晶粒平均直径的影响规律。结果表明:离子度20%的CPAM-ZnSO4高聚物溶液在0.3 V超低电压下获得的沉积层致密、晶粒尺寸均匀、表面平整光亮且电流密度达0.47 A/dm2;随着Zn2+和CPAM的质量浓度增加,镀层中锌含量增多,沉积层表面形貌由圆形颗粒变为片状晶体且表面晶粒细化;当Zn2+质量浓度40 g/L、CPAM质量浓度20 g/L、电压0.3 V时,电沉积5 min时,可制备出表面光亮、晶粒平均直径87 nm的镀锌层。     

电流密度对镍镀层结构和性能的影响

采用阴极移动电镀技术在电流密度为1～13A/dm2时制备镍镀层。利用扫描电镜(SEM)、X射线衍射仪(XRD)、X射线应力衍射仪以及硬度计等手段,研究电流密度对镍镀层的表面形貌、结晶取向、孔隙率、内应力和硬度的影响。结果表明:镍镀层的织构和性能随电流密度的变化而改变。当电流密度低于7A/dm2时,镀层表面球形颗粒较为粗大、孔隙率较高,在为4A/dm2时,镀层具有最低的拉应力约110 MPa;当电流密度为7A/dm2时,镀层表面球形颗粒均匀细小,具有最小的表面粗糙度Ra 0.69μm,最小的孔隙率0.08个/cm2以及最高的硬度330HV0.1;当电流密度大于7A/dm2时,镀层的表面粗糙度增加,择优取向由(200)晶面向(220)晶面发生转变,电流密度达到13A/dm2时,(220)晶面的织构系数达到了85.4%。     

离子液体AlCl_3-[bmim]Cl中电沉积铝的研究

在摩尔比为2:1的AlCl_3-[bmim]Cl离子液体中,加入一定量的甲苯,控制阴极电流密度,在基体铁片上获得银白色和平整致密的铝镀层。循环伏安实验表明离子液体中沉积铝源于Al_2Cl_7~-的还原,还原峰电位为-0.34V;当电流密度为20mA/cm~2时,最大电流效率达97%;所得铝镀层的厚度与电镀时间呈抛物线关系;在电流密度小于35mA/cm~2时,镀层厚度随电流密度增大呈逐渐递增趋势;扫描电镜、X射线能谱对铝镀层分析结果表明(45±2)℃温度得到平整致密纯度高的铝镀层;当电流密度为20mA/cm~2时,铝镀层呈薄片状生长,随电流密度的增大,镀铝层形貌由片状向粒状过渡,并伴随着晶粒的细化。     

CLAM钢表面室温离子液体电镀铝

采用AlCl_3-EMIC离子液体在室温下对国产低活性铁素体/马氏体钢(CLAM钢)表面进行镀铝处理。研究了镀前处理对镀层-基体界面的影响。采用SEM、EDS分析了不同电流密度对镀层表面形貌与界面形貌的影响,同时与脉冲电镀所得结果进行了比较。结果表明:在电化学前处理过程中,增大电流密度会增强镀层与基底结合力;电流脉冲的加入可以减弱溶液浓差极化现象,增加表面组织致密性;镀层晶粒大小随电流密度增大而减小,镀层球状组织随电流密度增大而增大。在优化的电镀工艺下(前处理电流密度控制在10 mA/cm~2以上,电镀电流密度控制在10~20 mA/cm~2,对应的电镀时间45~95 min,优选脉冲电流电镀),得到的铝镀层表面光滑,致密,结合力强,厚度可控。     

电沉积法制备组分调制Zn－Ni合金多层镀层

研究了Zn－Ni合金镀液中主盐的组成、电镀工艺参数对Zn－Ni合金镀层中的含镍量及镀层性能的影响，结果表明，电流密度是影响Zn－Ni合金镀层中含镍量的主要因素.在电沉积过程中，利用计算机控制电流输出的电镀电源，通过调整施镀电流密度，制备出了由2种组成不同的Zn－Ni合金薄层交替叠加而形成的Zn－Ni合金多层镀层.SEM表面及断面显微分析结果表明：Zn－Ni合金多层镀层表面无缺陷，断面呈清晰的层状结构.      

Ce3+对Zn-Ni合金镀层耐蚀性能的影响

在电镀液中添加铈盐,于Q235钢表面电镀Zn-Ni合金,考察了Ce3+添加量对Zn-Ni合金镀层耐蚀性能的影响.通过稳态阳极极化曲线、塔菲尔极化曲线和交流阻抗谱,研究了镀层在30℃3.5％NaCl溶液中的腐蚀行为;同时对比了Zn-Ni合金镀层在腐蚀前后的微观结构和表观形貌.结果表明:加入铈盐,不改变Zn-Ni合金镀层的晶面择优取向,但会改变各晶面的织构系数;添加铈盐后,Zn-Ni合金镀层的致钝电流密度和维钝电流密度明显降低,极化阻抗明显增大;当镀液中添加0.80 g/L铈盐时,镀层结晶粒度明显变小且致密,使得耐蚀性能显著增加.     

AZ31镁合金在TMPAC-AlCl3离子液体中电镀铝

采用TMPAC-AlCl3离子液体,在浸锌后的镁合金AZ31表面实施恒流电镀铝,采用电化学技术评估镀铝层的耐蚀性,并采用SEM/EDX等技术表征镀层。结果表明：在浸锌后的镁合金表面可获得表面光洁的银白色镀铝层。在不同的电流密度下,呈现出两种形貌不同的镀铝层;在较佳电流密度12.3mA/cm2时,镀铝层表面较致密;电镀时间越长,镀层越厚,镀铝层耐蚀性越好。     

还原剂对铝表面化学镀Ni-Co-P合金耐腐蚀性能的影响

研究镀液中还原剂浓度对铝表面化学镀Ni-Co-P合金性能的影响。运用增重法分析了浓度对镀速的影响;采用JSM-5610LV型扫描电镜、能谱仪、CHI660C型电化学工作站研究化学镀Ni-Co-P合金的表面形貌、微观成分和耐腐蚀性能。结果表明,镀液中还原剂浓度为30 g/L时,镀速最大,镀层均匀、紧凑、细小,镀层的镍、钴含量适中,耐腐蚀性较好。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

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.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.     

Structural Optimization of Electromagnetic Swirling Flow in Nozzle of Slab Continuous Casting

During the slab continuous casting process, the flow field of molten steel in the mold plays a decisive role in the quality of the slab. In this paper, electromagnetic swirling flow in nozzle technology is proposed to control the flow field in mold.This technology can drive molten steel to rotate inside the submerged entry nozzle by electromagnetic force, thereby controlling the flow field. This research shows that it can reduce the impact of molten steel on the bottom of nozzle and partly reduce the negative pressure at the upper part of nozzle outlet which is even eliminated by optimizing the structure and angle of nozzle. The area of heat flux of the mold wall becomes larger, and the crest value of heat flux gets lower than that without swirling in nozzle and any nozzle optimization. The meniscus fluctuates smoothly, and the flow velocity at the top surface is within a reasonable range. The temperature field distribution in the mold is uniform which was beneficial to the growth of equiaxed crystal and decreased element segregation.