KF-KCl熔体中电沉积TiB2镀层

在铝工业中TiB2是一种非常有前途的阴极内衬取代材料.本研究首先通过热力学分析验证了在Ti-B-C体系生成TiB2的可能性,然后在K2TiF6和KBF4作为活性物质的KF-KCl熔体中以石墨为基体通过直流电沉积(CCP)和周期断开电流电沉积(PIC)技术制备了TiB2镀层,并且研究了电流密度和电镀技术对镀层表面平整度、致密度和晶粒尺寸的影响.结果表明,当电流密度为0.8 A/cm2时,能够得到厚度均匀且和基体具有良好附着的TiB2镀层;和CCP相比,采用PIC技术制备的TiB2镀层表面平整度和致密度都得到明显改善,并且晶粒也更为细小.XRD分析表明镀层由相对纯净的TiB2组成,并且镀层择优取向均为(001)面,这和二维晶核理论的预测相吻合.     

电沉积金属Ni涂层的高温腐蚀性能

通过调控电沉积过程中的阴极电流密度制备具有不同晶粒尺寸和择优取向的Ni镀层.采用透射电镜(TEM)、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)对高温腐蚀前、后不同Ni镀层进行检测分析,对比研究不同Ni镀层经过960 ℃的78.07%Na3AlF6-9.5%AlF3-5%CaF2(质量分数)熔盐气氛腐蚀后的结构、成分和形貌.结果表明:在高电流密度下易获得晶粒细小,平均晶粒尺寸为120 nm,具有较强(100(择优取向的Ni镀层;而在低电流密度下所得的Ni镀层晶粒较粗大,平均晶粒尺寸为925 nm,具有较弱的(111(择优取向.在腐蚀气氛下,低电流密度下所得的Ni镀层在高温腐蚀后有利于生成晶粒粗大、且具有完整"八面体"结构的NiAl2O4尖晶石相;而高电流密度下所得Ni镀层表层腐蚀层的晶粒细小,且主要为NiO相.     

电镀工艺对镍纳米膜微观结构及硬度的影响

采用直流电沉积法制备纳米晶镍膜,研究了添加剂C12H2NaSO4,TJ,GL-100对镀层微观表面形貌、硬度、晶粒尺寸及织构的影响,同时探讨了电流密度对硬度的影响。结果表明：在无添加剂和仅加入C12H25NaSO4时,改变了镀层晶面的生长速率和晶粒快速的生长方向,使（200）晶面发生织构;TJ的添加显著细化晶粒;TJ和GL-100复合添加使镀层晶粒在（111）晶面择优取向生长。3种添加剂的复合作用,使镀层表面形貌及硬度达到最佳状态。在电镀条件相同时,镀层的硬度随电流密度的增加而增加。     

NiFe2O4尖晶石涂层用纳米Ni-Fe合金的电沉积制备与表征（英文）

采用直流电沉积技术在Ni基体上制备Fe含量为1%~39%(质量分数)的纳米晶FCC Ni-Fe合金涂层。利用X射线衍射技术研究Ni-Fe合金涂层的晶体结构、晶格应变、晶粒尺寸和晶格常数;利用X射线能量分散谱仪(EDS)和原子力显微镜(AFM)分析沉积层的化学成分和表面形态。结果表明,Fe含量对镍铁合金沉积层的择优取向、晶粒尺寸、晶格常数和晶格应变有较大影响。FCC Ni-Fe合金涂层的择优取向为(200)或(200)(111)。随着Fe含量的增加,(200)晶面的择优取向逐渐减弱,而(111)晶面的择优取向逐渐增强。当Fe含量为1.3%~25%(质量分数)时,Fe含量的增加使沉积层的晶粒显著细化。当Fe含量超过25%时,Fe含量的增加不再使FCC Ni-Fe合金晶粒尺寸减小。FCC Ni-Fe合金的晶格应变随Fe含量的增加而增大。由于Fe含量不低于25%的合金具有相似的晶粒尺寸(约为11 nm),所以晶格应变随Fe含量的增加不能归因于晶粒尺寸的变化。     

NiFe_2O_4尖晶石涂层用纳米Ni-Fe合金的电沉积制备与表征(英文)

采用直流电沉积技术在Ni基体上制备Fe含量为1%~39%(质量分数)的纳米晶FCC Ni-Fe合金涂层。利用X射线衍射技术研究Ni-Fe合金涂层的晶体结构、晶格应变、晶粒尺寸和晶格常数;利用X射线能量分散谱仪(EDS)和原子力显微镜(AFM)分析沉积层的化学成分和表面形态。结果表明,Fe含量对镍铁合金沉积层的择优取向、晶粒尺寸、晶格常数和晶格应变有较大影响。FCC Ni-Fe合金涂层的择优取向为(200)或(200)(111)。随着Fe含量的增加,(200)晶面的择优取向逐渐减弱,而(111)晶面的择优取向逐渐增强。当Fe含量为1.3%~25%(质量分数)时,Fe含量的增加使沉积层的晶粒显著细化。当Fe含量超过25%时,Fe含量的增加不再使FCC Ni-Fe合金晶粒尺寸减小。FCC Ni-Fe合金的晶格应变随Fe含量的增加而增大。由于Fe含量不低于25%的合金具有相似的晶粒尺寸(约为11 nm),所以晶格应变随Fe含量的增加不能归因于晶粒尺寸的变化。     

高择优取向烟酸体系镀层制备工艺及其对沉积速率和电流效率的影响

研究了烟酸体系镀银高择优取向镀层制备工艺条件与沉积速率和电流效率的关系。通过XRD测试镀层结晶的择优取向、结晶度、晶粒尺寸,称量法测试电流效率和沉积速率,随着Ag NO3浓度的提高晶粒尺寸不断增大,在(111)晶面择优取向先减小后增大,电流效率和沉积速率不断增大。随着导电盐K2CO3浓度的提高,晶粒尺寸不断增大,但是当K2CO3浓度达到95 g/L时,晶粒尺寸增大趋势减小,在(111)晶面的择优取向先减小后增大;电流效率和沉积速率先增大,在K2CO3浓度达到95 g/L时开始减小。     

镀银铜棒的制备与表面形貌的研究

采用无氰电镀银的工艺在纯铜基体上沉积具有纳米尺寸晶粒结构的银层。在不同的电流密度和电镀时间工艺下制备出一系列镀银试样。利用SEM、EDS和XRD对镀层的表面形貌和晶体结构进行分析。结果表明:优化后的电流密度为0.10 A/dm~2、电镀时间为40 min。在该参数下,所制备的镀层光亮、晶粒圆润均匀,(220)晶面为最优取向晶体面。     

脉冲电沉积Ni-Al2O3纳米复合镀层晶体结构的变化

用直流电镀法制备了纯Ni镀层和Ni-Al2O3纳米复合镀层,并采用双脉冲电镀电源制备了Ni-Al2O3纳米复合镀层.通过扫描电镜观察了镀层的表面微观形貌,用X射线衍射仪分析了镀层的微观晶体结构,探讨了Al2O3微粒对镀层的沉积和生长过程的影响.结果表明,纳米Al2O3颗粒的加入使镍镀层的晶体择优取向发生改变,晶粒细化.双脉冲电镀电源的引入使晶格点阵常数变大,晶格畸变增大,进一步细化了镀层的晶粒.     

硫代硫酸盐无氰镀银工艺及银镀层微观组织分析

采用硫代硫酸盐无氰镀银工艺,分别以 AgNO3和 AgBr 为主盐进行镀银。研究主盐含量、电流密度对Ag镀层表面质量、沉积速率和显微硬度的影响,并优化电镀参数。分析优化工艺下的Ag镀层结合强度和晶粒尺寸。结果表明：在AgNO3体系中,AgNO3最佳用量为40 g/L,最佳电流密度为0.25 A/dm2,制备的Ag镀层光亮平整,与基体结合良好,晶粒尺寸为35 nm。在AgBr体系中的最佳AgBr用量为30 g/L,最佳电流密度为0.20 A/dm2,与基体结合良好的Ag镀层的晶粒尺寸为55 nm。与AgBr体系相比,AgNO3体系适用的电镀电流密度范围较宽,制备的Ag镀层显微硬度高,晶粒尺寸小。     

在石墨基体上电沉积TiB2镀层的研究

采用K2TiFe-KBF4-KF-KCl融盐体系在石墨基体上电沉积制备TiB2镀层。考察了预电解条件和电活性组分的含量对镀层性能的影响。实验结果表明：预电解对镀层的组成影响较大；在K2TiF6与KBF4的摩尔比为1：2．5，并且其总含量较高的条件下，镀层与基体结合力好，重复性好，但是晶粒较大，含有少量杂质；在K2TiF6与KBF4的摩尔比为1：7．5，并且其总含量较低的条件下，得到的镀层晶粒细小，有金属光泽，TiB2的纯度很高，但是重复性较差。需要进一步进行电化学实验，明确电沉积的机理。     

Preparation of highly preferred orientation TiB2 coatings

This paper focuses on the preparation of titanium diboride （TiB2） coatings on the graphite substrate by continuous current plating （CCP） and pulse current plating （PIC） electrochemical techniques in fluoride electrolytes （LiF-NaF-KF） containing K2T1F6 and KBF4 as the electrochemically-active components at 700℃. Thick leveled and uniform coatings were obtained and were composed of relatively pure TiB2. The effect of the experimental parameters on the microstructure of the coatings was studied. The results showed the electrodeposition with PIC produced coatings with better quality, when compared with those obtained by CCP, under the conditions of the current density i = 0.6 A/cm^2, frequency = 100 Hz, and todtofr = 4/1. XRD analysis indicated that the preferred orientation of coatings is （110） plane, which is in accordance with the prediction of the two-dimensional crystal nuclei theory. The effect of a ratio of ton/toff and frequency on the crystal size, textule coefficient and microstress was also investigated.     

Preparation of TiB2 coatings by electroplating in molten salt

Titanium diboride （TIB2） coatings were prepared by electroplating in fluoride-chloride electrolytes （KF-KC1） containing K2T1F6 and KBF4 as the electrochemically-active components. An attempt was made to correlate the thermodynamic prediction and experimental observations. Thick, adherent, and uniform TtB2 coatings were obtained and the coating microhardness reaches the value of 33 GPa. The effects of the current density on the mechanical properties, structures, and morphologies of the coatings were studied. XRD analysis indicates that the preferred orientation of the coatings is （001）, which is in accordance with the prediction of the two-dimensional crystal nuclei theory. Thermodynamic prediction and experimental results show that some phases such as TixCy and BaCb are absent at the interface, which indicates the substrate and coatings bind mechanically or physically. Some cracks exist at the interface, which is attributed to the difference between the coefficients of thermal expansion of TiB2 and graphite.     

Nucleation interface of Al-Sb alloys on single crystal Al2O3 substrate

Lattice structure information of heterogeneous nucleation at nucleation interface was present. The crystal orientation, and interfacial structure characteristic of liquid Al alloys nucleated on the basal surface (0001) Al₂O₃ single crystal substrate were identified by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) analysis. The preferred crystal orientations of pure Al and Al-1%Sb (mass fraction) alloy adjacent to the nucleation interface were examined as (200) and (220) planes of Al, respectively, and two corresponding orientation relationships were obtained. An improved nucleation efficiency and refined grains were attributed to both the reduced interplanar spacing of preferred orientation and the decrease of lattice misfit from 16.4% to 7.0% in Al-1%Sb/Al₂O₃ nucleation group.     

Surface morphology and crystal orientation of electrodeposited tungsten coatings with different pulse parameters

This study was conducted to investigate the influence of pulse parameters on the surface morphology and crystal orientation of the tungsten coatings electrodeposited on pure copper substrates. The deposited coatings were analyzed by X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy-dispersive spectrometer(EDS). SEM analysis indicates that pulse parameters have significant influences on the surface morphology of the deposited coatings. Meanwhile, the change in grain size of the tungsten coatings demonstrates that the change in frequency and duty cycle could cause the variation of nucleation rate and grain growth of deposits.Moreover, no obvious diffusion layer at the coating/substrate interface is found by line analysis of EDS. XRD results reveal that tungsten coatings are of bcc structure and the preferred orientation of the deposits varies with duty cycle and period.     

电刷镀纳米晶镀层的组织及其强化机理

采用直流、脉冲和脉冲换向电流制备了Ni和n—SiO2／Ni电刷镀镀层，利用SEM、AFM、TEM和XRD等技术对镀层的表面形貌、显微组织和晶粒尺寸等进行了分析测量。结果表明，电刷镀层表面呈胞状组织，镀层的晶粒尺寸均在纳米量级，说明电刷镀技术是一个古老而未被认识的纳米技术；复合电刷镀过程中纳米颗粒的作用及脉冲换向电流，能进一步提高镀层的形核率及抑制晶粒的生长，从而减小纳米晶的尺寸。镀层的硬度与纳米晶的尺寸有很好的对应关系。     

Ti层对316L不锈钢表面TiB2薄膜结合力的影晌

基于多层膜优异的力学性能,采用磁控溅射法在316L不锈钢基体表面沉淀[Ti／TiB2]。（n=1,2,3）多层膜以增强TiB2薄膜的膜基结合强度。研究周期数对多层膜的结构、硬度及结合力的影响。结果表明：TiB：单层膜表现为（001）方向的织构。随着周期数的增加,多层膜的织构方向由（001）转变为（100）;多层膜的硬度从20GPa增加到26GPa,但略低于TiB2单层膜的硬度（33GPa）;相对于单膜的膜基结合力（9．5N）,多层膜表现出较好膜基结合力,最大结合力可达24N。     

TiB2 coating formed on nickel substrates by electroplating in molten salt of fluoride

The TiB2 coatings deposited over nickel substrate by electroplating was investigated, which is in molten salt of a fluoride mixture involving KF, NaF, K2 TiF6 and KBF4. Effects of temperature, cathodic current density (Jc) and duration on the coating's formation were examined. The composition, morphology and structure of the coatings were characterized by scanning electron microscopy (SEM), energy dispersive X-ray detector (EDS) and X-ray diffraction (XRD). The results show that the coatings, with black, smooth and uniform appearance, are composed of predominating TiB2 and small amounts of nickel titanium oxide (Ni0.75 Ti0.125 O). The coatings show a nodular morphology and the grain size is dependent on the Jc and ranges about 1 - 10 μm. There is a linear relationship between the coating's thickness and the time of electrolysis within certain duration range. The reduction of the potassium can take place simultaneously with the electrochemical synthesis of TiB2 as the Jc is in excess of certain level. The hardness of the TiB2 coatings is likely to be deteriorated due to the presence of potassium and Ni0.75Ti0.125 O in the coatings.     

电流模式对柠檬酸盐体系镀金的影响

针对作为密封层使用的镀金层存在沉积速率低、厚度不均匀的问题,使用自研精密电镀电源,对比直流（DC）、正向单脉冲（FPC）、正向群脉冲（FGPC）、周期换向脉冲（PPRC）对镀金的影响。仿真PPRC一个周期内镀层厚度的变化情况。使用场发射扫描电子显微镜（FESEM）、X射线衍射仪（XRD）和X射线荧光测厚仪分析镀层的表面形貌、结构、沉积速率、厚度均匀性和电流效率。结果表明：仿真中PPRC较FPC可以明显改善镀层的厚度均匀性,电流模式影响镀金层的晶面峰强和电流效率,DC、FPC、FGPC、PPRC镀金层的晶粒尺寸依次减小,镀金层表面的致密性和厚度均匀性提高,脉冲模式下阴极振动可显著提高沉积速率。使用适宜的PPRC参数镀金,可以在较高的沉积速率下获得厚度均匀、致密的镀金层。     

铱涂层的制备及性能

通过离子镀方法,在难熔金属Mo表面成功制得Ir涂层,制得的Ir涂层呈亮银白色且表面均匀,并分别采用X射线衍射及扫描电镜技术对其结构和微观形貌进行分析。结果显示:涂层均匀致密呈山丘状,无明显缺陷,Ir涂层呈多晶态,并沿(111)晶面优先生长,Ir涂层与基材结合良好,铱涂层抗氧化性能良好。