无锡钢上镀铬层的晶体织构与其机械寿命的关系(英文)

采用 X 射线衍射研究了在接近工业条件下制备的无锡钢上薄镀铬层(0.03 μm或每面 0.22 g/m2)的晶体织构特征。实验发现,铬镀层的晶体结构含以下组分:以垂直于镀层表面的[111]为轴心的轴向分量,(111)[112]受限分量以及一个自由分量。其中[111]轴向分量为主要织构分量,是初始阶段的生长织构;(111)[112]受限分量为次要织构分量,代表了外延生长。无锡钢上镀铬层织构与亚结构的定量特征之间的规律性变化取决于沉积参数。影响无锡钢上薄镀铬层机械寿命的主要因素之一是镀层中[111]轴向织构的形成。     

织构对电沉积纳米晶镍耐蚀性的影响

采用脉冲电沉积方法在304不锈钢表面制备出具有(111)或(200)择优取向的纳米晶镍。采用XRD对纳米晶镍的织构进行表征,并利用电化学工作站测试纳米晶镍的动电位极化曲线和交流阻抗谱。结果表明:织构对纳米晶镍的耐蚀性有明显的影响,具有(111)择优取向的纳米晶镍的耐蚀性最好;随着TC(111)的增大,纳米晶镍的耐蚀性增强。     

电沉积条件对甲基磺酸锡镀层织构的影响

为了在实际应用中控制甲基磺酸电镀锡镀层的织构以提高镀层性能,采用X-射线衍射分析方法研究了镀锡工艺中表面活性剂浓度、电流密度和镀层厚度对镀锡层织构的影响规律,XRD分析结果显示,表面活性剂聚乙二醇辛基苯基醚(OP)浓度高,镀层以(211)和(321)晶面择优;OP浓度低,镀层以(101)和(112)晶面择优低电流密度有利于镀层以(211)和(312)晶面择优,高电流密度则有利于(101)和(112)晶面择优;镀层较薄时没有明显的晶面择优,(211)晶面的衍射峰强度随着镀层厚度的增加而加大,当镀层厚度超过10μm镀层以(211)和(321)晶面的衍射峰为主,且基本不随镀层厚度的增加而变化.由于晶态基底会影响镀锡层的织构和形貌,本甲基磺酸镀锡工艺以多晶紫铜化学镀非晶态镍磷合金为阴极,对非晶态基底上得到的锡镀层进行研究。     

电沉积铁镍合金织构现象的研究

通过择优系数（Ｔｅ）的计算，探讨了电流密度对铁镍合金织构的影响。结果表明：随着电流密度的增大，铁镍合金的择优取向面由（２１１）面变为（２００）面。     

脉冲电流密度对电沉积纳米晶镍织构和硬度的影响

采用脉冲电沉积法制备了韧性较好的纳米晶镍镀层。考察了脉冲峰值电流密度对纳米晶镍镀层织构和硬度的影响。结果表明,随着脉冲峰值电流密度的增加,Ni(111)晶面择优取向程度逐渐增强,晶粒显著减小,镀层的硬度逐渐增加。纳米晶镍镀层硬度与晶粒尺寸的关系符合经典的Hall—Petch效应。     

水中Cl~-离子对电镀质量影响

通过讨论水质对电镀质量的影响,说明了水质对电镀生产的重要性.阐述了水中影响质量的主要是一些阴离子(如Cl-、SO42-、SiO22-、NO3-等),尤其是Cl-对耐蚀性的影响较大,引起镀层麻点等质量问题,并介绍了电镀用水的要求及其制备.     

Cl~-对泡沫镍制备工艺的影响

通过对比实验,研究了在制备泡沫镍材料的电沉积过程中Cl-对电镀阴极和阳极极化曲线、电沉积结晶形态以及电流效率的影响。提出在制备泡沫镍材料的工艺过程中,Cl-的质量浓度为10～15g/L时,能得到结晶致密、晶粒尺寸均匀的高性能金属材料,并且有利于提高阴极电流效率,节约生产成本。     

工艺参数对电解提纯铜层织构的影响

在硫酸铜电解液中加入硫酸钠,利用电沉积和X-射线衍射方法研究了不同提纯铜工艺制备的铜镀层及织构特征。结果表明,织构度受到电流密度、镀层厚度和温度的影响,在较小的电流密度、较高温度及在较薄厚度的铜镀层得到(111)晶面择优取向,在较高的电流密度及在镀层δ达到30μm时得到(220)晶面择优取向,而且铜镀层(220)晶面比(111)晶面更易保留,(220)晶面使纯铜能获得更好的电化学性能,保持纯铜晶面的择优取向对铜在半导体的应用产生了深远的影响。     

脉冲电沉积纳米晶镍镀层的织构与硬度

采用脉冲电沉积方法在304不锈钢表面制备出具有不同织构的纳米晶镍镀层。采用X射线衍射仪对镀镍层的结构进行了表征,并用超显微微米压痕仪测量了镀镍层的硬度。结果表明:随着电镀时间的延长,镀镍层的晶粒尺寸变化不大,约为(14±2)nm;择优晶面由(111)向(200)转变;硬度由6070 MPa降至3 750 MPa。织构的变化显著影响镀镍层的硬度,随着织构系数TC(111)的降低,镀镍层的硬度逐渐下降。     

高速镀锌工艺对镀层粗糙度及织构的影响

将旋转圆盘电极体系应用于高速镀锌层粗糙度的研究.研究了电流密度及镀液流速对高速镀锌钢板粗糙度的影响规律,结果表明,粗糙度随电流密度、流速的增大,先变小后增大;同时(101)、(102)、(103)晶面的丰度不断增大.     

电沉积铜基纳米碳化硅复合镀层实验研究

采用电沉积方法,制备铜基纳米碳化硅复合镀层。研究溶液搅拌方式或溶液中引入添加剂,对Cu-SiC纳米微粒复合镀层表面形貌和性能的影响。利用超声搅拌制备的Cu-SiC纳米微粒复合镀层的表面形貌平整而且致密,与磁力搅拌所得镀层相比显微硬度提高约32%,接近143 HV,磨损质量损失降低约33%,每平方毫米为0.056 mg。溶液中引入添加剂,制备的Cu-SiC纳米微粒复合镀层的表面形貌和性能无明显改观,但采用超声波搅拌制备的Cu-SiC纳米微粒复合镀层的表面形貌和性能改观较为明显。添加剂发挥的作用与超声搅拌引发的综合作用叠加,促使复合镀层的表面形貌和性能进一步改善。     

Texture and surface morphology in zinc electrodeposits

The texture and morphology of zinc coatings electrodeposited on low carbon steel substrate have been studied. The predominant texture component of zinc coating at low overpotentials was pyramidal (11.5) and (11.6) non-fiber while at high overpotentials (00.2) fiber component dominated. The morphological analysis of the coating surface indicates that the non-fiber texture component results from epitaxial growth of zinc which develops through 2D nucleation and bunching growth of substrate surface microsteps, while the (00.2) fiber component starts from 3D nucleation and oriented growth to promote the plane having the lowest surface energy (i.e., (00.2)) parallel to the steel substrate surface. Zinc hydroxide adsorption prevents 3D nucleation at low overpotentials and this process favors epitaxial growth of the zinc deposit. At high overpotentials, inhibited zinc adsorption, in addition to increased number of active nucleation sites, promotes strong (00.2) fiber component. Such variation in texture indicates that the electrodeposit texture is strongly dependant on overpotential.     

电沉积Fe－Ni－P合金镀层织构现象的研究

利用扫描电镜能谱技术和Ｘ射线衍射技术对Ｆｅ－Ｎｉ－Ｐ合金镀层的组成和微观结构，特别是晶体的择优取向进行了研究。试验发现，该合金镀层属于ｂｃｃ型α－Ｆｅ单相多晶组织，镀液中ＮａＨ２ＰＯ２·Ｈ２Ｏ浓度的改变以及镀液温度的改变对镀层的织构均有显著的影响。     

超声对铜电化学沉积速度及沉积产物结构的影响

测定了超声作用下铜电化学沉积过程的阴极稳态极化曲线,探讨了超声对沉积铜晶面取向及表面形貌的影响. 结果表明,在实验条件下,超声可以提高铜电化学沉积过程的阴极极限扩散电流密度,超声对铜电化学沉积过程极限扩散电流密度的影响随着反应体系温度的升高而下降,当系统温度从25oC升高到55oC时,有超声与无超声作用下的平均极限扩散电流密度的比值从14.1减低到8.4. 超声还能改变铜电沉积晶面的取向,明显改变电沉积铜的粒径.     

Optimization of chemical and electrochemical parameters for the preparation of n-type Bi2Te2.7Se0.3 thin films by electrodeposition

A 2^3–1 fractional factorial design comprising four runs and three centre points was applied in order to optimize the electrodeposition process to find a compound with the best stoichiometry leading to a Bi₂Te_2.7Se_0.3 thin film suitable for thermoelectric applications. The key factors considered were the deposition potential, the percentage of bismuth and the percentage of selenium in the solution. The Bi^III, Se^IV, Te^IV electrolyte mixtures in 1 M HNO₃ (pH 0), allowed deposition of ternary alloys to be achieved at room temperature on stainless steel substrates. The deposition mechanism was investigated by linear voltammetry. The films were characterized by micropobe analysis, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The XRD patterns of the film show that the as-deposited are polycrystalline and isostructural to Bi₂Te₃. The SEM study shows that the film is covered by crystallites while the AFM image reveals a low level of roughness.     

Texture of PAN- and pitch-based carbon fibers

The new technique of scanning microbeam X-ray diffraction is used to get information about the axial as well as the cross-sectional crystallographic texture of single PAN- and mesophase-pitch-based carbon fibers. The resulting preferred orientation in the axial direction is considerably higher than the values obtained from conventional X-ray diffraction measurements on fiber bundles. A change in azimuthal width of the 002 reflection was observed across some of the fibers, which can be attributed to a radial folded cross-sectional texture for pitch-based fibers, and to a different preferred orientation of skin and core layers for PAN-based fibers.     

电沉积Fe-Co-Ni合金工艺

研究了镀液温度及pH值对Fe-Co-Ni三元合金沉积及其性能的影响,并用X射线衍射分析了阴极电位对镀层性能的影响。结构表明,当加入一定有机添加剂、镀液温度为50—60℃、pH值3．0～4．5及阴极电位控制在-1．2V,得到的三元合金光亮、耐蚀性能好、显微硬度高,其综合性能接近硬铬镀层。