喷射电沉积纳米晶镍的研究

用喷射电沉积法制备纳米晶镍,研究了电解液喷射速度、电流密度、沉积速度等工艺参数之间的关系,分析了沉积层的组织结构。结果表明：电解液喷射速度为２～５．５ｍ／ｓ,电流密度在８０～１６０Ａ／ｄｍ＾２之间时,最大沉积速度为１４～３２μｍ／ｍｉｎ,沉积层外观光亮。ｘ－射线衍射谱观察和透射电镜的分析表明：沉积层平均晶粒尺寸为２０～３０ｎｍ,且存在（２２０）结构。     

电沉积纳米晶镍-铁-铬合金

采用直流和脉冲电沉积方式从三价铬的氯化物镀液中沉积出镍-铁-铬纳米合金镀层，利用扫描电镜分析镀层形貌及晶粒尺寸，研究了沉积速率，电流效率，三价铬浓度及pH值随沉积时间的变化关系，结果表明，脉冲电沉积所得镀层的结构和性能均优于直流电沉积，这是由于脉冲电沉积存在断电时间，使得电极表面扩散层中金属离子的浓度得到及时恢复。     

电沉积镍铁钨纳米晶合金及其表征

在含有FeSO4·7H20、NiSO4·6H2O、Na2WO4·2H2O、Na3C6H5O7·2H2O和YC-4添加剂的溶液中,电沉积制备了不同钨含量的镍铁钨合金,对所得镀层的化学组成、表面形貌、微观结构,显微硬度及耐蚀性进行了表征.随着镍铁钨合金镀层中钨含量的增加,其微观结构由晶态转变为非晶态.钨质量分数为21%的镍铁钨合金镀层表观光亮光滑,具有致密的纳米晶结构,其晶粒尺寸为30～40 nm,即使不通过热处理,也具有很好的显微硬度和耐蚀性.该工艺可望取代传统镀铬工艺.     

沉积时间对纳米晶Ni-Fe合金电沉积层耐蚀性的影响

采用直流电沉积法在黄铜基体上制备出纳米晶Ni-Fe合金,其成分为:Ni 76.6％±1.2％,Fe 23.4％±1.2％,晶粒尺寸约为9 nm.在质量分数为3.5％的NaCl溶液中,沉积时间为20 min时所得合金镀层的耐蚀性最好,自腐蚀电流密度约为0.453 μA/cm2,涂层电阻约为80 110 Ω;当沉积时间超过...     

电沉积Ni-Co合金工艺条件的研究

研究了硫酸镍 -硫酸钴 -氯化钠体系中钴含量在 4 0 %以下的 Ni- Co合金镀层的影响因素。讨论了温度、p H、电流密度、Ni/ Co质量比、时间等因素对镀层沉积速度和腐蚀速度的影响。通过试验得出了电沉积过程的最佳工艺条件。     

化学沉积Co-B纳米晶合金工艺的研究

采用正交实验法探索了化学沉积钴硼合金纳米晶涂层的制备工艺,并对其沉积速率进行了研究,从而得出较优的工艺参数,同时详细讨论了硫酸钴、酒石酸钠、DMAB(二甲基胺硼烷)、温度等因素对沉积速率的影响.     

电沉积Ni-Fe纳米合金工艺研究

采用直流电沉积方法在镀液中加入复合有机添加剂制备了镍铁纳米合金镀层。利用扫描电镜分析镀层形貌及晶粒尺寸,研究了硫酸亚铁铵浓度、电流密度、pH值对镀层中铁含量的影响,测定了镀层的耐腐蚀性能及结合力。结果表明,该纳米镀层表面致密、平整,且结合强度、耐腐蚀性能优良。     

电沉积Ni-W非晶态合金

研究电沉积Ni-W合金的非晶化条件,划分出结晶与非晶结构区。由X衍射实验判定,Ni-W合金镀层足以Ni为溶剂、W为济质的置换型固溶体,呈面心立方结构。通过计算晶格畸变度、晶粒直径及其随结构的变化,解释了非晶镀层的形成原因。测定了作品镀层在酸溶液中的腐蚀速率,用X射线光电子能谱仪(XPS)对其在酸溶液中形成的钝化膜进行了测试,钝化膜的化学结构式为i(OH)_2·WO_3、·nH_2O。     

添加剂对喷射电沉积纳米晶Co-Ni合金的影响

在氯化镍-硫酸钴体系电解液中采用添加剂喷射电沉积纳米晶Co-Ni合金,测定了其阴极极化曲线.研究了添加剂对阴极过电位、电流效率、镀层中Co含量、镀层的相结构、晶粒尺寸、表面形貌及显微硬度、软磁性能等影响.结果表明:添加剂增加了极化作用,影响了Co、Ni电沉积的动力学过程.当添加剂为2.5g/L时,与未加添加剂相比较,阴极过电位从3.594V增大到4.755 V,电流效率和沉积层中Co含量变化不大,但沉积层晶粒尺寸从12.8 nm明显降低到5.5 nm,维氏硬度从423升高到511,同时Co-Ni合金的软磁性能得以提高.     

电沉积梯度Ni-Co纳米合金镀层的研究

采用直流电沉积技术制备了梯度Ni-Co纳米合金厚镀层。测定了该镀层的内应力及显微硬度,采用X射线衍射仪及能谱仪分别对镀层的晶相结构与成分进行了分析,采用扫描电镜对镀层的表面形貌和磨痕进行了观察,并对其摩擦、磨损性能进行了研究。结果表明,该合金镀层具有较好的成分梯度和相应的结构梯度,具有优异的抗磨减摩性能。说明梯度化的设计可以有效降低合金镀层的内应力,提高镀层的抗磨和减摩性能。     

化学沉积纳米晶Co-P合金及其沉积速率影响因素的研究

化学沉积可得到均匀、致密的纳米晶薄膜,是一种较为理想的纳米晶制备方法。采用正交实验优化了化学沉积纳米晶钴磷合金的工艺配方,研究了正交实验5因素如硫酸钴、柠檬酸三钠、硼酸、次磷酸钠和温度及负载因子、沉积时间对沉积速度的影响。研究获得的优化工艺配方和参数为:0 06～0 12mol/LCoSO4·7H2O,0 40～0 55mol/LNaH2PO2·H2O,0 15～0 3mol/LNa3C6H5O7·2H2O,0 3～0 6mol/LH3BO3,50～80℃,负载因子0 4～0 8dm2/L。     

On the state of W in electrodeposited Ni-W alloys

We have derived an expression for the theoretical dependence of the Ni-W fcc phase lattice parameter on the atomic fraction of W, in a solid solution. This parameter was used to compare the actual quantity of W, in a solid solution of electrodeposited Ni-W alloys, with the value determined by EDX. It has been shown that not all of the W determined by EDX was present as a solute in the Ni-W fcc phase. The incorporation of tungstates prevailed at lower pH, while the presence of citric complexes dominated at higher pH values. This conclusion was based on the XRD phase analysis of electrodeposited alloys that were annealed in hydrogen or argon atmospheres at 1000 °C. The XRD data correlated well with the morphology results obtained via AFM. The incorporation of tungstates or citric complexes seems to be characteristic of the electrodeposited Ni-W alloys.     

脉冲占空比对Ni-W合金镀层耐蚀性的影响

采用脉冲电沉积方法在纯铜基体上制备出Ni-W合金镀层。研究了脉冲占空比(30%~60%)对镀层表面形貌、结构、成分和耐蚀性的影响。结果表明:制得的Ni-W合金镀层表面致密、平整,W的质量分数在46.84%~49.24%范围内窄幅波动,具有非晶态结构。脉冲占空比为50%时制得的镀层的耐蚀性最好。在3.5%的NaCl溶液中,自腐蚀电位较正,自腐蚀电流密度最小,电荷转移电阻最大。     

电沉积Ni-W梯度镀层及其结构表征

The Ni-W gradient deposit with nano-structure was prepared by an electrochemical deposition method.X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDXA) indicate that the crystallite size of the deposit decreases from 10.3nm to 1.5nm and the crystal grating aberrance increases with the increase of W content in the growing direction of the deposit. The structure of deposit changes from crystalline to amorphous stepwise with associated increase of crystal grating aberrance, and presents gradient distribution. These show that the deposit isgradient with nano-structure.     

复合电沉积(Ni-W)-PTFE工艺的研究

通过电沉积方法制得了(Ni-W)-PTFE复合镀层并研究了钨酸钠质量浓度和PTFE复配液质量浓度对复合镀层的成分及性能的影响。结果表明,钨酸钠质量浓度提高,镀层中钨的质量分数以及镀层的耐蚀性都有提高,PTFE复配液质量浓度提高会使镀层的摩擦系数降低,使镀层自润滑性得到改善。     

脉冲频率对Ni-W合金镀层耐蚀性的影响

采用脉冲电沉积方法在黄铜基体上制备出Ni-W合金镀层。研究不同脉冲频率(0.5~20.0kHz)对镀层表面形貌、微观结构、硬度及耐蚀性的影响。所有Ni-W合金镀层的表面均致密平整,W的质量分数为42.41%~48.92%。脉冲频率为5.0kHz时制备的Ni-W合金镀层在3.5%的NaCl溶液中的耐蚀性最好,自腐蚀电流密度为2.532μA/cm2,自腐蚀电位为-327mV。     

峰值电流密度对脉冲镀镍钴合金纳米镀层机械性能的影响

研究了峰值电流密度对脉冲镍钴合金纳米镀层的成分、晶粒尺寸、显微硬度、抗拉强度的影响.结果发现:在一定范围内,峰值电流密度的增大,可以降低镀层钴含量、表面粗糙度和晶粒尺寸,使菜花胞状结构更明显,提高镀层显微硬度(最高可达600 kg/mm2)和抗拉强度(最高可达1 200 MPa).然而,峰值电流密度太大又会使显微硬度和强度下降.与采用类似方法制得的纯镍纳米镀层相比,镍钴镀层的显微硬度并未明显升高.这说明在该纳米材料中,固溶强化效果并不很明显,而以细晶强化为主.     

High-speed jet electrodeposition and microstructure of nanocrystalline Ni-Co alloys

The jet electrodeposition from watts baths with a device of electrolyte jet was carried out to prepare nano-crystalline cobalt-nickel alloys. The influence of the concentration of Co²⁺ ions in the electrolyte and electrolysis parameters, such as the cathodic current density, the temperature as well as the electrolyte jet speed, on the chemistry and microstructure of Ni-Co-deposit alloys were investigated. Experimental results indicated that increasing the Co²⁺ ions concentration in the bath, the electrolyte jet speed and decreasing of the cathodic current density and decrease of the electrolyte temperature all results in an increase of cobalt content in the alloy. Detailed microstructure changes upon the changes of alloy composition and experimental conditions were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD results show the Ni-Co solid solution was formed through the jet electrodeposition. Phase constitution of solid solution changes progressively under different electrolyte concentration. Alloys with low Co concentration exhibit single phase of face-centered cubic (fcc) structure; The Co concentration over 60.39 wt.%, the alloys are composed of face-centered cubic (fcc) phase and hexagonal close-packed (hcp) phase. Furthermore, the formation of the nanostructured Ni-Co alloy deposit is investigated. Increasing the Co²⁺ ions concentration in the bath, the cathodic current density, the electrolyte temperature and the electrolyte jet speed all result in the finer grains in the deposits. Additives such as saccharin in the electrolyte also favor the formation of the finer grains in the alloy deposits.