代铬镀层--Ni-W、Ni-W-B非晶态合金镀层性能研究

通过在浓硝酸、ω=5％NaCl溶液c=1mol/L H2SO4溶液中的浸渍试验,研究了不同基体上的Ni-W非晶态合金镀层的耐蚀性;通过测定在ω=5％ NaCl溶液及c=1mol／1．的HNO3溶液、H2SO4溶液、HCl溶液中的阳极极化曲线,研究了Ni-W非晶态合金镀层薄膜本身的耐蚀性;采用线性极化方法对Ni—W—B非晶态合金镀层在u=5％ Na—Cl溶液、c=1mol／L H2SO4溶液及HNO3溶液中的腐蚀速度进行了测定,并测定了以上2种非晶态合金镀层的硬度与耐磨性.结果表明．非晶态的Ni—W、Ni-W-B镀层比晶态镀层的耐腐蚀性能要好．而Ni—W—B非晶态合金镀层比Ni—W非晶态合金镀层的耐蚀性能又明显提高;经热处理后,Ni—W—B非晶态镀层的硬度值明显高于Ni—W非晶态镀层,耐磨性能都提高了1倍以上Ni—W、Ni—W—B非晶态镀层极有望成为一种比较好的代铬镀层。     

Ni—W镀层的非晶化机制

用电沉积法制备Ｎｉ－Ｗ非晶态镀层，随着镀层中钨含量的增加，Ｎｉ－Ｗ合金镀层结构由晶诚向非晶态转变。Ｘ射线光电子能谱分析结果表明，Ｎｉ－Ｗ非晶态镀层中Ｎｉ，Ｗ均以零价态形式存在，没有形成金属间化合物。     

多层电镀提高Ni-P合金镀层防护性能的研究

提高Ni－P合金非晶态镀层防护性能的关键是消除针孔和微观缺陷。测试表明，多层电镀是减少孔隙率的有效途径。扫描电镜对镀层的微观测试为此提供了理论根据。     

电镀Ni-Fe-P合金硬度控制

电沉积Ni-F3-P非晶态合金晶化后具有很高的显微硬度，可作为表面耐磨镀层。研究了镇波成分、工艺参数、镀层热处理温度和时间等因素对Ni－Fe-P合金镀层显微硬度的影响规律。研究结果可根据生产需要，实现对Ni-Fe-P合金镀层显微硬度的控制。     

Fe—P非晶态合金电镀膜韧性研究

用直流电镀得到的Ｆｅ－Ｐ非晶态合金镀层脆性大。本工作研究了使用交、直流迭加电流和周期换向电流进行电镀时，电流参数对Ｆｅ－Ｐ非晶态合金镀层脆性的影响，以及在镀液中加入添加剂时镀层脆性的变化。试验表明，选择合适的迭加电流及周期换向电流参数可以使Ｆｅ－Ｐ非晶态合金镀层的韧性得到改善；糖精对改善Ｆｅ－Ｐ非晶态合金镀层的韧性有一定作用，但不是很显著。     

盐酸介质中镍基合金镀层的电化学腐蚀行为

在含有硫酸镍、钨酸钠和柠檬酸三铵的电解液中获得镍一钨合金电沉积层。在分别含有二甲基胺硼烷和二氧化锆粒子的上述电解液中,电沉积获得Ni—W—B合金和Ni—w—(ZrO2)复合镀层。采用电化学实验方法研究所获得的Ni—W、Ni—W—B和Ni—W—(ZrO2)镀层在盐酸介质中的腐蚀行为,结果表明：所获得的镀层均有较好的耐蚀性;Ni—W和Ni—W—B镀层比Ni—W—(ZrO2)镀层有较好的抗腐蚀能力。     

化学镀Co一W—P三元合金的研究

研究了镀液中各组分及pH值与镀层中钨、磷含量的关系，获得Co73W16P11合金镀层，并通过人工汗液浸泡试验比较了Co-W—P合金镀层与不锈钢、Co-P、Ni—W—P、Ni—P合金镀层的耐蚀性。     

非晶态镀层的进展

概述了非晶态镀层的发展趋势，重点讨论了金属－金属系中Ｆｅ－Ｗ、Ｆｅ－Ｍｏ、Ｎｉ－Ｗ、Ｎｉ－Ｍｏ、Ｃｏ－Ｗ，金属－半金属系中Ｎｉ－Ｐ、Ｃｏ－Ｐ、Ｎｉ－Ｍｏ－Ｐ、Ｎｉ－Ｗ－Ｐ、Ｆｅ－Ｎｉ－Ｃｒ－Ｐ，Ｃｒ－Ｃ等非晶态镀层的组成，结构，特性等。     

Ni-W合金电镀研究现状及发展趋势

本文综述了Ni—W合金的反应机理，镀层结构与性质，并介绍了Ni—W三元合金镀层与复合镀层的性质特点，最后指出了今后的发展趋势。     

非晶态Ni—P合金电镀层耐蚀性的研究

用极化曲线测试法，交流阻抗法以及失重法等手段研究了Ｎｉ－Ｐ非晶态合金在酸，碱，盐体系中的耐蚀性。结果表明，Ｎｉ－Ｐ非晶态电镀层耐蚀性较纯镍镀层要好的多。     

Ni—W非晶态镀层的制备和性能研究

提出了电沉积Ｎｉ－Ｗ非晶态合金镀层的方法，分析了镀液组成、温度、ｐＨ值、电流密度对镀层组成和结构的影响。采用热处理方法和ｘ－射线光电子能谱分别测试了镀层的热稳定性、耐蚀性。     

Electrodeposition of amorphous gold alloy films

The process for electroplating amorphous gold-nickel-tungsten alloy that we developed previously based on the addition of a gold salt to a known amorphous Ni-W electroplating solution was investigated further using the X-ray diffraction (XRD) method for the purpose of quickly surveying the effects of various experimental variables on the microstructure of the alloy. In this system the gold concentration in the plating bath was found to be critical; i.e., when it is either very low or very high, the deposit becomes crystalline to XRD. The deposit composition varies linearly with the mole ratio of Au to Ni in solution, and the alloy deposit is amorphous to XRD when the atomic ratio of Au/Ni in the deposit is between 0.5 and 1.5. At suitable concentrations of the metal ions, the deposit contains essentially no tungsten. By extending the work on the Au-Ni-W system, an amorphous Au-Co alloy plating process was also developed.     

电沉积非晶合金的形成条件

通过对Fe-W、Ni-W等9种非晶合金电沉积过程的分析,总结了电沉积条件(镀液组成、电流密度、镀液温度、pH)及镀层组成对镀层结构的影响,认为电沉积条件直接影响镀层中添加元素的含量,间接影响镀层结构。添加元素及其含量才是形成非晶镀层的决定性因素。     

钴硼合金化学镀工艺及其性能研究(Ⅱ)

采用化学镀制得钴硼磁性合金镀层,利用X射线衍射技术、透射电子显微技术和扫描电子显微技术研究了镀层在镀态以及不同热处理温度下的组织结构。另外,研究了热处理温度对镀层硬度和矫顽力的影响。钴硼合金在镀态下为非晶态结构,经热处理后,镀层向晶态转变,在400℃时,硬度和矫顽力达最大。     

钨对化学镀Ni-W-P合金镀层结构及性能的影响

通过不同的化学镀工艺配方,获得了4种不同钨含量的化学镀Ni-W-P三元合金镀层.研究了钨含量对镀层结构、硬度及在5%H2SO4溶液中耐蚀性的影响规律.研究发现,化学镀Ni-W-P三元合金镀层的结构受镀层中钨含量的影响较大,非晶态Ni-W-P三元合金镀层所需磷含量较非晶态Ni-P二元镀层所需磷含量要低,并且钨含量越高,所需磷含量越少;镀层硬度随镀层结构从非晶态→混晶态→纳米晶态转变而增加;镀层的耐蚀性随镀层中钨含量增加而变好,且非晶态镀层较混晶态和纳米晶态镀层更易形成钝化区.     

电沉积非晶态合金镀层磁性的控制

磁性元件薄膜化促进了磁性镀层的开发与应用。综述了镀液及镀层成分、电沉积工艺、镀层厚度及热处理对电沉积非晶态镀层性能的影响，以便在实际应用中控制非晶态合金镀层的磁性。     

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.     

Electrochemical characterization of Ni–P and Ni–Co–P amorphous alloy deposits obtained by electrodeposition

Ni–P and Ni–Co–P amorphous alloy deposits were obtained by electrodeposition at 80 °C on carbon steel substrates. The influence of the electrolyte Co²⁺ concentration and of applied current density was investigated. The corrosion behaviour of amorphous and crystalline deposits was evaluated by polarization curves and electrochemical impedance spectroscopy in NaCl 0.1 M solution at room temperature. Impedances were measured for samples under total immersion (free potential against time) and for polarized samples in predefined regions of the polarization curves. It was found that the alloy deposit composition is highly affected by the composition of the electrolyte but displays no significant dependence on applied current density. The results showed that the presence of Co on Ni–P amorphous alloys improves the deposit performance in the studied corrosive medium. It was also verified that the amorphous structure provides higher corrosion resistance to both Ni–P and Ni–Co–P alloys.     

Establishing relationships between bath chemistry, electrodeposition and microstructure of Co-W alloy coatings produced from a gluconate bath

Electrodeposited Fe group: W and Mo alloys have the potential to replace hard Cr coatings for use in engineering applications where wear and corrosion resistance are needed. Electrochemical studies have concentrated in the past on Ni-W alloy deposition, but now interest in Co-W alloys has developed as they possess lower coefficients of friction when in contact with another metal. The most attractive coating composition is in the range 14-20 at.% W, if controlled deposition promotes crystalline alloys of high hardness, rather than softer amorphous alloys containing >20 at.% W. This paper employs ammonia free baths with low concentrations of cobalt and sodium tungstate and varying additions of sodium gluconate to produce alloys at close to 50% efficiency. Voltammetry, UV and visible spectrometry, and potentiostatic deposition have been performed on such baths, whilst XRD, SEM and TEM observations have been made on the deposits. This aims to optimise the process and to understanding the relationships between bath contents, electrochemical kinetics and alloy composition. Efficient deposition of coatings with hardness values up to 1000 kgf mm⁻² occurred from a bath containing a high concentration of gluconate. Such deposits arise from concentrations of Co-W-gluconate complexes which promote the formation of nanoscale alloy grains. Current densities up to 2.75 A dm⁻² in the agitated bath promoted deposition kinetics to form these highly orientated structures. These kinetics produced nano-segregation of W which may be assisted by the migration of Co-W clusters to boundary sites during the growth of the deposit.