化学镀Ni-P镀层耐蚀性的研究进展

文章通过介绍化学镀Ni-P反应机理、耐蚀性机理和镀层封孔技术等理论知识,同时对化学镀Ni-P技术的稀土催化、多元金属共沉积和多层复合三大趋势进行了归纳,并对化学镀Ni-P技术未来的发展进行了展望。

镁合金上高耐蚀性组合镀层

开发了一种镁合金上组合镀层 ,化学镀层与碱性锌镍镀层的组合 ,镀层耐蚀性大幅度提高。厚度不超过 35 μm的镀层可以承受 80 0～ 10 0 0h的中性盐雾腐蚀 ,镀层可作为镁合金苛刻环境下的保护镀层。

化学镀Ni-P合金工艺及镀层耐蚀性的研究

介绍了一种高稳定性的化学镀Ni-P合金工艺 ,讨论了各种成分和工艺条件对Ni-P合金镀层中wP 的影响 。

涤纶短纤后处理设备的耐蚀耐磨涂镀层

论述了陶瓷涂层、电镀梨面铬等耐蚀耐磨涂镀层的特性及其在涤纶短纤后处理设备制造中的应用,解决了此类设备制造中的难题。并指出伴随着纺织工业的发展将会有更多的新型表面处理工艺得到广泛的应用。

浅谈镀前处理对硬铬镀层耐蚀性的影响

0 前言 电镀硬铬过程中最常见的镀层缺陷是粗糙、毛刺、电击伤、麻点和针孔等。本文主要解释硬铬镀层出现麻点的原因并提出相应的控制措施。 1产生的原因 基体金属长时间放置，会导致其局部产生点状、线状的锈斑。锈蚀会使基底表面形成凹坑，硬铬镀层本身没有整平能力，只能覆盖凹坑，无法将其填平[1]。硬铬镀层经抛光，锈斑区域的镀层厚度明显变薄，增加硬铬镀层微裂纹延伸至基底的可能性，降低镀层的耐蚀性[2]。下面就其根源进行分析。 1．1镀前活塞杆磨削质量分析 磨削过程仅使用一种型号的砂轮对工件进行磨削，省去精磨砂轮。该种做法导致粗磨产生的缺陷无法通过后续抛光予以消除，在工件上留下深度咬伤或划痕。如果镀铬前不能消除这些缺陷，进入电镀工序后镀层出现麻坑，影响镀层的耐蚀性[3]。

电镀前弱腐蚀对镀层耐蚀性的影响

为提高减振器连杆表面电镀硬铬层的耐腐蚀性能及使用寿命,研究了电镀前弱腐蚀对镀层耐腐蚀性能的影响。结果表明,弱腐蚀溶液浓度、电流密度和通电时间对镀层耐腐蚀性能均有影响,采用适当的弱腐蚀工艺可提高硬铬层的耐腐蚀性能。

高磷高稳定性高耐蚀性化学镀镍磷合金镀液研究

采用正交试验法研究了络合剂、促进剂和 pH值对镀层和溶液性能的影响 ,并验证了促进剂和氯化稀土对提高镀层磷含量、耐蚀性和镀液稳定性均有良好的作用 。

掺入稀土元素Ce的铝镀层研究

在AlCl3-NaCl-KCl-CeCl3的熔融盐中于钢铁基体上进行电镀,获得掺入Ce的铝镀层。利用X射线衍射、扫描电镜等测试了Al-Ce镀层的微观结构、表面形貌。在w(NaCl)=3.5%的NaCl溶液中,测试了该镀层的塔菲尔极化曲线。试验结果表明,在熔盐中加入CeCl3提高了镀层的耐腐蚀性能,加强了Al(222)相的生长。

酸性化学镀镍工艺研究

通过沉积速度、镀层耐蚀性和镀液稳定性的测试实验,研究了酸性化学镀镍工艺中复合添加剂,如稳定剂、络合剂、加速剂浓度对化学镀液速度、稳定性,镀层耐蚀性的影响,确定了所用添加剂的最佳浓度和工艺条件。当温度在90℃,pH在5.5时,所得镀层含磷量为7.8%,镀层光亮、耐蚀性优良。

Structure and effects of electroless Ni-Sn-P transition layer during acid electroless plating on magnesium alloys

An electroless ternary Ni-Sn-P transition layer with high corrosion resistance was applied for acid electroless nickel plating on magnesium alloys. The surface morphologies and microstructure of the traditional alkaline electroless Ni-P and novel Ni-Sn-P transition layers were compared by SEM and XRD, and the bonding strengths between the transition layers and AZ31 magnesium alloys were tested. The corrosion resistance of the samples was analyzed by porosity test, potentiodynamic polarization, electrochemical impedance spectroscopy（EIS） in acid electroless solution at p H 4.5 and immersion test in 10% HCl. The results indicate that the transition layer is essential for acid electroless plating Ni-P coatings on magnesium alloys. Under the same thin thickness（-6 μm）, the electroless Ni-Sn-P transition layer possesses superior properties to the traditional Ni-P transition layer, including high amorphization, smooth and dense surface without pores, enhanced bonding strength and corrosion resistance. Most importantly, acid electroless Ni-P coatings can be successfully deposited on magnesium alloys by using Ni-Sn-P transition layer.

镁合金化学镀镍-磷新工艺

研究了一种新的镁合金化学镀镍-磷工艺,该工艺使用简单无害环境的前处理工艺,化学镀过程易于控制,并且在较大程度上降低了镁合金化学镀的成本,在化学镀过程中不产生对环境有害的物质,镀层耐蚀性良好。

Effect of mechanical attrition on microstructure and property of electroplated Ni coating

Ni coating was deposited on carbon steel by a mechanical attrition enhanced electroplating （MAEE） process. During the electroplating, the mechanical attrition（MA） was introduced by impact of glass balls on the sample surface with a special vibrating frequency. The surface and cross-sectional images of Ni coating were observed with SEM. The microstructure and crystallinity of coating were examined with TEM and XRD. The electrochemical performance of coating was measured with polarization curves and electrochemical impedance spectroscopy （EIS） and its mechanical behaviours, such as tensile strength and hardness, were studied. The results show that the MA has significant effects on the microstructure and property of the electroplated Ni coating. By MA, the coating becomes smooth, compact, thin and has refined grains and is free of cracks and pores. Consequently, the adhesion, tensile strength, hardness and corrosion resistance of coating are improved significantly.

Corrosion properties of stainless steel 316L/Ni-Cu-P coatings in warm acidic solution

In order to improve corrosion resistance of stainless steel 316L in warm acidic solution, Ni？Cu？P coatings with high copper and phosphorus contents were deposited onto stainless steel 316L substrates via electroless plating. The structure of the film and its resistance to corrosion in a warm acidic environment were investigated using scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction spectrometry （XRD）, polarization curves, electrochemical impedance spectroscopy （EIS）, and dipping corrosion tests, respectively. The results demonstrate that Ni？Cu？P coatings consist of two types of nodules, which are 19.98% Cu and 39.17% Cu （mass fraction） respectively. The corrosion resistance of the 316L substrate when subjected to a warm acidic solution is significantly improved by the addition of the new type of the Ni？Cu？P coating. The as-plated coatings demonstrate better corrosion resistance than annealed coatings. As-plated coatings and those annealed at 673 K are found to corrode selectively, while pitting is observed to be the main corrosion mechanism of coatings annealed at 773 and 873 K.

钢铁热镀锌层的合金化处理

钢铁热镀锌后进行退火合金化处理，改变镀层组织结构，促使η相和ζ相向δ１相转变，从而使镀层均匀性试验ＣｕＳＯ４浸渍次数由５次提高到１０次以上，且明显改善镀层结合力和耐蚀性．考虑到热镀锌工艺因素和合金化处理工艺因素等进行正因素正交设计，正交试验结果表明，在Ｚｎ—０．０７％Ａｌ镀液中，于４５０～４８０℃进行浸镀，然后在４５０～５１０℃进行合金化处理，可获得性能优良的热镀锌层．

Pulse electroplating of Ni-W-P coating and its anti-corrosion performance

Ni-W-P coatings were electrodeposited on copper substrates by pulse electroplating.Effects of electrolyte pH(1-3),temperature(40-80°C),average current density(1-7A/dm2)and pulse frequency(200-1000Hz)on deposition rate,structure and corrosion resistance performance of Ni-W-P coatings were studied by single factor method.Surface morphology,crystallographic structure and composition of Ni-W-P coatings were investigated by means of scanning electron microscopy,X-ray diffractometry and energy dispersive X-ray spectroscopy,respectively.Corrosion resistance performances of Ni-W-P coatings were studied by potentiodynamic polarization and electrochemical impedance spectroscopy in3.5%NaCl solution(mass fraction)and soil-containing solution.It was found that the pulse electroplated Ni-W-P coatings have superior corrosion resistance performance and the electroplating parameters significantly affect the structure and corrosion resistance performance of Ni-W-P coatings.The optimized parameters of pulse electroplating Ni-W-P coatings were as follows:pH2.0,temperature60°C,average current density4A/dm2,and pulse frequency600Hz.The Ni-W-P coating prepared under the optimized parameters has superior corrosion resistance(276.8kΩ)and compact surface without any noticeable defect.

Electrochemical evaluation of zinc and magnesium alloy coatings deposited on electrogalvanized steel by PVD

Zinc alloy coating attracted much attention due to its high anti-corrosive properties.Particularly,zinc alloy coatings containing magnesium was considered a promising metallic alloy due to a remarkable improvement of corrosion resistance.The proper magnesium content for Zn-Mg alloy coatings was studied.The samples were prepared using thermal evaporation method.The influence of Zn-Mg alloy coating on corrosion resistance was evaluated using immersion test,potentiodynamic test,and galvanic test in 3% NaCl solution at room temperature.The results show that the corrosion resistance of Zn-Mg alloy coatings is strongly dependent on magnesium content.Corrosion potential decreases with increasing magnesium content,whereas current density increases up to 15% magnesium content,and passivity region was found only in Zn-Mg coatings.

Effect of sodium lauryl sulphate on microstructure, corrosion resistance and microhardness of electrodeposition of Ni-Co3O4 composite coatings

Ni?Co3O4 composite coatings were electrodeposited on mild steel surface from a Watts-type bath in the presence of sodium lauryl sulfate(SLS).The dispersed Co3O4 particles in the presence of SLS have a greater tendency to move towards cathode and get incorporated in the coating.SLS modifies chemical composition,surface morphology and microstructure of the Ni?Co3O4 composite coating.The developed composite coating exhibits higher corrosion resistance and microhardness than the pure nickel coating.The loadings of bath solution with different concentrations of Co3O4 particles in the presence of SLS provide hydrophobic nature to the coating surface,which is much effective in enhancing the corrosion resistance of Ni?Co3O4 composite coating.The agglomeration of Co3O4 particles(>3 g/L)under high bath load condition develops defects and dislocation on the coating surface,which results in lower corrosion resistance of the deposit.The mechanical properties of the hydrophobic coatings were assessed by the linear abrasion test.

BH-88三价铬镀铬工艺

与传统的六价铬电镀工艺相比，广州市二轻研究所推出的BH-88三价铬镀铬工艺具有电流效率高，分散能力、覆盖能力好，镀层耐蚀性能优异等特点，研制的阳极为贵金属氧化物涂层阳极，可明显提高镀液稳定性等其他性能。此三价铬电镀工艺，可降低能耗30％以上，并从源头上消除六价铬的污染，具有显著的经济效益和社会效益。

线材镀锌工艺的改进

0前言目前线材镀锌普遍使用单盐硫酸锌工艺,其具有镀液简单、成本低廉、镀层光亮等优点。然而,该工艺使用表面活性剂和苄叉丙酮配制的光亮剂,存在镀层耐蚀性差、废水COD高、镀锌丝不耐高温、不适合二次加工等缺点。