Wear and Corrosion Resistance of Electroless Plating Ni-P Coating on P110 Steel

In order to improve the surface performance and increase the lifetime of P 110 oil casing tube steel during operation, electroless plating was conducted to form Ni-P coating onto its surface. The surface morphology/element distribution and phase constitution of the Ni-P coating were analyzed using scanning electron microscope （SEM） equipped with energy dispersive spectrometry （EDS） and X-ray diffraction （XRD）. Tribological and electrochemical measurement tests were applied to investigate the wear and corrosion resistance of P110 steel and the Ni-P coating. The results showed that a uniform and compact, high phosphorous Ni-P coating was formed. The obtained Ni-P coating indicated certain friction-reduction effect and lower mass loss during friction-wear tests. The Ni-P coating also exhibited higher corrosion resistance in comparison with bared P 110 steel. The obtained N i-P coating has significantly improved the surface performance of P110 steel.

The study of electroless Ni-W-P alloy plating on glass fibers

Ni-W-P coatings were deposited on the surface of glass fibers by the electroless plating process. The bath was very stable through the palladium salt test. There was no phenomenon of peeling and blistering on the surface of the Ni-W-P alloy glass fibers in the thermal shock test. It showed that the deposit had high impact strength and good adhesion. The morphology of the coatings was observed by scanning electron microscope （SEM）. The elements and their contents were tested and analyzed by energy dispersion spectrometer （EDS）. The tungsten content reached up to 12.1 wt.%. The effects of the concentrations of NiSO4, Na2WO4, and NaH2PO2.H20 on the conductivity of the coatings were studied. The resistivity of the Ni-W-P alloy glass fibers reached 7.39 × 10^-3 Ωcm. The alloy coatings on glass fibers were analyzed by XRD. The results indicated that the deposit had an amorphous structure and good heat stability. The suitable work temperature range was lower than 190℃. Finally, the electromagnetic parameters of the Ni-W-P alloy glass fibers were tested and analyzed primarily. The magnetic loss reached 0.04023 and the dielectric loss reached -5.80239. The plated alloy is a kind of soft magnetic material.

Corrosion and wear properties of electroless Ni-P plating layer on AZ91D magnesium alloy

A direct electroless Ni-P plating treatment was applied to AZ91D magnesium alloy for improving its corrosion resistance and wear resistance. Corrosion resistance of the Ni-P coatings was evaluated by potentiodynamic polarization and immersing experiments in 3.5% NaCl solution. The wear resistance of the coatings was investigated by the wear track and the mass change after ball-on-disk experiment. The results show that corrosion resistance and wear resistance of the AZ91D alloy are greatly improved after direct electroless Ni-P plating. No discoloration is noticed until 4 d of immersion in 3.5% NaCl solution. Potentiodynamic polarization experiments show that the free corrosion potential of magnesium alloy is shifted from -1 500 mV to -250 mV and passivation occurs at 1 350 mV after direct electroless plating. The friction coefficients and wear rates of Ni-P coating and Ni-P coating after tempering are 0.10-0.351, 9.038×10-3 mm3/m and 0.13-0.177, 3.056×10-4 mm3/m, respectively, at a load of 1.5 N with dry sliding. Although minor hurt on corrosion resistance was caused, significant improvement of wear resistance was obtained after tempering treatment of the coating.

Mechanical assisted electroless barrel-plating Ni-P coatings on magnesium alloy

A mechanically assisted electroless barrel-plating Ni-P was carried out in a rolling drum containing Mg alloy specimens and ceramic balls, which was submerged in a bath containing electroless plating solution deposited by this novel technique have a It is demonstrated that the Ni-P coatings crystallized Ni-P solid solution structure, showing fine-grains, higher hardness, and higher corrosion resistance compared with the conventional electroless plated amorphous Ni-P coatings. After heat treatment at 400 ℃ for 1 h, the structure of such Ni-P coatings were transformed to a structure with Ni-Ni3P double phases, and cracks in these coatings could not be observed, whereas cracks appeared seriously in the conventional electroless plated Ni-P coating after same heat treatment. Therefore, both hardness and corrosion resistance of these Ni-P coatings can be improved further by heat treatment. All of these beneficial effects can be attributed to the role of mechanical attrition during the mechanically assisted electroless barrel-plating process.

Effect of Heat Treatment on Structure and Magnetic Performance of Ni-Fe-P Alloy Obtained by Electroless Plating

The electroless deposition of Ni68-Fe10.5-P21.5 alloy has been investigated. The crystallization behavior of the deposit was comparatively studied by using differential scanning calorimetry and X-ray diffractometry. The deposit transforms into a square Ni3P phase at 380. 0 ℃, then changes into a cubic FeNi3 phase at 490. 0 ℃. The microhardness, the size of the formed grains and the magnetic performance of the deposit increase with the increase of the heat treatment temperature below 500 ℃, then they decrease after this temperature. The effect of heat treatment time at 500 ℃ on the surface micromorphology, the structure and the magnetic performance of the deposit were also studied. The resuits show that with the increase of heat treatment time, the extent of crystallization of the deposit increases and the size of the formed grains becomes uniform. The results also show that the magnetic performance of the deposit under heat treatment for 40 min is maximal and then decreases with the increase of heat treatment time. The property change of the deposit is related to the crystal structure and the size of the formed grains of the deposit.

Electrochemical behavior of Cu-Zn-Al shape memory alloy after surface modification by electroless plated Ni-P

The electrochemical behavior of Cu-Zn-Al shape memory alloy (SMA) with andwithout electroless plated Ni-P was investigated by electrochemical methods, in artificial Tyrode'ssolution. The results showed that Cu-Zn-Al SMA engendered dezincification corrosion in Tyrode'ssolution. The anodic active current densities as well as electrochemical dissolution sensitivity ofthe electroless plated Ni-P Cu-Zn-Al SMA increased with NaCl concentration rising, pH of solutiondecreasing and environmental temperature uprising. X-ray diffraction analysis indicated that aftersurface modification by electroless plated Ni-P, an amorphous plated film formed on the surface ofCu-Zn-Al SMA. This film can effectively isolate matrix metal from corrosion media and significantlyimprove the electrochemical property of Cu-Zn-Al SMA in artificial Tyrode's solution.

Research of Kinetics of Electroless Ni-Cu-P Alloy Plating on Polyester Fabric

All the variables that may affect the Ni-Cu-P alloy deposition rate on polyester fabric were studied , and the activation energy and the reaction orders were determined. The deposition rate equation was also derived.

Preparation and characterization of bimetallic Pt^Ni-P/CNT catalysts via galvanic displacement reaction on electrolessly-plated Ni-P/CNT

Platinum-based bimetallic catalysts have broad applications in polymer electrolyte membrane fuel cells and water splitting. In this work,galvanic displacement reaction was employed to prepare Pt^Ni-P/CNT catalysts using electrolessly-plated Ni-P/CNT. These catalysts were extensively characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Catalytic activities towards methanol oxidation and hydrogen evolution reactions were evaluated and benchmarked with a commercial Pt/C catalyst. Uniform dispersion of Pt on Ni-P particles led to high Pt utilization, and the electrochemical surface area of Pt^Ni-P/CNT with 12.1% Pt loading was found to be 126 m2 gà1, higher than that of a commercial Pt/C(77.9 m2 gà1). The Tafel slopes for the Pt^Ni-P/CNT catalysts were also found to be smaller than that of Pt/C indicating faster kinetics for hydrogen evolution reaction.

Direct electroless Ni-P plating on AZ91D magnesium alloy

An electroless Ni-P plating treatment was applied on AZ91D magnesium alloy to improve its corrosion resistance. Optimum pretreatment conditions and optimum bath of electroless nickel plating for magnesium alloy were found through many experiments. In order to avoid bother of pre-plating medium layer, a set of procedure of direct electroless Ni-P under the acid condition was investigated. The properties of the coating with 10% phosphorus were investigated. The results show that a coating with high hardness, low porosity and good adhesive strength is obtained. X-ray diffraction patterns show that the structure of the coating is an amorphous phase. After annealing at 400℃, the amorphous phase of Ni-P is transformed to crystalline phases, and some intermetallics as Ni3P and Ni5P2 are deposited from Ni-P solid solution along with an enhancing hardness from Hv 450 to Hv 910.

Effects of Mm(NiCoAlMn)_5 hydrogen storage alloy coated with Ni-Co-P alloy by electroless plating on electrochemical properties of hydride electrodes

The effect of chemical plating with Ni Co P alloy on the properties of MH electrodes is investigated. The results show that the efficiency of storage alloy and the activation of MH electrode have been improved by introducing 1.74% cobalt in the Ni Co P alloy coating. The initial discharge capacity is 208 mAh/g. The maximum discharge capacity gets to 298.5 mAh/g. At the same time the cycle life of MH electrodes is improved. The discharge capacity of MH electrodes coated with Ni Co P is 88% of the maximum discharge capacity after 300 cycles. Whereas the discharge capacity of bare alloy electrodes retains 62% of the maximum capacity after 300 cycles. An increment of discharge capacity is mainly due to the superposition of the oxidation current of Co as well as improved efficiency of microcurrent collection. The effect of Ni Co P alloy coating by electroless plating on the kinetic properties of hydride electrode has been systematically investigated by electrochemical techniques. The results indicate that the kinetic properties of MH electrodes, including exchange current density, limiting current density, have been improved markedly. This improvement of kinetic properties leads to the decrease of the overpotential of anodic and cathodic polarization.

低浓度硫酸铜对化学镀Ni-P镀层微观结构及性能的影响

为改善镍磷(Ni-P)镀层的表面质量、提高Ni-P镀层的性能,在化学镀Ni-P镀液中加入少量的硫酸铜(CuSO_(4)·5H_(2)O)制备Ni-P镀层。利用扫描电镜、能谱仪、X射线衍射仪分析了镀层的表面形貌、成分和结构,研究了CuSO_(4)·5H_(2)O浓度对镀层的微观结构、表面粗糙度、光泽度、硬度、耐磨性和耐蚀性的影响。研究表明:当CuSO_(4)·5H_(2)O浓度为0.1 g/L时,镀层为致密的非晶态节瘤状组织,具有最佳的耐蚀性;当CuSO_(4)·5H_(2)O浓度为0.2 g/L时,镀层表面质量最好,硬度高、耐磨性优异,但镀层中出现少量微晶态Ni-Cu固溶体,耐蚀性下降;当CuSO_(4)·5H_(2)O浓度超过0.2 g/L后,镀层为混晶态菜花状组织,镀层表面的质量和耐蚀性随CuSO_(4)·5H_(2)O浓度的增加不断恶化。

超声功率对化学镀Ni-W-P镀层微观结构及性能的影响

目的提高Ni-W-P镀层的耐磨性和耐蚀性。方法以NiSO_(4)·6H_(2)O和Na_(2)WO_(4)·2H_(2)O为主盐配制化学镀液,将Q235钢前处理后在可调功率的超声设备中进行化学镀以获得Ni-W-P镀层。通过显微硬度测试、摩擦磨损实验、电化学实验分别评价Ni-W-P镀层的硬度、耐磨性和耐蚀性,通过扫描电子显微镜对表面、截面和磨痕形貌进行分析,通过X射线衍射仪分析镀层的物相组成。结果超声辅助化学镀可以细化晶粒、减少孔洞、提高镀层的致密性,降低镀层的磷含量,提高镀层的晶化程度,相同时间内可显著提高镀层厚度,但镀层与基体的结合强度会降低。超声功率75 W时:镀层厚度为不加超声的1.61倍;镀层最大硬度为674.80HV0.05;镀层的摩擦因数为0.38低于不加超声的摩擦因数0.47,且均低于Q235钢的摩擦因数0.58;磨损率为0.69×10^(-5)mm^(3)/(N·m)低于不加超声镀层的磨损率2.41×10^(-5)mm^(3)/(N·m),且均低于Q235钢的磨损率5.28×10^(-5)mm^(3)/(N·m);Q235钢的磨损失效形式为黏着磨损+磨粒磨损,Ni-W-P镀层的磨损失效形式为磨粒磨损+疲劳磨损;腐蚀电流密度2.23×10^(-7)A/cm^(2)低于不加超声的腐蚀电流密度2.21×10^(-6)A/cm^(2),均低于Q235钢的腐蚀电流密度2.08×10^(-5)A/cm^(2);腐蚀电位-0.362 V高于不加超声的-0.377 V,且均高于Q235钢的-0.611 V;镀层总电阻R_t为24338Ω·cm^(2)低于不加超声的10629Ω·cm^(2),且均高于Q235钢的592Ω·cm^(2),电化学极化测试结果与电化学阻抗测试结果表现出较好的一致性,样品耐蚀性显著提高。结论超声辅助化学镀可以细化晶粒、减少孔洞、提高镀层的致密性,降低镀层磷含量,提高镀层的晶化程度、硬度、耐磨性和耐蚀性。但超声的引入会导致镀层与基体的结合强度下降。

PRIMARY STUDY FOR THE TECHNOLOGY OF ELECTROLESS PLATING Fe-Al-P ALLOYS

Manuscript received 24 June 1999 The Fe Al P alloy deposits were plated on copper sheets by electroless plating. The change law of the deposition rate, composition, surface appearance and structure for the deposits was studied by changing the metallic salt ratios (AlCl 3/AlCl 3+FeSO 4), the concentration of metallic salt AlCl 3 and reductant NaH 2PO 2. The optimum plating bath was obtained. It was found that the choices of ligand and reductant were the key of increasing Al content for the deposits.

Electroless Ni-Co-P Coating of Cenospheres Using Ag(NH_(3))_(2)^(+) Activator

Electroless Ni-Co-P-coating of fly-ash cenosphere particles is demonstrated in the present investigation. The Electroless Ni-Co-P-coating process is modified by replacing the conventional sensitization and activation steps with only using activation step with Ag(NH3)2+ activator. The cenospheres are characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), X-ray diffraction analysis (XRD) and X-ray photoelectron spectroscopy (XPS) during and after the coating process. Relatively uniform coating is obtained under the given coating conditions. The possible mechanism of electroless Ni-Co-P-coating of cenospheres utilizing Ag(NH3)2+ activator is suggested. The low density Ni-Co-P coated cenospheres may be utilized for manufacturing conducting polymers for EMI-shielding application and microwave absorbing materials.

紫铜表面Ni-Mo-P三元合金镀层工艺的优化及耐蚀性能研究

为探究工艺参数对紫铜基底化学镀Ni-Mo-P三元合金镀层耐蚀性的影响,采用单因素变量法,通过改变镀液pH值、Na_(2)MoO_(4)·2H_(2)O浓度和施镀温度,以质量分数3.5%NaCl溶液中的电化学测试结果为衡量指标,确定Ni-Mo-P三元合金镀层最优的化学镀液配方和工艺参数。对该条件下镀层进行微观结构和元素组成分析,进一步探究了其耐腐蚀机理最优镀液配方和工艺参数,结果为:NiSO_(4)·6H_(2)O 27 g/L,NaH_(2)PO_(2)·H_(2)O 20 g/L,纳米复合添加剂30 g/L,Na_(2)MoO_(4)·2H_(2)O 4 g/L,SDBS 0.008 g/L,pH=9.0,温度90℃。在该条件下Ni-Mo-P三元合金镀层具有优异的耐腐蚀性,表面平整致密,以及良好的疏水性。镀层表面元素分布均匀,但Mo的含量增多导致P的含量下降,使其非晶态特征减弱。本研究中Ni-Mo-P三元合金镀层工艺为在紫铜表面制备优异耐蚀性能的多元镀层提供了新的思路。

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。

Ni-P基化学复合镀的研究与应用

综述了 Ni-P 基化学复合镀的研究概况,包括微米和纳米化学复合镀、镀层形成机理、工艺因素对镀层形成的影响、镀后热处理和镀层的组织结构性能,介绍了 Ni-P 基化学复合镀的应用情况,并对其发展进行了展望。

Ni-P化学镀的机理及其研究方法

Ni P化学镀镀液体系复杂 ,影响因素甚多 ,因此多种Ni P化学镀机理理论共存 ,综述并评价了目前流行的几种化学镀的机理理论 。

玻璃纤维表面化学镀Ni-P合金涂层的研究

采用化学镀工艺在玻璃纤维表面包覆一层Ni-P合金涂层,用扫描电子显微镜、X射线能谱仪、X射线衍射仪、热震实验对涂层的形貌、组成、结构和性能进行了表征。结果表明,玻璃纤维表面化学镀Ni-P合金涂层由直径为0.1-1μm的颗粒所组成,涂层厚度约为1-1.5μm。涂层与玻璃纤维之间的结合力好,电阻率达到1.25×10-3Ω.cm。化学镀玻璃纤维具有较好的导电性,可作为制备导电高分子材料的填料。