表面活性剂对镁合金Ni-P-nano-Si_3N_4化学复合镀层组织和性能的影响

研究了表面活性剂对AZ31镁合金Ni-P-nano-Si3N4化学复合镀层形貌、镀速、镀层中nano-Si3N4颗粒的含量以及镀层硬度的影响。结果表明,采用阴离子表面活性剂,使Ni-P-Si3N4镀层的组织均匀且致密,镀层的硬度和沉积率都较高。

表面活性剂在Ni-P化学复合镀中的应用

恰当地选择和使用表面活性剂是分散镀液中不溶性颗粒的一种有效方法。对化学复合镀机理及表面活性剂在化学复合镀中的分散机理进行了探讨。介绍了表面活性剂在化学复合镀中的应用情况。对表面活性剂在化学复合镀中的广阔应用前景进行了展望。

表面活性剂对镁合金化学复合镀Ni-P-SiC的影响

本工作系统地考察了十二烷基苯磺酸钠(ABS-Na)、十二烷基硫酸钠(DS)、聚乙二醇(6000)(PEG(6000))、吐温-80(Tween-80)等表面活性剂及其组合对镁合金化学复合镀Ni-P-SiC的镀液稳定性、镀速、镀层表面形貌和性能的影响,并优选了适合镁合金化学复合镀Ni-P-SiC镀层的表面活性剂。结果表明:随着表面活性剂加入,镀液稳定性明显改善;表面活性剂的种类对镀速有重要影响,含十二烷基苯磺酸钠+聚乙二醇(6000)复合型表面活性剂的镀液镀速最快。综合考虑复合镀层的表面质量、显微硬度和耐腐蚀性能,优选的适于镁合金化学复合镀Ni-P-SiC的表面活性剂是十二烷基硫酸钠+聚乙二醇(6000)的复合物。

涤纶织物化学复合镀Ni-P-纳米ZnO

为了研究纳米ZnO微粒对化学镀镍织物电磁波屏蔽和耐磨性能的影响,采用化学复合镀技术制备了Ni-P-ZnO复合镀层。利用SEM、EDX、XRD和TG分析手段对化学镀层的组织特征、相结构转变、热稳定性进行了分析,结果表明:涤纶织物经过纳米ZnO微粒复合镀Ni-P之后,热起始分解温度有所下降;化学镀镍液中添加纳米ZnO微粒后,Ni-P镀层结构没有发生改变;当增重率和镀层成分相同时,镀层致密性对电磁波屏蔽性能影响显著;纳米ZnO微粒的加入使镀速加快,镀层孔隙率增大,致密性变差,Ni-P镀层与纤维基体的结合牢度受到影响,从而使纳米ZnO微粒复合镀Ni-P织物的耐磨性变差。

硬质合金表面Ni-P/纳米Ti(C,N)化学复合镀研究

研究了硬质合金表面Ni P 纳米Ti(C,N)化学复合镀工艺以及热处理对复合镀层性能影响的规律。结果表-);2)较好的明:1)施镀工艺中各因素对镀速影响的显著性顺序是:温度→pH值→纳米Ti(C,N)加入量→χ(Ni2+ H2PO2施镀工艺为:28g L氯化镍、25.76g L次亚磷酸钠,50g L氯化铵、45g L柠檬酸钠,0.001g LPbCl2,6g L纳米Ti(C,N),pH=10,温度为80℃。3)Ni P 纳米Ti(C,N)复合镀层较优的热处理工艺为:在400℃保温150min。采用所推荐的施镀和热处理工艺,获得了硬度是硬质合金基体硬度的2.16倍的Ni P 纳米Ti(C,N)复合镀层。并对以上结果产生的原因进行了简单讨论。

挤出机滤网保护板表面化学复合镀Ni-P-PTFE-MoS_2的强化效果

为了提高挤出机滤网保护板的表面润滑性能,通过化学复合镀在其表面制备了N i-P-PTFE-MoS2镀层,并通过显微硬度测试、热震试验和干摩擦试验考察了强化层的性能。结果表明,强化层具有良好的自润滑性能和抗磨性,经强化处理后的保护板使用寿命延长了1倍。

Preparation and tribological performances of Ni-P-multi-walled carbon nanotubes composite coatings

Multi-walled carbon nanotubes （MWNTs） were wet-milled in the presence of ammonia and cationic surfactant and then used as reinforcements to prepare Ni-P-MWNTs composite coatings by electroless plating. The tribological performances of the composite coatings under dry condition were investigated in comparison with 45 steel and conventional Ni-P coating, Micrographs show that short MWNTs with uniform length and open tips were obtained through the wet-milling process. The results of wear test reveal that the Ni-P-MWNTs composite coatings posses much better friction reduction and anti-wear performances when compared with 45 steel and Ni-P coating. Within the MWNTs content range of 0.74%-1.97%, the friction coefficient and the volume wear rate of the composite coatings decrease gradually and reach the minimum values of 0.08 and 6.22x10-15 m3/（N.m）, respectively. The excellent tribological performances of the composite coatings can be attributed to the introduction of MWNTs, which play both roles of reinforcements and solid lubricant during the wear process.

Effect of wear conditions on tribological properties of electrolessly-deposited Ni-P-Gr-SiC hybrid composite coating

The friction and wear properties of the electrolessly-deposited Ni-P-Gr-SiC composites were investigated. The effects of graphite content, load and rotation speed on the friction coefficient and wear resistance of the composite coatings were mainly investigated. The worn surface and cross section of the coatings were characterized by scanning electron microscopy and energy-dispersive X-ray analysis. The results show that the composite coatings reveal good antifriction and wear resistance due to the synergic effect of graphite and SiC particles. The formation of graphite-rich mechanically mixed layer （GRMML） on the surface of Ni-P-Gr-SiC coating contributes to the good tribological behavior of the wear counterparts and SiC particles play a load bearing role in protecting GRMML from shearing easily.

Electroless plating and growth kinetics of Ni-P alloy film on SiC_p/Al composite with high SiC volume fraction

After Sn/Pd activating, the SiCp/Al composite with 65% SiC (volume fraction) was coated by electroless Ni?P alloy plating. Surface morphology of the composite and its effect on the Ni?P alloy depositing process and bonding action of Ni and P atoms in the Ni?P alloy were studied. The results show that inhomogeneous distribution of the Sn/Pd activating points results in preferential deposition of the Ni?P alloy particles on the Al alloy and rough SiC particle surfaces and in the etched caves. The Ni?P alloy film has an amorphous structure where chemical bonding between Ni and P atoms exists. After a continuous Ni?P alloy film formed, electroless Ni?P alloy plating is not affected by surface morphology and characteristics of the SiCp/Al composite any longer, but by the electroless plating process itself. The Ni?P alloy film follows linear growth kinetics with an activation energy of 68.44 kJ/mol.

Study of Electroless Ni-P-CNTs Composite Plating

The electroless Ni-P-carbon nanotubes composite plating was studied on the copper substrate. Metallurgical microscope, scanning electronic microscope, X-ray diffractometer and micro hardness tester were used to study the structure, constitution and performance of the electroless Ni-P-carbon nanotubes composite deposit. Experiential results show that, with the increment of carbon nanotubes content in electroless plating solution, the grain size on the sample surface decreases whereas the density of grains and the hardness for composite deposit increases. Moreover, adding carbon nanotubes not only improves the degree of crystallization for the composite deposit but also helps their transformation from the amorphous state to the nanocrystal state.

Effect of Micro/nano-SiC_(P)on Microstructure and Properties of Electroless Ni-P-SiC_(P)Composite Coatings

Ni-P-SiC_(P) coatings were deposited on 42CrMo steel by electroless plating.The surface morphologies and phase structures of the Ni-P-SiC_(P) coatings processed under different SiC_(P) concentrations at different heat treatment temperatures were analyzed.The microhardness,corrosion resistance,and wear resistance of the Ni-P-SiC_(P) coatings were studied.Results show that Ni-P-SiC_(P) coatings exhibit cauliflower-like morphology.Increasing the SiC_(P) concentration can reduce the size of cellular structure.The microhardness and corrosion resistance are initially increased and then decreased with the increase in SiC_(P) concentration.The maximum microhardness and corrosion potential are 7379 MPa and−0.363 V,respectively,when the SiC_(P) concentration is 5 g/L.The Ni-P-SiC_(P) coatings exhibit an amorphous structure,and the width of the diffuse diffraction peak becomes narrower with the increase in SiC_(P) concentration.It is suggested that SiC_(P) inhibits the deposition of P and promotes the microcrystalline transformation.After heat treatment at 350℃,the Ni-P-SiC_(P) coatings are crystallized,resulting in the precipitation of Ni3P phase.Heat treatment at 400℃ for 1 h maximizes the structure.The synergistic effect of the Ni3P precipitate phase and SiC_(P) dispersion phase promotes the densification of the cellular structure,leading to the optimal microhardness(13828 MPa),optimal corrosion resistance(−0.277 V),and excellent wear resistance.The wear mechanism is dominated by micro-cutting abrasive wear with slight adhesive and oxidative wear.