化学镀Ni—P—SiC复合镀层的研究

研究了化学镀Ｎｉ－Ｐ－ＳｉＣ复合镀层的工艺、镀液组成和镀层性能。镀液中的ＳｉＣ微粒含量为１０￣１５ｇ／Ｌ时，可得以硬度和耐蚀都较高的镀层。     

化学复合镀镍-磷-氧化铝工艺研究

为进一步提高化学镀镍磷合金层的性能，在镀液中加入氧化铝粒子制度得镍－磷－氧化铝复合镀层。研究了镀液中各成分及操作条件对镀速的影响，并对镀层的组织结构和性能进行了测试。结果表明，该工艺镀液稳定性好，所得复合镀层的硬度和耐磨性优于镍磷合金镀层。     

复合电镀(Ni-P)石-墨工艺及镀层性能的研究

用复合电镀方法在低碳钢基体上镀覆(Ni-P)-石墨复合镀层.研究了表面活性剂、石墨微粒的悬浮量及阴极电流密度对镀层中石墨微粒含量的影响.结果表明,当镀液中石墨微粒约为12g/L、搅拌速度120 r/min、温度为45℃、pH为4,镀层中石墨微粒含量最高.对镀层的表面形貌、耐蚀性、硬度、减摩性及耐磨性进行了测定,与Ni-P合金镀层相比,(Ni-P)-石墨复合镀层有良好的综合性能.     

电刷镀／纳米级WC镀层修复机械设备磨损件的工艺研究

本文阐述了镍基纳米碳化钨复合电刷镀镀液的研制方法：制定了镍基纳米碳化钨复合电刷镀工艺优化过程；分析了镍基纳米碳化钨复合电刷镀镀层的微观组织、性能与强化机理；介绍了镍基纳米碳化钨复合电刷镀技术在机械设备维修中的应用。     

镍-钨-碳化钨复合电极在盐酸介质中的阳极极化行为的研究

复事电极发展迅速,应用广泛。为节约资源,回收废弃复合镀层中的金属元素,以镍－钨碳化金属复合镀层为便,采用复合电沉积法制得镍－钨碳化乌复合电极。研究 烨微粒的共沉积量、温度及盐酸浓度对镍－钨碳化乌复合电极在盐酸溶液中的阳极极化行为的影响,分析了阳极钝化的原因并研究了采用电化学溶液法回收镍－钨碳化钨复合电极中的镍的工艺条件     

复合镀Zn－Co－TiO_2工艺研究

提出了复合镀Ｚｎ－Ｃｏ－ＴｉＯ_２工艺规范，讨论了镀液各成份的作用和工艺条件对镀层的影响。对镀液的电化学性能和镀层性能的测试结果表明：在弱酸性氯化钾镀液中能获得含二氧化铁固体微粒０．５％～１．５％的复合镀层，镀层光亮细致，钝化膜色泽鲜艳，氢脆性小，其耐蚀性能比镀锌层提高２～５倍，和镉镀层相当，可用于恶劣环境下的零件的表面防护。     

钛合金Ni-P-PTFE-SiC复合镀工艺研究

在传统镀液中添加软质微粒PTFE和硬质微粒Si C,使两种微粒充分混合分散在镀液中,施镀时发生Ni-P-PTFESi C共沉积,在钛合金表面形成Ni-P-PTFE-Si C四元复合镀层。并与Ni-P镀层、Ni-P-PTFE复合镀层、Ni-P-Si C复合镀层进行了比对,分析了复合镀层微观形貌的变化情况及PTFE微粒和Si C微粒的加入对其摩擦磨损性能的影响。结果表明,Ni-PPTFE-Si C复合镀层具有较高的硬度和良好的耐磨减摩性能。     

镍/纳米二氧化硅纳米复合镀层耐腐蚀性能的研究

制备了纳米氧化硅镍复合镀层材料,并利用静态浸泡法对纯镍镀层和由镀液中不同微粒含量制备的复合镀层样品的耐蚀性能进行了研究,讨论镀液中纳米微粒含量对镀层抗蚀性能的影响。并用扫描电镜观察镀层的表面形貌。     

(Ni-P)-纳米Si3N4复合刷镀层结构及性能研究

1引言 复合刷镀是指在镀液中纳米级的不溶性的固体形成纳米复合刷镀层.用具有很好悬浮性能的纳米Si3N4固体微粒作为复合刷镀液的第二相粒子,通过搅拌使其悬浮在镀液中,用电刷镀的方法使Ni-P合金与纳米Si3N4微粒共沉积于基体表面.它具有沉积速度快、镀层硬度高和耐磨性好等优异的性能.     

影响复合电镀层中微粒复合量的因素

镀层中微粒的含量对复合镀层的性能有着重要的影响.本文综述了复合电镀中微粒复合量的影响因素,包括镀液中微粒含量、微粒尺寸、表面活性剂、电流、pH、镀液搅拌强度等,阐述了各因素对微粒沉积量的作用规律.     

Facile synthesis of tungsten carbide-carbon composites for oxygen reduction reaction

Tungsten carbide-carbon composite (XWC-C, where X=10 or 30 represents the tungsten content) supports were prepared by pyrolyzing tungsten-adsorbed poly(4-vinylpyridine)-functionalized carbon. The supports were used to prepare Pt catalysts (Pt/XWC-C) for oxygen reduction reactions (ORR) in alkaline solution. Prepared XWC-C revealed highly dispersed tungsten carbide species composed of WC and W₂C phases. The tungsten carbide species proved to have a positive effect on the dispersion of Pt particles. Compared to the Pt catalyst supported on carbon (Pt/ C), Pt/XWC-C showed higher ORR performance. In addition, the catalytic performance of Pt/XWC-C was enhanced with increasing tungsten carbide content. The highest ORR activity was achieved for the Pt/30WC-C catalyst, which had a 2.9-fold enhanced performance (at 0.8V vs. RHE) compared to that of Pt/C. It is believed that the unique interaction between Pt and the tungsten carbide species was responsible for the enhanced ORR performance of the Pt/XWC-C catalysts.     

Formation of nanocrystalline Zinc on ITO and Silicon substrates by electrochemical deposition

Zn was deposited by means of cyclic voltammetry (CV) and square wave pulsating overpotential (OP) methods on ITO (indium tin oxide) and n-doped silicon (n-Si) substrates from an acetate-based electrolyte at two different temperatures in the absence of additives. The surface morphology of the Zn deposits was studied by scanning electron microscopy (SEM). The preferred orientation and the average size of the Zn electrodeposited particles on n-Si substrates were obtained by X-ray diffraction and the microhardness of the deposits was measured by standard means. The results show that the grain size of the electrodeposits increases as the temperature rises, and on the other hand that the PO method yields smaller grains and higher hardness values compared with those obtained by CV, irrespective of the temperature. Furthermore, in PO conditions a preferential (101) orientation is obtained for the growth of the Zn electrodeposits, but for long deposition times the growth direction is that [100] corresponding to the basal plane (002).     

Electrochemical preparation and characterization of Ni/SiC compositionally graded multilayered coatings

In our study, Ni/SiC functionally graded coatings have been obtained by electrochemical deposition of silicon carbide microparticles (mean diameter 2 μm) from nickel Watts baths with different concentrations of SiC particles in solution. The SiC particles were characterized by electroacustics technique in order to determine zeta potential and particle size. Moreover, the effect of the concentration of SiC particles in solution on the amount of SiC deposited in the nickel layer was investigated. Further experiments showed that the degree of particle incorporation provoked changes in the texture of the nickel matrix. The characterization of the coatings proved that the Ni/SiC graded composite coatings were bright and compact, presented good adhesion and improved the hardness and wear resistance of pure nickel electrodeposits.     

中温化学镀镍工艺研究

通过正交试验优选出一种较佳的中温化学镀镍工艺。研究了镀液主要成分及操作条件对沉积速度和镀层质量的影响。利用Ｘ射线衍射法测定了镀层组成和晶体结构,并测量了其耐蚀性。结果获得含磷１０．６ｗｔ％的非晶态镀层,耐蚀性优于光亮镀镍层。     

Composites from WC powders sputter-deposited with iron rich binders

Composite powders of tungsten carbide (WC) and iron rich binder were prepared by an innovative approach, which consists in sputtering of a metallic binder on the tungsten carbide particles. The phase composition, microstructure and mechanical behaviour of WC coated powder composites with binder contents from 6 to 9 wt.% were characterized. η-Phase is early formed during sintering and its effect on the mechanical behaviour was investigated and related to the microstructure and atomic structure. The results show that the presence of η-phase has not a hazardous role in toughness as is previewed in conventional cemented carbide. Despite the presence of η-phase, a good compromise between toughness and hardness was attained in composites prepared from iron rich binders sputtered on WC powders.     

纳米碳化钨的合成及其电催化活性研究

以钨酸和丙烯腈为原料,采用共沉淀法合成碳化钨（WC）前驱体,于H₂和Ar混合气氛中高温还原碳化制备纳米WC。采用傅立叶红外光谱、X射线衍射及扫描电镜等对试样进行表征,在酸性介质中采用循环伏安法测试Pt/WC电化学催化活性。结果表明,实验合成了较纯的纳米碳化钨,其颗粒形貌近似球形,粒径80 nm左右。Pt/WC的电化学表面积（ESA）较传统的Pt/C有较大提高,10%Pt/WC电流密度为51.2 mA·cm^-2。     

通过电磁场法原位合成WC颗粒(英文)

在1300℃时,对由金属钨丝与灰口铸铁熔体组成的体系施加一电磁场,金属钨原子与灰口铸铁中的碳原子集团原位反应形成WC颗粒和残余钨丝共同增强的铁基复合材料。通过X射线衍射、扫描电镜和能谱分析了复合材料的显微结构和组成。结果表明:当电流为15A时,随着电磁场频率的增加,原位合成的WC颗粒数量增减增多,钨丝的量不断减少。当电磁场频率达到5kHz时,钨丝反应完全。电磁场能够加速质量传递和元素的扩散速率,有助于在钨丝周围形成一系列的Fe-W-C三元体系微区,该微区内的钨浓度较大,改善了原位合成WC颗粒的动力学条件,而在颗粒间隙类似与过滤器降低了元素的扩散速率。     

The topotactic transformation of tungsten oxide to a cubic tungsten carbide

The solid transformation of tungsten trioxide to a cubic tungsten carbide via nitride has been studied. Product carbide particles possessed specific surface area ofca. 90 m²g^*-1 and average diameter ofca. 4 nm. Transmission electron microscope (TEM) exhibited that these particles formed porous aggregates with a spotty electron diffraction pattern. This provides an evidence that the topotactic solid transformation has been involved.     

Preparation and electrocatalytic property of WC/carbon nanotube composite

Tungsten carbide/carbon nanotube composite was prepared by surface decoration and in situ reduction-carbonization. The samples were characterized by XRD, SEM, EDS, TEM, HRTEM and BET, respectively. The XRD results show that the sample is composed of carbon nanotube, tungsten carbide and tungsten oxide. The EDS results show that the distribution of tungsten oxide is consistent with that of tungsten carbide. SEM, TEM and HRTEM results show that the tungsten carbide nanoparticle with irregular granule grows on the outside surface of carbon nanotube homogenously. The electrocatalytic activity of the sample for p-nitrophenol reduction was tested by a powder microelectrode in a basic solution. The results show that the electrocatalytic activity of the sample is higher than that of granular tungsten carbide, hollow globe tungsten carbide with mesoporosity and carbon nanotube purified. The improvement of the electrocatalytic activity of the sample can be attributed to its components and composite structure. These results indicate that tungsten carbide/carbon nanotube composite is one of the effective ways to improve the electrocatalytic activity of tungsten carbide.