电感耦合等离子体发射光谱法测定镍−磷合金镀层中的磷

采用硝酸溶解从基体剥离下来的镍-磷合金镀层试样,以基体匹配法配制系列校准曲线溶液,选择213.617nm作为磷的分析谱线,建立了电感耦合等离子体发射光谱法(ICP-OES)测定镍-磷合金镀层中磷含量的方法。该方法的校准曲线的线性相关系数大于0.999,实际样品测定结果的相对标准偏差不大于3%,能够满足镍-磷合金镀层的常规和快速检验的需求。

高压开关断路器操动机构化学镀镍−钨−磷三元合金及镀层性能

针对高压开关断路器机构上的液压缸、活塞杆等零部件加工精度要求高,面临磨损、高油压、腐蚀等复杂工况的问题,以高压开关机构零部件常用的45钢为基体,进行Ni-W-P三元合金化学镀。考察了Ni-W-P合金镀层的显微形貌、耐蚀性、显微硬度和耐磨性。结果显示,化学镀Ni-W-P合金镀层的综合性能优于电镀Zn-Ni合金,并且能够通过样机试验,有望替代现有的电镀Zn-Ni合金工艺。

稀土铈对高碳钢电机轴化学镀镍-磷合金耐磨性的影响

对高碳钢电机轴表面化学镀Ni-P合金,以提高其耐磨性。研究了稀土铈质量浓度对Ni-P合金镀层形貌、相结构、结合力和耐磨性的影响。结果表明:镀液中添加5~20 mg/L Ce^(4+)能够提高镀层的致密性、平整性和结合力。Ce^(4+)质量浓度为20 mg/L时,制备的Ni-P合金镀层结合力达56 N,耐磨性最佳。当Ce^(4+)质量浓度过高(如50 mg/L)时,镀层的综合性能反而不如未加Ce^(4+)时。

不同组合配位剂对化学镀镍−钨−磷合金的影响

以柠檬酸钠为主要配位剂,乳酸、甘氨酸、硫酸铵分别为辅助配位剂,在硬铝上二次浸锌后化学镀Ni-W-P合金。基础镀液和工艺条件为:NiSO_(4)·6H_(2)O 20 g/L,Na_(2)WO_(4)·2H_(2)O 20 g/L,NaH_(2)PO_(2)·H_(2)O 30 g/L,CH_(3)COONa·3H_(2)O 20 g/L,硫脲2 mg/L,pH 8.0,温度85℃,时间1 h。研究了不同配位剂组合对化学镀Ni-W-P合金沉积速率及镀层显微硬度和孔隙率的影响。结果表明,使用30 g/L柠檬酸钠+10 mL/L乳酸时,所得镀层的孔隙率最低,为0.63个/cm^(2);使用30 g/L柠檬酸钠+10 g/L甘氨酸时,镀层的显微硬度较单一使用柠檬酸钠时有所提高;使用30 g/L柠檬酸钠+25 g/L硫酸铵时,沉积速率最高,为14.69 mg/(cm^(2)·h),镀层的显微硬度高达786.9 HV。

预镀镍时间对装饰铜合金化学镀镍基合金的影响

对装饰铜合金预镀Ni后再化学镀Ni–P合金、Ni–Mo–P合金或Ni–P/Ni–Mo–P合金,研究了预镀Ni时间对Ni–P合金和Ni–Mo–P合金镀层表面形貌、孔隙率和耐蚀性的影响,并对比了不同厚度组合的Ni–P/Ni–Mo–P合金镀层的性能。结果表明,预镀Ni有助于提高Ni–P合金和Ni–Mo–P合金镀层的性能,较佳的预镀Ni时间为5 min。当总厚度固定为20μm不变时,随内层Ni–P合金厚度增大,Ni–P/Ni–Mo–P组合镀层的各项性能均先改善后变差。当Ni–P合金和Ni–Mo–P合金厚度分别为14μm和6μm时,Ni–P/Ni–Mo–P组合镀层的耐蚀性最佳。

循环伏安法电沉积镍-钴-磷/泡沫镍电极及其析氢催化活性研究

以泡沫镍(NF)为基体,采用循环伏安(CV)电沉积法制备Ni-Co-P/NF催化电极,电沉积液组成和工艺条件为:NiSO4·6H2O 0.07 mol/L,CoSO4·7H2O 0.03 mol/L,NaH2PO2·H2O 0.6 mol/L,扫描电位区间−0.6~−1.2 V(相对于饱和甘汞电极),扫描速率0.01 V/s,扫描14次。采用扫描电镜(SEM)和能谱仪(EDS)分析了电极的表面形貌和元素组成。通过阴极极化曲线和塔菲尔斜率对比了NF、Ni-P/NF和Ni-Co-P/NF电极在1 mol/L NaOH和0.5 mol/L H2SO4溶液中的析氢催化活性,并通过循环伏安和电流密度−时间曲线测试了电极的稳定性。结果表明,Ni-Co-P/NF电极在碱性和酸性条件下都表现出优于Ni-P/NF的析氢活性和稳定性。

田口法优化铝合金超声波辅助化学预镀镍工艺

先在超声波辅助下对6061铝合金进行碱性化学预镀Ni,再化学镀Ni–P合金。基于田口法设计试验,以后续化学镀Ni的沉积速率和Ni镀层耐蚀性为指标,分析了预镀时镀液pH、温度以及超声波频率和功率对化学预镀Ni效果的影响,得到较佳的预镀Ni工艺条件为:超声波频率40 kHz,超声波功率80 W,pH 12,温度45℃,时间6 min。在该条件下预镀Ni时,后续化学镀Ni的沉积速率为13.87μm/h,所得Ni–P合金镀层的耐蚀性最佳。

化学镀Ni-Sn-P和磁控溅射TiN对Mn-Cu合金耐腐蚀性能和阻尼性能的影响

分别对Mn-Cu阻尼合金表面化学镀1 h和磁控溅射2 h,获得了5.42μm厚的Ni-Sn-P合金层和1.43μm厚的TiN层。对比了Mn-Cu合金及其表面化学镀Ni-Sn-P合金和磁控溅射TiN后的微观形貌、元素组成、结构、耐蚀性和阻尼性能。结果表明,化学镀和磁控溅射都能提高Mn-Cu合金的耐蚀性,Ni-Sn-P合金镀层的耐蚀性最好。化学镀Ni-Sn-P合金能够在一定程度上改善Mn-Cu合金的阻尼性能,而磁控溅射TiN会使基体的阻尼性能轻微下降。

Composition Dependent Magnetic Properties of Ni-Co-P Coated Carbon Nanotubes

Carbon nanotubes were coated with a layer of nickel-cobalt-phosphorus （Ni-Co-P） alloy with different compositions of Ni/Co through electroless plating. The effects of the concentration ratio of Co^2＋ to Ni^2＋, bath temperature, and pH on deposition rate are discussed. The prepared carbon nanotubes covered with Ni-Co-P were characterized and analyzed by fieldemission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive spectroscopy, and a vibrating sample magnetometer. The results show that the deposition rate reached the maximum when the concentration ratio of Co^2＋ to Ni^2＋ is 1 and the pH is 9; the deposition rate increases with the increase of bath temperature. The measurements of the magnetic properties of the obtained carbon nanotubes covered with Ni-Co-P indicate that the magnetic properties greatly depend on the concentration ratio of Co^2＋ to Ni^2＋, and the magnetic saturation reaches the maximum value when the Co^2＋ to Ni^2＋ ratio is 1. In addition, there are two peaks in the coercivity curve at Co^2＋ to Ni^2＋ ratios of 1/2 and 4/1, while the two peaks in the magnetic conductivity curve are located at Co^2＋ to Ni^2＋ ratios of 1/4 and 4/1.

Progress of electroplating and electroless plating on magnesium alloy

The current research processes of electroplating and electroless Ni-P alloy plating on magnesium alloys were reviewed. Theoretically,the reason for difficulties in electroplating and electroless plating on magnesium alloys was given.The zinc immersion, copper immersion,direct electroless Ni-P alloy plating and electroplating and electroless plating on magnesium alloys prepared by chemical conversion coating were presented in detail.Especially,the research development of magnesium alloy AZ91 and AZ31 was discussed briefly.Based on the analysis,the existing problems and future research directions were then given.

Influence of pH values on electroless Ni-P-SiC plating on AZ91D magnesium alloy

A novel Ni-P-SiC composite coating was prepared by electroless plating in order to improve the corrosion capacity and wear resistance of AZ91D magnesium alloy.The influence of pH values on deposition rates and properties of the coatings was studied.The microstructure and phase structure of the Ni-P-SiC coatings were analyzed by scanning electron microscopy(SEM)and X-ray diffractometry(XRD).The corrosion and wear resistance performances of the coatings were also investigated through electrochemical technique and pin-on-disk tribometer,respectively.The results indicate that the composite coating is composed of Ni, P and SiC.It exhibits an amorphous structure and good adhesion to the substrate.The coatings have higher open circuit potential than that of the substrate.The composite coating obtained at pH value of 5.2 possesses optimal integrated properties,which shows similar corrosion resistance and ascendant wear resistance properties to the substrate.

Triethanolamine-mediated photodeposition formation of amorphous Ni-P alloy for improved H2-evolution activity of g-C3N4

Developing efficient,stable,and low-cost novel electron-cocatalysts is crucial for photocatalytic hydrogen evolution reaction.Herein,amorphous Ni-P alloy particles were successfully modified onto g-C3N4 to construct the Ni-P/g-C3N4 photocatalyst through a simple and green triethanolamine(TEOA)-mediated photodeposition method.It was found that the TEOA could serve as an excellent complexing agent to coordinate with Ni2+to form[Ni(TEOA)]^2+complex,which can promote the rapid and effective deposition of amorphous Ni-P alloy on the g-C3N4 surface.Photocatalytic tests suggest that the hydrogen-evolution performance of gC3N4 can be greatly promoted through integrating amorphous Ni-P alloy.Especially,the Ni-P/g-C3N4(5 wt%)exhibits the superior H2-generation activity(118.2μmol h^-1g^-1),which is almost 35.8 times that of bare g-C3N4.Furthermore,the amorphous Ni-P alloy cocatalyst can also serve as the general hydrogen-production cocatalyst to greatly enhance the photocatalytic performance of traditional semiconductor materials such as Ti O2 and Cd S.Based on the present results,the mechanism of the amorphous Ni-P alloy as the high-efficiency electron transfer medium was proposed for the boosted H2-generation rate.The present facile route may broaden the horizons for the efficient development of highly active cocatalysts in photocatalytic field.