Solution combustion synthesis of Ni-Y_2O_3 nanocomposite powder

Ni-Y2O3 nanocomposite powder with uniform distribution of fine oxide particles in the metal matrix was successfully fabricated via solution combustion process followed by hydrogen reduction. The combustion behavior was investigated by DTA-TG analysis. The influence of urea to nickel nitrate（U/Ni） ratio on the combustion behavior and morphology evolution of the combusted powder was investigated. The morphological characteristics and phase transformation of the combusted powder and the reduced powder were characterized by FESEM, TEM and XRD. The HRTEM image of Ni-Y2O3 nanocomposite powder indicated that Y2O3 particles with average particle size of about 10 nm dispersed uniformly in the nickel matrix.

The design and fabrication of Co3O4/Co3V2O8/Ni nanocomposites as high-performance anodes for Li-ion batteries

The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, whereas the 1D CoVOnanowires adhered to parts of CoOnanowires.Most of the hybrid nanowires were inlayed with each other, forming a 3D hybrid nanowires network.As a result, the discharge capacity of CoO/CoVO/Ni nanocomposites could reach 1201.8 mAh/g after100 cycles at 100 mA/g. After 600 cycles at 1 A/g, the discharge capacity was maintained at 828.1 mAh/g.Moreover, even though the charge/discharge rates were increased to 10 A/g, it rendered reversible capacity of 491.2 mAh/g. The superior electrochemical properties of nanocomposites were probably ascribed to their unique 3D architecture and the synergistic effects of two active materials. Therefore, such CoO/CoVO/Ni nanocomposites could potentially be used as anode materials for high-performance Li-ion batteries.

Crystalline texture evolution, control of the tribocorrosion behavior, and significant enhancement of the abrasion properties of a Ni-P nanocomposite coating enhanced by zirconia nanoparticles

This paper describes an investigation of the effect of ZrO2 nanoparticles on the abrasive properties,crystalline texture developments,and tribocorrosion behavior of Ni-P nanostructured coatings.In the investigation,Ni-P and Ni-P-ZrO2 nanostructured coatings are deposited on St52 steel via the electroless method.Transmission electron microscopy(TEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),energy dispersive spectroscopy(EDS),cyclic-static polarization tests in 3.5wt%NaCl solution,the tribocorrosion test(by back-and-forth wear in electrochemical cell),and the microhardness test using the Vickers method were performed to characterize and analyze the deposited coatings.The results of this study showed that the addition of ZrO2 nanoparticles to the Ni-P electroless bath produced the following:a sharp increase in wear and hardness resistance,the change of the wear mechanism from sheet to adhesive mode,the reduction of pitting corrosion resistance,significant reduction in the tribocorrosion protective properties,change in the preferred orientation of the crystalline texture coating from(111)to(200),increase in the sedimentation rate during the deposit process,and a sharp increase in the thickness of the Ni-P nanostructured coatings.

Electrodeposition of Ni-SiC nanocomposite film

The point of zero charge(PZC) of SiC nanoparticles was determined by means of standard potentiometric titration method, while the influences of the main technological parameters on the microstructure of electrodeposited Ni-SiC composite film were studied and optimized. The results show that high bath pH value favors SiC nanoparticles negatively charged and high bath temperature promotes them positively charged. Under the experimental conditions, sodium dodecyl-glycol is proven to be an effective surface modification anionic surfactant for SiC nanoparticles. The results also show that the optimized Ni-SiC composite film is composed of the nanoparticles with the average grain size in the nanometer range (100 nm), and SiC nanoparticles disperse into the nickel matrix uniformly.

EFFECT OF SURFACTANTS ON Ni-TiN NANOCOMPOSITE COATINGS PREPARED BY ULTRASONIC ELECTRODEPOSlTION

Ni-TiN nanocomposite coatings were prepared by ultrasonic electrodeposition, and the effects of the surfactants on the coatings were investigated and the microstructure and micro rigidity of the coatings were characterized. Samples were also submitted to corrosion tests in 3% NaCl solution. The results showed that the surfactants had great effects on Ni-TiN nanocomposite coatings. The composite coatings prepared by ultrasonic electrodeposition with the surfactants were better than that of the coatings prepared without surfactants. The favorable properties of Ni-TiN nanocomposite coatings were prepared with the mixing of the non-ion and positive ion surfactants. The concentration of the mixing was 80 mg/L, and the ratio of the non-ion and positive ion surfactants was 1： 2.

Beneficial effects of Co^(2+) on co-electrodeposited Ni-SiC nanocomposite coating

Ni-SiC nanocomposites were fabricated by co-electrodeposition of nickel with silicon carbide nanoparticles on the pure nickel substrates from a nickel sulfate bath with and without the addition of Co2+. The presence of Co2+ in the electrolyte modifies the Ni matrix to Ni-Co solid solution matrix. It helps to refine the grain size of the nanocomposite coating and improves the content of SiC dispersed in the matrix, and consequently results in higher microhardness. The cathodic polarization curves and electrochemical impedance spectroscopy (EIS) at cathodic potential were investigated in the electrolyte with and without Co2+. A modified cathodic polarization curve with a positive shift in reduction potential and a smaller capacitive loop of EIS are observed. These are attributed to the strong adsorption of Co2+ on the SiC nanoparticles. Consequently, it increases the forces of electrostatic attraction between the SiC nanoparticles and the cathode, which promotes the codeposition of SiC nanoparticles in the matrix.

Hydrogen storage properties of nanocomposite Mg-Ni-MnO_2 made by mechanical milling

The hydrogen storage properties of the nanocomposite Mg 95 Ni 3(MnO 2) 2 (mass fraction, %) were studied. The temperature changes in hydriding/dehydriding process were investigated. The nanocomposite was fabricated by ball milling process of mixed elemental Mg, Ni and oxide maganese MnO 2 under hydrogen pressure (approximately 0.6?MPa). The hydrogen absorption and desorption properties of the samples milled for various times were investigated. A remarkable enhancement of hydrogen absorption kinetics and low operational desorption temperature have been found after the sample milled for over 57?h. For example, this nanocomposite can absorb hydrogen more than 6.0% (mass fraction) in 60?s at 200?℃ under 2.0?MPa, and desorption capacity also exceeds 6.0% (mass fraction) in 400?s at 310?℃ under 0.1?MPa. The storage properties of samples milled for various times were studied and the kinetics of the samples were analyzed.

Superplasticity and Superplastic Bulging Behavior of ZrO_2/Ni Nanocomposite

ZrO2/Ni nanocomposite was produced by pulse electrodeposition and its superplastic properties were investigated by the tensile and bulging tests. The as-deposited nickel matrix has a narrow grain size distribution with a mean grain size of 45 nm. A maximum elongation of 605% was observed at 723 K and a strain rate of 1.67×10-3s-1 by tensile test. Superplastic bulging tests were subsequently performed using dies with diameters of 1 mm and 5 mm respectively based on the optimal superplastic forming temperature. The effects of forming temperature and gas pressure on bulging process were experimentally investigated. The results indicated that ZrO2/Ni nanocomposite samples can be readily bulged at 723 K with H/d value （defined as dome apex height over the die diameter） larger than 0.5, indicating that the nanocomposite has good bulging ability. SEM and TEM were used to examine the microstructure of the as-deposited and bulged samples. The observations showed that significant grain coarsening occurs during superplastic bulging, and the microstructure is found to depend on the forming temperature.

High Efficient Photocatalytic Degradation of 3,7-Bis(Dimethylamino)-Phenothiazin-5-Ium Chloride Dye and Kinetics of H2 Evolution of N2H4H2O by Synthesized CdS/NiS Nanocomposite by Electrochemical Method

CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity and photo-catalysis. The synthesized nanocomposites were characterized by BET, UV-VIS, XRD, FE-SEM (EDAX) techniques. X-Ray diffraction (XRD) reveals crystallite size to be 23.22 nm which was calculated using Williamson-Hall (W-H) plot method. The energy of the band gap for CdS/NiS could be thus estimated to be 3.26 eV. The photocatalytic activity of the sample was evaluated by the degradation of textile dye methylene Blue (MB) in aqueous solutions under UV radiation. Hydrogen energy is regarded as a promising alternative in terms of energy conversion and storage. Hydrogen Evolution Reaction (HER) was carried out in both visible light and UV light by using Hydrazine (N2H4H2O) in the presence of CdS/NiS nanocomposite. The synthesized photocatalyst shows applicable performance for kinetics of Hydrogen Evolution Reaction (HER) in Visible light and UV light. The decomposition of hydrazine (N2H4H2O) proceeded rapidly to generate free hydrogen rich gas through OH radical contact with CdS/NiS nanocomposite at room temperature. The rate of HER is limited by either proton adsorption onto an active site or evolution of formed hydrogen from the surface. A high Tafel slope is indicative of proton adsorption as the rate limiting step, while a lower Tafel slope (20 - 45 mV) indicates that the evolution of molecules hydrogen from the catalyst is rate limiting. In the present case the Tafel slopes for visible light 23.5 mV and 42.5 mV for UV light. Blank experiments show poor activity for HER i.e. 10.1 - 13.5 mV.

Ni掺杂对TiB_(2)硬质涂层组织结构和力学性能的影响

TiB_(2)涂层独特的晶体结构和强共价键赋予其超高的硬度和化学稳定性,但也存在韧性差及膜基结合力较差的问题。结合高功率脉冲磁控溅射技术和射频磁控溅射技术制备了Ni掺杂的TiB_(2)涂层,采用SEM、EPMA、XRD、XPS、纳米压痕仪、划痕试验仪、高温摩擦磨损试验机对比研究了不同Ni含量的TiB_(2)⁃Ni涂层的微观形貌、化学成分、物相结构、力学性能、摩擦学性能等。结果表明:Ni掺杂的TiB_(2)⁃Ni涂层中,少量Ni元素固溶于TiB_(2)晶格,过量的Ni元素以金属相形式存在,在晶界处形成了纳米复合结构,限制了TiB_(2)晶粒的生长,导致涂层柱状晶细化和纳米化。Ni元素掺杂导致TiB_(2)涂层的硬度与弹性模量明显下降,膜基结合力和涂层韧性随着Ni元素含量的增加持续增加,涂层摩擦系数先降低后升高,磨损形貌显示为磨粒磨损和粘接磨损。TiB_(2)⁃Ni涂层通过生成Ni金属相,在裂纹扩展时发生形变,以吸收断裂能量来提高涂层韧性,Ni含量为4.9%(原子分数)的TiB_(2)⁃Ni涂层具有较好的硬度和韧性。

珊瑚状Ag/Ni(OH)_(2)纳米复合电极的制备及其葡萄糖无酶传感

本文采用连续离子层吸附法在镍基底上制备珊瑚状Ag/Ni(OH)_(2)纳米复合电极,建立灵敏度优异的无酶葡萄糖传感器,采用循环伏安法(CV)和安培电流法(i~t)对该传感器的电化学特性进行了研究。结果表明,在0.5 V下,该传感器具有较好的电化学传感性能,其灵敏度为1102μA·mmol·L^(-1)·cm^(-2),线性范围为0.002 mmol/L~10.11 mmol/L,检出限为0.29μmol/L(S/N=3),且重复性好,抗干扰性强,重现性和稳定性好,这主要是因为银、镍纳米复合材料间的相互协同效应,比表面积增大,使其具有更多的活性位点,提高了电极的电化学性能。该传感器可用于检测葡萄糖注射液中葡萄糖的浓度,表明制备的Ag/Ni(OH)_(2)纳米复合电极具有检测葡萄糖的应用潜力。

电沉积方式对Ni-CeO_2纳米复合镀层摩擦磨损性能的影响

采用直流电沉积、脉冲电沉积和超声辅助脉冲电沉积制备Ni-CeO2纳米复合镀层,研究电沉积方式对纳米复合镀层表面形貌、显微硬度和摩擦磨损性能的影响,并用扫描电子显微镜分析其磨损机理。结果表明:电沉积方式对Ni-CeO2纳米复合镀层的晶粒尺寸和性能有较大影响;当超声波引入脉冲电沉积过程时,超声波的强力搅拌作用和超声空化效应能促进CeO2纳米颗粒在镀层中均匀分布,进一步减小镀层的晶粒尺寸,明显提高镀层的显微硬度,从而改善镀层的摩擦磨损性能;Ni-CeO2纳米复合镀层的摩擦磨损性能均优于纯Ni镀层的;而超声辅助脉冲电沉积制备的Ni-CeO2纳米复合镀层的晶粒更加细小、显微硬度最高,其摩擦因数最低,耐磨损性能最佳。

电沉积方式对Ni-SiC纳米镀层耐腐蚀性能的影响

采用直流电沉积、脉冲电沉积和超声-脉冲电沉积方法,在45钢表面制备Ni-SiC纳米镀层。研究电沉积方式对Ni-SiC纳米镀层显微组织、成分及耐腐蚀性能的影响。结果表明,超声-脉冲电沉积Ni-SiC纳米镀层显微组织更加致密、光滑。直流电沉积镀层的镍粒径和SiC粒子的平均粒径为175.4和81.5nm;而超声-脉冲电沉积镀层的镍粒径和SiC粒子的平均粒径为74.8和36.3nm。SEM和EDS分析可知,电沉积方式对Ni-SiC纳米镀层的耐腐蚀性能有很大影响,超声-脉冲电沉积镀层的耐腐蚀性能较好。

超声场中脉冲电沉积Ni-CeO_2纳米复合镀层的耐蚀性

在超声场中用脉冲电沉积法制备了Ni-CeO2纳米复合镀层,考察了镀层中CeO2含量及表面形貌,研究了镀层在10wt%HCl溶液中的耐蚀性,分析了超声作用下脉冲参数对镀层耐蚀性的影响.结果表明:脉冲参数和超声波对镀层中CeO2含量和微观组织均有影响,适宜的脉冲参数可以提高镀层中CeO2含量,细化镀层晶粒,而超声波可促使镀层晶粒进一步细化;Ni-CeO2纳米复合镀层的耐蚀性与镀层中CeO2含量、镀层晶粒大小及组织致密程度有关;在占空比0.2、脉冲频率1000Hz时超声作用下制备的镀层中CeO2含量较高,镀层晶粒细小、组织致密,腐蚀速率最低,表现出优良的耐蚀性.

化学镀Ni-P-CNTs-纳米SiC复合镀层的摩擦学行为

采用化学共沉积方法制备了Ni-P-CNTs-纳米SiC复合镀层,并研究了其复合镀层的摩擦学行为。结果表明:与在相同参数下制备的Ni-P,Ni-P-SiC,Ni-P-CNTs,Ni-P-CNTs-微米SiC复合镀层相比,Ni-P-CNTs-纳米SiC复合镀层表现出最低的摩擦系数与最好的耐磨性。

超声电沉积制备Ni-ZrO_2纳米复合镀层及其结构和性能的研究

制备了纯Ni镀层和Ni-ZrO2纳米复合镀层,并在沉积过程中引入超声波制备了超声Ni-ZrO2纳米复合镀层,对比分析了3种镀层的微观结构及高温抗氧化性、显微硬度、耐磨性。结果表明,超声电沉积Ni-ZrO2纳米复合镀层晶粒尺寸细小,具有良好的高温抗氧化性能、高的显微硬度和优良的耐磨性,并进一步分析了纳米颗粒和超声波在提高镀层性能方面所起的作用。

纳米Ni-20Fe颗粒增韧Al_2O_3复合材料的力学性能与磁性能

用机械化学及热压烧结方法成功制备了高致密Ni-20Fe/Al2O3纳米复合材料。通过X-ray、FE-SEM、力学性能、磁性能测试,结果表明,复合后材料断裂韧性从纯-αAl2O3相的4.7 MPa.m1/2提高到6.2 MPa.m1/2(19%(Ni-20Fe)/Al2O3),断裂方式有沿晶断裂和穿晶断裂两种。当Ni-20Fe合金的体积百分数达到19%时,复合材料的饱和磁化强度达33 emu/g,矫顽力为200 Oe,且在低于500℃的情况下,矫顽力基本不随温度而变,具有良好的磁热稳定性。

AZ91D镁合金表面电沉积n-ZrO_2/Ni复合镀层及耐蚀性研究

在AZ91D镁合金表面化学镀Ni-P的基础上电沉积n-ZrO2/Ni复合镀层和纯Ni电镀层,并对其表面形貌、截面形貌和耐蚀性进行了对比分析。结果表明AZ91D镁合金表面电沉积纳米复合镀层比纯镍镀层组织更细小,镀层更致密、平整。n-ZrO2/Ni复合镀层具有明显的钝化区,具有良好耐蚀性。

Ni-CeO_2纳米复合镀层的摩擦磨损性能

采用复合电镀技术,通过向普通电镀溶液中加入平均粒度约为10nm的CeO2颗粒的方法在Ni基上制备了Ni-CeO2纳米复合涂层。XRD和SEM/EDAX分析结果表明,CeO2纳米颗粒均匀分布在Ni纳米晶中,由于纳米CeO2颗粒的加入,Ni-CeO2纳米复合涂层的择优取向由单Ni镀层的(200)变为(111),在镀层中起弥散强化作用的CeO2同时细化了基体Ni的晶粒尺寸,使得与单Ni镀层相比,Ni-CeO2纳米复合镀层表现出了更高的硬度、低的摩擦系数和更好的耐磨性能。

电沉积工艺参数对Ni-TiN-CeO_2二元纳米复合镀层中粒子复合量的影响

采用超声-脉冲电沉积法制备了Ni-TiN-CeO2二元纳米复合镀层,研究了工艺参数对镀层中CeO2及TiN粒子复合量的影响,并对镀层的表面形貌及成分进行了测试和分析。结果表明,超声-脉冲电沉积Ni-TiN-CeO2纳米复合镀层的最佳工艺参数为阴极电流密度4A/dm2,TiN粒子添加量15g/L,CeO2粒子添加量40g/L,正向脉冲占空比20%,超声波功率180W。在该工艺条件下,可获得CeO2质量分数为3.3%、TiN质量分数为4.4%的Ni-TiN-CeO2二元纳米复合镀层。同时,TiN与CeO2二元纳米粒子的加入,充分发挥了两种纳米粒子复合的协同效应,优化了粒子与基质金属的共沉积方式,大大改善了镀层质量。