Preparation of one-step NiO/Ni-CGO composites using factorial design

International Nuclear Information System (INIS)

Araujo, A.J.M. de; Sousa, A R.O. de; Camposa, L.F.A.; Macedo, D.A.; Loureiro, F. J.A.; Fagg, D.P.

2016-01-01

This work deals with the synthesis, processing and characterization of NiO/Ni- CGO composite materials as potential solid oxide fuel cell (SOFC) anodes. The particulate materials were obtained by a one-step synthesis method and characterized by thermal analysis (prior to calcination) and X-ray diffraction (calcined powder). The ceramic processing of samples containing from 30 to 70 wt.% NiO was carried out by factorial design. Besides the NiO content controlled during the chemical synthesis, the impacts of the pore-former content (citric acid, used in proportions of 0, 7.5 and 15 wt.%) and the sintering temperature (1300, 1350 and 1400 °C) were also investigated. The open porosity of NiO-CGO composites and reduced Ni-CGO cermets was modeled as a function of factors (NiO content, citric acid content and sintering temperature) and interaction of factors. (author)

Shape and size effects on layered Ni/PZT/Ni composites magnetoelectric performance

Energy Technology Data Exchange (ETDEWEB)

Pan, D A; Zhang, S G; Qiao, L J [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A [Department of Mechanical Engineering, University of South Florida, Tampa FL 33620 (United States)], E-mail: lqiao@ustb.edu.cn

2008-09-07

This paper presents the magnetoelectric (ME) effect in trilayered Ni/PZT/Ni composites which is related to their size and shape. The ME composites with the same interfacial areas but different geometrical shapes have different ME voltage coefficients. Longitudinal resonant modes in the rectangular and triangular trilayered ME composites were studied. One should choose optimized size, shape and working frequency of the ME composites in order to gain the maximum ME effect. This study plays a guiding role for trilayered ME composites design for real applications. (fast track communication)

Easily Dispersible NiFe2O4/RGO Composite for Microwave Absorption Properties in the X-Band

Science.gov (United States)

Bateer, Buhe; Zhang, Jianjao; Zhang, Hongchen; Zhang, Xiaochen; Wang, Chunyan; Qi, Haiqun

2018-01-01

Composites with good dispersion and excellent microwave absorption properties have important applications. Therefore, an easily dispersible NiFe2O4/reduced graphene oxide (RGO) composite has been prepared conveniently through a simple hydrothermal method. Highly crystalline, small size (about 7 nm) monodispersed NiFe2O4 nanoparticles (NPs) are evenly distributed on the surface of RGO. The microwave absorbability revealed that the NiFe2O4/RGO composite exhibits excellent microwave absorption properties in the X-band (8-12 GHz), and the minimum reflection loss of the NiFe2O4/RGO composite is -27.7 dB at 9.2 GHz. The NiFe2O4/RGO composite has good dispersibility in nonpolar solvent, which facilitates the preparation of stable commercial microwave absorbing coatings. It can be a promising candidate for lightweight microwave absorption materials in many application fields.

Effects of Ni-5%RExOy Composite Additives on Electrochemical Hydrogen Storage Performances of Mg2Ni

Directory of Open Access Journals (Sweden)

ZHANG Guo-fang

2017-11-01

Full Text Available The Ni-5%RExOy (CeO2, La2O3, Eu2O3 as composite additives, Mg2Ni-Ni-5%RExOy composites were prepared by the ball milling method. The effects of different additives on the structure, morphology, electrochemistry and kinetic properties of Mg2Ni alloy were studied systematically. The results show that composite additives can improve the proportion of amorphous and nanocrystalline structure of Mg2Ni alloy. The particle size is homogeneous but the agglomeration is observed in the sample with Ni-5%CeO2 additives. The composites with additives show higher maximum discharge capacity and better cycle stabilities. All of these three kinds of composite additives can improve the kinetic properties of the composites effectively, including optimizing the charge-transfer ability, the reversibility of the electrochemical reaction on the alloy surface, and enhancing the diffusion coefficients of H atoms in the bulk of alloy. Among these three kinds of additives, Ni-5%CeO2 additive shows the best catalysis effect on promoting the kinetic properties of the composites.

Functional multi-walled carbon nanotube/polysiloxane composite films as supports of PtNi alloy nanoparticles for methanol electro-oxidation

International Nuclear Information System (INIS)

Wang Zhicai; Ma Zhengming; Li Hulin

2008-01-01

We demonstrate the use of molecular monolayers to enhance the nucleation of electrocatalytically active PtNi alloy nanoparticles onto the multi-walled carbon nanotubes (MWCNTs). After the siloxane was polymerized on the nanotube surfaces, the carbon nanotubes were embedded within the polysiloxane shell with a hydrophilic amino group situated outside. Subsequent deposition of PtNi nanoparticles led to high density of 3-10 nm diameter PtNi alloy nanoparticles uniformly deposited along the length of the carbon nanotubes. The presence of MWCNTs and PtNi in the composite films was confirmed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersion X-ray spectra analysis (EDS). The electrocatalytic activity of the PtNi-modified MWCNT/polysiloxane (PtNi/Si-MWCNT) composite electrode for electro-oxidation of methanol was investigated by cyclic voltammetry (CV), and excellent electrocatalytic activity can be observed

In situ intercalative polymerization of poly (ε-caprolactone)/ 12-amino lauric acid-modified clay nano composites

International Nuclear Information System (INIS)

Reyes, Larry; Monserate, Juvy J.; Sumera, Florentino

2013-01-01

Polymer/layered silicate nano composites were prepared by in situ intercalative polymerization method from from ε-caprolactone (ε-CL) and 12-amino lauric acid modified montmorillonite (AMMT). The organo-modified clay was investigated for its capacity to facilitate ring-opening polymerization of ε-caprolactone within its silicate layers. The effect of varying the organo-modified clay loading (5%, 10% and 15% by weight) on the molecular weight of the poly (ε-caprolactone) (PCL) product was assessed by gel-permeation chromatography. The molecular weight of the polymer with different clay loadings ranged from ∼30,000 g/mo to ∼70,000 g/mol, where the 10% loading produced the highest molecular weight. Fourier Transform infrared (FTIR), and 1 H and 13 C Nuclear Magnetic Resonance (NMR) Spectroscopy were conducted to probe the composition of the polymer and the catalytic activity of AMMT to polymerize ε-CL. FTIR analyses showed two medium intensity and narrow CO-O stretching vibrations for the PCL products at around 1240 cm-1 and 1160 cm-1, which are attributed to ester skeletal backbone. 1 HNMR spectroscopic analysis revealed signals at 4.07 ppm and 3.66 ppm which can be attributed to εmethylene of caprolactone and methyl of ending ester group, respectively. The formation of the nano composites were assessed by X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM), XRD analyses showed a broadening and disappearance of diffraction peak of AMMT in the nana composite which may indicate the formation of the intercalated and partially exfoliated PCVL/AMMT nana composites. TEM observations corroborated the presence of intercalated and exfoliated layers of AMMT after polymerization. The present work demonstrates that AMMT can be used as an alternative g reen catalyst's for the production of biodegradable polymers, where the in situ intercalative polymerization was employed as a direct method of preparing polymer/layered silicates (author)

Redox poly[Ni(saldMp)] modified activated carbon electrode in electrochemical supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Gao Fei [Department of Physical Chemistry, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Li Jianling, E-mail: lijianling@ustb.edu.c [Department of Physical Chemistry, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Zhang Yakun; Wang Xindong [Department of Physical Chemistry, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083 (China); Kang Feiyu [Department of Material Science and Engineering, Tsinghua University, Beijing 100083 (China)

2010-08-01

The complex (2,2-dimethyl-1,3-propanediaminebis(salicylideneaminato))-nickel(II), [Ni(saldMp)], was oxidatively electropolymerized on activated carbon (AC) electrode in acetonitrile solution. The poly[Ni(saldMp)] presented an incomplete coated film on the surface of carbon particles of AC electrode by field emission scanning electron microscopy. The electrochemical behaviors of poly[Ni(saldMp)] modified activated carbon (PAC) electrode were evaluated in different potential ranges by cyclic voltammetry. Counterions and solvent swelling mainly occurred up to 0.6 V for PAC electrode by the comparison of D{sup 1/2}C values calculated from chronoamperometry experiments. Both the Ohmic resistance and Faraday resistance of PAC electrode gradually approached to those of AC electrode when its potential was ranging from 1.2 V to 0.0 V. Galvanostatic charge/discharge experiments indicated that both the specific capacitance and energy density were effectively improved by the reversible redox reaction of poly[Ni(saldMp)] film under the high current density up to 10 mA cm{sup -2} for AC electrode. The specific capacitance of PAC electrode decreased during the first 50 cycles but thereafter it remained constant for the next 200 cycles. This study showed the redox polymer may be an attractive material in supercapacitors.

Hydrogen absorption kinetics in powdered V + 80 wt.% LaNi5 composite

International Nuclear Information System (INIS)

Kumar, Sanjay; Tirpude, Amit; Taxak, Manju; Krishnamurthy, Nagaiyar

2013-01-01

Highlights: •Vanadium prevents the pulverization of LaNi 5 . •H absorption capacity LaNi 5 –V composite is higher than LaNi 5 . •H absorption kinetics of LaNi 5 –V composite is relatively faster than V and LaNi 5 . •Fermi energy level of LaNi 5 –V composite lowered by vanadium addition. -- Abstract: The hydrogen absorption behavior of V + 80 wt.% LaNi 5 composite, LaNi 5 and V has been investigated. The LaNi 5 –V composite was prepared by high energy ball-milling technique using high pure vanadium and LaNi 5 powder. Lattice expansion of the composite has been observed in X-ray analysis which indicates the solid solution formation. Presence of free V and traces of V 2 O 5 phase were also observed in the composite. The hydrogen absorption capacity and absorption kinetics of the composite showed improvement as compared to LaNi 5 . The improved kinetics of the composite has been co-related to the change in lattices parameter, Fermi energy level and catalytic property of vanadium. Integrity of the composite has found to be effective even after 20 numbers of hydriding and dehydriding cycles due to the presence of vanadium

Morphological and compositional engineering of Ni/carbon ...

Indian Academy of Sciences (India)

Ni/multi-walled carbon nanotubes (MWCNTs) composite films were deposited on the glassy carbon electrode (GCE) by a Ni plating bath containing homogeneously dispersed MWCNTs using polyvinylpyrrolidone (PVP) as dispersion additive. Incorporation of MWCNTs into Ni matrix was greatly enhanced by the application ...

A study on the chemical stability and electrode performance of modified NiO cathodes for molten carbonate fuel cells

International Nuclear Information System (INIS)

Kim, Seung-Goo; Yoon, Sung Pil; Han, Jonghee; Nam, Suk Woo; Lim, Tae Hoon; Oh, In-Hwan; Hong, Seong-Ahn

2004-01-01

The chemical stabilities of modified NiO cathodes doped with 1.5 mol% CoO and 1.5 mol% LiCoO 2 fabricated by a conventional tape casting method were evaluated through the real MCFC single cell operation. The heat-treated samples before oxidation had proper porosities and microstructures for a MCFC cathode. At 150 mA cm -2 in current density, the MCFC single cell using a CoO-doped NiO cathode showed stable cell voltages in the range of 0.833-0.843 V for 1000 h. In contrast, the cell using a LiCoO 2 -doped NiO cathode with a maximum of 0.836 V at 500 h degraded to 0.826 V at 1000 h due to a wet seal breakdown at the cathode side. The amounts of nickel precipitated in the electrolytes of the cells using modified NiO cathodes doped with CoO and LiCoO 2 after the operation for 1000 h were 1.2 and 1.4 wt.%, respectively, which were about 60% lower than that of the standard cells using pure NiO cathodes. The enhanced chemical stability of modified NiO cathodes seems to be attributed to the fact that the presence of cobalt increases the lithium content in the cathodes by converting Ni 2+ to Ni 3+ , resulting in stabilizing the layered crystal structure

Preparation of Ni(OH)2-graphene sheet-carbon nanotube composite as electrode material for supercapacitors

International Nuclear Information System (INIS)

Liu, Y.F.; Yuan, G.H.; Jiang, Z.H.; Yao, Z.P.; Yue, M.

2015-01-01

Highlights: • CNT is introduced into graphene to prevent restacking by solvothermal reaction. • Ethanol as a low cost and green solvent is used in solvothermal reaction. • Ni(OH) 2 nanosheets were chemically precipitated into GS-CNT to increase the capacitance. - Abstract: Ni(OH) 2 -graphene sheet-carbon nanotube composite was prepared for supercapacitance materials through a simple two-step process involving solvothermal synthesis of graphene sheet-carbon nanotube composite in ethanol and chemical precipitation of Ni(OH) 2 . According to N 2 adsorption/desorption analysis, the Brunauer–Emmett–Teller surface area of graphene sheet-carbon nanotube composite (109.07 m 2 g −1 ) was larger than that of pure graphene sheets (32.06 m 2 g −1 ), indicating that the added carbon nanotubes (15 wt.%) could prevent graphene sheets from restacking in the solvothermal reaction. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Ni(OH) 2 nanosheets were uniformly loaded into the three-dimensional interconnected network of graphene sheet-carbon nanotube composite. The microstructure enhanced the rate capability and utilization of Ni(OH) 2 . The specific capacitance of Ni(OH) 2 -graphene sheet-carbon nanotube composite was 1170.38 F g −1 at a current density of 0.2 A g −1 in the 6 mol L −1 KOH solution, higher than those provided by pure Ni(OH) 2 (953.67 Fg −1 ) and graphene sheets (178.25 F g −1 ). After 20 cycles at each current density (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 A g −1 ), the capacitance of Ni(OH) 2 -graphene sheet-carbon nanotube composite decreased 26.96% of initial capacitance compared to 74.52% for pure Ni(OH) 2

Fabrication of steel matrix composites locally reinforced with different ratios of TiC/TiB2 particulates using SHS reactions of Ni-Ti-B4C and Ni-Ti-B4C-C systems during casting

International Nuclear Information System (INIS)

Yang Yafeng; Wang Huiyuan; Liang Yunhong; Zhao Ruyi; Jiang Qichuan

2007-01-01

Steel matrix composites locally reinforced with different molar ratios of in situ TiC/TiB 2 particulates (2:1, 1:1 and 1:2, respectively) have been fabricated successfully utilizing the self-propagating high-temperature synthesis (SHS) reactions of Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems during casting. Differential thermal analysis (DTA) and X-ray diffraction (XRD) results reveal that the exothermic reactions of the Ni-Ti-B 4 C and Ni-Ti-B 4 C-C systems proceed in such a way that Ni initially reacts with B 4 C and Ti to form Ni 2 B and Ti 2 Ni compounds, respectively, with heat evolution at 1037 deg. C; Subsequently, the external heat and the evolved heat from these exothermic reactions promote the reactions forming TiC and TiB 2 at 1133 deg. C. In the composites reinforced with 1:2 molar ratio of TiC/TiB 2 , almost all TiB 2 grains have clubbed structures, while TiC grains exhibit near-spherical morphologies. Furthermore, TiB 2 grain sizes decrease, with the increase of TiC content. In particular, in the composites reinforced with 2:1 molar ratio of TiC/TiB 2 , it is difficult to find the clubbed TiB 2 grains. Macro-pores and blowholes are absent in the local reinforcing region of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 , while a few macro-pores can be observed in the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . Moreover, the densities of the composites reinforced with 1:1 and 1:2 molar ratios of TiC/TiB 2 are higher than that of the composite reinforced with 2:1 molar ratio of TiC/TiB 2 . The composite reinforced with 1:2 molar ratio of TiC/TiB 2 has the highest hardness and the best wear resistance

Development of high performance electroless Ni-P-HNT composite coatings

Science.gov (United States)

Ranganatha, S.; Venkatesha, T. V.; Vathsala, K.

2012-12-01

Halloysite nanotubes (HNTs) of the dimension 50 nm × 1-3 μm (diameter × length) are utililized to fabricate the alloy composite by employing electroless/autocatalytic deposition technique. Electroless Ni-P-HNT binary alloy composite coatings are prepared successfully on low carbon steel. These nanotubes were made to get inserted/incorporated into nickel matrix and corresponding composites are examined for their electrochemical, mechanical and tribological performances and compared with that of plain Ni-P. The coatings were characterized using scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDX) techniques to analyze surface nature and composition correspondingly. Small amount of incorporated HNTs made Ni-P deposits appreciable enhancement and betterment in corrosion resistance, hardness and friction resistance. This drastic improvement in the properties reflects the effect of addition of HNTs into Ni-P matrix leading to the development of high performance Ni-P-HNT composite coatings.

Development of high performance electroless Ni-P-HNT composite coatings

Energy Technology Data Exchange (ETDEWEB)

Ranganatha, S., E-mail: kamath.ranganath@gmail.com [Department of studies in chemistry, School of chemical sciences, Kuvempu university, Shankaraghatta-577451, Shimoga, Karnataka (India); Venkatesha, T.V., E-mail: drtvvenkatesha@yahoo.co.uk [Department of studies in chemistry, School of chemical sciences, Kuvempu university, Shankaraghatta-577451, Shimoga, Karnataka (India); Vathsala, K., E-mail: vathsala.mahesh@gmail.com [Nanotribology Laboratory, Mechanical engineering department, Indian Institute of Science, Bangalore 560012, Karnataka (India)

2012-12-15

Highlights: Black-Right-Pointing-Pointer Novel Ni-P composites were prepared by incorporating Halloysite nanotubes. Black-Right-Pointing-Pointer Mild steel specimens surface engineered by nickel using electroless technique. Black-Right-Pointing-Pointer Incorporated halloysite nanotubes made nickel matrix highly corrosion resistant. Black-Right-Pointing-Pointer HNT composite exhibits high hardness and largely reduces friction. - Abstract: Halloysite nanotubes (HNTs) of the dimension 50 nm Multiplication-Sign 1-3 {mu}m (diameter Multiplication-Sign length) are utililized to fabricate the alloy composite by employing electroless/autocatalytic deposition technique. Electroless Ni-P-HNT binary alloy composite coatings are prepared successfully on low carbon steel. These nanotubes were made to get inserted/incorporated into nickel matrix and corresponding composites are examined for their electrochemical, mechanical and tribological performances and compared with that of plain Ni-P. The coatings were characterized using scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDX) techniques to analyze surface nature and composition correspondingly. Small amount of incorporated HNTs made Ni-P deposits appreciable enhancement and betterment in corrosion resistance, hardness and friction resistance. This drastic improvement in the properties reflects the effect of addition of HNTs into Ni-P matrix leading to the development of high performance Ni-P-HNT composite coatings.

Adsorptive Stripping Determination of Trace Nickel Using Bismuth Modified Mesoporous Carbon Composite Electrode

Science.gov (United States)

Ouyang, Ruizhuo; Feng, Kai; Su, Yongfu; Zong, Tianyu; Zhou, Xia; Lei, Tian; Jia, Pengpeng; Cao, Penghui; Zhao, Yuefeng; Guo, Ning; Chang, Haizhou; Miao, Yuqing; Zhou, Shuang

Novel bismuth nanoparticle-modified mesoporous carbon (MPC) was successfully prepared on a glassy carbon electrode (Bi@MPC/GCE) for the adsorptive stripping voltammetric determination of nickel by complexing with dimethylglyoxime (DMG). The presence of MPC obviously improved the properties of Bi particles like the electron transfer ability, particle size and hydrophicility, important parameters to achieve preferable analytical performances of Bi@MPC/GCE toward Ni(II). The best electrochemical behaviors of Bi@MPC/GCE was obtained for the stripping determination of Ni(II), compared with electrodes individually modified with Bi and MPC. The synergic effect between metallic Bi and ordered MPC (forming a 3D array like Bi microelectrodes) made major contribution to such improved electrochemical properties of Bi@MPC/GCE for Ni(II) sensing. The good linear analytical curve was achieved in a Ni(II) concentration range from 0.1μM to 5.0μM with a correlation coefficient of 0.9995. The detection limit and sensitivity were calculated to be 1.2nM (S/N=3) and 1410μAmM-1cm-2, respectively. The new method was successfully applied to Ni(II) determination in soybean samples with recoveries higher than 99% and proved to be a simple, efficient alternative for Ni(II) monitoring in real samples.

Preparation and characterization of a supported system of Ni2P/Ni12P5 nanoparticles and their use as the active phase in chemoselective hydrogenation of acetophenone

Science.gov (United States)

Costa, Dolly C.; Soldati, Analía L.; Pecchi, Gina; Bengoa, José Fernando; Marchetti, Sergio Gustavo; Vetere, Virginia

2018-05-01

Ni2P/Ni12P5 nanoparticles were obtained by thermal decomposition of nickel organometallic salt at low temperature. The use of different characterization techniques allowed us to determine that this process produced a mixture of two nickel phosphide phases: Ni2P and Ni12P5. These nickel phosphides nanoparticles, supported on mesoporous silica, showed activity and high selectivity for producing the hydrogenation of the acetophenone carbonyl group to obtain 1-phenylethanol. This is a first report that demonstrates the ability of supported Ni2P/Ni12P5 nanoparticles to produce the chemoselective hydrogenation of acetophenone. We attribute these special catalytic properties to the particular geometry of the Ni–P sites on the surface of the nanoparticles. This is an interesting result because the nickel phosphides have a wide composition range (from Ni3P to NiP3), with different crystallographic structures, therefore we think that different phases could be active and selective to hydrogenate many important molecules with more than one functional group.

Microscopic mechanism on the evolution of plasticity in nanolamellar γ-Ni/Ni_5Zr eutectic composites

International Nuclear Information System (INIS)

Maity, T.; Singh, A.; Dutta, A.; Das, J.

2016-01-01

The evolution of microstructure and the mechanical properties of a series of (Ni_0_._9_1_2Zr_0_._0_8_8)_1_0_0_-_xAl_x (0≤x≤4) eutectic composites, constitute of γ-Ni and Ni_5Zr nanolamellar phases, have been presented. Al dissolves in γ-Ni phase preferentially, decreases its hardness and refines the microstructure. Strain rate jump test was performed in order to investigate the rate sensitivity. It has been found that activation volume increases from 39b"3 to 46b"3 upon Al addition. The strain rate sensitivity of the composites has been estimated to be ~0.008. The scanning and transmission electron microscopic studies have confirmed that dislocation meditated flow in nano-lamellar phases dominates the plastic deformation mechanism. Analysis based on Stroh's pile-up model suggests that the required shear stress for slip decreases and that for cleavage crack nucleation increases around a dislocation pile-up at the lamellae interface, upon Al addition. The nano-lamellar Ni_5Zr strengthen the composite, whereas, dislocation slip endorses the global plasticity of high strength Ni-Zr-(Al) nanoeutectic composites.

Electrodeposition and properties of Zn-Ni-CNT composite coatings

International Nuclear Information System (INIS)

Praveen, B.M.; Venkatesha, T.V.

2009-01-01

Zn-Ni-CNT composite coatings were prepared by electrodeposition from a sulphate bath. The effect of CNTs on the corrosion behavior, wear resistance and hardness of the composite coatings was investigated. Their corrosion properties were evaluated by polarization, impedance, weight loss and salt spray tests. The CNT particles inclusion improved the corrosion resistance, hardness and wear resistance of the coating. The grain size of the composite coating was smaller than that of a pure Zn-Ni coating with the same Zn/Ni ratio. Scanning electron microscope images and X-ray diffraction patterns of coating revealed its fine-grain nature.

Cofiring behavior and interfacial structure of NiCuZn ferrite/PMN ferroelectrics composites for multilayer LC filters

International Nuclear Information System (INIS)

Miao Chunlin; Zhou Ji; Cui Xuemin; Wang Xiaohui; Yue Zhenxing; Li Longtu

2006-01-01

The cofiring behavior, interfacial structure and cofiring migration between NiCuZn ferrite and lead magnesium niobate (PMN)-based relaxor ferroelectric materials were investigated via thermomechanical analyzer (TMA), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Mismatched sintering shrinkage between NiCuZn ferrite and PMN was modified by adding an appropriate amount of sintering aids, Bi 2 O 3 , into NiCuZn ferrite. Pyrochlore phase appeared in the mixture of NiCuZn ferrite and PMN, which is detrimental to the final electric properties of LC filters. EDS results indicated that the interdiffusion at the heterogeneous interfaces in the composites, such as Fe, Pb, Zn, existed which can strengthen combinations between ferrite layers and ferroelectrics layers

Density of liquid NiCoAlCr quarternary alloys measured by modified sessile drop method

Institute of Scientific and Technical Information of China (English)

FANG Liang; ZHANG Shu-fang; XIAO Feng; YANG Ling-chuan; DONG Jian-xin; CAO Chun-lan; TAO Zai-nan; K. MUKAI

2006-01-01

The densities of liquid NiCoAlCr quaternary alloys with a fixed molar ratio of Ni to Co to Al (x(Ni)-x(Co)-x(Al)≈73-12-15) which is close to the average value of the commercial Ni-based superalloys TMS75, INCO713, CM247LC and CMSX-4, and the mass fraction of chromium changes from 0 to 9% were measured by a modified sessile drop method. It is found that with increasing temperature and chromium concentration in the alloys, the densities of the liquid NiCoAlCr quaternary alloys decrease, whereas the molar volume of the liquid NiCoAlCr quaternary alloys increases. And the liquid densities of NiCoAlCr quaternary alloys calculated from the partial molar volumes of nickel, cobalt, aluminum and chromium in the corresponding Ni-bases binary alloys are in good agreement with the experimental ones, i.e. within the error tolerance range the densities of the liquid Ni-based multi-component alloys can be predicted from the partial volumes of elements in Ni-based binary alloys in liquid state. The molar volume of liquid NiCoAlCr binary alloy shows a negative deviation from the ideal linear mixing and the deviation changes small with the increase of chromium concentration at the same temperature.

Fabrication of TiNi/CFRP smart composite using cold drawn TiNi wires

Science.gov (United States)

Xu, Ya; Otsuka, Kazuhiro; Toyama, Nobuyuki; Yoshida, Hitoshi; Jang, Byung-Koog; Nagai, Hideki; Oishi, Ryutaro; Kishi, Teruo

2002-07-01

In recent years, pre-strained TiNi shape memory alloys (SMA) have been used for fabricating smart structure with carbon fibers reinforced plastics (CFRP) in order to suppress microscopic mechanical damages. However, since the cure temperature of CFRP is higher than the reverse transformation temperatures of TiNi SMA, special fixture jigs have to be used for keeping the pre-strain during fabrication, which restricted its practical application. In order to overcome this difficulty, we developed a new method to fabricate SMA/CFRP smart composites without using special fixture jigs by controlling the transformation temperatures of SMA during fabrication. This method consists of using heavily cold-worked wires to increase the reverse transformation temperatures, and of using flash electrical heating of the wires after fabrication in order to decrease the reverse transformation temperatures to a lower temperature range again without damaging the epoxy resin around SMA wires. By choosing proper cold-working rate and composition of TiNi alloys, the reverse transformation temperatures were well controlled, and the TiNi/CFRP hybrid smart composite was fabricated without using special fixture jigs. The damage suppressing effect of cold drawn wires embedded in CFRP was confirmed.

Metal oxides modified NiO catalysts for oxidative dehydrogenation of ethane to ethylene

KAUST Repository

Zhu, Haibo

2014-06-01

The sol-gel method was applied to the synthesis of Zr, Ti, Mo, W, and V modified NiO based catalysts for the ethane oxidative dehydrogenation reaction. The synthesized catalysts were characterized by XRD, N2 adsorption, SEM and TPR techniques. The results showed that the doping metals could be highly dispersed into NiO domains without the formation of large amount of other bulk metal oxide. The modified NiO materials have small particle size, larger surface area, and higher reduction temperature in contrast to pure NiO. The introduction of group IV, V and VI transition metals into NiO decreases the catalytic activity in ethane ODH. However, the ethylene selectivity is enhanced with the highest level for the Ni-W-O and Ni-Ti-O catalysts. As a result, these two catalysts show improved efficiency of ethylene production in the ethane ODH reaction. © 2014 Elsevier B.V. All rights reserved.

Development of novel Mg–Ni60Nb40 amorphous particle reinforced composites with enhanced hardness and compressive response

International Nuclear Information System (INIS)

Jayalakshmi, S.; Sahu, Shreyasi; Sankaranarayanan, S.; Gupta, Sujasha; Gupta, M.

2014-01-01

Development of amorphous alloy/glassy particle reinforced light metal composites is an emerging research field. In this investigation, we have synthesized and characterized Ni 60 Nb 40 amorphous alloy particle reinforced Mg-composites with varying volume fractions. Microwave-assisted two-directional rapid sintering technique followed by hot extrusion was used to produce these pure Mg-based composites. The structural and mechanical properties of the developed composites were investigated, and are discussed using structure–property relationship. Structural analysis indicated the retention of amorphous structure of the reinforcement in all the composites. It was found that the distribution of the reinforcement was strongly dependent on the volume fraction (V f ). The addition of Ni 60 Nb 40 amorphous alloy particles modified the preferred crystal orientation of Mg, as was observed from X-ray diffraction (XRD) analysis. The composites showed significant improvement in hardness (increment up to 120%) and compressive strength (∼85% increase at 5% V f ). Comparison of mechanical properties of the developed composites with those of conventional Mg-composites having ceramic/metallic reinforcements, highlight the effectiveness of using amorphous particles as promising reinforcement materials. - Highlights: • Novel Mg-composites reinforced with Ni 60 Nb 40 amorphous particles were developed . • Microwave sintering and hot extrusion were used to synthesize the composites. • Reinforcements retained the amorphous structure, and changed Mg-crystal orientation. • Composites showed significant enhancement in hardness and compressive properties. • Performance of developed composites are superior/competitive to conventional MMCs

Effect of composition and heat treatment on carbide phases in Ni-Mo alloys

International Nuclear Information System (INIS)

Svistunova, T.V.; Tsvigunov, A.N.; Stegnukhina, L.V.; Sakuta, N.D.

1984-01-01

The investigation results of vanadium, iron, carbon and silicon effect and heat treatment regime on the type and composition of carbides in Ni-(26...31)%Mo alloys are presented. It is shown that type, composition and quantity of carbide phases forming in alloys are determined not only by molybdenum and carbon content, but presence of other elements (V, Fe), admixtures (C, Si) and reducers as well as by regime of thermal treatment. In the alloy, containing 26...31% Mo, 0.01...0.03% C ( 12 C type with a=1.083...1.089 nm lattice parameter, in which V and Ti, Fe and Si are presented besides Mo and Ni. In the temperature range of 600-800 deg C high dispersed carbides segregate on grain boundaries. Silicon initiates segregation of the carbide phases among them by grain boundaries at the temperatures of 800 deg C as well as regulates carbide of M 12 C type with a=1.094...1.098 nm lattice parameter

Preparation of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite as electrode material for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Liu, Y.F. [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); College of Environmental and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin 150022 (China); Yuan, G.H., E-mail: ygh@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Jiang, Z.H., E-mail: jiangzhaohua@hit.edu.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Yao, Z.P. [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Yue, M. [Shenzhen BTR New Energy Materials INC., Shenzhen 528206 (China)

2015-01-05

Highlights: • CNT is introduced into graphene to prevent restacking by solvothermal reaction. • Ethanol as a low cost and green solvent is used in solvothermal reaction. • Ni(OH){sub 2} nanosheets were chemically precipitated into GS-CNT to increase the capacitance. - Abstract: Ni(OH){sub 2}-graphene sheet-carbon nanotube composite was prepared for supercapacitance materials through a simple two-step process involving solvothermal synthesis of graphene sheet-carbon nanotube composite in ethanol and chemical precipitation of Ni(OH){sub 2}. According to N{sub 2} adsorption/desorption analysis, the Brunauer–Emmett–Teller surface area of graphene sheet-carbon nanotube composite (109.07 m{sup 2} g{sup −1}) was larger than that of pure graphene sheets (32.06 m{sup 2} g{sup −1}), indicating that the added carbon nanotubes (15 wt.%) could prevent graphene sheets from restacking in the solvothermal reaction. The results of field emission scanning electron microscopy and transmission electron microscopy showed that Ni(OH){sub 2} nanosheets were uniformly loaded into the three-dimensional interconnected network of graphene sheet-carbon nanotube composite. The microstructure enhanced the rate capability and utilization of Ni(OH){sub 2}. The specific capacitance of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite was 1170.38 F g{sup −1} at a current density of 0.2 A g{sup −1} in the 6 mol L{sup −1} KOH solution, higher than those provided by pure Ni(OH){sub 2} (953.67 Fg{sup −1}) and graphene sheets (178.25 F g{sup −1}). After 20 cycles at each current density (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 A g{sup −1}), the capacitance of Ni(OH){sub 2}-graphene sheet-carbon nanotube composite decreased 26.96% of initial capacitance compared to 74.52% for pure Ni(OH){sub 2}.

Surface treatment of NiTi shape memory alloy by modified advanced oxidation process

Institute of Scientific and Technical Information of China (English)

CHU Cheng-lin; WANG Ru-meng; YIN Li-hong; PU Yue-pu; DONG Yin-sheng; GUO Chao; SHENG Xiao-bo; LIN Ping-hua; CHU Paul-K

2009-01-01

A modified advanced oxidation process(AOP) utilizing a UV/electrochemically-generated peroxide system was used to fabricate titania films on chemically polished NiTi shape memory alloy(SMA). The microstructure and biomedical properties of the film were characterized by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS), inductively-coupled plasma mass spectrometry(ICPMS), hemolysis analysis, and blood platelet adhesion test. It is found that the modified AOP has a high processing effectiveness and can result in the formation of a dense titania film with a Ni-free zone near its top surface. In comparison, Ni can still be detected on the outer NiTi surface by the conventional AOP using the UV/H2O2 system. The depth profiles of O, Ni, Ti show that the film possesses a smooth graded interface structure next to the NiTi substrate and this structure enhances the mechanical stability of titania film. The titania film can dramatically reduce toxic Ni ion release and also improve the hemolysis resistance and thromboresistance of biomedical NiTi SMA.

Microstructures evolution and physical properties of laser induced NbC modified nanocrystalline composites

Science.gov (United States)

Li, Jianing; Liu, Kegao; Yuan, Xingdong; Shan, Feihu; Zhang, Bolun; Wang, Zhe; Xu, Wenzhuo; Zhang, Zheng; An, Xiangchen

2017-10-01

The nanoscale quasicrystals (NQs), amorphous and ultrafine nanocrystals (UNs) modified hard composites are produced by laser cladding (LC) of the Ni60A-TiC-NbC-Sb mixed powders on the additive manufacturing (AM) TA1 titanium alloy. The LC technique is favorable to formations of icosahedral quasicrystals (I-phase) with five-fold symmetry due to its rapid cooling and solidification characteristics. The formation mechanism of this I-phase is explained here. Under the actions of NQs, amorphous and UNs, such LC composites exhibited an extremely high micro-hardness. UNs may also intertwin with amorphous, forming yarn-shape materials. This research provides essential theoretical basis to improve the quality of laser-treated composites.

Hollow NiO nanofibers modified by citric acid and the performances as supercapacitor electrode

International Nuclear Information System (INIS)

Ren, Bo; Fan, Meiqing; Liu, Qi; Wang, Jun; Song, Dalei; Bai, Xuefeng

2013-01-01

Graphical abstract: The possible formation process of NiO nanofibers without citric acid (a), and modified by citric acid (b). When the nanofibers is modified by citric acid, the nickel citrate is produced by complexing action of citric acid and nickel nitrate. Because of the larger space steric hindrance, the structure is limited by the molecular geometry. Under high temperature, the hollow nanofibers composed of NiO slices formed after the removal of PVP. Highlights: ► The method of obtaining hollow nanofibers is raised for the first time. ► The prepared NiO nanofibers are hollow tube and comprised of many NiO sheets. ► The hollow structure facilitated the electrolyte penetration. ► The hollow NiO nanofibers have good electrochemical properties. -- Abstract: NiO nanofibers modified by citric acid (NiO/CA) for supercapacitor material have been fabricated by electrospinning process. The characterizations of the nanofibers are investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. Results show that the NiO/CA nanofibers are hollow tube and comprised of many NiO sheets. Furthermore, the NiO/CA nanofibers have good electrochemical reversibility and display superior capacitive performance with large capacitance (336 F g −1 ), which is 2.5 times of NiO electrodes. Moreover, the NiO/CA nanofibers show excellent cyclic performance after 1000 cycles

Effect of nano-hydroxyapatite reinforcement in mechanically alloyed NiTi composites for biomedical implant

International Nuclear Information System (INIS)

Akmal, Muhammad; Raza, Ahmad; Khan, Muhammad Mudasser; Khan, M. Imran; Hussain, Muhammad Asif

2016-01-01

Equi-atomic NiTi alloy composites reinforced with 0, 2, 4 and 6 vol.% nano-hydroxyapatite (HA) were successfully synthesized using pressureless sintering. Pure Ni and Ti elements were ball milled for 10 h in order to produce a mechanically alloyed equi-atomic NiTi alloy (MA-NiTi). Mechanically alloyed NiTi and HA powders were blended, compacted and then sintered for 3 h at 1325 K. The sintered density varied inversely with volume percent of HA reinforcement. The X-Ray diffraction spectra and SEM images showed the formation of multiple phases like NiTi, NiTi 2 , Ni 3 Ti, and Ni 4 Ti 3 . The back scattered-SEM image analysis confirmed the presence of Ni-rich and Ti-rich phases with increasing HA content. The 6 vol.% HA reinforced composite showed Ni 3 Ti as the major phase having the highest hardness value which can be attributed to the presence of relatively harder phases along with higher HA content as a reinforcement. The composite of MA-NiTi with 2 vol.% HA manifested the most desirable results in the form of better sintering density mainly due to the minute decomposition of NiTi into other phases. Therefore, the 2 vol.% reinforced MA-NiTi composite can be exploited as a novel material for manufacturing biomedical implants. - Highlights: • NiTi-HA composites were synthesized using powder metallurgy route. • New phases such as NiTi 2 , Ni 3 Ti and Ni 4 Ti 3 were observed for sintered composites. • Mechanical properties enhanced with the increasing content of HA and new phases. • No martensitic transformation was observed for all composites by DSC analysis. • 2 vol.% HA composite is a novel candidate for biomedical implants.

Effect of nano-hydroxyapatite reinforcement in mechanically alloyed NiTi composites for biomedical implant

Energy Technology Data Exchange (ETDEWEB)

Akmal, Muhammad, E-mail: muhammad.akmal@giki.edu.pk [Faculty of Materials and Chemical Engineering, GIK Institute of Engineering Sciences and Technology, Topi 23640 (Pakistan); Raza, Ahmad, E-mail: ahmadrazac@yahoo.com [Faculty of Materials and Chemical Engineering, GIK Institute of Engineering Sciences and Technology, Topi 23640 (Pakistan); Khan, Muhammad Mudasser; Khan, M. Imran [Faculty of Materials and Chemical Engineering, GIK Institute of Engineering Sciences and Technology, Topi 23640 (Pakistan); Hussain, Muhammad Asif [Department of Chemical Engineering, Kangwon National University, Samcheok, 25913 (Korea, Republic of)

2016-11-01

Equi-atomic NiTi alloy composites reinforced with 0, 2, 4 and 6 vol.% nano-hydroxyapatite (HA) were successfully synthesized using pressureless sintering. Pure Ni and Ti elements were ball milled for 10 h in order to produce a mechanically alloyed equi-atomic NiTi alloy (MA-NiTi). Mechanically alloyed NiTi and HA powders were blended, compacted and then sintered for 3 h at 1325 K. The sintered density varied inversely with volume percent of HA reinforcement. The X-Ray diffraction spectra and SEM images showed the formation of multiple phases like NiTi, NiTi{sub 2}, Ni{sub 3}Ti, and Ni{sub 4}Ti{sub 3}. The back scattered-SEM image analysis confirmed the presence of Ni-rich and Ti-rich phases with increasing HA content. The 6 vol.% HA reinforced composite showed Ni{sub 3}Ti as the major phase having the highest hardness value which can be attributed to the presence of relatively harder phases along with higher HA content as a reinforcement. The composite of MA-NiTi with 2 vol.% HA manifested the most desirable results in the form of better sintering density mainly due to the minute decomposition of NiTi into other phases. Therefore, the 2 vol.% reinforced MA-NiTi composite can be exploited as a novel material for manufacturing biomedical implants. - Highlights: • NiTi-HA composites were synthesized using powder metallurgy route. • New phases such as NiTi{sub 2}, Ni{sub 3}Ti and Ni{sub 4}Ti{sub 3} were observed for sintered composites. • Mechanical properties enhanced with the increasing content of HA and new phases. • No martensitic transformation was observed for all composites by DSC analysis. • 2 vol.% HA composite is a novel candidate for biomedical implants.

Optimisation of optical absorption properties of spectrally selective C-NiO composite coatings

CSIR Research Space (South Africa)

Tile, N

2011-05-01

Full Text Available and expensive. Carbon in Nickel Oxide (C-NiO) composite material has been found to have a very good spectral selectivity1,2. Moreover this material has a potential of low cost large scale fabrication since it can be fabricated by a simple sol-gel technique...

In-situ conversion of rGO/Ni2P composite from GO/Ni-MOF precursor with enhanced electrochemical property

Science.gov (United States)

Lv, Zijian; Zhong, Qin; Bu, Yunfei

2018-05-01

Owing to the metalloid characteristic and superior electrical conductivity, the metal phosphides have received increasing interests in energy storage systems. Here, xrGO/Ni2P composites are successfully synthesized via an In-situ phosphorization process with GO/Ni-MOF as precursors. Compared to pure Ni2P, the xrGO/Ni2P composites appear enhanced electrochemical properties in terms of the specific capacitance and cycling performance as electrodes for supercapacitors. Especially, the 2rGO/Ni2P electrode shows a highest specific capacitance of 890 F g-1 at 1 A g-1 among the obtained composites. The enhancement can be attributed to the inherited structure from Ni-MOF and the well assembled of rGO and Ni2P through the In-situ conversion process. Moreover, when applied as positive electrode in a hybrid supercapacitor, an energy density of 35.9 W h kg-1 at a power density of 752 W kg-1 has been achieved. This work provides an In-situ conversion strategy for the synthesis of rGO/Ni2P composite which might be a promising electrode material for SCs.

3D flexible NiTi-braided elastomer composites for smart structure applications

International Nuclear Information System (INIS)

Heller, L; Vokoun, D; Šittner, P; Finckh, H

2012-01-01

While outstanding functional properties of thin NiTi wires are nowadays well recognized and beneficially utilized in medical NiTi devices, development of 2D/3D wire structures made out of these NiTi wires remains challenging and mostly unexplored. The research is driven by the idea of creating novel 2D/3D smart structures which inherit the functional properties of NiTi wires and actively utilize geometrical deformations within the structure to create new/improved functional properties. Generally, textile technology provides attractive processing methods for manufacturing 2D/3D smart structures made out of NiTi wires. Such structures may be beneficially combined with soft elastomers to create smart deformable composites. Following this route, we carried out experimental work focused on development of 3D flexible NiTi-braided elastomer composites involving their design, laboratory manufacture and thermomechanical testing. We describe the manufacturing technology and structural properties of these composites; and perform thermomechanical tests on the composites, focusing particularly on quasistatic tensile properties, energy absorption, damping and actuation under tensile loading. Functional thermomechanical properties of the composites are discussed with regard to the mechanical properties of the components and architecture of the composites. It is found that the composites indeed inherit all important features of the thermomechanical behavior of NiTi wires but, due to their internal architecture, outperform single NiTi wires in some features such as the magnitude of recoverable strain, superelastic damping capacity and thermally induced actuation strain. (paper)

Electrolytic Synthesis of Ni-W-MWCNT Composite Coating for Alkaline Hydrogen Evolution Reaction

Science.gov (United States)

Elias, Liju; Hegde, A. Chitharanjan

2018-03-01

Nickel-tungsten multi-walled carbon nanotube (Ni-W-MWCNT) composite films were fabricated by an electrodeposition technique, and their electrocatalytic activity toward hydrogen evolution reaction (HER) was studied. Ni-W-MWCNT composite films with a homogeneous dispersion of MWCNTs were deposited from an optimal Ni-W plating bath containing functionalized MWCNTs, under galvanostatic condition. The presence of functionalized MWCNT was found to enhance the induced codeposition of the reluctant metal W and resulted in a W-rich composite coating with improved properties. The electrocatalytic behaviors of Ni-W-MWCNT composite coating toward HER were studied by cyclic voltammetry (CV) and chronopotentiometry techniques in 1.0 M KOH medium. Further, Tafel polarization and electrochemical impedance spectroscopy (EIS) studies were carried out to establish the kinetics of HER on the alloy and composite electrodes. The experimental results revealed that the addition of MWCNTs (having a diameter of around 10-15 nm) into the alloy plating bath has a significant effect on the electrocatalytic behavior of Ni-W alloy deposit. The Ni-W-MWCNT composite coating was found to show better HER activity than the conventional Ni-W alloy coating. The enhanced electrocatalytic activity of Ni-W-MWCNT composite coating is attributed to the MWCNT intersticed in the deposit matrix, evidenced by surface morphology, composition and phase structure of the coating through SEM, EDS and XRD analyses, respectively.

Welding of heterogeneous 12Kh2MFSR steels with the Mn-Cr-Si-Ni system

International Nuclear Information System (INIS)

Smirnov, A.N.; Belogolov, E.I.

1978-01-01

The process of welding pipes of the 12Kh2MFSR pearlitic steels and austenitic steels of the Mn-Cr-Si-Ni system was studied. The filler materials were selected, and the working capacity of welded joints was examined in ageing and cyclic heatings. The microhardness of steels was measured, and the ultimate strength of welded joints was determined. The following has been established: the composite joints of steels of the Mn-Cr-Si-Ni system and 12Kh2MFSR steel are advisable to be welded on a coating layer welded by the EhA395/9 electrodes on the surface of a pipe of the 12Kh2MFSR pearlitic steel; this guarantees the sufficient working capacity of welded joints

A Comparative Study of the Microstructure, Mechanical Properties and Corrosion Resistance of Ni- or Fe- Based Composite Coatings by Laser Cladding

Science.gov (United States)

Wan, M. Q.; Shi, J.; Lei, L.; Cui, Z. Y.; Wang, H. L.; Wang, X.

2018-04-01

Ni- and Fe-based composite coatings were laser cladded on 40Cr steel to improve the surface mechanical property and corrosion resistance, respectively. The microstructure and phase composition were analyzed by x-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) equipped with an energy-dispersive spectrometer (EDS). The micro-hardness, tribological properties and electrochemical corrosion behavior of the coatings were evaluated. The results show that the thickness of both the coatings is around 0.7 mm, the Ni-based coating is mainly composed of γ-(Ni, Fe), FeNi3, Ni31Si12, Ni3B, CrB and Cr7C3, and the Fe-based coating is mainly composed of austenite and (Fe, Cr)7C3. Micro-hardness of the Ni-based composite coating is about 960 HV0.3, much higher than that of Fe-based coating (357.4 HV0.3) and the 40Cr substrate (251 HV0.3). Meanwhile, the Ni-based composite coating possesses better wear resistance than the Fe-based coating validated by the worn appearance and the wear loss. Electrochemical results suggested that Ni-based coating exhibited better corrosion resistance than the Fe-based coating. The 40Cr substrate could be well protected by the Ni-based coating.

Effect of PW12–GPK on the acid characteristics of Ni-, Pd- and Pt- catalysts deposited onto pillared Al montmorillonite

Directory of Open Access Journals (Sweden)

D. Zhumadullaev

2012-03-01

Full Text Available Acid characteristics of Ni-, Pd-, Pt- catalyzers , deposited to Al pillared CaH montmorillonite modified by heteropolyacid H3PW12O40·xH2O (PW12 by ammonia thermoadsorbtion method has been studied.

Bath temperature effect on magnetoelectric performance of Ni-lead zirconate titanate-Ni laminated composites synthesized by electroless deposition

Energy Technology Data Exchange (ETDEWEB)

Wu, W. [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Wang, Y.G., E-mail: yingang.wang@nuaa.edu.c [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Bi, K. [College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

2011-03-15

Magnetoelectric (ME) Ni-lead zirconate titanate-Ni laminated composites have been prepared by electroless deposition at various bath temperatures. The structure of the Ni layers deposited at various bath temperatures was characterized by X-ray diffraction, and microstructures were investigated by transmission electron microscopy. The magnetostrictive coefficients were measured by means of a resistance strain gauge. The transverse ME voltage coefficient {alpha}{sub E,31} was measured with the magnetic field applied parallel to the sample plane. The deposition rate of Ni increases with bath temperature. Ni layer with smaller grain size is obtained at higher bath temperature and shows higher piezomagnetic coefficient, promoting the ME effect of corresponding laminated composites. It is advantageous to increase the bath temperature, while trying to avoid the breaking of bath constituents. - Research Highlights: Laminated composites without interlayer are prepared by electroless deposition. Bath temperature affects the grain size of the deposited Ni layers. Higher bath temperature is beneficial to obtain stronger ME response.

Remarkable sensitivity for detection of bisphenol A on a gold electrode modified with nickel tetraamino phthalocyanine containing Ni-O-Ni bridges.

Science.gov (United States)

Chauke, Vongani; Matemadombo, Fungisai; Nyokong, Tebello

2010-06-15

This work reports the electrocatalysis of bisphenol A on Ni(II) tetraamino metallophthalocyanine (NiTAPc) polymer modified gold electrode containing Ni-O-Ni bridges (represented as Ni(OH)TAPc). The Ni(II)TAPc films were electro-transformed in 0.1 mol L(-1) NaOH aqueous solution to form 'O-Ni-O oxo bridges', forming poly-n-Ni(OH)TAPc (where n is the number of polymerising scans). poly-30-Ni(OH)TAPc, poly-50-Ni(OH)TAPc, poly-70-Ni(OH)TAPc and poly-90-Ni(OH)TAPc films were investigated. The polymeric films were characterised by electrochemical impedance spectroscopy and the charge transfer resistance (R(CT)) values increased with film thickness. The best catalytic activity for the detection of bisphenol A was on poly-70-Ni(OH)TAPc. Electrode resistance to passivation improved with polymer thickness. The electrocatalytic behaviour of bisphenol A was compared to that of p-nitrophenol in terms of electrode passivation and regeneration. The latter was found to passivate the electrode less than the former. The poly-70-Ni(OH)TAPc modified electrode could reliably detect bisphenol A in a concentration range of 7x10(-4) to 3x10(-2)mol L(-1) with a limit of detection of 3.68x10(-9)mol L(-1). The sensitivity was 3.26x10(-4)A mol(-1) L cm(-2). Copyright 2010 Elsevier B.V. All rights reserved.

Damping behavior of polymer composites with high volume fraction of NiMnGa powders

Science.gov (United States)

Sun, Xiaogang; Song, Jie; Jiang, Hong; Zhang, Xiaoning; Xie, Chaoying

2011-03-01

Polymer composites inserted with high volume fraction (up to 70 Vol%) of NiMnGa powders were fabricated and their damping behavior was investigated by dynamic mechanical analysis. It is found that the polymer matrix has little influence on the transformation temperatures of NiMnGa powders. A damping peak appears for NiMnGa/epoxy resin (EP) composites accompanying with the martensitic transformation or reverse martensitic transformation of NiMnGa powders during cooling or heating. The damping capacity for NiMnGa/EP composites increases linearly with the increase of volume fraction of NiMnGa powders and, decreases dramatically as the test frequency increases. The fracture strain of NiMnGa/EP composites decrease with the increase of NiMnGa powders.

Electrochemical synthesis, structure and phase composition of nano structured amorphous thin layers of NiW and Ni-Mo

International Nuclear Information System (INIS)

Vitina, I.; Lubane, M.; Belmane, V.; Rubene, V.; Krumina, A.

2006-01-01

Full text: Nano structured Ni-W thin layers containing W 6-37 wt.% were electrodeposited on a copper substratum. The W content in the layer changes, and it is determined by the electrolyte pH in the range 8.0-9.6 and the cathode current density in the range 1.0-10.0 A/dm 2 . The atomic composition and thermal stability of structure of the electrodeposited thin layers depend for the most part on the conditions of the electrodeposition and less on the W content in the layer. Cracking of the Ni-W layers electrodeposited at the electrolyte pH 8.5 and containing 34-37 wt.% W and 8.5 wt.% W was observed. The cracking increases at heating at 400 deg C for 50 h. On the contrary, no cracking of the Ni-W layer electrodeposited at the electrolyte pH 9.0 and containing 25 wt.% W was observed. The atomic composition of the layer remains practically unchanged at heating at 400 deg C for 50 h. The layer binds oxygen up to 7 wt.%. According to X-ray diffraction, in spite of the W content 35-37 wt.% in the layer, nano structured layers rather than amorphous layers were obtained which at heating at 400 deg C depending on the W content crystallises as Ni or intermetallic compounds Ni x W y if the W content is approx. 25 wt.%. Amorphous Ni-Mo alloys containing 35-52 wt.% Mo was electrodeposited on copper substratum at the cathode current densities of 0.5-1.5 A/dm2 and the electrolyte pH 6.8-8.6. Formation of thin layer (∼1-2μm) of X-ray amorphous Ni-Mo alloy, the Mo content, the characteristics of structure depend on the electrodeposition process, the electrolyte pH, and the cathode current density. The Ni-Mo layer deposited at the electrolyte pH above 8.6 and below average 6.8 had a nanocrystalline structure rather than characteristics of amorphous structure. Ni- W and Ni-Mo alloys were electrodeposited from citrate electrolyte not containing ammonium ions

Electrochemical preparation and characteristics of Ni-Co-LaNi5 composite coatings as electrode materials for hydrogen evolution

International Nuclear Information System (INIS)

Wu Gang; Li Ning; Dai Changsong; Zhou Derui

2004-01-01

Electrocatalytic activity for the hydrogen evolution reaction on Ni-Co-LaNi 5 composite electrodes prepared by electrochemical codeposition technique was evaluated. The relationship between the current density for hydrogen evolution reaction and the amount of LaNi 5 particles in Ni-Co baths is like the well-known 'volcano plot'. The Surface morphology and microstructure of Ni-Co-LaNi 5 coatings were determined by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The kinetic parameters were determined from electrochemical steady-state Tafel polarization and electrochemical impedance spectroscopy technology in 1 M NaOH solution. The values obtained for the apparent energies of activation are 32.48, 46.29 and 57.03 kJ mol -1 for the Ni-Co-LaNi 5 , Ni-Co and Ni electrodes, respectively. The hydrogen evolution reaction on Ni-Co-LaNi 5 proceeds via Volmer-Tafel reaction route with the mixed rate determining characteristics. The composite coating Ni-Co-LaNi 5 is catalytically more active than Ni and Ni-Co electrodes due to the increase in its real surface areas and the decrease in the apparent free energy of activation caused by the electrocatalytic synergistic effect of the Ni-Co alloys and the hydrogen storage intermetallic particles on the electrode surface

Al/Ni metal intermetallic composite produced by accumulative roll bonding and reaction annealing

International Nuclear Information System (INIS)

Mozaffari, A.; Hosseini, M.; Manesh, H. Danesh

2011-01-01

Highlights: → Al/Ni metallic composites produced by accumulative roll bonding were heat treated at different temperatures and periods, to investigate the effect of reaction annealing on the structure and mechanical properties. → Based on the annealing conditions, various intermetallic phases were formed. The structure and composition of the composites were detected by SEM and XRD techniques. → The strength of the initial metallic composite can be improved due to the formation of the hard intermetallic phases, by the heat treatment process. - Abstract: In this research, Al/Ni multilayers composites were produced by accumulative roll bonding and then annealed at different temperatures and durations. The structure and mechanical properties of the fabricated metal intermetallic composites (MICs) were investigated. Scanning electron microscopy and X-ray diffraction analyses were used to evaluate the structure and composition of the composite. The Al 3 Ni intermetallic phase is formed in the Al/Ni interface of the samples annealed at 300 and 400 deg. C. When the temperature increased to 500 deg. C, the Al 3 Ni 2 phase was formed in the composite structure and grew, while the Al 3 Ni and Al phases were simultaneously dissociated. At these conditions, the strength of MIC reached the highest content and was enhanced by increasing time. At 600 deg. C, the AlNi phase was formed and the mechanical properties of MIC were intensively degraded due to the formation of structural porosities.

Preparation of Cerium (III) 12-tungstophosphoric acid/ordered mesoporous carbon composite modified electrode and its electrocatalytic properties

International Nuclear Information System (INIS)

Liu Lin; Ndamanisha, Jean Chrysostome; Bai Jing; Guo Liping

2010-01-01

In this work, a novel structured Cerium (III) 12-tungstophosphoric acid (CePW)/ordered mesoporous carbon (OMC) composite is synthesized. The characterization of the material by the Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical characterization shows that the novel CePW/OMC composite has improved properties based on the combination of CePW and OMC properties. CePW/OMC can be used to modify the glassy carbon (GC) electrode and the CePW/OMC/GC modified electrode shows an enhanced electrocatalytic activity. This property can be applied in the determination of some biomolecules. Especially, the detection and determination of the guanine (G) in the presence of adenine (A) is achieved. The catalytic current of G versus its concentration shows a good linearity with two good linear ranges from 4.0 x 10 -6 to 8.0 x 10 -5 M and from 8.0 x 10 -5 to 1.9 x 10 -3 M (correlation coefficient = 0.999 and 0.996) with a detection limit of 5.7 x 10 -9 M (S/N = 3). The linear range for adenine is 4.0 x 10 -6 -7.0 x 10 -4 M with a detection limit of 7.45 x 10 -8 M. With good stability and reproducibility, the present CePW/OMC/GC modified electrode should be a good model for constructing a novel and promising electrochemical sensing platform for further electrochemical detection of other biomolecules.

NiCo-lead zirconium titanate-NiCo trilayered magnetoelectric composites prepared by electroless deposition

International Nuclear Information System (INIS)

Zhou, M. H.; Wang, Y. G.; Bi, K.; Fan, H. P.; Zhao, Z. S.

2015-01-01

The NiCo layers with various Ni/Co atomic ratio have been successfully electroless deposited on PZT layers by varying the bath composition. As the cobalt atomic ratio in the deposited layer increases from 17.2 to 54.8 wt%, the magnetostrictive coefficient decreases. The magnetoelectric effect depends strongly on the magnetostrictive properties of magnetostrictive phase. The magnetoelectric coefficient of NiCo/PZT/NiCo trilayers increases with Ni/Co atomic ratio of the deposited NiCo layers increasing from 45:55 to 83:17. A maximum ME voltage coefficient of α E,31 = 2.8 V ⋅ cm −1 ⋅ Oe −1 is obtained at a frequency of about 88 kHz, which makes these trilayers suitable for applications in actuators, transducers and sensors

Quasicrystalline and crystalline precipitation during isothermal tempering in a 12Cr-9Ni-4Mo maraging stainless steel

International Nuclear Information System (INIS)

Liu, P.; Stigenberg, A.H.; Nilsson, J.O.

1995-01-01

A thorough microstructural investigation has been performed on a high strength maraging steel of the type 12%Cr-9%Ni-4%Mo-2%Cu-1%Ti. The major precipitate formed during isothermal aging at 475 C is a quasicrystalline phase possessing icosahedral symmetry termed R'-phase with a typical chemical composition of 48%Mo-33%Fe-13%Cr-2%Ni-4%Si. At 550 C the major precipitate is trigonal R-phase with a typical composition of 45%Mo-31%Fe-18%Cr-4%Ni-2%Si. At 550 C also Laves phase with a composition of 48%Mo-35%Fe-13%Cr-2%Ni-2%Si could be observed. At both 475 and 550 C an ordered phase termed L-phase precipitated. This minority phase has an ordered face centered cubic (f.c.c.) structure of type L1 0 . Its composition is typically 9%Fe-4%Cr-52%Ni-15%Mo.-16%Ti-4%Al. R'-phase formed at 475 C transformed to R-phase and Laves phase during aging at 550 C. In an analogous manner, R-phase and Laves phase formed at 550 C transformed to R'-phase during subsequent aging at 475 C. This transformation was rationalized by a strong similarity in crystal structure between quasicrystalline R'-phase of icosahedral symmetry and Frank-Kasper phases such as R-phase and Laves phase

Synthesis of novel amperometric urea-sensor using hybrid synthesized NiO-NPs/GO modified GCE in aqueous solution of cetrimonium bromide.

Science.gov (United States)

Parsaee, Zohreh

2018-06-01

In this study NiO nanostructures were synthesized via combinational synthetic method (ultrasound-assisted biosynthesis) and immobilized on the glassy carbon electrode (GCE) as a highly sensitive and selective enzyme-less sensor for urea detection. NiO-NPs were fully characterized using SEM, EDX, XRD, BET, TGA, FT-IR, UV-vis and Raman methods which revealed the formation of NiO nanostructures in the form of cotton like porous material and crystalline in nature with the average size of 3.8 nm. GCE was modified with NiO-NPs in aqueous solution of cetrimonium bromide(CTAB). Highly adhesive NiO/CTAB/GO nanocomposite membrane has been formed on GCE by immersing NiO/CTAB modified GCE in GO suspension. CTAB has a major role in the production and immobilization of the nanocomposites on the GCE surface and the binding NiO nanoparticles on GO plates. In addition, CTAB/GO composition made a highly adhesive surface on the GCE. The resulting NiO/CTAB/GO/GCE contains potently sensitive to urea in aqueous environments. The response of as developed amperometric sensor was linear in the range of 100-1200 µM urea with R 2 value of 0.991 and limit of detection (LOD), 8 µM. The sensor responded negligibly to various interfering species like glucose, uric acid and ascorbic acid. This sensor was applied successfully for determining urea in real water samples such as mineral water, tap water and river water with acceptable recovery. Copyright © 2018 Elsevier B.V. All rights reserved.

Preparation of TiC/Ni3Al Composites by Upward Melt Infiltration

Institute of Scientific and Technical Information of China (English)

无

2000-01-01

TiC/Ni3Al composites have been prepared using upward infiltration method. The densificstion was performed by both Ni3Al melt filling and TiC sintering during the infiltration. The dissolution of TiC in liquid Ni3Al has been evidenced by finding Ni3(Al,Ti)C after fast cooling in the TiC/Ni3Al composites. The dissolution may be responsible for the infiltration and sintering. Compared with downward infiltration, the upward infiltration brought about higher strength and fracture toughness and shorter infiltration time. TiC/20 vol. pct Ni3Al composite processed by upward infiltration had a flexural strength of 1476 Mpa with a statistic Weibull modulus of 20.2 and a fracture toughness of 20.4 Mpa(m). Better mechanical properties may be attributed to melt unidirectional movement in upward infiltration.

Density Measurement of Liquid Ni-Ta Alloys by a Modified Sessile Drop Method

Institute of Scientific and Technical Information of China (English)

FANG Liang; XIAO Feng; TAO Zainan; Kusuhiro Mukai

2005-01-01

The density of liquid Ni-Ta alloys was measured by using a modified sessile drop method. It is found that the density of the liquid Ni-Ta alloys decreases with the increasing temperature, but increases with the increase of tantalum concentration in the alloys. The molar volume of liquid Ni-Ta binary alloys increases with the increase of temperature and tantalum concentration.

In situ synthesis of NiAl–NbB2 composite powder through combustion synthesis

International Nuclear Information System (INIS)

Shokati, Ali Akbar; Parvin, Nader; Sabzianpour, Naser; Shokati, Mohammad; Hemmati, Ali

2013-01-01

Highlights: ► A Novel NiAl matrix composite powder with 0–40 wt.% NbB 2 was synthesized. ► Composite powders were synthesized by thermal explosion reaction of Ni–Al–Nb–B system. ► Microhardness of NiAl considerably increased with raising NbB 2 content. ► Synthesized composite powders is a good candidate as precursor for thermal barrier application. - Abstract: Synthesis of a novel NiAl matrix composite powder reinforced with 0–40 wt.% NbB 2 by combustion synthesis in thermal explosion mode was investigated. The elemental powders of Ni, Al, Nb, and amorphous boron were used as starting material. For all compositions final products consisted of only the NiAl and NbB 2 phases. Coarser NbB 2 with a relatively uniform distribution in NiAl matrix was formed with rising NbB 2 content. Microhardness of NiAl considerably increased from 377 ± 13 HV 0.05 to 866 ± 81 HV 0.05 for NiAl with 40 wt.% NbB 2 . High microhardness, proper size and distribution of NbB 2 in NiAl matrix make it a good candidate as precursor for thermal spray application.

NiO/nanoporous graphene composites with excellent supercapacitive performance produced by atomic layer deposition

International Nuclear Information System (INIS)

Chen, Caiying; Chen, Chaoqiu; Duan, Feifei; Zhao, Shichao; Qin, Yong; Huang, Peipei; Li, Ping; Fan, Jinchuan; Song, Weiguo

2014-01-01

Nickel oxide (NiO) is a promising electrode material for supercapacitors because of its low cost and high theoretical specific capacitance of 2573 F g −1 . However, the low electronic conductivity and poor cycling stability of NiO limit its practical applications. To overcome these limitations, an efficient atomic layer deposition (ALD) method is demonstrated here for the fabrication of NiO/nanoporous graphene (NG) composites as electrode materials for supercapacitors. ALD allows uniform deposition of NiO nanoparticles with controlled sizes on the surface of NG, thus offering a novel route to design NiO/NG composites for supercapacitor applications with high surface areas and greatly improved electrical conductivity and cycle stability. Electrochemical measurements reveal that the NiO/NG composites obtained by ALD exhibited excellent specific capacitance of up to ∼1005.8 F g −1 per mass of the composite electrode (the specific capacitance value is up to ∼1897.1 F g −1 based on the active mass of NiO), and stable performance after 1500 cycles. Furthermore, electrochemical performance of the NiO/NG composites is found to strongly depend on the size of NiO nanoparticles. (paper)

Alloy composition dependence of formation of porous Ni prepared by rapid solidification and chemical dealloying

Energy Technology Data Exchange (ETDEWEB)

Qi Zhen [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Zhang Zhonghua [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)], E-mail: zh_zhang@sdu.edu.cn; Jia Haoling [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Qu Yingjie [Shandong Labor Occupational Technology College, Jingshi Road 388, Jinan 250022 (China); Liu Guodong; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)

2009-03-20

In this paper, the effect of alloy composition on the formation of porous Ni catalysts prepared by chemical dealloying of rapidly solidified Al-Ni alloys has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and N{sub 2} adsorption experiments. The experimental results show that rapid solidification and alloy composition have a significant effect on the phase constituent and microstructure of Al-Ni alloys. The melt spun Al-20 at.% Ni alloy consists of {alpha}-Al, NiAl{sub 3} and Ni{sub 2}Al{sub 3}, while the melt spun Al-25 and 31.5 at.% Ni alloys comprise NiAl{sub 3} and Ni{sub 2}Al{sub 3}. Moreover, the formation and microstructure of the porous Ni catalysts are dependent upon the composition of the melt spun Al-Ni alloys. The morphology and size of Ni particles in the Ni catalysts inherit from those of grains in the melt spun Al-Ni alloys. Rapid solidification can extend the alloy composition of Al-Ni alloys suitable for preparation of the Ni catalysts, and obviously accelerate the dealloying process of the Al-Ni alloys.

NiCo-lead zirconium titanate-NiCo trilayered magnetoelectric composites prepared by electroless deposition

Energy Technology Data Exchange (ETDEWEB)

Zhou, M. H.; Wang, Y. G.; Bi, K., E-mail: bike@bupt.edu.cn [State Key Laboratory of Information Photonics and Optical Communications and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Fan, H. P. [School of Mechanical and Electrical Engineering, Qingdao Technological University Qindao College, Qingdao 266106 (China); Zhao, Z. S. [Shandong Engineering Consulting Institute, Jinan 250013 (China)

2015-04-15

The NiCo layers with various Ni/Co atomic ratio have been successfully electroless deposited on PZT layers by varying the bath composition. As the cobalt atomic ratio in the deposited layer increases from 17.2 to 54.8 wt%, the magnetostrictive coefficient decreases. The magnetoelectric effect depends strongly on the magnetostrictive properties of magnetostrictive phase. The magnetoelectric coefficient of NiCo/PZT/NiCo trilayers increases with Ni/Co atomic ratio of the deposited NiCo layers increasing from 45:55 to 83:17. A maximum ME voltage coefficient of α{sub E,31} = 2.8 V ⋅ cm{sup −1} ⋅ Oe{sup −1} is obtained at a frequency of about 88 kHz, which makes these trilayers suitable for applications in actuators, transducers and sensors.

Chemistry and Ni-isotope composition of ureilites and their components

Science.gov (United States)

Gabriel, A. D.; Quitté, G.; Pack, A.

2008-09-01

Ureilites are olivine-pigeonite bearing achondrites with interstitial carbonaceous material and metal. The latter is present as balance calculations assuming a chondritic parent body yield a metal core with 7 to 11 wt% Ni and 0.3 to 0.55 wt% Co. Thermodynamic calculations of Fe-Ni and Fe-Co exchange between olivine and vein metal show that vein metal cannot be in equilibrium with the olivine at any temperature. We conclude that the vein metal is genetically not linked to the ureilite olivine and may have been injected into the parent body by an impactor. Recently published data show a deficit in 60Ni of - 0.24+/-0.02 ɛ-units for various achondrites including ureilites [1]. This has been interpreted as evidence for a late injection of 60Fe after formation of these achondrites. However, our chemical data for vein metal, which is the dominant Ni host in ureilites, demonstrate that bulk Ni isotope data have little meaning with respect to the formation of ureilite silicates. In this work we present Ni isotope data for bulk samples but also vein material and the silicate phase of 4 ureilites (ALHA77257, EET87157, EET96041, Kenna). Bulk ureilites have a ɛ60 between -0.05+/-0.12 and 0.08+/-0.12; the vein metal gives ɛ60 = -0.05+/-0.13 to 0.11+/-0.16. No resolvable deficit in ɛ60 was found, in disagreement with results reported in Bizzarro et al. (2007). The vein material and the bulk samples have, within uncertainty, the same isotopic composition, confirming that the global Ni budget is controlled by the vein material. In ureilite silicates ɛ60 varies from -0.77+/-0.31 to -0.12+/-0.21. Due to the high Fe/Ni ratio of silicates, clear excesses of 60Ni (at least several ɛ-units) are expected if they formed early in the solar system. This is not observed. There is thus no evidence for life 60Fe in ureilites, which may be interpreted in different ways: either 60Fe was injected at a later time into the protoplanetary disk as suggested by [1] (but this is difficult to

Microstructure and Mechanical Properties of Zn-Ni-Al2O3 Composite Coatings

Directory of Open Access Journals (Sweden)

Yang Bai

2018-05-01

Full Text Available Zn-Ni-Al2O3 composite coatings with different Ni contents were fabricated by low-pressure cold spray (LPCS technology. The effects of the Ni content on the microstructural and mechanical properties of the coatings were investigated. According to X-ray diffraction patterns, the composite coatings were primarily composed of metallic-phase Zn and Ni and ceramic-phase Al2O3. The energy-dispersive spectroscopy results show that the Al2O3 content of the composite coatings gradually decreased with increasing of Ni content. The cross-sectional morphology revealed thick, dense coatings with a wave-like stacking structure. The process of depositing Zn and Ni particles and Al2O3 particles by the LPCS method was examined, and the deposition mechanism was demonstrated to be mechanical interlocking. The bond strength, micro hardness and friction coefficient of the coatings did not obviously change when the Ni content varied. The presence of Al2O3 and Ni increased the wear resistance of the composite coatings, which was higher than that of pure Zn coatings, and the wear mechanism was abrasive and adhesive wear.

Study and development of NiAl intermetallic coating on hypo-eutectoid steel using highly activated composite granules of the Ni-Al system

Energy Technology Data Exchange (ETDEWEB)

Shahzad, Aamir; Zadorozhnyy, Vladislav Yu.; Pavlov, Mikhail D.; Semenov, Dmitri V.; Kaloshkin, Sergey D. [National Univ. of Science and Technology (MISIS), Moscow (Russian Federation)

2018-01-15

NiAl intermetallic coating thickness of about 50 μm was fabricated on hypo-eutectoid steel by mechanical alloying using pre-activated Ni-Al composite granules as coating material. First, Ni and Al powders were mixed with the composition of Ni-50 at.% Al and mechanically activated in a planetary ball mill, until the composite granules of this powder mixture, having maximum activity (9 cm sec{sup -1}), were formed after 120 min of milling at 200 rpm. The composite granules were then taken out from the planetary ball mill just before the critical time, i. e. the time at which these granules synthesize and convert to an intermetallic NiAl compound. The highly activated composite granules of Ni-Al were then put into the vial of a vibratory ball mill with the substrate on top of the chamber. After mechanical alloying for 60 min in the vibratory ball mill, the composite granules were synthesized fully and heat was produced during the synthesis which helped producing a thick and strong adhesive coating of NiAl intermetallic on the steel substrate. The main advantage of this technique is that not only is time saved but also there is no need for any post mechanical alloying process such as annealing or laser treatment etc. to get homogeneous, strongly bonded intermetallic coatings. X-ray diffraction analysis clearly indicates the formation of NiAl phase. Micro-hardness of the coating and substrate was also measured. The cross-sectional microstructure of the composite granules and the final coating were studied by scanning electron microscopy.

Design and tailoring of Ni-Sn-W composites for bonded abrasive applications

Energy Technology Data Exchange (ETDEWEB)

Kourtoukova, G.L.; Demetry, C.; Biederman, R.R. [Worcester Polytechnic Inst., MA (United States). Materials Science and Engineering Program; Ramanath, S.; Andrews, R.M.; Jacobs, D.S. [Saint-Gobain/Norton Company, Worcester, MA (United States)

2000-01-15

The combination of properties ideal for metal bonds in abrasive products can rarely be achieved in a monolithic material. This research demonstrates a successful approach for producing a composite bond with higher elastic modulus without a significant increase in wear resistance, by taking advantage of the reaction between matrix and reinforcement to produce intermetallics. Composites comprised of a Ni-Sn matrix with continuous W fiber and/or W powder dispersoid were prepared by powder metallurgy methods. Composite specimens densified by hot pressing were characterized with a combination of scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses, measurements of wear resistance, and measurements of Young's modulus and hardness by both bulk and nanoindentation methods. A significant stiffening effect was observed; the elastic modulus of the composites was up to 30% greater than that predicted by a rule of mixtures based on the moduli of the unreacted fiber and matrix constituents alone. As desired, the wear resistance of the composite was approximately equal to that of the Ni-Sn matrix. One contribution to this combination of properties is believed to be the high elastic moduli and likely low fracture toughness of the Ni-W and Ni-Sn intermetallics that are formed. Properties of the Ni-Sn-W composites are contrasted with those of a Ni-Sn matrix reinforced with WC particulate, where no reaction occurs at the interface. (orig.)

Stability of the composites: NiAl - cellular high-melting point metal

International Nuclear Information System (INIS)

Belomyttsev, M.Yu.; Kozlov, D.A.

2006-01-01

For sintered composite materials (CM) NiAl-W and NiAl-W-Mo the structure and mechanical properties are studied. A comparative analysis of the effect of hot deformation by compression at 1000-1300 Deg C on the integrity of microsamples themselves and tungsten shells of NiAl granules in CM with a cellular structure is accomplished. Local chemical composition of a NiAl/refractory metal interface in CM with cellular structure and free of it is determined. A CM structural state effect on compression yield strength at 1000 Deg C is estimated. The treatment is proposed which permits approaching cellular structured CM oxidation resistance at 1000-1100 Deg C to the level of heat stability of unalloyed NiAl or its alloy with Hf [ru

Electrodeposition and characterization of Ni-Mo-ZrO2 composite coatings

Science.gov (United States)

Laszczyńska, A.; Winiarski, J.; Szczygieł, B.; Szczygieł, I.

2016-04-01

Ni-Mo-ZrO2 composite coatings were produced by electrodeposition technique from citrate electrolytes containing dispersed ZrO2 nanopowder. The influence of deposition parameters i.e. concentration of molybdate and ZrO2 nanoparticles in the electrolyte, bath pH and deposition current density on the composition and surface morphology of the coating has been investigated. The structure, microhardness and corrosion properties of Ni-Mo-ZrO2 composites with different molybdenum and ZrO2 content have been also examined. It was found that ZrO2 content in the deposit is increased by rising the nanoparticles concentration in the plating solution up to 20 g dm-3. An increase in molybdate concentration in the electrolyte affects negatively the amount of codeposited ZrO2 nanoparticles. The correlation between the deposition current efficiency and ZrO2 content in the composite coating has been also observed. A decrease in deposition current efficiency leads to deposition of Ni-Mo-ZrO2 composite with low nanoparticles content. This may be explained by formation of higher amounts of gas bubbles on the cathode surface, which prevent the adsorption of ZrO2 nanoparticles on the growing deposit. The XRD analysis revealed that all the studied Ni-Mo-ZrO2 coatings were composed of a single, nanocrystalline phase with FCC structure. It was found that the incorporation of ZrO2 nanoparticles into Ni-Mo alloy matrix affects positively the microhardness and also slightly improves the corrosion properties of Ni-Mo alloy coating.

Electrochemical preparation and characteristics of Ni-Co-LaNi{sub 5} composite coatings as electrode materials for hydrogen evolution

Energy Technology Data Exchange (ETDEWEB)

Wu Gang; Li Ning; Dai Changsong; Zhou Derui

2004-02-15

Electrocatalytic activity for the hydrogen evolution reaction on Ni-Co-LaNi{sub 5} composite electrodes prepared by electrochemical codeposition technique was evaluated. The relationship between the current density for hydrogen evolution reaction and the amount of LaNi{sub 5} particles in Ni-Co baths is like the well-known 'volcano plot'. The Surface morphology and microstructure of Ni-Co-LaNi{sub 5} coatings were determined by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The kinetic parameters were determined from electrochemical steady-state Tafel polarization and electrochemical impedance spectroscopy technology in 1 M NaOH solution. The values obtained for the apparent energies of activation are 32.48, 46.29 and 57.03 kJ mol{sup -1} for the Ni-Co-LaNi{sub 5}, Ni-Co and Ni electrodes, respectively. The hydrogen evolution reaction on Ni-Co-LaNi{sub 5} proceeds via Volmer-Tafel reaction route with the mixed rate determining characteristics. The composite coating Ni-Co-LaNi{sub 5} is catalytically more active than Ni and Ni-Co electrodes due to the increase in its real surface areas and the decrease in the apparent free energy of activation caused by the electrocatalytic synergistic effect of the Ni-Co alloys and the hydrogen storage intermetallic particles on the electrode surface.

Effects of magnetic field treatment on dielectric properties of CCTO@Ni/PVDF composite with low concentration of ceramic fillers

Energy Technology Data Exchange (ETDEWEB)

Chi, Q. G., E-mail: qgchi@hotmail.com, E-mail: empty-cy@l63.com [Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin 150080 (China); State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University, Xi’an 710049 (China); Gao, L. [Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin 150080 (China); College of Electrical Engineering, Suihua University, Suihua 152061 (China); Wang, X.; Chen, Y., E-mail: qgchi@hotmail.com, E-mail: empty-cy@l63.com; Dong, J. F.; Cui, Y.; Lei, Q. Q. [Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin 150080 (China)

2015-11-15

Using melt mixing, we produced a ceramic/polymer composite with a matrix of polyvinylidene fluoride (PVDF) and a filler of 5 vol.% Ni-deposited CaCu{sub 3}Ti{sub 4}O{sub 12} core-shell ceramic particles (CCTO@Ni), and studied its prominent dielectric characteristics for the first. Its phase composition and morphology were analyzed by X-ray diffraction and scanning electron microscopy, respectively. After treating the composite films with various durations of a magnetic field treatment, we compared their dielectric properties. We found that the CCTO@Ni ceramic had a typical urchin-like core-shell structure, and that different durations of the magnetic field treatment produced different distributions of ceramic particles in the PVDF matrix. The dielectric permittivity of the untreated CCTO@Ni/PVDF composite was 20% higher than that of neat PVDF, and it had a low loss tangent. However, only the composite treated for 30 min in the magnetic field had an ultra-high dielectric permittivity of 1.41 × 10{sup 4} at 10 Hz, three orders of magnitude higher than the untreated composite, which declined dramatically with increasing frequency, accompanied by an insulating-conducting phase transition and an increase in loss tangent. Our results demonstrate that changes in the dielectric properties of PVDF composites with magnetic field treatment are closely related to the percolation effect and interfacial polarization.

NiCoCrAl/YSZ laminate composites fabricated by EB-PVD

International Nuclear Information System (INIS)

Shi Guodong; Wang Zhi; Liang Jun; Wu Zhanjun

2011-01-01

Highlights: → The metal-ceramic laminate composites were fabricated by EB-PVD. → Both metal and ceramic layers consisted of straight columns with banded structures. → Columnar grain size was limited by the periodic layer interfaces in the laminates. → Effect of columns on fracture property was decreased by limiting layer thickness. → Laminates showed greater specific strength than monolithic metal foil. - Abstract: Two NiCoCrAl/YSZ laminate composites (A and B) with different metal-layer thickness (∼35 μm and 14 μm, respectively) were fabricated by electron beam physical vapor deposition (EB-PVD). Their microstructure was examined and their mechanical properties were compared with the 289 μm thick NiCoCrAl monolithic foil produced by EB-PVD. Both the YSZ and NiCoCrAl layers of the laminate composites had columnar grain structure. But the periodic layer interfaces limited the columnar grain size. Some pores between the columns were also observed. It was found that the strength of the laminate A was equal approximately to that of the NiCoCrAl monolithic foil, and that laminate B had the greater strength. Moreover, the density of the foils decreased with the increasing thickness ratio of YSZ/NiCoCrAl layers and the increasing the layer number. Thus, comparing with the NiCoCrAl monolithic foil, the NiCoCrAl/YSZ laminate composites not only had the equal or greater strength, but also had the much greater specific strength.

Tunable Twin Matching Frequency (fm1/fm2) Behavior of Ni1-xZnxFe2O4/NBR Composites over 2-12.4 GHz: A Strategic Material System for Stealth Applications

Science.gov (United States)

Saini, Lokesh; Patra, Manoj Kumar; Jani, Raj Kumar; Gupta, Goutam Kumar; Dixit, Ambesh; Vadera, Sampat Raj

2017-03-01

The gel to carbonate precipitate route has been used for the synthesis of Ni1-xZnxFe2O4 (x = 0, 0.25, 0.5 and 0.75) bulk inverse spinel ferrite powder samples. The optimal zinc (50%) substitution has shown the maximum saturation magnetic moment and resulted into the maximum magnetic loss tangent (tanδm) > -1.2 over the entire 2-10 GHz frequency range with an optimum value ~-1.75 at 6 GHz. Ni0.5Zn0.5Fe2O4- Acrylo-Nitrile Butadiene Rubber (NBR) composite samples are prepared at different weight percentage (wt%) of ferrite loading fractions in rubber for microwave absorption evaluation. The 80 wt% loaded Ni0.5Zn0.5Fe2O4/NBR composite (FMAR80) sample has shown two reflection loss (RL) peaks at 5 and 10 GHz. Interestingly, a single peak at 10 GHz for 3.25 mm thickness, can be scaled down to 5 GHz by increasing the thickness up to 4.6 mm. The onset of such twin matching frequencies in FMAR80 composite sample is attributed to the spin resonance relaxation at ~5 GHz (fm1) and destructive interference at λm/4 matched thickness near ~10 GHz (fm2) in these composite systems. These studies suggest the potential of tuning the twin frequencies in Ni0.5Zn0.5Fe2O4/NBR composite samples for possible microwave absorption applications.

Processing and Mechanical Properties of NiAl-Based In-Situ Composites. Ph.D. Thesis Final Report

Science.gov (United States)

Johnson, David Ray

1994-01-01

In-situ composites based on the NiAl-Cr eutectic system were successfully produced by containerless processing and evaluated. The NiAl-Cr alloys had a fibrous microstructure while the NiAl-(Cr,Mo) alloys containing 1 at. percent or more molybdenum exhibited a lamellar structure. The NiAl-28Cr-6Mo eutectic displays promising high temperature strength while still maintaining a reasonable room temperature fracture toughness when compared to other NiAl-based materials. The Laves phase NiAlTa was used to strengthen NiAl and very promising creep strengths were found for the directionally solidified NiAl-NiAlTa eutectic. The eutectic composition was found to be near NiAl-15.5Ta (at. percent) and well aligned microstructures were produced at this composition. An off-eutectic composition of NiAl-14.5Ta was also processed, consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of these two phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Polyphase in-situ composites were generated by directional solidification of ternary eutectics. The systems investigated were the Ni-Al-Ta-X (X=Cr, Mo, or V) alloys. Ternary eutectics were found in each of these systems and both the eutectic composition and temperature were determined. Of these ternary eutectics, the one in the NiAl-Ta-Cr system was found to be the most promising. The fracture toughness of the NiAl-(Cr,Al)NiTa-Cr eutectic was intermediate between those of the NiAl-NiAlTa eutectic and the NiAl-Cr eutectic. The creep strength of this ternary eutectic was similar to or greater than that of the NiAl-Cr eutectic.

Ni modified ceramic anodes for direct-methane solid oxide fuel cells

Science.gov (United States)

Xiao, Guoliang; Chen, Fanglin

2016-01-19

In accordance with certain embodiments of the present disclosure, a method for fabricating a solid oxide fuel cell is described. The method includes synthesizing a composition having a perovskite present therein. The method further includes applying the composition on an electrolyte support to form an anode and applying Ni to the composition on the anode.

Investigation on corrosion and wear behaviors of nanoparticles reinforced Ni-based composite alloying layer

International Nuclear Information System (INIS)

Xu Jiang; Tao Jie; Jiang Shuyun; Xu Zhong

2008-01-01

In order to investigate the role of amorphous SiO 2 particles in corrosion and wear resistance of Ni-based metal matrix composite alloying layer, the amorphous nano-SiO 2 particles reinforced Ni-based composite alloying layer has been prepared by double glow plasma alloying on AISI 316L stainless steel surface, where Ni/amorphous nano-SiO 2 was firstly predeposited by brush plating. The composition and microstructure of the nano-SiO 2 particles reinforced Ni-based composite alloying layer were analyzed by using SEM, TEM and XRD. The results indicated that the composite alloying layer consisted of γ-phase and amorphous nano-SiO 2 particles, and under alloying temperature (1000 deg. C) condition, the nano-SiO 2 particles were uniformly distributed in the alloying layer and still kept the amorphous structure. The corrosion resistance of composite alloying layer was investigated by an electrochemical method in 3.5%NaCl solution. Compared with single alloying layer, the amorphous nano-SiO 2 particles slightly decreased the corrosion resistance of the Ni-Cr-Mo-Cu alloying layer. X-ray photoelectron spectroscopy (XPS) revealed that the passive films formed on the composite alloying consisted of Cr 2 O 3 , MoO 3 , SiO 2 and metallic Ni and Mo. The dry wear test results showed that the composite alloying layer had excellent friction-reduced property, and the wear weight loss of composite alloying layer was less than 60% of that of Ni-Cr-Mo-Cu alloying layer

Fe-Cr-Ni system alloys

International Nuclear Information System (INIS)

Levin, F.L.

1986-01-01

Phase diagram of Fe-Cr-Ni system, which is the basic one for production of corrosion resistant alloys, is considered. Data on corrosion resistance of such alloys are correlated depending on a number of factors: quality and composition of modifying elements, corrosion medium, temperature, alloy structure, mechanical and thermal treatment. Grades of Fe-Ni-Cr alloys are presented, and fields of their application are pointed out

Preparation of Ni-C Ultrafine Composite from Waste Material

Directory of Open Access Journals (Sweden)

Mahmoud A. Rabah

2017-06-01

Full Text Available This work depicts the preparation of Ni-C ultrafine composite from used engine oil. The used oil was emulsified with detergent loaded with Ni (OH2. The loaded emulsion was sprayed on electric plasma generated between two C electrodes to a DC main 28 V and 70-80 A. The purged Ni-doped carbon fume was trapped on a polymer film moistened with synthetic adhesive to fix the trapped smoke. Characterization of the deposit was made using SEM. XRD examined the crystal morphology. Carbon density in the cloud was calculated. The average size and thickness of the deposited composite is 120-160 nm. Aliphatic hydrocarbons readily decompose to gaseous products. Solid carbon smoke originates from aromatic compounds. Plasma heat blasts the oil in short time to decompose in one step.

Mechanical properties of NiO/Ni-YSZ composites depending on temperature, porosity and redox cycling

DEFF Research Database (Denmark)

Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg

2009-01-01

The Impulse Excitation Technique (IET) was used to determine the elastic modulus and specific damping of different Ni/NiO-YSZ composites suitable for use in solid oxide fuel cells (SOFC). The porosity of the as-sintered samples varied from 9 to 38% and that of the reduced ones from 31 to 52%. For...

Study of xCo{sub 0.8}Ni{sub 0.2}Fe{sub 2}O{sub 4}+(1−x) Pb{sub 0.99625} La{sub 0.0025}Zr{sub 0.55}Ti{sub 0.45}O{sub 3} magnetoelectric composites

Energy Technology Data Exchange (ETDEWEB)

Dipti [Electroceramics Research Lab, G.V.M. Girls College, Sonepat 131001 (India); School of Physics & Materials Science, Thapar University, Patiala 147004 (India); Singh, Sangeeta, E-mail: Sangeetaasingh@gmail.com [Department of Physics, G.V.M. Girls College, Sonepat 131001 (India); Juneja, J.K. [Department of Physics, Hindu College, Sonepat 131001 (India); Raina, K.K. [School of Physics & Materials Science, Thapar University, Patiala 147004 (India); Dehradun Institute of Technology, DIT University, Dehradun 248009 (India); Kotnala, R.K. [National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Prakash, Chandra [Solid State Physics Laboratory, Lucknow Road, Delhi 110054 (India)

2016-06-01

We are reporting here, the studies of the structural, dielectric, ferroelectric and magnetic properties of magnetoelectric composites of La modified lead zirconate titanate (PLZT) and Ni modified cobalt ferrite (CNFO) with compositional formula xCo{sub 0.8}Ni{sub 0.2}Fe{sub 2}O{sub 4}+(1−x) Pb{sub 0.99625}La{sub 0.0025}Zr{sub 0.55}Ti{sub 0.45}O{sub 3} (x=0.00, 0.05, 0.10, 0.15 and 1.00 by weight) prepared by the solid state reaction method. Coexistence of both the phases in composites was confirmed by X-Ray diffraction technique. The microstructure and average grain size were determined from Scanning Electron Micrograph (SEM) in backscattered mode. Both the phases could be observed clearly. The variations of dielectric properties with frequency and temperature were also studied. P–E and M–H hysteresis measurements were carried. Magnetoelectric coupling (ME) coefficient for samples with x=0.05 and 0.10 were measured as a function of DC magnetic field. Maximum value of ME coefficient (1.2 mV/cm Oe) and piezoelectric coefficient (96 pC/N) for x=0.05 were observed. - Highlights: • ME composites PLZT–CNFO were studied for various properties. • Substitution of Ni and La in CFO and in PZT phase improves ME Coefficient. • The samples are good for various application due to high ME coeff. of PLZT-CNFO.

Spherical NiO-C composite for anode material of lithium ion batteries

International Nuclear Information System (INIS)

Huang, X.H.; Tu, J.P.; Zhang, C.Q.; Chen, X.T.; Yuan, Y.F.; Wu, H.M.

2007-01-01

Spherical NiO-C composite was prepared by dispersing spherical NiO in glucose solution and subsequent carbonization under hydrothermal conditions at 180 o C. The microstructure and morphology of the NiO-C and NiO powders were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the electrodes were measured by galvanostatic charge-discharge tests, cyclic voltammetric analysis (CV), and electrochemical impedance spectroscopy (EIS). SEM images showed that the amorphous carbon not only coated on the surface but also filled the inner pores of the NiO spheres. Electrochemical tests showed that the NiO-C composite exhibited higher initial coulombic efficiency (66.6%) than NiO (56.4%), and better cycling performances. The improvement of these properties is attributed to the carbon, as it can reduce the specific surface area of porous sphere, and enhance the conductivity of porous NiO

Nanocrystalline LaOx/NiO composite as high performance electrodes for supercapacitors.

Science.gov (United States)

Du, Guo; Zeng, Zifan; Xiao, Bangqing; Wang, Dengzhi; Yuan, Yuan; Zhu, Xiaohong; Zhu, Jiliang

2017-12-21

Nanocrystalline LaO x /NiO composite electrodes were synthesized via two types of facile cathodic electrodeposition methods onto nickel foam followed by thermal annealing without any binders. Scanning electron microscopy and transmission electron microscopy investigation revealed that LaO x nanocrystalline particles with an average diameter of 50 nm are uniformly distributed in the NiO layer or alternately deposited with the NiO layer onto the substrate. It is speculated that LaO x particles can participate in the faradaic reaction directly and offer more redox sites. Besides this, the unique Ni/La layered structure facilitates the diffusion of ions and retards the electrode polarization, thus leading to a better rate capability and cycling stability of NiO. As a result, the obtained electrodes display very competitive electrochemical performance (a specific capacitance of 1238 F g -1 at a current density of 0.5 A g -1 , excellent rate capability of 86% of the original capacitance at 10 A g -1 and excellent cycling stability of 93% capacitance after 10 000 cycles). In addition, asymmetric coin devices were assembled using LaO x /NiO as the positive electrode and active carbon as the negative electrode. The assembled asymmetric devices demonstrate a high energy density of 13.12 W h kg -1 at a power density of 90.72 W kg -1 .

Predicting glass-forming compositions in the Al-La and Al-La-Ni systems

International Nuclear Information System (INIS)

Gargarella, P.; de Oliveira, M.F.; Kiminami, C.S.; Pauly, S.; Kuehn, U.; Bolfarini, C.; Botta, W.J.; Eckert, J.

2011-01-01

Research highlights: → The glass-forming ability of the Al-La and Al-La-Ni systems was studied using the λ* and the λ.Δe criteria. → Both criteria predicted with just 1% at. of error the best glass-former verified so far in the Al-La system. → Four new glass-former compositions could be predicted in the Al-La-Ni system using the λ.Δe criterion. → The best glass-former reported so far in the Al-La-Ni system was found. - Abstract: In this work, a criterion considering the topological instability (λ) and the differences in the electronegativity of the constituent elements (Δe) was applied to the Al-La and Al-Ni-La systems in order to predict the best glass-forming compositions. The results were compared with literature data and with our own experimental data for the Al-La-Ni system. The alloy described in the literature as the best glass former in the Al-La system is located near the point with local maximum for the λ.Δe criterion. A good agreement was found between the predictions of the λ.Δe criterion and literature data in the Al-La-Ni system, with the region of the best glass-forming ability (GFA) and largest supercooled liquid region (ΔT x ) coinciding with the best compositional region for amorphization indicated by the λ.Δe criterion. Four new glassy compositions were found in the Al-La-Ni system, with the best predicted composition presenting the best glass-forming ability observed so far for this system. Although the λ.Δe criterion needs further refinements for completely describe the glass-forming ability in the Al-La and Al-La-Ni systems, the results demonstrated that this criterion is a good tool to predict new glass-forming compositions.

Effects of Bond Coating on NiCrBSi-Mo Composite Functional Coating Properties in Plasma Spraying NiCrBSi-Mo/Ni Coating

OpenAIRE

DU Ji-yu; LI Fang-yi; LU Hai-yang; SHANG Jian-tong; LI Zhen

2017-01-01

Nickel-based bond coating and composite functional coating were sprayed on leaf blade steel material FV520B successively by using air plasma spraying system. NiCrBSi-Mo powder deposition rate, coating porosity, bonding strength and surface hardness were tested. The results indicate that, for the NiCrBSi-Mo/Ni coating, bond coating with 180-220μm thickness can improve NiCrBSi-Mo powder deposition rate while the surface coating with lower porosity, higher bonding strength and high hardness is p...

High Temperature Dry Sliding Friction and Wear Performance of Laser Cladding WC/Ni Composite Coating

Directory of Open Access Journals (Sweden)

YANG Jiao-xi

2016-06-01

Full Text Available Two different types of agglomerate and angular WC/Ni matrix composite coatings were deposited by laser cladding. The high temperature wear resistance of these composite coatings was tested with a ring-on-disc MMG-10 apparatus. The morphologies of the worn surfaces were observed using a scanning electron microscopy (SEM equipped with an energy dispersive spectroscopy (EDS for elemental composition. The results show that the high temperature wear resistance of the laser clad WC/Ni-based composite coatings is improved significantly with WC mass fraction increasing. The 60% agglomerate WC/Ni composite coating has optimal high temperature wear resistance. High temperature wear mechanism of 60% WC/Ni composite coating is from abrasive wear of low temperature into composite function of the oxidation wear and abrasive wear.

Effects of Ni and carbon-coated Ni addition on the thermoelectric properties of 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} base composites

Energy Technology Data Exchange (ETDEWEB)

Yoon, Sang Min; Dharmaiah, Peyala; Femi, Olu Emmanuel; Lee, Chul Hee; Hong, Soon-Jik, E-mail: hongsj@kongju.ac.kr

2017-07-01

In this paper, we report the effect of nickel (Ni) and carbon coated nickel (C-Ni) on the thermoelectric and mechanical properties of 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} (GA) base composites. Ni and C-Ni powders were synthesized using pulse wire evaporation and mixed with 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} in a planetary ball mill. The morphology of the Ni and C-Ni powders and GA + x (x = none, Ni, or C-Ni) composites were examined using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The thermoelectric properties of the GA + x (x = none, Ni, or C-Ni) composites shows that the addition of Ni increases the carrier concentration while the presence of C-Ni reduces the carrier concentration to a level comparable to the bare sample (x = 0). Subsequently, the Seebeck coefficient of the GA + C-Ni sample increases by about 18% more than in the bare sample. The thermal conductivity of the GA + Ni and GA + C-Ni samples was considerably lower at room temperature compared to the bare sample. The mechanical properties of the GA + Ni and GA + C-Ni composite samples show a three-fold improvement compared to the bare sample. - Highlights: • Ni and carbon-coated Ni nanoparticles were incorporated into 25Bi{sub 2}Te{sub 3}+75Sb{sub 2}Te{sub 3} (BST) matrix. • Seebeck coefficient increased by 18% for BST/carbon coated Ni composites. • BST/carbon coated Ni composite reduces the thermal conductivity (21%). • The Vickers hardness of the BST/C-Ni composite samples significantly improved.

Hybrid Composite Ni(OH)(2)@NiCo2O4 Grown on Carbon Fiber Paper for High-Performance Supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Huang, L; Chen, DC; Ding, Y; Wang, ZL; Zeng, ZZ; Liu, ML

2013-11-13

We have successfully fabricated and tested the electrochemical performance of supercapacitor electrodes consisting of Ni(OH)(2) nanosheets coated on NiCo2O4 nanosheets grown on carbon fiber paper (CFP) current collectors. When the NiCo2O4 nanosheets are replaced by Co3O4 nanosheets, however, the energy and power density as well as the rate capability of the electrodes are significantly reduced, most likely due to the lower conductivity of Co3O4 than that of NiCo2O4. The 3D hybrid composite Ni(OH)(2)/ NiCo2O4/CFP electrodes demonstrate a high areal capacitance of 5.2 F/cm(2) at a cycling current density of 2 rnA/cm(2), with a capacitance retention of 79% as the cycling current density was increased from 2 to 50 mA/cm(2). The remarkable performance of these hybrid composite electrodes implies that supercapacitors based on them have potential for many practical applications.

Hybrid composite Ni(OH)2@NiCo2O4 grown on carbon fiber paper for high-performance supercapacitors.

Science.gov (United States)

Huang, Liang; Chen, Dongchang; Ding, Yong; Wang, Zhong Lin; Zeng, Zhengzhi; Liu, Meilin

2013-11-13

We have successfully fabricated and tested the electrochemical performance of supercapacitor electrodes consisting of Ni(OH)2 nanosheets coated on NiCo2O4 nanosheets grown on carbon fiber paper (CFP) current collectors. When the NiCo2O4 nanosheets are replaced by Co3O4 nanosheets, however, the energy and power density as well as the rate capability of the electrodes are significantly reduced, most likely due to the lower conductivity of Co3O4 than that of NiCo2O4. The 3D hybrid composite Ni(OH)2/NiCo2O4/CFP electrodes demonstrate a high areal capacitance of 5.2 F/cm(2) at a cycling current density of 2 mA/cm(2), with a capacitance retention of 79% as the cycling current density was increased from 2 to 50 mA/cm(2). The remarkable performance of these hybrid composite electrodes implies that supercapacitors based on them have potential for many practical applications.

Ni-P/Zn-Ni compositionally modulated multilayer coatings - Part 2: Corrosion and protection mechanisms

Science.gov (United States)

Bahadormanesh, Behrouz; Ghorbani, Mohammad

2018-06-01

The Ni-P/Zn-Ni compositionally modulated multilayer coatings CMMCs were electrodeposited from a single bath by switching the deposition current density. The corrosion resistance of the deposits was studied and compared with that of monolayers of Ni-P and Zn-Ni alloys via Tafel polarization, EIS and salt spray tests. Characterization of corrosion products by means of EDS and XRD revealed more details from the corrosion mechanism of the monolayers and multilayers. The corrosion current density of Ni-P/Zn-Ni CMMCs were around one tenth of Zn-Ni monolayer. The CMMC with incomplete layers performed lower polarization resistance and higher corrosion current density compared to the CMMC with complete layers. The electrical circuit that was proposed for modeling the corrosion process based on the EIS spectrum, proved that layering reduces the porosity and consequently improves the barrier properties. Although, layering of Zn-Ni layers with Ni-P deposits increased the time to red rust in salt spray test, the time for white rust formation decreased. The corrosion mechanism of both Zn-Ni and Ni-P (containing small amount of Zn) was preferential dissolution of Zn and the corrosion products were comprised of mainly Zn hydroxychloride and Zn hydroxycarbonate. Also, Ni and P did not take part in the corrosion products. Based on the electrochemical character of the layers and the morphology of the corroded surface, the corrosion mechanism of multilayers was discussed.

Deposition of Ni-CGO composite anodes by electrostatic assisted ultrasonic spray pyrolysis method

International Nuclear Information System (INIS)

Chen, J.-C.; Chang, C.-L.; Hsu, C.-S.; Hwang, B.-H.

2007-01-01

Deposition of composite films of Ni and Gd-doped ceria was carried out using the electrostatic assisted ultrasonic spray pyrolysis method for the first time. The composite films were highly homogeneous, as revealed by element mapping via energy-dispersive spectrometry. Scanning electron microscope examinations revealed that deposition temperature and electric field strength had profound influence on resultant microstructure, while composition of the precursor solution had little effect. A highly porous cauliflower structure ideal for solid oxide fuel cell anode performance was obtained with a deposition temperature of 450 deg. C under an electric field introduced by an applied voltage of 12 kV. Films obtained with a lower deposition temperature of 250 deg. C or a higher applied voltage of 15 kV resulted in denser films with low porosity, while lower applied voltages of 7 or 5 kV resulted in thinner or discontinuous films due to the insufficient electrostatic attraction on the aerosol droplets. As revealed by AC impedance measurement, the area specific resistances of the Ni-CGO anode with porous cauliflower structure were rather low and a value of 0.09 Ω cm 2 at 550 deg. C was obtained

Fabrication of Ni-Al/diamond composite based on layered and gradient structures of SHS system

Directory of Open Access Journals (Sweden)

Lu Jiafeng

2017-01-01

Full Text Available In this paper layered and gradient structures of Ni-Al SHS system were adopted to manufacture Ni-Al/diamond composites. The effect of the layered and the diamond mesh gradient structures of Ni-Al/diamond on the SHS process and the microstructure of the composites were investigated. It is found that with the increasing of the number of layers, the combustion wave velocity is decreased. The combustion wave velocity for diamond mesh size gradient structure of Ni-Al SHS is faster than that for the layered structure. A well bonding can be formed between diamond and the matrix in layered and gradient structure Ni-Al/diamond composites due to the melt of Ni-Cr brazing alloy.

Natural Rosin-based Phosphate Diester Surfactant Assisted One-step Synthesis of 3D Flowerlikeβ-Ni(OH)2/γ-Ni(OH)2 Composite Nano-microspheres

Institute of Scientific and Technical Information of China (English)

BoShi Wu; Juan Li; ChunRui Han; Feng Xu

2018-01-01

Self-assembled uniform 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres with hollow interiors were successfully synthesized via a facile aqueous-ethanol mixed solvothermal method, using nickel sulfate as a precursor, urea as a precipitant, and dehydroabietic based phosphate diester sodium (DDPDS) as a surfactant. The prepared 3D flowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres were tested as supercapacitors in a two-electrode cell with 6 mol/L KOH electrolyte. In addition, the influence of DDPDS concentration on the morphology and size of 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres was studied at 180℃. X-ray diffraction (XRD), scanning electron microscopy (SEM), BET(Brunauer, Emmett and Teller)techniques, and equity default swap (EDS) were used to characterize the structure, morphology, and size of the as-prepared samples. Moreover, a possible formation mechanism of the 3Dflowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres was proposed based on the effects of DDPDS concentrationand reaction time. The surfactant micelles were used as soft templates to induce the self-assembly of nanosheets. The crystallinity of the 3D flowerlikeβ-Ni(OH)2/g-Ni(OH)2composite nano-microspheres improved with the increase of DDPDS concentration, and the morphology and size of synthetic nano-microspheres could be controlled.

Preparation of Fe–Si–Ni soft magnetic composites with excellent high-frequency properties

Energy Technology Data Exchange (ETDEWEB)

Xu, Wei; Wu, Chen, E-mail: chen_wu@zju.edu.cn; Yan, Mi, E-mail: mse_yanmi@zju.edu.cn

2015-05-01

Fe–Si–Ni powders were firstly prepared into soft magnetic composites (SMCs) by ball milling, surface passivation and subsequent compaction. The morphology, phase composition, and magnetic properties of the Fe–Si–Ni powders and their high-frequency performance as SMCs were investigated. The Fe–Si–Ni powders, with saturation magnetization (M{sub s}) of 254.40 emu/g after annealing, were milled down to particle sizes ranging from 40 μm to 150 μm. Surface passivation of the powders was carried out with 0.2–1.0 wt% phosphoric acid solution prior to compaction. Evolution of the high-frequency properties for the Fe–Si–Ni SMCs with the passivator concentration and the molding pressure was studied. With optimized preparation parameters, high saturation flux density (B{sub s}) of 1.23 T, stable permeability, and superior dc-bias property with a percentage permeability above 70% while H=50 Oe were achieved for the Fe–Si–Ni SMC. Minimum core loss (285 mW/cm{sup 3}) was also measured at 50 kHz for B{sub m}=50 mT. - Highlights: • Fe–Si–Ni as a new type of magnetic powder has been prepared into soft magnetic composites. • Effective surface passivation of the Fe–Si–Ni powders can be achieved by phosphate treatment. • Influence of the passivator concentration and molding pressure has been investigated. • The obtained Fe–Si–Ni soft magnetic composites exhibit excellent high-frequency performance.

Wettability and interface considerations in advanced heat-resistant Ni-base composites

International Nuclear Information System (INIS)

Asthana, R.; Mileiko, S.T.; Sobczak, N.

2006-01-01

Oxide fiber-reinforced Ni-base composites have long been considered as attractive heat-resistant materials. After several decades of active research, however, interest in these materials began to decline around mid-1990's due chiefly to 1) a lack of manufacturing technology to grow inexpensive single-crystal oxide fibers to be used in structural composites, and 2) fiber strength loss during processing due to chemical interactions with reactive solutes in the matrix. The cost disadvantage has been mitigated to a large extent by the development of innovative fiber fabrication processes such as the Internal Crystallization Method (ICM) that produces monocrystalline oxide fibers in a cost-effective manner. Fiber strength loss has been an equally restrictive issue but recent work has shown that it may be possible to design creep-resistant composites even when fiber surface reconstruction from chemical interactions has degraded the strength of extracted fibers tested outside the matrix. The key issue is the optimization of the composite- and interface structure. Reaction-formed defects may be healed by the matrix (or a suitable coating material) so that the fiber residing in the matrix may exhibit diminished sensitivity to flaws as compared to fibers extracted from the matrix and tested in isolation of the matrix. Generally, the Ni-base/Al 2 O 3 composites exhibit acceptable levels of wettability and interface strength (further improved with the aid of reactive solutes), which are required for elevated-temperature creep-resistance. In order to harness the full potential of these composites, the quality of the interface as manifested in the fiber/matrix wettability, interface composition, interphase morphology, and interface strength must be designed. We identify key issues related to the measurement of contact angle, interface strength, and chemical and structural properties at the fiber/matrix interface in the Ni/alumina composites, and present the current state-of the

Direct STM evidence of a surface interaction between chiral modifier and pro-chiral reagent: Methylacetoacetate on R, R-tartaric acid modified Ni {1 1 1}

Science.gov (United States)

Jones, T. E.; Baddeley, C. J.

2002-11-01

The asymmetric hydrogenation of methylacetoacetate to R-methyl-3-hydroxybutyrate over R, R-tartaric acid modified Ni catalysts is a well known example of heterogeneous enantioselective catalysis. Using STM, RAIRS and TPD, we investigate the adsorption of methylacetoacetate on Ni{1 1 1} and R, R-TA modified Ni{1 1 1} in order to shed light on the molecular mechanisms underlying the enantioselective catalysis. We show that methylacetoacetate adsorption can only occur in regions of low R, R-tartaric acid coverage. Once adsorption occurs, methylacetoacetate is able to locally rearrange the tartrate modifiers to produce a two-dimensional co-crystal. We consider the implications of our work in explaining the mechanism of enantioselective hydrogenation in this type of system.

Preparation and application of PVDF-HFP composite polymer electrolytes in LiNi0.5Co0.2Mn0.3O2 lithium-polymer batteries

International Nuclear Information System (INIS)

Yang, Chun-Chen; Lian, Zuo-Yu; Lin, S.J.; Shih, Jeng-Ywan; Chen, Wei-Houng

2014-01-01

Graphical abstract: - Highlights: • PVDF-HFP/SBA15 membrane and NCM cathode material were prepared for Li ion battery. • SBA15 fillers can trap more liquid electrolytes to enhance the ionic conductivity. • Modified fillers with functional groups play a key role in reducing impedance. • LiNi 0.5 Co 0.2 Mn 0.3 O 2 polymer battery showed excellent electrochemical performance. - Abstract: This study reports the preparation of a composite polymer electrolyte for application in LiNi 0.5 Co 0.2 Mn 0.3 O 2 lithium-polymer batteries. Poly(vinylidiene fluoride-hexafluoropropylene) (denoted as PVDF-HFP) was used as the polymer host and mesoporous modified-silica fillers (denoted as m-SBA15) used as the solid plasticizer were added into the polymer matrix. The characteristic properties of the composite polymer membranes were examined using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and an AC impedance method. The discharge capacities of LiNi 0.5 Co 0.2 Mn 0.3 O 2 polymer batteries with a PE separator, pure PVDF-HFP polymer membrane, or a PVDF-HFP/10 wt.%m-SBA15 composite at 0.1 C were determined to be 155.5, 159.5, and 198.6 mAh g −1 , respectively. The LiNi 0.5 Co 0.2 Mn 0.3 O 2 polymer battery containing the PVDF-HFP/10 wt.%m-SBA15 composite achieved discharge capacities of 194, 170, 161, 150, 129, 115, and 87 mAh g −1 at 0.1, 0.2, 0.5, 1, 3, 5, and 10 C, respectively. The lithium-polymer battery demonstrated a high coulomb efficiency of ca. 99%. The PVDF-HFP/m-SBA15 composite membrane is a strong candidate for application in LiNi 0.5 Co 0.2 Mn 0.3 O 2 lithium-polymer batteries

Functional properties of electrospun NiO/RuO2 composite carbon nanofibers

International Nuclear Information System (INIS)

Wu Yongzhi; Balakrishna, Rajiv; Reddy, M.V.; Nair, A. Sreekumaran; Chowdari, B.V.R.; Ramakrishna, S.

2012-01-01

Highlights: ► Fabrication of carbon nanofibers with nickel–ruthenium composites by electrospinning. ► An interesting observation of increase in capacitance with increase in the number of cycles for supercapacitor applications. ► Li ion battery testing showed a stable capacity ranging from 350 mAh g −1 to 400 mAh g −1 . ► Lower impedance with the incorporation of 15 wt% Ru precursor than those without Ru. - Abstract: One-dimensional (1D) nickel oxide/ruthenium oxide (NiO/RuO 2 )–carbon composite nanofibers (NiRu–C–NFs) were fabricated via electrospinning of a homogenous mixture of polyacrylonitrile (PAN) and Ni/Ru salt precursors at different ratios followed by heat treatments. The 1D nanostructures of the composite material were characterized by field-emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), Rietveld refinement and Brunauer–Emmett–Teller (BET) surface area measurements. Li-cycling properties were evaluated using cyclic voltammetry and galvanostatic properties. The asymmetric hybrid supercapacitor studies were carried out with activated carbon as a cathode and NiRu–C–NFs composites as anodes in the cycling range, 0.005–3.0 V using 1 M LiPF 6 (EC;DMC) electrolyte. NiRu–C–NFs fabricated from 5 wt% nickel (II) and 15 wt% ruthenium (III) precursors showed a capacitance up to ∼60 F g −1 after 30 cycles. Anodic Li-cycling studies of NiRu–C–NF-0 and NiRu–C–NF-2 composite samples showed a reversible capacity of 230 and 350 m Ahg −1 at current rate of 72 mA g −1 at the end of 40th cycle in the voltage range of 0.005–3.0 V. Electrochemical impedance studies (EIS) on NiRu–C–NFs showed lower impedance value for 15 wt% Ru than the bare sample.

Tunable Twin Matching Frequency (fm1/fm2) Behavior of Ni1−xZnxFe2O4/NBR Composites over 2–12.4 GHz: A Strategic Material System for Stealth Applications

Science.gov (United States)

Saini, Lokesh; Patra, Manoj Kumar; Jani, Raj Kumar; Gupta, Goutam Kumar; Dixit, Ambesh; Vadera, Sampat Raj

2017-01-01

The gel to carbonate precipitate route has been used for the synthesis of Ni1−xZnxFe2O4 (x = 0, 0.25, 0.5 and 0.75) bulk inverse spinel ferrite powder samples. The optimal zinc (50%) substitution has shown the maximum saturation magnetic moment and resulted into the maximum magnetic loss tangent (tanδm) > −1.2 over the entire 2–10 GHz frequency range with an optimum value ~−1.75 at 6 GHz. Ni0.5Zn0.5Fe2O4- Acrylo-Nitrile Butadiene Rubber (NBR) composite samples are prepared at different weight percentage (wt%) of ferrite loading fractions in rubber for microwave absorption evaluation. The 80 wt% loaded Ni0.5Zn0.5Fe2O4/NBR composite (FMAR80) sample has shown two reflection loss (RL) peaks at 5 and 10 GHz. Interestingly, a single peak at 10 GHz for 3.25 mm thickness, can be scaled down to 5 GHz by increasing the thickness up to 4.6 mm. The onset of such twin matching frequencies in FMAR80 composite sample is attributed to the spin resonance relaxation at ~5 GHz (fm1) and destructive interference at λm/4 matched thickness near ~10 GHz (fm2) in these composite systems. These studies suggest the potential of tuning the twin frequencies in Ni0.5Zn0.5Fe2O4/NBR composite samples for possible microwave absorption applications. PMID:28294151

Electrochemical behavior of low phosphorus electroless Ni-P-Si3N4 composite coatings

International Nuclear Information System (INIS)

Balaraju, J.N.; Ezhil Selvi, V.; Rajam, K.S.

2010-01-01

In the present investigation the electroless Ni-P-Si 3 N 4 composite coatings were prepared by using a low phosphorus bath containing submicron size silicon nitride particles. Plain Ni-P deposits were also prepared for comparison. The phosphorus contents present in electroless plain Ni-P and Ni-P-Si 3 N 4 coatings are 3.7 and 3.4 wt.%, respectively. Scanning electron microscope (SEM) images obtained for composite coatings (cross-sections) showed that the second phase particles are uniformly distributed throughout the thickness of the deposits. It was found that nodularity increased with particle codeposition in Ni-P matrix. To find out the electrochemical behavior of plain Ni-P and composite coatings, potentiodynamic polarization and electrochemical impedance (EIS) studies were carried out in 3.5 wt.% sodium chloride solution in non-deaerated condition. Second phase particle incorporation in Ni-P matrix indicated a marginal decrease in corrosion current density compared to the plain Ni-P deposits. This was further confirmed by EIS studies and SEM analysis of the corroded samples.

Hydrogen desorption properties of MgH2–Ni–Ni2Si composites prepared by mechanochemical method

International Nuclear Information System (INIS)

Shimada, Motoki; Higuchi, Eiji; Inoue, Hiroshi

2013-01-01

Highlights: ► The MgH 2 –Ni composite showed fast hydrogen desorption rate at 250 °C. ► The MgH 2 –Ni–Ni 2 Si composite showed fast hydrogen desorption rate at 220 °C. ► Nanocrystalline Mg 2 Ni and Mg 2 Si were formed between Mg and adjacent Ni or Si. ► Ni 2 Si did not form any alloys and work as a catalyst. -- Abstract: To improve hydrogen desorbability of Mg, some composites were prepared from MgH 2 , Ni and Ni 2 Si mixed powders by the mechanochemical method. The MgH 2 –Ni(2 mol%)–Ni 2 Si(1 mol%) composite was slower in hydrogen desorption rate at 250 °C than the MgH 2 –Ni(2 mol%) composite, while the hydrogen desorption rate at 220 °C for the former was faster than that for the latter. The XRD pattern of the MgH 2 –Ni(2 mol%) composite showed that after hydrogen desorption at 400 °C small diffraction peaks assigned to Mg 2 Ni were observed with peaks assigned to Mg. They shifted to smaller angles after hydrogen absorption at 250 °C and come back to the original positions after hydrogen desorption at 250 °C, suggesting reversible hydrogen absorption/desorption of Mg 2 Ni. In contrast, Ni 2 Si was not changed over the whole processes. These results indicated that Ni 2 Si worked as a catalyst for hydrogen desorption, leading to the improvement of desorbability at 220 °C

Ni@Ru and NiCo@Ru Core-Shell Hexagonal Nanosandwiches with a Compositionally Tunable Core and a Regioselectively Grown Shell.

Science.gov (United States)

Hwang, Hyeyoun; Kwon, Taehyun; Kim, Ho Young; Park, Jongsik; Oh, Aram; Kim, Byeongyoon; Baik, Hionsuck; Joo, Sang Hoon; Lee, Kwangyeol

2018-01-01

The development of highly active electrocatalysts is crucial for the advancement of renewable energy conversion devices. The design of core-shell nanoparticle catalysts represents a promising approach to boost catalytic activity as well as save the use of expensive precious metals. Here, a simple, one-step synthetic route is reported to prepare hexagonal nanosandwich-shaped Ni@Ru core-shell nanoparticles (Ni@Ru HNS), in which Ru shell layers are overgrown in a regioselective manner on the top and bottom, and around the center section of a hexagonal Ni nanoplate core. Notably, the synthesis can be extended to NiCo@Ru core-shell nanoparticles with tunable core compositions (Ni 3 Co x @Ru HNS). Core-shell HNS structures show superior electrocatalytic activity for the oxygen evolution reaction (OER) to a commercial RuO 2 black catalyst, with their OER activity being dependent on their core compositions. The observed trend in OER activity is correlated to the population of Ru oxide (Ru 4+ ) species, which can be modulated by the core compositions. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Graphite oxide/β-Ni(OH)2 composites for application in supercapacitors

Science.gov (United States)

Singh, Arvinder; Chandra, Amreesh

2013-06-01

Graphite oxide/β-Ni(OH)2 composites have been investigated as electrode material in supercapacitors. Phase formation of electrode material is investigated using diffraction measurements. Particle shape-size studies show deposition of β-Ni(OH)2 nanoparticles on graphite oxide (GO) sheets. Electrochemical performance of GO/β-Ni(OH)2 composite in supercapacitors is discussed based on the analysis of electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvanostatic charge-discharge studies. Excellent energy density of ˜53 Wh/kg in 1M Na2SO4 aqueous electrolyte is reported at power density of ˜1364W/kg. The significance of results is discussed in the paper.

Microstructure and property of directionally solidified Ni-Si hypereutectic alloy

Science.gov (United States)

Cui, Chunjuan; Tian, Lulu; Zhang, Jun; Yu, Shengnan; Liu, Lin; Fu, Hengzhi

2016-03-01

This paper investigates the influence of the solidification rate on the microstructure, solid/liquid interface, and micro-hardness of the directionally solidified Ni-Si hypereutectic alloy. Microstructure of the Ni-Si hypereutectic alloy is refined with the increase of the solidification rate. The Ni-Si hypereutectic composite is mainly composed of α-Ni matrix, Ni-Ni3Si eutectic phase, and metastable Ni31Si12 phase. The solid/liquid interface always keeps planar interface no matter how high the solidification rate is increased. This is proved by the calculation in terms of M-S interface stability criterion. Moreover, the Ni-Si hypereutectic composites present higher micro-hardness as compared with that of the pure Ni3Si compound. This is caused by the formation of the metastable Ni31Si12 phase and NiSi phase during the directional solidification process.

ELECTROCHEMICAL OXIDATION OF ETHANOL USING Ni-Co-PVC COMPOSITE ELECTRODE

Directory of Open Access Journals (Sweden)

Riyanto Riyanto

2011-07-01

Full Text Available The morphological characteristics and electrochemical behavior of nickel metal foil (Ni, nickel-polyvinyl chloride (Ni-PVC and nickel-cobalt-polyvinyl chloride (Ni-Co-PVC electrodes in alkaline solution has been investigated. The morphological characteristics of the electrode surface were studied using SEM and EDS, while the electrochemical behavior of the electrodes was studied using cyclic voltammetry (CV. It was found that composite electrodes (Ni-PVC and Ni-Co-PVC have a porous, irregular and rough surface. In situ studies using electrochemical technique using those three electrodes exhibited electrochemical activity for redox system, as well as selectivity in the electrooxidation of ethanol to acetic acid. The studies also found that an electrokinetics and electrocatalytic activity behaviors of the electrodes prepared were Ni metal foil

The Deoxygenation Pathways of Palmitic Acid into Hydrocarbons on Silica-Supported Ni12P5 and Ni2P Catalysts

Directory of Open Access Journals (Sweden)

Wenjun Zhou

2018-04-01

Full Text Available Pure Ni12P5/SiO2 and pure Ni2P/SiO2 catalysts were obtained by adjusting the Ni and P molar ratios, while Ni/SiO2 catalyst was prepared as a reference against which the deoxygenation pathways of palmitic acid were investigated. The catalysts were characterized by N2 adsorption, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, transmission election microscopy (TEM, infrared spectroscopy of pyridine adsorption (Py-IR, H2-adsorption and temperature-programmed desorption of hydrogen (H2-TPD. The crystallographic planes of Ni(111, Ni12P5(400, Ni2P(111 were found mainly exposed on the above three catalysts, respectively. It was found that the deoxygenation pathway of palmitic acid mainly proceeded via direct decarboxylation (DCO2 to form C15 on Ni/SiO2. In contrast, on the Ni12P5/SiO2 catalyst, there were two main competitive pathways producing C15 and C16, one of which mainly proceeded via the decarbonylation (DCO to form C15 accompanying water formation, and the other pathway produced C16 via the dehydration of hexadecanol intermediate, and the yield of C15 was approximately twofold that of C16. Over the Ni2P/SiO2 catalyst, two main deoxygenation pathways formed C15, one of which was mainly the DCO pathway and the other was dehydration accompanying the hexadecanal intermediate and then direct decarbonylation without water formation. The turn over frequency (TOF followed the order: Ni12P5/SiO2 > Ni/SiO2 > Ni2P/SiO2.

FeCoNi coated glass fibers in composite sheets for electromagnetic absorption and shielding behaviors

Science.gov (United States)

Lee, Joonsik; Jung, Byung Mun; Lee, Sang Bok; Lee, Sang Kwan; Kim, Ki Hyeon

2017-09-01

To evaluate the electromagnetic (EM) absorption and shield of magnetic composite sheet, we prepared the FeCoNi coated glass fibers filled in composite sheet. The FeCoNi was coated by electroless plating on glass fiber as a filler. The coated FeCoNi found that consist of mixtures of bcc and fcc phase. The magnetization and coercivity of coated FeCoNi are about 110 emu/g and 57 Oe, respectively. The permittivity and permeability of the FeCoNi composite sheet were about 21 and 1, respectively. Power absorption increased 95% with the increment of frequency up to 10 GHz. Inter-decoupling of this composite sheet showed maximum 30 dB at around 5.3 GHz, which is comparable to that of a conductive Cu foil. Shielding effectiveness (SE) was measured by using rectangular waveguide method. SE of composite obtained about 37 dB at X-band frequency region.

Preparation of one-step NiO/Ni-CGO composites using factorial design; Efeitos do processamento e do teor de formador de poros na microestrutura de cermets Ni-CGO

Energy Technology Data Exchange (ETDEWEB)

Araujo, A.J.M. de; Sousa, A R.O. de; Camposa, L.F.A.; Macedo, D.A. [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Loureiro, F. J.A.; Fagg, D.P., E-mail: allanjp1993@hotmail.com [Universidade de Aveiro (Portugal)

2016-07-01

This work deals with the synthesis, processing and characterization of NiO/Ni- CGO composite materials as potential solid oxide fuel cell (SOFC) anodes. The particulate materials were obtained by a one-step synthesis method and characterized by thermal analysis (prior to calcination) and X-ray diffraction (calcined powder). The ceramic processing of samples containing from 30 to 70 wt.% NiO was carried out by factorial design. Besides the NiO content controlled during the chemical synthesis, the impacts of the pore-former content (citric acid, used in proportions of 0, 7.5 and 15 wt.%) and the sintering temperature (1300, 1350 and 1400 °C) were also investigated. The open porosity of NiO-CGO composites and reduced Ni-CGO cermets was modeled as a function of factors (NiO content, citric acid content and sintering temperature) and interaction of factors. (author)

Controlling the alloy composition of PtNi nanocrystals using solid-state dewetting of bilayer films

Energy Technology Data Exchange (ETDEWEB)

Seo, Okkyun; Oh, Se An; Lee, Ji Yeon; Ha, Sung Soo; Kim, Jae Myung; Choi, Jung Won; Kim, Jin-Woo [Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of); Kang, Hyon Chol [Department of Materials and Science Engineering, Chosun University, Gwangju 61542 (Korea, Republic of); Noh, Do Young, E-mail: dynoh@gist.ac.kr [Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of)

2016-05-15

We demonstrate that solid-state dewetting of bilayer films is an effective way for obtaining bimetallic alloy nanocrystals of controlled composition. When a Pt–Ni bilayer film were annealed near 700 °C, Pt and Ni atoms inter-diffused to form a PtNi bimetallic alloy film. Upon annealing at higher temperatures, the bilayer films transformed into <111> oriented PtNi alloy nanocrystals in small-rhombicuboctahedron shape through solid-state dewetting process. The Pt content of the nanocrystals and the alloy films, estimated by applying the Vegard's law to the relaxed lattice constant, was closely related to the thickness of each layer in the as-grown bilayer films which can be readily controlled during bilayer deposition. - Highlights: • Composition control of PtNi nanoparticles using solid state dewetting is proposed. • PtNi alloy composition was controlled by thickness ratio of Pt–Ni bilayer films. • PtNi alloy nanocrystals were obtained in small-rhombicuboctahedron shape.

Modification effect of Ni-38 wt.%Si on Al-12 wt.%Si alloy

International Nuclear Information System (INIS)

Wu Yuying; Liu Xiangfa; Jiang Binggang; Huang Chuanzhen

2009-01-01

Modification effect of Ni-38 wt.%Si on the Al-12 wt.%Si alloy has been studied by differential scanning calorimeter, torsional oscillation viscometer and liquid X-ray diffraction experiments. It is found that there is a modification effect of Ni-38 wt.%Si on Al-12 wt.%Si alloy, i.e. primary Si can precipitate in the microstructure of Al-12 wt.%Si alloy when Ni and Si added in the form of Ni-38 wt.%Si, but not separately. Ni-38 wt.%Si alloy brings 'genetic materials' into the Al-Si melt, which makes the melt to form more ordering structure, promotes the primary Si precipitated. Moreover, the addition of Ni-38 wt.%Si, which decreases the solidification supercooling degree of Al-12 wt.%Si alloy, is identical to the effect of heterogeneous nuclei.

Modification effect of Ni-38 wt.%Si on Al-12 wt.%Si alloy

Energy Technology Data Exchange (ETDEWEB)

Wu Yuying [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Ji' nan 250061 (China)], E-mail: wyy532001@163.com; Liu Xiangfa [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Ji' nan 250061 (China); Shandong Binzhou Bohai Piston Co., Ltd., Binzhou 256602, Shandong (China); Jiang Binggang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Ji' nan 250061 (China); Huang Chuanzhen [School of Mechanical Engineering, Shandong University, Jinan 250061 (China)

2009-05-27

Modification effect of Ni-38 wt.%Si on the Al-12 wt.%Si alloy has been studied by differential scanning calorimeter, torsional oscillation viscometer and liquid X-ray diffraction experiments. It is found that there is a modification effect of Ni-38 wt.%Si on Al-12 wt.%Si alloy, i.e. primary Si can precipitate in the microstructure of Al-12 wt.%Si alloy when Ni and Si added in the form of Ni-38 wt.%Si, but not separately. Ni-38 wt.%Si alloy brings 'genetic materials' into the Al-Si melt, which makes the melt to form more ordering structure, promotes the primary Si precipitated. Moreover, the addition of Ni-38 wt.%Si, which decreases the solidification supercooling degree of Al-12 wt.%Si alloy, is identical to the effect of heterogeneous nuclei.

Influence of additives on microstructures, mechanical properties and shock-induced reaction characteristics of Al/Ni composites

Energy Technology Data Exchange (ETDEWEB)

Xiong, Wei; Zhang, Xianfeng, E-mail: lynx@mail.njust.edu.cn; Wu, Yang; He, Yong; Wang, Chuanting; Guo, Lei

2015-11-05

Granular composites containing aluminum (Al) and nickel (Ni) are typical structural energetic materials, which possess ideal combination of both mechanical properties and energy release capability. The influence of two additives, namely Teflon (PTFE) and copper (Cu), on mechanical properties and shock-induced chemical reaction (SICR) characteristics of Al/Ni material system has been investigated. Three composites, namely Al/Ni, Al/Ni/PTFE and Al/Ni/Cu with same volumetric ratio of Al powder to Ni powder, were processed by means of static pressing. Scanning electron microscopy was used to study the microstructure of the mentioned three composites. Quasi static compression tests were also conducted to determine the mechanical properties and fracture behavior of the mentioned three composites. It was shown that the additives affected both compressive strength and fracture mode of the three composites. Impact initiation experiments on the mentioned three composites were performed to determine their shock-induced chemical reaction characteristics by considering pressure histories measured in the test chamber. The experimental results showed that the additives had significant effects on critical initiation velocity, reaction rate, reaction efficiency and post-reaction behavior. - Highlights: • .Al/Ni, Al/Ni/PTFE and Al/Ni/Cu were processed by means of static pressing. • .Microstructures, mechanical properties and shock-induced reactions were studied. • .Microstructures affect both compressive strength and fracture mode. • .Impact velocity is an important factor in shock-induced chemical characteristics. • .Each additive has significant effects on energy release behavior.

Influence of additives on microstructures, mechanical properties and shock-induced reaction characteristics of Al/Ni composites

International Nuclear Information System (INIS)

Xiong, Wei; Zhang, Xianfeng; Wu, Yang; He, Yong; Wang, Chuanting; Guo, Lei

2015-01-01

Granular composites containing aluminum (Al) and nickel (Ni) are typical structural energetic materials, which possess ideal combination of both mechanical properties and energy release capability. The influence of two additives, namely Teflon (PTFE) and copper (Cu), on mechanical properties and shock-induced chemical reaction (SICR) characteristics of Al/Ni material system has been investigated. Three composites, namely Al/Ni, Al/Ni/PTFE and Al/Ni/Cu with same volumetric ratio of Al powder to Ni powder, were processed by means of static pressing. Scanning electron microscopy was used to study the microstructure of the mentioned three composites. Quasi static compression tests were also conducted to determine the mechanical properties and fracture behavior of the mentioned three composites. It was shown that the additives affected both compressive strength and fracture mode of the three composites. Impact initiation experiments on the mentioned three composites were performed to determine their shock-induced chemical reaction characteristics by considering pressure histories measured in the test chamber. The experimental results showed that the additives had significant effects on critical initiation velocity, reaction rate, reaction efficiency and post-reaction behavior. - Highlights: • .Al/Ni, Al/Ni/PTFE and Al/Ni/Cu were processed by means of static pressing. • .Microstructures, mechanical properties and shock-induced reactions were studied. • .Microstructures affect both compressive strength and fracture mode. • .Impact velocity is an important factor in shock-induced chemical characteristics. • .Each additive has significant effects on energy release behavior

Preparation and properties of electrodeposited Ni-TiO2 composite coating

Directory of Open Access Journals (Sweden)

Sukhdev Singh Bhogal

2015-03-01

Full Text Available Mechanical properties of cutting tool like microhardness, coating adhesiveness & corrosion resistance are some important parameters, which affects the tool life and further indirectly affects the component cost. In this paper Ni-TiO2 composite coating was prepared through electrocodeposition in order to improve the mechanical properties of tungsten carbide cutting tools. Microhardness of Ni-TiO2 composite layer have been studied by varying input current density (mA, pH vale of electrolyte & particle concentration of TiO2 in electrolyte bath. Microstructure and phase structure of composite layer were investigated using atomic force microscope (AFM, scanning electronic microscope (SEM and X-ray diffraction (XRD. Surface morphology of Ni-TiO2 coated layer shows fine grained structures is obtained at low currents with higher microhardness of composite coating. Maximum microhardness 1483 HV of coated layer is found at 15mA of current and at 4.5 pH of watt’s solution. It has also been seen that with the increase of Ti, microhardness of the layer is also increases.  

The fabrication and the coercivity mechanism of segmented (Ni/Fe)m composite nanowire arrays

International Nuclear Information System (INIS)

Xue, D S; Shi, H G; Si, M S

2004-01-01

Arrays of segmented (Ni/Fe) m (m = 1,2,3,4,5) composite nanowires about 3 μm in length and with aspect ratios of about 60 were electrodeposited on anodic porous alumina templates using a dual bath. The structure, morphology and magnetic properties of the samples were characterized by means of x-ray diffraction, transmission electron microscopy and vibrating sample magnetometry, respectively. It is found that Fe(110) and Ni(111) orientations along nanowire axis are preferred. The large aspect ratio of the composite nanowires reveals a strong shape magnetic anisotropy. As the number of the Ni/Fe composite segments m increases, the coercivity of the nanowire arrays, with the magnetic field applied parallel to the wire, gradually increases. The coercivity variation of the segmented composite nanowires is closely related to the effective exchange coupling between the Ni and Fe segments

Facile synthesis of hybrid CNTs/NiCo2S4 composite for high performance supercapacitors

Science.gov (United States)

Li, Delong; Gong, Youning; Pan, Chunxu

2016-07-01

In this work, a novel carbon nanotubes (CNTs)/NiCo2S4 composite for high performance supercapacitors was prepared via a simple chemical bath deposition combined with a post-anion exchange reaction. The morphologies and phase structures of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and low-temperature sorption of nitrogen (BET). The electro-chemical tests revealed that the CNT/NiCo2S4 composite exhibited high electrochemical performance, because the CNTs were used as a conductive network for the NiCo2S4 hexagonal nanoplates. Compared with pure NiCo2S4 and the mechanically mixed CNTs/NiCo2S4 composite, the CNTs/NiCo2S4 composite electrode material exhibited excellent supercapacitive performance, such as a high specific capacitance up to 1537 F/g (discharge current density of 1 A/g) and an outstanding rate capability of 78.1% retention as the discharge current density increased to 100 A/g. It is therefore expected to be a promising alternative material in the area of energy storage.

Facile synthesis of hybrid CNTs/NiCo2S4 composite for high performance supercapacitors.

Science.gov (United States)

Li, Delong; Gong, Youning; Pan, Chunxu

2016-07-11

In this work, a novel carbon nanotubes (CNTs)/NiCo2S4 composite for high performance supercapacitors was prepared via a simple chemical bath deposition combined with a post-anion exchange reaction. The morphologies and phase structures of the composites were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and low-temperature sorption of nitrogen (BET). The electro-chemical tests revealed that the CNT/NiCo2S4 composite exhibited high electrochemical performance, because the CNTs were used as a conductive network for the NiCo2S4 hexagonal nanoplates. Compared with pure NiCo2S4 and the mechanically mixed CNTs/NiCo2S4 composite, the CNTs/NiCo2S4 composite electrode material exhibited excellent supercapacitive performance, such as a high specific capacitance up to 1537 F/g (discharge current density of 1 A/g) and an outstanding rate capability of 78.1% retention as the discharge current density increased to 100 A/g. It is therefore expected to be a promising alternative material in the area of energy storage.

Facile synthesis of MnO2/rGO/Ni composite foam with excellent pseudocapacitive behavior for supercapacitors

International Nuclear Information System (INIS)

Sun, Youyi; Zhang, Wenhui; Li, Diansen; Gao, Li; Hou, Chunlin; Zhang, Yinghe; Liu, Yaqing

2015-01-01

In this study, the MnO 2 /reduced graphene oxide/Ni (MnO 2 /rGO/Ni) composite foam as a binder-free supercapacitor electrode was prepared by a facile method. The rGO film has been firstly coated on the skeletons of Ni foam current collectors by chemical deposition method and that have been used as substrates for preparation of a novel three dimensional rGO/Ni composite foam-supported porous MnO 2 film by the hydrothermal method. The structure of MnO 2 /rGO/Ni composite foam was characterized by Raman spectra, IR spectra and Scanning electron microscopy. It indicated that the high-quality rGO film have been coated on skeletons of Ni foam current collectors and the MnO 2 film had a 3D network microstructure, consisting of interlaced nanosheets. Furthermore, the binder-free MnO 2 /rGO/Ni composite foam electrode has been characterized by the cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectra. It exhibited excellent pseudocapacitive behavior with specific capacitance of 479.0 F/g. The capacitance could retain about 83.5% after 1000 charge–discharge cycles. This simple synthetic approach provides a convenient route for the large scale preparation of 3D porous MnO 2 /rGO/Ni composite foam for lots of applications in future. - Graphical abstract: The MnO 2 /rGO/Ni composite foam was prepared by a facile method as shown in Fig. 1 and the unique structure of composite foam was suited to be a binder-free supercapacitor electrode due to low resistance, 3D network and porous structure. - Highlights: • The MnO 2 /rGO directly grown on Ni foam was firstly reported. • The MnO 2 /rGO/Ni composite foam was prepared by a facile method. • The MnO 2 /graphene/Ni composite foam as a binder-free supercapacitor electrode exhibited excellent pseudocapacitive behavior

Additives for cement compositions based on modified peat

Energy Technology Data Exchange (ETDEWEB)

Kopanitsa, Natalya, E-mail: kopanitsa@mail.ru; Sarkisov, Yurij, E-mail: sarkisov@tsuab.ru; Gorshkova, Aleksandra, E-mail: kasatkina.alexandra@gmail.com; Demyanenko, Olga, E-mail: angel-n@sibmail.com [Tomsk State University of Architecture and Building, 2, Solyanaya sq., Tomsk, 634003 (Russian Federation)

2016-01-15

High quality competitive dry building mixes require modifying additives for various purposes to be included in their composition. There is insufficient amount of quality additives having stable properties for controlling the properties of cement compositions produced in Russia. Using of foreign modifying additives leads to significant increasing of the final cost of the product. The cost of imported modifiers in the composition of the dry building mixes can be up to 90% of the material cost, depending on the composition complexity. Thus, the problem of import substitution becomes relevant, especially in recent years, due to difficult economic situation. The article discusses the possibility of using local raw materials as a basis for obtaining dry building mixtures components. The properties of organo-mineral additives for cement compositions based on thermally modified peat raw materials are studied. Studies of the structure and composition of the additives are carried out by physicochemical research methods: electron microscopy and X-ray analysis. Results of experimental research showed that the peat additives contribute to improving of cement-sand mortar strength and hydrophysical properties.

Chemical composition of silica-based biocidal modifier

Directory of Open Access Journals (Sweden)

Grishina Anna Nikolaevna

2016-11-01

Full Text Available Increase of the amount of fungi spores and micotixines causes the increase in the number of different diseases. Because of this, ensuring the biological safety in buildings is becoming more and more important today. The preferred way to guarantee the biological safety of a building is to employ modern building materials that prevent the settlement of the fungi colonies on the inner surfaces of walls. Such building materials can be produced using novel biocidal modifiers that allow controlling the number of microorganisms on the surface and in the bulk of a composite construction. The precipitation product of zinc hydrosilicates and sodium sulfate is one of the mentioned modifiers. Till now, the exact chemical composition of such precipitation product is controversial; it is obvious, though, that the efficacy of the biocidal modifier is mostly determined by the type of the copper compounds. In the present work an integrated approach is used for the investigation of the chemical composition of the biocidal modifier. Such an approach consists in the examination of the modifier’s composition by means of different, yet complementary, research methods: X-ray diffraction, infrared spectroscopy and DTA. It is shown that the chemical composition of the modifier mainly depends on the amount of precipitant. X-ray diffraction reveals that the major part of the modifier is represented by amorphous phase. Along with the increase of the precipitant’s amount the crystalline phase Zn4SO4(OH6•xH2O formation takes place. Such a crystalline phase is not appropriate as a component of the biocidal modifier. Another two methods - DTA and IR spectroscopy - reveal that the amorphous phase consists essentially of zinc hydrosilicates.

Creep behaviour of a casting titanium carbide reinforced AlSi12CuNiMg piston alloy at elevated temperatures; Hochtemperaturkriechverhalten der schmelzmetallurgisch hergestellten dispersionsverstaerkten Kolbenlegierung AlSi12CuNiMg

Energy Technology Data Exchange (ETDEWEB)

Michel, S.; Scholz, A. [Zentrum fuer Konstruktionswerkstoffe, TU Darmstadt (Germany); Tonn, B. [Institut fuer Metallurgie, TU Clausthal (Germany); Zak, H.

2012-03-15

This paper deals with the creep behaviour of the titanium carbide reinforced AlSi12CuNiMg piston alloy at 350 C and its comparison to the conventional AlSi12Cu4Ni2MgTiZr piston alloy. With only 0,02 vol-% TiC reinforcement the creep strength and creep rupture strength of the AlSi12CuNiMg piston alloy are significantly improved and reach the level of the expensive AlSi12Cu4Ni2MgTiZr alloy. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Synthesis, Characterization, and NIR Reflectance of Highly Dispersed NiTiO3 and NiTiO3/TiO2 Composite Pigments

Directory of Open Access Journals (Sweden)

Yuping Tong

2016-01-01

Full Text Available The highly dispersed nanostructured NiTiO3 pigments and NiTiO3/TiO2 composite pigments can be synthesized at relative low temperature. The activation energy of crystal growth of NiTiO3 during calcinations via salt-assistant combustion method is 9.35 kJ/mol. The UV-vis spectra results revealed that the absorbance decreased with the increasing of calcinations temperature due to small size effect of nanometer particles. The optical data of NiTiO3 nanocrystals were analyzed at the near-absorption edge. SEM showed that the obtained NiTiO3 nanocrystals and NiTiO3/TiO2 nanocomposite were composed of highly dispersed spherical-like and spherical particles with uniform size distribution, respectively. The chromatic properties and diffuse reflectance of samples were investigated. The obtained NiTiO3/TiO2 composite samples have higher NIR reflectance than NiTiO3 pigments.

Fabrication of Sn–Ni/MWCNT composite coating for Li-ion batteries by pulse electrodeposition: Effects of duty cycle

Energy Technology Data Exchange (ETDEWEB)

Uysal, Mehmet, E-mail: mehmetu@sakarya.edu.tr; Cetinkaya, Tugrul; Alp, Ahmet; Akbulut, Hatem

2015-04-15

Highlights: • Sn–Ni/MWCNT composite electrodes prepared by pulse electrodeposition at different duty cycle. • The effect of duty cycle studied on electrochemical properties of composite electrodes. • A high reversible capacity, and good cyclability were achieved for Sn–Ni/MWNT (75% duty cycle). - Abstract: Nanocrystalline Sn–Ni/MWCNT composite was prepared by ultrasonic-pulse electrodeposition on a copper substrate in a pyrophosphate bath at different duty cycles. Surface morphology of produced Sn–Ni/MWCNT composites were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) was conducted to understand the elemental surface composition of composites. X-ray diffraction analysis (XRD) was carried out to investigate structure of Sn–Ni/MWCNT composites. The electrochemical performance of Sn–Ni/MWCNT composite electrodes were investigated by charge/discharge tests and cyclic voltammetric experiments. The cells discharge capacities were determined by cyclic testing by a battery tester at a constant current in voltage range between 0.02 V and 1.5 V. The duty cycle was shown to be a crucial factor to improve Sn–Ni/MWCNT composite anodes for cyclability and reversible capacity.

Nanotextured Spikes of α-Fe2O3/NiFe2O4 Composite for Efficient Photoelectrochemical Oxidation of Water.

Science.gov (United States)

Hussain, Shabeeb; Tavakoli, Mohammad Mahdi; Waleed, Aashir; Virk, Umar Siddique; Yang, Shihe; Waseem, Amir; Fan, Zhiyong; Nadeem, Muhammad Arif

2018-03-27

We demonstrate for the first time the application of p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe 2 O 4 and Fe 2 O 3 ) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe 2 O 4 /n-Fe 2 O 3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured p-NiFe 2 O 4 /n-Fe 2 O 3 device with equal molar 1:1 ratio of NiFe 2 O 4 and Fe 2 O 3 was found to be highly efficient for PEC water oxidation as compared with pure hematite, 1:2 and 1:3 molar ratios of composite. The photocurrent density of 1:1 composite thin film on planar substrate was equal to 1.07 mA/cm 2 at 1.23 V RHE , which was 1.7 times higher current density as compared with pure hematite device (0.63 mA/cm 2 at 1.23 V RHE ). The performance of p-NiFe 2 O 4 /n-Fe 2 O 3 composites in PEC water oxidation was further enhanced by their deposition over 3D-NSP substrate. The highest photocurrent density of 2.1 mA/cm 2 at 1.23 V RHE was obtained for the 1:1 molar ratio p-NiFe 2 O 4 /n-Fe 2 O 3 composite on NSP (NF1-NSP), which was 3.3 times more photocurrent density than pure hematite. The measured applied bias photon-to-current efficiency (ABPE) value of NF1-NSP (0.206%) was found to be 1.87 times higher than that of NF1-P (0.11%) and 4.7 times higher than that of pure hematite deposited on FTO-coated glass (0.044%). The higher PEC water oxidation activity of p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin film as compared with pure hematite is attributed to the Z-path scheme and better separation of electrons and holes. The increased surface area and greater light

Ionic Liquid-Assisted Synthesis of a NiO/CNTs Composite and Its Electrochemical Capacitance

Directory of Open Access Journals (Sweden)

Yitong Chen

2014-01-01

Full Text Available A novel solid-state method has been developed for synthesizing nickel oxide (NiO/carbon nanotubes (CNTs composite using an ionic liquid (IL, 1-butyl-3-methylimidazolium chloride as the reaction medium. Ultraviolet-visible (UV-vis absorbance spectroscopy, infrared spectroscopy (IR, and scanning electron microscopy (SEM were employed to investigate the structure, morphology, and formation mechanism of the synthesized sample. The results demonstrated that the IL is effective for dispersing CNTs, which allows the tethering of nickel (II ions onto the surfaces of the CNTs and facilitates the subsequent chemical deposition of NiO to obtain the NiO/CNTs composite. The electrochemical properties of the composite were determined using cyclic voltammetry and galvanostatic charge/discharge measurements in 6 M KOH. Because of its unique structure, the prepared NiO/CNTs electrode exhibited good capacitive behavior and cyclability. The high specific capacitance (521 F g−1 and good rate capability (91% capacity retention at 0.5 A g−1 of the NiO/CNTs composite enable its use as a practical supercapacitor electrode material.

In-situ studies of the TGO growth stresses and the martensitic transformation in the B2 phase in commercial Pt-modified NiAl and NiCoCrAlY bond coat alloys

Energy Technology Data Exchange (ETDEWEB)

Hovis, D.; Hu, L.; Reddy, A.; Heuer, A.H. [Dept. of Materials Science and Engineering, Case Western Reserve Univ., Cleveland, OH (United States); Paulikas, A.P.; Veal, B.W. [Materials Science Div., Argonne National Lab., Argonne, IL (United States)

2007-12-15

Oxide growth stresses were measured in situ at 1100 C on commercial Pt-modified NiAl and NiCoCrAlY bond coat alloys using synchrotron X-rays. Measurements were taken on samples that had no preoxidation, as well as on samples that had experienced 24 one-hour thermal exposures at 1150 C, a condition known to induce rumpling in the Pt-modified NiAl alloy, but not in the NiCoCrAlY alloy. The NiCoCrAlY alloy showed continuous stress relaxation under all conditions, whereas the Pt-modified NiAl alloys would typically stabilize at a fixed (often non-zero) stress suggesting a higher creep strength in the 'Thermally Grown Oxide' on the latter alloy, though the precise behavior was dependent on initial surface preparation. The formation of martensite in the Pt-modified NiAl alloys was also observed upon cooling and occurred at temperatures below 200 C for all of the samples observed. Based on existing models, this M{sub s} temperature is too low to account for the rumpling observed in these alloys. (orig.)

Synthesis and densification of Cu-coated Ni-based amorphous composite powders

International Nuclear Information System (INIS)

Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

2007-01-01

Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv

Microstructure and Properties of Ni and Ni/Al2O3 Coatings Electrodeposited at Various Current Densities

Directory of Open Access Journals (Sweden)

Góral A.

2016-03-01

Full Text Available The study presents investigations of an influence of various direct current densities on microstructure, residual stresses, texture, microhardness and corrosion resistance of the nickel coatings electrodeposited from modified Watt’s baths. The properties of obtained coatings were compared to the nano-crystalline composite Ni/Al2O3 coatings prepared under the same plating conditions. The similarities and differences of the obtained coatings microstructures visible on both their surfaces and cross sections and determined properties were presented. The differences in the growth character of the Ni matrix and in the microstructural properties were observed. All electrodeposited Ni and Ni/Al2O3 coatings were compact and well adhering to the steel substrates. The thickness and the microhardness of the Ni and Ni/Al2O3 deposits increased significantly with the current density in the range 2 - 6 A/dm2. Residual stresses are tensile and they reduced as the current density increased. The composite coatings revealed better protection from the corrosion of steel substrate than pure nickel in solution 1 M NaCl.

Influence of interfacial reactions on the fiber push-out behavior in sapphire fiber-reinforced-NiAl(Yb) composites

International Nuclear Information System (INIS)

Tewari, S.N.; Asthana, R.; Tiwari, R.; Bowman, R.R.

1993-01-01

The influence of microstructure of the fiber-matrix interface on the fiber push-out behavior has been examined in sapphire fiber-reinforced NiAl and NiAl(Yb) matrix composites synthesized using powder metallurgy techniques combined with zone directional solidification (DS). The push-out stress-displacement curves were observed to consist of an initial 'pseudoelastic' region, wherein the stress increased linearly with displacement, followed by an 'inelastic' region, where the slope of the stress-displacement plot decreased until a maximum stress was reached, and the subsequent stress drop to a constant 'frictional' stress. Chemical reaction between the fiber and the matrix resulted in higher interfacial shear strength in powder cloth processed sapphire-NiAl(Yb) composites as compared to the sapphire-NiAl composites. Grain boundaries in contact with the fibers on the back face of the push-out samples were the preferred sites for crack nucleation in PM composites. The frictional stress was independent of the microstructure and processing variables for NiAl composites, but showed strong dependence on these variables for the NiAl(Yb) composites. The DS processing enhanced the fiber-matrix interfacial shear strength of feedstock PM-NiAl/sapphire composites. However, it reduced the interfacial shear strength of PM-NiAl(Yb)-sapphire composites

Density of Liquid Ni-Mo Alloys Measured by a Modified Sessile Drop Method

Institute of Scientific and Technical Information of China (English)

Liang FANG; Zushu LI; ZaiNan TAO; Feng XIAO

2004-01-01

The density of liquid binary Ni-Mo alloys with molybdenum concentration from 0 to 20% (mass fraction) was measured by a modified sessile drop method. It has been found that the density of the liquid Ni-Mo alloys decreases with increasing temperature, but increases with the increase of molybdenum concentration in the alloys. The molar volume of liquid Ni-Mo binary alloys increases with the increase of temperature and molybdenum concentration. The partial molar volume of molybdenum in Ni-Mo binary alloy has been approximately calculated as [13.18 - 2.65 × 10-3T + (-47.94 + 3.10 × 10-2T) × 10-2XMo] × 10-6m3·mol-1. The molar volume of Ni-Mo alloy determined in the present work shows a negative deviation from the ideal linear mixing molar volume.

Improving tribological properties of (Zn–Ni)/nano Al{sub 2}O{sub 3} composite coatings produced by ultrasonic assisted pulse plating

Energy Technology Data Exchange (ETDEWEB)

Ataie, Sayed Alireza, E-mail: ataie_s_alireza@metaleng.iust.ac.ir; Zakeri, Alireza

2016-07-25

In this study pulse electroplating was used to deposit the composite coating of (Zn–Ni) strengthened by Al{sub 2}O{sub 3} nanoparticles on mild steel plate. The effect of Al{sub 2}O{sub 3} fraction and ultrasonic irradiation on the properties of the composite coating was also investigated. Scanning electron microscopy and energy dispersive spectroscopy techniques were employed to characterize the morphology and composition of the coating. Topography and surface roughness were investigated by atomic force microscopy. Also in order to evaluate the mechanical properties of the coating micro hardness and wear tests were conducted. It was found that coating hardness was increased from 538 HV to 750 HV and friction coefficient was decreased from 0.588 to 0.392. Results revealed that tribological properties of coating could be improved significantly by using suitable ultrasonic intensity simultaneously with pulse plating. - Highlights: • SEM indicated on the elimination of cracks and pores when ultrasounds were used. • XRD result showed nano sized grains of Zn–Ni matrix was developed in this research. • Simultaneous pulse plating and ultrasonic conditions improved the properties of the coating. • A (Zn–Ni)/nano alumina uniform composite coating for especial applications was developed. • Micro hardness and wear behavior of the coating was modified by intensifying the ultrasound.

Microstructural characterization of HIP consolidated NiTi–nano Al{sub 2}O{sub 3} composites

Energy Technology Data Exchange (ETDEWEB)

Farvizi, M., E-mail: mmfarvizi@yahoo.com [Ceramic Division, Materials and Energy Research Center, P.O. Box 14155-4777, Tehran (Iran, Islamic Republic of); Ebadzadeh, T. [Ceramic Division, Materials and Energy Research Center, P.O. Box 14155-4777, Tehran (Iran, Islamic Republic of); Vaezi, M.R. [Nanotechnology and Advanced Materials Division, Materials and Energy Research Center, P.O. Box 14155-4777, Tehran (Iran, Islamic Republic of); Yoon, E.Y.; Kim, Y-J. [Korea Institute of Materials Science, Changwon 642-831 (Korea, Republic of); Kim, H.S. [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Simchi, A. [Department of Materials Science and Engineering and Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 11365-9466, Tehran (Iran, Islamic Republic of)

2014-09-01

Highlights: • NiTi–6 wt.% nano α-Al{sub 2}O{sub 3} composites have been produced using a HIP method. • Both elemental and prealloyed powders were used for the fabrication of composites. • Generation of mismatch stress and intermetallics affected martensitic transformation. • Nanoparticles partially inhibited thermally induced martensitic transformation. • An interwoven austenite–martensite structure was observed in the composite samples. - Abstract: The microstructure and phase transformational behavior of NiTi-based composites reinforced with 6 wt.% of α-alumina nanoparticles have been investigated. Two kinds of starting materials, elemental Ni–Ti and prealloyed austenitic NiTi, were used to prepare the composites. The samples were consolidated using a hot isostatic pressing method. The X-ray diffraction results showed that while unreinforced NiTi mainly contained B2 phase at room temperature, martensitic B19′ phase appeared in the microstructure after addition of the α-alumina nanoparticles. The differential scanning calorimetry measurements indicated that the martensitic transformation temperatures were elevated in the composite samples, but the transformational enthalpy was reduced in comparison with the NiTi sample. It is believed that the generation of thermal mismatch stress during the sintering and the formation of small contents of NiTi{sub 2}/Ni{sub 3}Ti intermetallics in the composite samples are responsible for this increment of the martensitic transformation temperatures. Also, due to the nanometric size of α-Al{sub 2}O{sub 3}, a larger fraction of the matrix is disturbed by the presence of the nanoparticles, which yields the formation of effective barriers to the thermally induced martensitic transformation in the nanocomposite samples. The high-resolution transmission electron microscopy studies of the samples confirmed the higher defect density and partial microplastic deformation in the composite samples.

Functional properties of electrospun NiO/RuO{sub 2} composite carbon nanofibers

Energy Technology Data Exchange (ETDEWEB)

Wu Yongzhi [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Physics Department, National University of Singapore, Singapore 117542 (Singapore); NUS Graduate School for Integrated Science and Engineering, 10 Kent Ridge Crescent, National University of Singapore, Singapore 119260 (Singapore); Balakrishna, Rajiv [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Physics Department, National University of Singapore, Singapore 117542 (Singapore); Reddy, M.V., E-mail: phymvv@nus.edu.sg [Physics Department, National University of Singapore, Singapore 117542 (Singapore); Nair, A. Sreekumaran, E-mail: nniansn@nus.edu.sg [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Chowdari, B.V.R. [Physics Department, National University of Singapore, Singapore 117542 (Singapore); Ramakrishna, S. [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Kind Saud University, Riyadh 11451 (Saudi Arabia)

2012-03-15

Highlights: Black-Right-Pointing-Pointer Fabrication of carbon nanofibers with nickel-ruthenium composites by electrospinning. Black-Right-Pointing-Pointer An interesting observation of increase in capacitance with increase in the number of cycles for supercapacitor applications. Black-Right-Pointing-Pointer Li ion battery testing showed a stable capacity ranging from 350 mAh g{sup -1} to 400 mAh g{sup -1}. Black-Right-Pointing-Pointer Lower impedance with the incorporation of 15 wt% Ru precursor than those without Ru. - Abstract: One-dimensional (1D) nickel oxide/ruthenium oxide (NiO/RuO{sub 2})-carbon composite nanofibers (NiRu-C-NFs) were fabricated via electrospinning of a homogenous mixture of polyacrylonitrile (PAN) and Ni/Ru salt precursors at different ratios followed by heat treatments. The 1D nanostructures of the composite material were characterized by field-emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), Rietveld refinement and Brunauer-Emmett-Teller (BET) surface area measurements. Li-cycling properties were evaluated using cyclic voltammetry and galvanostatic properties. The asymmetric hybrid supercapacitor studies were carried out with activated carbon as a cathode and NiRu-C-NFs composites as anodes in the cycling range, 0.005-3.0 V using 1 M LiPF{sub 6} (EC;DMC) electrolyte. NiRu-C-NFs fabricated from 5 wt% nickel (II) and 15 wt% ruthenium (III) precursors showed a capacitance up to {approx}60 F g{sup -1} after 30 cycles. Anodic Li-cycling studies of NiRu-C-NF-0 and NiRu-C-NF-2 composite samples showed a reversible capacity of 230 and 350 m Ahg{sup -1} at current rate of 72 mA g{sup -1} at the end of 40th cycle in the voltage range of 0.005-3.0 V. Electrochemical impedance studies (EIS) on NiRu-C-NFs showed lower impedance value for 15 wt% Ru than the bare sample.

One-pot synthesis of NiO/C composite nanoparticles as anode materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lipeng, E-mail: lipeng.zhang@jcu.edu.au [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China); College of Science, Technology and Engineering, James Cook University, Douglas, Queensland 4811 (Australia); Mu, Jiechen; Wang, Zhao; Li, Guomin; Zhang, Yanling [School of Chemical Engineering, Shandong University of Technology, Zibo 255049 (China); He, Yinghe, E-mail: yinghe.he@jcu.edu.au [College of Science, Technology and Engineering, James Cook University, Douglas, Queensland 4811 (Australia)

2016-06-25

Nanostructured NiO/C composite particles with controlled carbon content for lithium-ion battery anode were prepared via a one-pot hydrothermal approach and subsequent calcination in a high purity nitrogen atmosphere. The composites were composed of amorphous carbon and nanocrystalline NiO. The structure of the NiO crystals was determined with X-ray diffraction (XRD) analysis and the content of carbon was calculated from the energy dispersive spectroscopy (EDS) results. Scanning electron microscopy (SEM) images showed a relatively narrow distribution of particle size for both the neat NiO and NiO/C nanoparticles. Electrochemical performance measurements demonstrated that, after 50 cycles, NiO/C nanocomposites maintained a high reversible capacity of 585.9 mAh g{sup −1}, much higher than that of 356.1 mAh g{sup −1} of the neat NiO nanoparticles without carbon. The NiO/C nanoparticles also exhibited a remarkable discharge capacity, a high charge/discharge rate and an excellent cycle stability. The improvements can be attributed to the even carbon coating on the NiO particles, which significantly enhances the conductivity and improves the structural stability of the electrode. - Highlights: • NiO/C nanocomposite material is prepared via a one-pot hydrothermal approach. • Both NiO and NiO/C composite have a narrow particle size distribution. • Carbon in the NiO/C enhanced the conductivity and suppressed particle aggregation. • NiO/C composites maintained a reversible capacity of 585.9 mAh g{sup −1} after 50 cycles.

Synthesis, characterization, and photocatalytic properties of Ni12P5 hollow microspheres

Science.gov (United States)

Liu, Shuling; Han, Xiaoli; Zhang, Hongzhe; Liu, Hui

2017-05-01

Ni12P5 hollow microspheres were prepared by a simple mixed cetyltrimethyl ammonium bromide/sodium dodecyl sulfate surfactant-assisted hydrothermal route. The as-prepared Ni12P5 microstructures were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). It was interesting to find that cetyltrimethyl ammonium bromide/sodium dodecyl sulfate could form a micro-reactor by the mixed micelles in the aqueous solution, which served as a soft template for Ni12P5 hollow microspheres with a diameter of 2 6 μm. Moreover, the as-prepared Ni12P5 hollow microspheres exhibited a good photocatalytic degradation activity for some organic dyes (such as Rhodamine B, Methylene Blue, Pyronine B, and Safranine T), and the degradation ratio could achieve more than 80%.

Effect of cold rolling on fatigue crack propagation of TiNi/A16061 shape memory composite

International Nuclear Information System (INIS)

Lee, Jin Kyung; Lee, Sang Pill; Park, Young Chul; Lee, Kyu Chang; Cho, Youn Ho; Lee, Joon Hyun

2005-01-01

TiNi alloy fiber was used to recover the original shape of materials using its shape memory effect. The shape memory alloy plays an important role within the metal matrix composite. The shape memory alloy can control the crack propagation in metal matrix composite, and improve the tensile strength of the composite. In this study, TiNi/A16061 Shape Memory Alloy(SMA) composite was fabricated by hot press method, and pressed by a roller for its strength improvement. The four kinds of specimens were fabricated with 0%, 3.2%, 5.2% and 7% volume fraction of TiNi alloy fiber, respectively. A fatigue test has performed to evaluate the crack initiation and propagation for the TiNi/A16061 SMA composite fabricated by this method. In order to study the shape memory effect of the TiNi alloy fiber, the test has also done under both conditions of the room temperature and high temperature. The relationship between the crack growth rate and the stress intensity factor was clarified for the composite, and the cold rolling effect was also studied

Perovskite-Ni composite: a potential route for management of radioactive metallic waste.

Science.gov (United States)

Mahadik, Pooja Sawant; Sengupta, Pranesh; Halder, Rumu; Abraham, G; Dey, G K

2015-04-28

Management of nickel - based radioactive metallic wastes is a difficult issue. To arrest the release of hazardous material to the environment it is proposed to develop perovskite coating for the metallic wastes. Polycrystalline BaCe0.8Y0.2O3-δ perovskite with orthorhombic structure has been synthesized by sol-gel route. Crystallographic analyses show, the perovskite belong to orthorhombic Pmcn space group at room temperature, and gets converted to orthorhombic Incn space group at 623K, cubic Pm3m space group (with a=4.434Å) at 1173K and again orthorhombic Pmcn space group at room temperature after cooling. Similar observations have been made from micro-Raman study as well. Microstructural studies of BaCe0.8Y0.2O3-δ-NiO/Ni composites showed absence of any reaction product at the interface. This suggests that both the components (i.e. perovskite and NiO/Ni) of the composite are compatible to each other. Interaction of BaCe0.8Y0.2O3-δ-NiO/Ni composites with simulated barium borosilicate waste glass melt also did not reveal any reaction product at the interfaces. Importantly, uranium from the waste glass melt was found to be partitioned within BaCe0.8Y0.2O3-δ perovskite structure. It is therefore concluded that BaCe0.8Y0.2O3-δ can be considered as a good coating material for management of radioactive Ni based metallic wastes. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and electrochemical properties of composite galvanic Ni with carbon nanomaterials and PVD Mo coatings

International Nuclear Information System (INIS)

Drozdovich, V.B.; Chayeuski, V.V.; Zhdanok, S.A.; Barkovskaya, M.M.

2011-01-01

Double layer coatings Ni – Mo were obtained by electrolytic deposition of galvanic Ni and following arc PVD deposition of molybdenum. The ion plating coatings Mo on Ni foil and composition electrolytic Ni coatings with carbon nanomaterials (CNM) deposited on mild steel has been also investigated. Composite galvanic Ni coatings with CNM and ion plating coatings Mo contain separately obtained cubic α-Mo phase as well as fragmentary solid solution Mo in Ni. Such coatings exclude hydrogenation of Ni foundation in alkaline solution and possess enlarged electrocatalytic properties while emitting hydrogen and oxygen. Availability of carbon based nanomaterials in combined coatings is cause of an active absorption hydrogen after cathodic polarization. A formation on the surface layer of nanostructure solid solution (Ni, Mo) after compression plasma flows treatment with fixed parameters of patterns Mo/Ni/ mild steel take place. (authors)

Composition dependency of the glass forming ability (GFA) in Mg-Ni-Si system by mechanical alloying

International Nuclear Information System (INIS)

Xie Haowen; Lin Jianguo; Li Yuncang; Hodgson, Peter D.; Wen Cuie

2007-01-01

The pure elemental powder mixtures with the compositions of Mg 65 Ni x Si 35-x (x = 10, 20, 25, 33 at.%) were subject to high-energy ball mill, and the structures of the mixtures at different intervals of milling were characterised by X-ray diffraction (XRD). The compositional dependency of the glass forming ability (GFA) in Mg-Ni-Si system was evaluated based on the experimental results and the theoretical calculation. The compositional dependency of GFA in Mg-Ni-Si system can be understood well by comparing the enthalpies of the crystalline and amorphous phases based on the Miedema's theory for the formation enthalpy of alloys. Increasing the Ni/Mg ratio and/or decreasing Si content can improve the amorphous formability. The calculation results might be of great help in optimising the composition with high GFA in Mg-Ni-Si system

Silver effect of Co–Ni composite material on energy storage and structural behavior for Li-ion batteries

International Nuclear Information System (INIS)

Gnanamuthu, RM.; Prasanna, K.; Subburaj, T.; Jo, Yong Nam; Lee, Chang Woo

2013-01-01

Ag powder has been comparatively applied to the Co–Ni materials preparing by mixing method and the prepared electrodes were used as negative electrodes for Li-ion batteries applications. The prepared Co–Ni and Ag–Co–Ni with 10 wt.% of Ag composite electrodes are characterized by XRD, FE-SEM with EDX, impedance and electrochemical charge-discharge studies. These electrochemical studies are demonstrated at current rates of 0.1 C and 0.5 C between 0.01 and 2.0 V vs. Li/Li + . The porous Co–Ni and Ag–Co–Ni composite materials are electrochemically tested in lithium half cells. The porous Ag–Co–Ni composite material demonstrates that the initial and end of discharge capacity up to 20th cycles is, respectively, 860 and 715 mAh g −1 at 0.1 C rate maintaining at approximately 83%. The porous Ag–Co–Ni composite electrode may be a good candidate for high power lithium-ion batteries.

Microstructure and erosive wear behaviors of Ti6Al4V alloy treated by plasma Ni alloying

Energy Technology Data Exchange (ETDEWEB)

Wang, Z.X.; Wu, H.R.; Shan, X.L.; Lin, N.M.; He, Z.Y., E-mail: tyuthzy@126.com; Liu, X.P.

2016-12-01

Graphical abstract: The Ni modified layers were prepared on the surface of Ti6Al4V substrate by the plasma surface alloying technique. The surface and cross-section morphology, element concentration and phase composition were investigated by thermal field emission scanning electron microscopy (SEM), and glow discharge optical emission spectroscopy (GDOES), X-ray diffraction (XRD), respectively. The cross-section nano-scale hardness of Ni modified layer was measured by nano indenter. The results showed that Ni modified layers exhibited triple layers structure and continuous gradient distribution of the concentration. From the surface to the matrix, they were 2 μm Ni deposition layer, 8 μm Ni-rich alloying layer including the phases of Ni{sub 3}Ti, NiTi, Ti{sub 2}Ni, AlNi{sub 3} and 24 μm Ni-poor alloying layer forming the solid solution of nickel. With increasing of the thickness of Ni modified layer, the microhardness increased first, reached the climax, then gradient decreased. The erosion tests were performed on the surface of the untreated and treated Ti6Al4V sample using MSE (Micro-slurry-jet Erosion) method. The experiment results showed that the wear rate of every layer showed different value, and the Ni-rich alloying layer was the lowest. The strengthening mechanism of Ni modified layer was also discussed. - Highlights: • The Ni modified layers were prepared by the plasma surface alloying technique. • Triple layers structure was prepared. • Using Micro-slurry-jet Erosion method. • The erosion rate of Ni modified layer experienced the process of descending first and then ascending. • Improvement of erosion resistance performance of Ni-rich alloying layer was prominent. The wear mechanism of Ni modified layer showed micro-cutting wearing. - Abstract: The Ni modified layers were prepared on the surface of Ti6Al4V substrate by the plasma surface alloying technique. The surface and cross-section morphology, element concentration and phase composition

Facile synthesis of MnO{sub 2}/rGO/Ni composite foam with excellent pseudocapacitive behavior for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Sun, Youyi; Zhang, Wenhui [Research Center for Engineering Technology of Polymeric Composites of Shanxi Province, North University of China, Taiyuan 030051 (China); Li, Diansen [Key Laboratory of Bio-Inspired Energy Materials and Devices, School of Chemistry and Environment, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Gao, Li; Hou, Chunlin [Research Center for Engineering Technology of Polymeric Composites of Shanxi Province, North University of China, Taiyuan 030051 (China); Zhang, Yinghe [International Center for Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Liu, Yaqing, E-mail: lyqzgz2010@163.com [Research Center for Engineering Technology of Polymeric Composites of Shanxi Province, North University of China, Taiyuan 030051 (China)

2015-11-15

In this study, the MnO{sub 2}/reduced graphene oxide/Ni (MnO{sub 2}/rGO/Ni) composite foam as a binder-free supercapacitor electrode was prepared by a facile method. The rGO film has been firstly coated on the skeletons of Ni foam current collectors by chemical deposition method and that have been used as substrates for preparation of a novel three dimensional rGO/Ni composite foam-supported porous MnO{sub 2} film by the hydrothermal method. The structure of MnO{sub 2}/rGO/Ni composite foam was characterized by Raman spectra, IR spectra and Scanning electron microscopy. It indicated that the high-quality rGO film have been coated on skeletons of Ni foam current collectors and the MnO{sub 2} film had a 3D network microstructure, consisting of interlaced nanosheets. Furthermore, the binder-free MnO{sub 2}/rGO/Ni composite foam electrode has been characterized by the cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectra. It exhibited excellent pseudocapacitive behavior with specific capacitance of 479.0 F/g. The capacitance could retain about 83.5% after 1000 charge–discharge cycles. This simple synthetic approach provides a convenient route for the large scale preparation of 3D porous MnO{sub 2}/rGO/Ni composite foam for lots of applications in future. - Graphical abstract: The MnO{sub 2}/rGO/Ni composite foam was prepared by a facile method as shown in Fig. 1 and the unique structure of composite foam was suited to be a binder-free supercapacitor electrode due to low resistance, 3D network and porous structure. - Highlights: • The MnO{sub 2}/rGO directly grown on Ni foam was firstly reported. • The MnO{sub 2}/rGO/Ni composite foam was prepared by a facile method. • The MnO{sub 2}/graphene/Ni composite foam as a binder-free supercapacitor electrode exhibited excellent pseudocapacitive behavior.

Morphology and chemical composition of Cu/Sn/Cu and Cu(5 at-%Ni)/Sn/Cu(5 at-%Ni) interconnections

NARCIS (Netherlands)

Wierzbicka-Miernik, A.; Wojewoda-Budka, J.; Litynska-Dobrzynska, L.; Kodentsov, A.; Zieba, P.

2012-01-01

In the present paper, scanning and transmission electron microscopies as well as energy dispersive X-ray spectroscopy investigations were performed to describe the morphology and chemical composition of the intermetallic phases growing in Cu/Sn/Cu and Cu(Ni)/Sn/Cu(Ni) interconnections during the

Compressive Properties of PTFE/Al/Ni Composite Under Uniaxial Loading

Science.gov (United States)

Wang, Huai-xi; Li, Yu-chun; Feng, Bin; Huang, Jun-yi; Zhang, Sheng; Fang, Xiang

2017-05-01

To investigate the mechanical properties of pressed and sintered PTFE/Al/Ni (polytetrafluoroethylene/aluminum/nickel) composite, uniaxial quasi-static and dynamic compression experiments were conducted at strain rates from 10-2 to 3 × 103/s. The prepared samples were tested by an electrohydraulic press with 300 kN loading capacity and a split Hopkinson pressure bar (SHPB) device at room temperature. Experimental results show that PTFE/Al/Ni composite exhibits evident strain hardening and strain rate hardening. Additionally, a bilinear relationship between stress and {{log(}}\\dot{ɛ} ) is observed. The experimental data were fit to Johnson-Cook constitutive model, and the results are in well agreement with measured data.

Composite Ni-Co-fly ash coatings on 5083 aluminium alloy

Energy Technology Data Exchange (ETDEWEB)

Panagopoulos, C.N., E-mail: chpanag@metal.ntua.gr [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece); Georgiou, E.P.; Tsopani, A.; Piperi, L. [Laboratory of Physical Metallurgy, National Technical University of Athens, Zografos, 15780 Athens (Greece)

2011-03-15

Ni-Co-fly ash coatings were deposited on zincate treated 5083 wrought aluminium alloy substrates with the aid of the electrodeposition technique. Structural and chemical characterization of the produced composite coatings was performed with the aid of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron dispersive X-ray analysis (EDS) techniques. The Ni-Co-fly ash coatings were found to consist of a crystalline Ni-Co solid solution with dispersed fly ash particles. In addition, chemical analysis of the Ni-Co matrix showed that it consisted of 80 wt.% Ni and 20 wt.% Co. The co-deposition of fly ash particles leads to a significant increase of the microhardness of the coating. The corrosion behaviour of the Ni-Co-fly ash/zincate coated aluminium alloy, in a 0.3 M NaCl solution (pH = 3.5), was studied by means of potentiodynamic corrosion experiments.

Microstructure and kinetics of a functionally graded NiTi-TiC x composite produced by combustion synthesis

International Nuclear Information System (INIS)

Burkes, Douglas E.; Moore, John J.

2007-01-01

Production of a NiTi-TiC x functionally graded material (FGM) composite is possible through use of a combustion synthesis (CS) reaction employing the propagating mode (SHS). The NiTi-TiC x FGM combines the well-known and understood superelastic and shape memory capabilities of NiTi with the high hardness, wear and corrosion resistance of TiC x . The material layers were observed as functionally graded both in composition and porosity with distinct interfaces, while still maintaining good material interaction and bonding. XRD of the FGM composite revealed the presence of TiC x with equi-atomic NiTi and minor NiTi 2 and NiTi 3 phases. The TiC x particle size decreased with increasing NiTi content. Microindentation performed across the length of the FGM revealed a decrease in hardness as the NiTi content increased

Influence of Ni(II) and Fe(III) complexes of 1,2 dihydroxy 9,10 anthraquinone on the modification in calf thymus DNA upon gamma irradiation

International Nuclear Information System (INIS)

Das, Saurabh; Mandal, Parikshit C.

2009-01-01

Ionizing radiation when allowed to fall upon cells or DNA, the radicals produced modify the base-pair region of the double strands. Radiation-induced double-strand modifications in calf thymus DNA were detected using Ni(II) and Fe(III) complexes of 1,2 dihydroxy 9,10 anthraquinone (DHA). 60 Co was used as the source for γ-radiation and ethidium bromide (EB) as the fluorescent dye for detecting double-strand modifications caused in DNA. Results show that the Fe(III)-DHA complex is more efficient in modifying the base-pair region in double-stranded DNA in comparison to DHA or the Ni(II)-DHA complex

Electrospun NiO, ZnO and composite NiO–ZnO nanofibers/photocatalytic degradation of dairy effluent

DEFF Research Database (Denmark)

Kanjwal, Muzafar Ahmad; Chronakis, Ioannis S.; Barakat, Nasser A.M.

2015-01-01

Among the food wastes, the dairy effluent (DE) is considered to be the most polluting one because of the large volume of wastewater generated and its high organic load. Photocatalytic degradation of DE and organic dye methylene blue (MB) was studied using Zinc oxide nanofibers (ZnO NFs), Nickel....... The significant enhancement of degradation in the composite ZnO–NiO NFs is attributed to the photoactivity of material under visible light irradiation. The composite ZnO–NiO NFs eliminated 40% of DE and 65% of MB dye, after 1h and maximum degradation of 80% DE after 3h and 100% MB dye after 90min. Overall...

Fabrication and Characterization of Ni-CNT Composites by Electrical Explosion of Wire in Different Liquids

Directory of Open Access Journals (Sweden)

Thuyet-Nguyen M.

2017-06-01

Full Text Available In this study, Ni-CNT powders and colloids were synthesized via the Electrical explosion of wire (EEW in different liquid conditions. The influence of ambient solvents (D.I. Water, ethanol, methanol, acetone and ethylene-glycol on characteristics of the as-synthesized Ni-CNT was investigated. The morphology and size were observed by field emission scanning electron microscopy (FE-SEM. The Ni particles were spherical or near spherical shape. The phase of the composite powders analyzed via X-ray diffraction demonstrate the presence of CNTs in composite powders is not affect the structure of Ni. However, the phase of the composites was changed based on the changing of liquid conditions. Stability of colloids was investigated by Turbiscan technique. Magnetic properties were also investigated by Vibrating sample magnetometer (VSM at room temperature. The as-synthesized composite powders revealed a ferromagnetic characteristic material.

The Technology and Properties of Digital Double Pulse Electrodepositing Ni-HA Composite Coating of Bioceramics

Institute of Scientific and Technical Information of China (English)

DONG He-yan; WANG Zhou; SHI Gu-guizhi; FU Chuan-qi; CHEN Wei-rong; JIN Zhong-hong; LI Yan

2004-01-01

This article discusses and analyses the technology, the surface image, microstructure and ability of digital double pulse electrodepositing Ni-HA composite coatings of bioceramics made on 1Crl8Ni9Ti substrate by SEM ,XRD and so on. The results shows that ( 1 ) the HA particles exit in substrate uniformly; (2) XRD result shows that there are HA peaks at 78. 023 ° ,43. 246°and 73. 120°differently; (3) The microhardnees of the composite coatings is increased with the rise of content of HA particles, and on the same conditions the microhardnees value is greater than that of common non-pulse electrodepositing Ni-HA composite coatings of bioceramics. (4) The grain size of digital double pulse electrodepositing Ni-HA composite coatings of bioceramics is much thinner than that of common D. C.

Nickel coated flyash (Ni-FAC) cenosphere doped polyaniline composite film for electromagnetic shielding

International Nuclear Information System (INIS)

Bora, Pritom J; Ramamurthy, Praveen C; Madras, Giridhar; Vinoy, K J; Kishore

2015-01-01

A solid waste material fly ash cenosphere (FAC) was nickel coated and polyaniline in situ polymerized at −30 ± 2 °C in nitrogen atmosphere. A thin film of this composite material was prepared by solution processing and surface morphology/topography was studied. High electromagnetic shielding effectiveness (SE) was obtained for this film; 59 ± 4 μm and 133 ± 4 μm films show an average of 38 and 60 dB SE, respectively, in the frequency range 8.2–12.4 GHz (X-band). Unlike PANI film, the SE of these composite films is high at high frequency. The presence of magneto dielectric microsphere (Ni-FAC) increases the heterogeneity of the composite film in an efficient way for EMI shielding by changing film topography and increasing ac conductivity and permeability. (paper)

Preparation of NiFe₂O₄/graphene nanocomposite and its application as a modifier for the fabrication of an electrochemical sensor for the simultaneous determination of tramadol and acetaminophen

Energy Technology Data Exchange (ETDEWEB)

Afkhami, Abbas, E-mail: afkhami@basu.ac.ir [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Khoshsafar, Hosein [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of); Bagheri, Hasan [Chemical Injuries Research Center, Baqiyatallah University of Medical Sciences, Tehran (Iran, Islamic Republic of); Madrakian, Tayyebeh [Faculty of Chemistry, Bu-Ali Sina University, Hamedan (Iran, Islamic Republic of)

2014-06-01

Highlights: • A new modified electrochemical sensor was constructed and used. • NiFe₂O₄/graphene was used as the modifier. • The sensor was used for the determination of tramadol and acetaminophen in real samples. • Modification improved the sensitivity and detection limit of the method. • The oxidation of tramadol and acetaminophen at the surface of the electrode was studied. Abstract: An effective electrochemical sensor for the rapid and simultaneous determination of tramadol and acetaminophen based on carbon paste electrode (CPE) modified with NiFe₂O₄/graphene nanoparticles was developed. The structures of the synthesized NiFe₂O₄/graphene nanocomposite and the electrode composition were confirmed by X-ray diffraction (XRD) spectrometry, Fourier transform infrared (FT-IR) spectrometry and scanning electron microscopy (SEM). The peak currents of square wave voltammetry of tramadol and acetaminophen increased linearly with their concentration in the range of 0.01–9 μmol L⁻¹. The detection limit for their determination was found to be 0.0036 and 0.0030 μmol L⁻¹, respectively. The results show that the combination of graphene and NiFe₂O₄ nanoparticles causes a dramatic enhancement in the sensitivity of the sensor. The fabricated sensor exhibited high sensitivity and good stability, and would be valuable for the clinical assay of tramadol and acetaminophen.

Microstructural response of an Al-modified Ni-Cr-Fe ternary alloy during thermal processing

Energy Technology Data Exchange (ETDEWEB)

Akinlade, D.A. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, MB (Canada)], E-mail: dotun172@yahoo.co.uk; Caley, W.F. [Department of Process Engineering and Applied Science, Dalhousie University, Halifax, NS (Canada); Richards, N.L.; Chaturvedi, M.C. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, MB (Canada)

2008-07-15

A thermodynamic package was used to predict the phase transformations that occurred during thermal processing of a superalloy based on the composition of a ternary Ni-Cr-Fe alloy. The effect of the addition of 6 w/o Al on phase transformation in the material sintered were estimated and compared with results obtained experimentally by X-ray diffraction and metallography, while the transformation temperature of the modified alloy was corroborated by differential scanning calorimetry (DSC). Mechanical property of the alloy was estimated in terms of Vickers hardness. These results suggest that despite potential problems encountered in high-temperature powder processing of superalloys that often tend to influence the feasibility of using thermodynamic predictions to model such alloy systems, the software and predictions used in this study offer a way to simulate both design and characterisation of the experimental alloy.

Surface treated fly ash filled modified epoxy composites

Directory of Open Access Journals (Sweden)

Uma Dharmalingam

2015-01-01

Full Text Available Abstract Fly ash, an inorganic alumino silicate has been used as filler in epoxy matrix, but it reduces the mechanical properties due to its poor dispersion and interfacial bonding with the epoxy matrix. To improve its interfacial bonding with epoxy matrix, surface treatment of fly ash was done using surfactant sodium lauryl sulfate and silane coupling agent glycidoxy propyl trimethoxy silane. An attempt is also made to reduce the particle size of fly ash using high pressure pulverizer. To improve fly ash dispersion in epoxy matrix, the epoxy was modified by mixing with amine containing liquid silicone rubber (ACS. The effect of surface treated fly ash with varying filler loadings from 10 to 40% weight on the mechanical, morphological and thermal properties of modified epoxy composites was investigated. The surface treated fly ash was characterized by particle size analyzer and FTIR spectra. Morphological studies of surface treated fly ash filled modified epoxy composites indicate good dispersion of fillers in the modified epoxy matrix and improves its mechanical properties. Impact strength of the surface treated fly ash filled modified epoxy composites show more improvement than unmodified composites.

The crystallization of (NiCu)ZrTiAlSi glass/crystalline composite

International Nuclear Information System (INIS)

Czeppe, T.; Sypien, A.; Ochin, P.; Anastassova, S.

2007-01-01

Alloys of composition (Ni 1-x Cu x ) 60 Zr 18 Ti 13 A1 5 Si 4 were investigated in the form of ribbons and massive samples. The microstructure of the massive samples consists of dendritic crystals in the amorphous or nanocrystalline matrix. The amount of the amorphous phase is the lowest in the sample with the highest Cu content. The segregation in the liquid phase, leading to the local differences in density and the composition of the crystallizing dendrites in the samples crystallized in the copper mould was shown. The typical compositions of the multi-component crystals could be distinguished; one with the increased content of aluminum, the second with the high content of silicon and third, with the high content of (NiCu) and (ZrTi). The cubic phase Ni(Cu)Ti(Zr) with Cu and Zr dissolved could be identified. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Effects of heat treatment on optical absorption properties of Ni-P/AAO nano-array composite structure

Energy Technology Data Exchange (ETDEWEB)

Liu, Yi-Fan; Wang, Feng-Hua; Guo, Dong-Lai; Huang, Sheng-You; Zou, Xian-Wu [Wuhan University, Department of Physics, Wuhan (China); Sang, Jian-Ping [Wuhan University, Department of Physics, Wuhan (China); Jianghan University, Department of Physics, Wuhan (China)

2009-11-15

Ni-P/AAO nano-array composite structure assemblies with Ni and P grown in the pores of anodic aluminum oxide (AAO) membranes were prepared by electroless deposition. The results of SEM, TEM and SAED show that as-deposited Ni-P nanowires have an amorphous structure and a few nanocrystallites form after annealing. The optical absorption spectra reveal that, as the annealing temperature increases, the absorption band edge of the Ni-P/AAO composite structure is obviously blue shifted, which is attributed to a decrease of the internal pressure after heat treatment. Meanwhile, the annealed Ni-P/AAO nano-array composite structure exhibits the absorption behavior of a direct band gap semiconductor. Details of this behavior are discussed together with the implications for potential device applications. (orig.)

Study of the electroplating mechanism and physicochemical proprieties of deposited Ni-W-Silicate composite alloy

International Nuclear Information System (INIS)

Sassi, W.; Dhouibi, L.; Berçot, P.; Rezrazi, M.; Triki, E.

2014-01-01

In this work, layers based on Nickel-Tungsten (Ni-W) were electroplated from citrate-ammonia bath with and without silicate addition. Firstly, Electrochemical Quartz Crystal Microbalance (EQCM) and Global Discharge Optical Emission Spectroscopy (GDOES) were used to investigate the electroplating mechanism of both coatings. The gain mass was 14 and 4.13 μg cm −2 for Ni-W-Sil and Ni-W coatings, respectively. Secondly, the morphology of the composite alloy shows a smooth and homogenous surface with compact cauliflower like-structure identified as silicate incorporation. Finally, after a long immersion into chloride solution, Ni-W-Sil composite film showed a good surface stability and a remarkable mechanical hardness. These proprieties enhanced the electrochemical behavior of the composite alloy

Fabrication and AE characteristics of TiNi/A16061 shape memory alloy composite

International Nuclear Information System (INIS)

Park, Young Chul; Lee, Jin Kyung

2004-01-01

TiNi/A16061 Shape Memory Alloy (SMA) composite was fabricated by hot press method to investigate the microstructure and mechanical properties. Interface bonding between TiNi reinforcement and A1 matrix was observed by using SEM and EDS. Pre-strain was imposed to generate compressive residual stress inside composite. A tensile test for specimen, which underwent pre-strain, was performed at high temperature to evaluate the variation of strength and the effect of pre-strain. It was shown that interfacial reactions occurred at the bonding between matrix and fiber, creating two inter-metallic layers. And yield stress increased with the amount of pre-strain. Acoustic emission technique was also used to nondestructively clarify the microscopic damage behavior at high temperature and the effect of pre-strain of TiNi/A16061 SMA composite

Adsorption behavior of multiwall carbon nanotube/iron oxide magnetic composites for Ni(II) and Sr(II)

International Nuclear Information System (INIS)

Chen Changlun; Hu Jun; Shao Dadong; Li Jiaxing; Wang Xiangke

2009-01-01

Multiwall carbon nanotube (MWCNT)/iron oxide magnetic composites were prepared, and were characterized by scan electron microscopy using a field emission scanning electron microscope, X-ray diffraction and vibrating sample magnetometer. The adsorptions of Ni(II) and Sr(II) onto MWCNT/iron oxide magnetic composites were studied as a function of pH and ionic strength. The results show that the adsorptions of Ni(II) and Sr(II) on the magnetic composites is strongly dependent on pH and ionic strength. The adsorption capacity of the magnetic composites is much higher than that of MWCNTs and iron oxides. The solid magnetic composites can be separated from the solution by a magnetic process. The Langmuir model fits the adsorption isotherm data of Ni(II) better than the Freundlich model. Results of desorption study shows that Ni(II) adsorbed onto the magnetic composites can be easily desorbed at pH < 2.0. MWCNT/iron oxide magnetic composites may be a promising candidate for pre-concentration and solidification of heavy metal ions and radionuclides from large volumes of aqueous solution, as required for remediation purposes.

The formation mechanism of eutectic microstructures in NiAl-Cr composites.

Science.gov (United States)

Tang, Bin; Cogswell, Daniel A; Xu, Guanglong; Milenkovic, Srdjan; Cui, Yuwen

2016-07-20

NiAl-based eutectic alloys, consisting of an ordered bcc matrix (B2) and disordered bcc fibers (A2), have been a subject of intensive efforts aimed at tailoring the properties of many of the currently used nickel-based superalloys. A thermodynamic phase field model was developed on a thermodynamic foundation and fully integrated with a thermo-kinetic database of the Ni-Al-Cr ternary system to elucidate the resulting peculiar eutectic microstructure. Invoking a variation of the liquid/solid interfacial thickness with temperature, we simulated the characteristic sunflower-like eutectic microstructures in the NiAl-Cr composites, consistent with experimental observations. The mechanism that governs the formation of the peculiar eutectic morphology was envisioned from the modeled evolutions associated with six sequential steps. Our calculations show that the conditional spinodal decomposition occurring in sequence could further trim and revise the microstructure of the eutectics by generating fine-domain structures, thereby providing an additional method to explore the novel NiAl-based eutectic composites with tunable properties at elevated temperatures.

Synthesis and electrochemical characteristics of Sn-Sb-Ni alloy composite anode for Li-ion rechargeable batteries

International Nuclear Information System (INIS)

Guo Hong; Zhao Hailei; Jia Xidi; Qiu Weihua; Cui Fenge

2007-01-01

Micro-scaled Sn-Sb-Ni alloy composite was synthesized from oxides of Sn, Sb and Ni via carbothermal reduction. The phase composition and electrochemical properties of the Sn-Sb-Ni alloy composite anode material were studied. The prepared alloy composite electrode exhibits a high specific capacity and a good cycling stability. The lithiation capacity was 530 mAh g -1 in the first cycle and maintained at 370-380 mAh g -1 in the following cycles. The good electrochemical performance may be attributed to its relatively large particle size and multi-phase characteristics. The former reason leads to the lower surface impurity and thus the lower initial capacity loss, while the latter results in a stepwise lithiation/delithiation behavior and a smooth volume change of electrode in cycles. The Sn-Sb-Ni alloy composite material shows a good candidate anode material for the rechargeable lithium ion batteries

Tough and Reinforced Polypropylene/Kaolin Composites using Modified Kaolin

Science.gov (United States)

Yao, J. L.; Zhu, H. X.; Qi, Y. B.; Guo, M. J.; Hu, Q.; Gao, L.

2018-05-01

Polypropylene (PP)/kaolin composites have been prepared by filling modified kaolin with diethylenetriaminepentaacetic acid (DTPA) into the PP matrix. The surface modification of kaolin particles effectively improves the compatibility between kaolin and PP matrix. It is conducive for uniform dispersion of inorganic particles in the matrix, and enhances the mechanical performance of the composites. Compared with plain kaolin, the mechanical properties of the modified composites exhibit higher tensile strength, bending strength, impact strength and melt index simultaneously. The DTPA modification of kaolin overall enhances the mechanical properties of PP composites. It meets the requirements in various applications, and makes the modified experiment interesting in modern teaching.

Synthesis of molybdenum and tungsten modified composite systems based on bisorbent from rice husk

Directory of Open Access Journals (Sweden)

Duisek Haisagalievich Kamysbaev

2017-12-01

Full Text Available The article presents results of the synthesis of a new composite material modified with polyvalent metals. Rice husk was chosen as a raw material for obtaining a carrier – a bisorbent consisting of carbon and amorphous silicon oxide. The sorption material was obtained from the products of thermal decomposition of rice husks. Further it was modified with ammonium salts of molybdenum and tungsten: (NH46Mo7O24·4H2O and (NH42O·12WO3·5H2O in Mo/W ratios: 5/5 wt. %, 10/5 wt. % and reducted by heating in a stream of hydrogen. The registration of the voltammetric curves in the medium of 1-methyl-4-piperidone was carried out in various background electrolytes: 0.2 M Li2SO4, pH = 6.36 and 0.1 M KOH, pH = 13, 2,5·10–2 M K2HPO4 + 2,5·10–2 M NaH2PO4, pH = 6.86. Differential voltammetric curves were analyzed. The electrochemical activity of the obtained modified composites in the potential range from -1.2 V to 0.5 V was determinated. The mechanism of the proceeding electrochemical processes on these modified electrode materials has been studied. The possibility of further use of synthesized composite systems based on bisorbents from the rice husk for the electrochemical reduction of 1-methyl-4-piperidone was shown.

Data on the synthesis processes optimization of novel β-NiS film modified CdS nanoflowers heterostructure nanocomposite for photocatalytic hydrogen evolution

Directory of Open Access Journals (Sweden)

Yu Zhang

2018-02-01

Full Text Available The data presented in this article are related to a research article entitled ‘Novel β-NiS film modified CdS nanoflowers heterostructure nanocomposite: extraordinarily highly efficient photocatalysts for hydrogen evolution’ (Zhang et al., 2018 [1]. In this article, we report original data on the synthesis processes optimization of the proposed nanocomposite on the basis of their optimum photocatalytic performance together with the comparison on the results of literatures and comparative experiments. The composition, microstructure, morphology, photocatalytic hydrogen evolution and photocatalytic stability of the corresponding samples are included in this report. The data are presented in this format in order to facilitate comparison with data from other researchers in the field and understanding the mechanism of similar catalysts. Keywords: NiS/CdS nanoflowers heterostructure, Photocatalysts, Water splitting, Hydrothermal synthesis, Optimization

Hot corrosion testing of Ni-based alloys and coatings in a modified Dean rig

Science.gov (United States)

Steward, Jason Reid

Gas turbine blades are designed to withstand a variety of harsh operating conditions. Although material and coating improvements are constantly administered to increase the mean time before turbine refurbishment or replacement, hot corrosion is still considered as the major life-limiting factor in many industrial and marine gas turbines. A modified Dean rig was designed and manufactured at Tennessee Technological University to simulate the accelerated hot corrosion conditions and to conduct screening tests on the new coatings on Ni-based superalloys. Uncoated Ni-based superalloys, Rene 142 and Rene 80, were tested in the modified Dean rig to establish a testing procedure for Type I hot corrosion. The influence of surface treatments on the hot corrosion resistance was then investigated. It was found that grit-blasted specimens showed inferior hot corrosion resistance than that of the polished counterpart. The Dean rig was also used to test model MCrAlY alloys, pack cementation NiAl coatings, and electro-codeposited MCrAlY coatings. Furthermore, the hot corrosion attack on the coated-specimens were also assessed using a statistical analysis approach.

High Temperature Oxidation Behavior of gamma-Ni+gamma'-Ni3Al Alloys and Coatings Modified with Pt and Reactive Elements

Energy Technology Data Exchange (ETDEWEB)

Mu, Nan [Iowa State Univ., Ames, IA (United States)

2007-12-01

Materials for high-pressure turbine blades must be able to operate in the high-temperature gases (above 1000 C) emerging from the combustion chamber. Accordingly, the development of nickel-based superalloys has been constantly motivated by the need to have improved engine efficiency, reliability and service lifetime under the harsh conditions imposed by the turbine environment. However, the melting point of nickel (1455 C) provides a natural ceiling for the temperature capability of nickel-based superalloys. Thus, surface-engineered turbine components with modified diffusion coatings and overlay coatings are used. Theses coatings are capable of forming a compact and adherent oxide scale, which greatly impedes the further transport of reactants between the high-temperature gases and the underlying metal and thus reducing attack by the atmosphere. Typically, these coatings contain β-NiAl as a principal constituent phase in order to have sufficient aluminum content to form an Al₂O₃ scale at elevated temperatures. The drawbacks to the currently-used {beta}-based coatings, such as phase instabilities, associated stresses induced by such phase instabilities, and extensive coating/substrate interdiffusion, are major motivations in this study to seek next-generation coatings. The high-temperature oxidation resistance of novel Pt + Hf-modified γ-Ni + γ-Ni₃Al-based alloys and coatings were investigated in this study. Both early-stage and 4-days isothermal oxidation behavior of single-phase γ-Ni and γ'-Ni₃Al alloys were assessed by examining the weight changes, oxide-scale structures, and elemental concentration profiles through the scales and subsurface alloy regions. It was found that Pt promotes Al₂O₃ formation by suppressing the NiO growth on both γ-Ni and γ'Ni₃Al single-phase alloys. This effect increases with increasing Pt content. Moreover, Pt exhibits this effect even at

In-situ formation of Ni4Ti3 precipitate and its effect on pseudoelasticity in selective laser melting additive manufactured NiTi-based composites

Science.gov (United States)

Gu, Dongdong; Ma, Chenglong

2018-05-01

Selective laser melting (SLM) additive manufacturing technology was applied to synthesize NiTi-based composites via using ball-milled Ti, Ni, and TiC mixed powder. By transmission electron microscope (TEM) characterization, it indicated that the B2 (NiTi) matrix was obtained during SLM processing. In spite of more Ti content (the Ti/Ni ratio >1), a mass of Ni-rich intermetallic compounds containing Ni4Ti3 with nanostructure features and eutectic Ni3Ti around in-situ Ti6C3.75 dendrites were precipitated. Influence of the applied laser volume energy density (VED) on the morphology and content of Ni4Ti3 precipitate was investigated. Besides, nanoindentation test of the matrix was performed in order to assess pseudoelastic recovery behavior of SLM processed NiTi-based composites. At a relatively high VED of 533 J/mm3, the maximum pseudoelastic recovery was obtained due to the lowest content of Ni4Ti3 precipitates. Furthermore, the precipitation mechanism of in-situ Ni4Ti3 was present based on the redistribution of titanium element and thermodynamics analysis, and then the relationship of Ni4Ti3 precipitate, VED and pseudoelastic recovery behavior was also revealed.

Activation behaviour of ZrCrNi mechanically milled with nickel

International Nuclear Information System (INIS)

Jung, C. B.; Ho Kim, J.; Sub Lee, K.

1998-01-01

AB 2 type Laves phase alloys have some promising properties as a negative electrode in rechargeable Ni/MH batteries because of high electrochemical capacity and good cyclic life. However, they have the disadvantage of requiring many charge-discharge cycles for activation. In this study, the mechanical milling with nickel has been introduced to modify the electrochemical behaviour of the ZrCrNi alloy. A composite-like structure (ZrCrNi+nickel) and nanocrystalline ZrCrNi were obtained through the mechanical milling and the hydrogenation behaviour of the electrode was greatly improved. (orig.)

Deformation behavior of an electrodeposited nano-Ni/amorphous Fe78Si9B13 laminated composite sheet

Directory of Open Access Journals (Sweden)

Zhang Kaifeng

2015-01-01

Full Text Available A nano-Ni/amorphous Fe78Si9B13 composite sheet was prepared in the form of three-ply (Ni-Fe78Si9B13-Ni laminated structure by an electrodeposition method. The average grain size of Ni layers is about 50 nm. The interface of laminated composite was investigated with SEM equipped with energy dispersive scanning (EDS and line analysis technique. The laminated composite has a good interfacial bonding between amorphous layer and nano-Ni layers due to the mutual diffusion of atoms in Fe78Si9B13 and Ni layers during the process of electrodeposition. A maximum elongation of 115.5% was obtained when the volume fraction of nano-Ni layers (VNi was 0.77, which is greatly higher than that of monolithic amorphous Fe78Si9B13 ribbon (36.3% tested under the same conditions. Bulging tests were carried out to evaluate plastic forming properties of the Fe78Si9B13/Ni laminated composite. Under the condition of 450 °C, 4.0 MPa and 30 min, a good bulging part with the relative bulging height (RBH of 0.4 was obtained.

Influence of Ni/Co molar ratio on electromagnetic properties and microwave absorption performances for Ni/Co paraffin composites

Energy Technology Data Exchange (ETDEWEB)

Yan, S.J., E-mail: shaojiuyan@126.com [Department of Structural Steel, Functional Materials and Heat Treatment Processing, AVIC Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Aviation Key Laboratory of Science and Technology on Stealth Materials, Beijing 100095 (China); Dai, S.L. [The Office of AVIC Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Ding, H.Y.; Wang, Z.Y. [Aviation Key Laboratory of Science and Technology on Stealth Materials, Beijing 100095 (China); Liu, D.B [Department of Structural Steel, Functional Materials and Heat Treatment Processing, AVIC Beijing Institute of Aeronautical Materials, Beijing 100095 (China)

2014-05-01

Ni and Co metallic microparticles with submicron size were synthesized with a simple wet chemical reduction method at a relatively low temperature. Then their morphologies and structures were characterized by SEM and XRD. Ni metallic microparticles have spherical-shape morphology with fcc crystalline structure, however, Co has a distinct leaf-like morphology with the fcc and hcp mixed phases crystalline structures. For the characterization of their electromagnetic properties, paraffin matrix composites containing different molar ratio Ni and Co mixture powder as fillers were prepared. It was found that both the electromagnetic properties and electromagnetic microwave absorption performances of absorber layer were remarkably influenced by Ni/Co molar ratio. The electromagnetic microwave absorption performances were significantly improved by blending Ni and Co metallic microparticles into paraffin matrix with changing Ni/Co molar ratio, and enhanced mechanism were discussed. - Highlights: • Ni and Co microparticles were synthesized by a wet chemical reduction method. • EM properties of absorber were remarkably influenced by Ni/Co molar ratio. • EMA performances can be adjusted by artificially changing Co/Ni molar ratio. • Enhanced EMA performances result from multiple EM attenuation mechanisms.

Magnetic behavior of NiCu nanowire arrays: Compositional, geometry and temperature dependence

International Nuclear Information System (INIS)

Palmero, E. M.; Bran, C.; Real, R. P. del; Vázquez, M.; Magén, C.

2014-01-01

Arrays of Ni 100−x Cu x nanowires ranging in composition 0 ≤ x ≤ 75, diameter from 35 to 80 nm, and length from 150 nm to 28 μm have been fabricated by electrochemical co-deposition of Ni and Cu into self-ordered anodic aluminum oxide membranes. As determined by X-ray diffraction and Transmission Electron Microscopy, the crystalline structure shows fcc cubic symmetry with [111] preferred texture and preferential Ni or Cu lattice depending on the composition. Their magnetic properties such as coercivity and squareness have been determined as a function of composition and geometry in a Vibrating Sample Magnetometer in the temperature range from 10 to 290 K for applied magnetic fields parallel and perpendicular to the nanowires axis. Addition of Cu into the NiCu alloy up to 50% enhances both parallel coercivity and squareness. For the higher Cu content, these properties decrease and the magnetization easy axis becomes oriented perpendicular to the wires. In addition, coercivity and squareness increase by decreasing the diameter of nanowires which is ascribed to the increase of shape anisotropy. The temperature dependent measurements reflect a complex behavior of the magnetic anisotropy as a result of energy contributions with different evolution with temperature.

A nano lamella NbTi–NiTi composite with high strength

Energy Technology Data Exchange (ETDEWEB)

Jiang, Jiang [Jiangxi Key Laboratory of Advanced Copper and Tungsten Materials, Jiangxi Academy of Sciences, Nanchang 330029 (China); Institute of Applied Physics of Jiangxi Academy of Sciences, Nanchang 330029 (China); State Key Laboratory of Heavy Oil Processing and Department of Materials Science and engineering, China University of Petroleum, Beijing 102249 (China); Jiang, Daqiang [State Key Laboratory of Heavy Oil Processing and Department of Materials Science and engineering, China University of Petroleum, Beijing 102249 (China); School of Mechanical and Chemical Engineering, The University of Western Australia, WA 6009 (Australia); Hao, Shijie; Yu, Cun; Zhang, Junsong [State Key Laboratory of Heavy Oil Processing and Department of Materials Science and engineering, China University of Petroleum, Beijing 102249 (China); Ren, Yang [X-ray Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Lu, Deping; Xie, Shifang [Jiangxi Key Laboratory of Advanced Copper and Tungsten Materials, Jiangxi Academy of Sciences, Nanchang 330029 (China); Institute of Applied Physics of Jiangxi Academy of Sciences, Nanchang 330029 (China); Cui, Lishan, E-mail: lishancui63@126.com [State Key Laboratory of Heavy Oil Processing and Department of Materials Science and engineering, China University of Petroleum, Beijing 102249 (China)

2015-05-01

A hypereutectic Nb{sub 60}Ti{sub 24}Ni{sub 16} (at%) alloy was prepared by vacuum induction melting, and a nano lamellae NbTi–NiTi composite was obtained by hot-forging and wire-drawing of the ingot. Microscopic analysis showed that NbTi and NiTi nano lamellae distributed alternatively in the composite, and aligned along the wire axial direction, with a high volume fraction (~70%) of NbTi nano lamellae. In situ synchrotron X-ray diffraction analysis revealed that stress induced martensitic transformation occurred upon loading, which would effectively weaken the stress concentration at the interface and avoid the introduction of defects into the nano reinforced phase. Then the embedded NbTi nano lamellae exhibited a high elastic strain up to 2.72%, 1.5 times as high as that of the Nb nanowires embedded in a conventional plastic matrix, and the corresponding stress carried by NbTi was evaluated as 2.53 GPa. The high volume fraction of NbTi nano lamellae improved the translation of high strength from the nano reinforced phase into bulk properties of the composite, with a platform stress of ~1.7 GPa and a fracture strength of ~1.9 GPa.

Preparation of NiFe2O4/graphene nanocomposite and its application as a modifier for the fabrication of an electrochemical sensor for the simultaneous determination of tramadol and acetaminophen

International Nuclear Information System (INIS)

Afkhami, Abbas; Khoshsafar, Hosein; Bagheri, Hasan; Madrakian, Tayyebeh

2014-01-01

Highlights: • A new modified electrochemical sensor was constructed and used. • NiFe 2 O 4 /graphene was used as the modifier. • The sensor was used for the determination of tramadol and acetaminophen in real samples. • Modification improved the sensitivity and detection limit of the method. • The oxidation of tramadol and acetaminophen at the surface of the electrode was studied. - Abstract: An effective electrochemical sensor for the rapid and simultaneous determination of tramadol and acetaminophen based on carbon paste electrode (CPE) modified with NiFe 2 O 4 /graphene nanoparticles was developed. The structures of the synthesized NiFe 2 O 4 /graphene nanocomposite and the electrode composition were confirmed by X-ray diffraction (XRD) spectrometry, Fourier transform infrared (FT-IR) spectrometry and scanning electron microscopy (SEM). The peak currents of square wave voltammetry of tramadol and acetaminophen increased linearly with their concentration in the range of 0.01–9 μmol L −1 . The detection limit for their determination was found to be 0.0036 and 0.0030 μmol L −1 , respectively. The results show that the combination of graphene and NiFe 2 O 4 nanoparticles causes a dramatic enhancement in the sensitivity of the sensor. The fabricated sensor exhibited high sensitivity and good stability, and would be valuable for the clinical assay of tramadol and acetaminophen

Fabrication of BaTiO3/Ni composite particles and their electro-magneto responsive properties

International Nuclear Information System (INIS)

Lu, Yaping; Gao, Lingxiang; Wang, Lijuan; Xie, Zunyuan; Gao, Meixiang; Zhang, Weiqiang

2017-01-01

Graphical abstract: The spherical BaTiO 3 /Ni particles with excellent structure were made by one-step method through fixing the metal Ni(0) reduced by a specific reducing agent (N 2 H 4 ·H 2 O) on the surface of the BaTiO 3 particles with grain diameter of ∼500 nm. BaTiO 3 /Ni particle has double responses of electric and magnetic field simultaneously. Consequentially, coating magnetic metal on BT particle is proposed an effective method to prepare novel electro-magneto responsive particles and one basis of electro-magneto responsive elastomers. - Highlights: • The BaTiO 3 /Ni composite particles were fabricated. • The content of Ni(0) in nickel sheath is 70.2%. • The BaTiO 3 /Ni particles have double responses of electric and magnetic field. - Abstract: BaTiO 3 (BT)/Ni composite particles were made by one-step method through agglomerating the metal Ni(0) nanoparticles reduced by a specific reducing agent (N 2 H 4 ·H 2 O) on the surface of BT sphere with diameter of ∼500 nm. The BT/Ni composite particles were characterized by the means of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). In BT/Ni particles, pure BT spherical particle was coated with Ni nanoparticles agglomerated on its surface. The average thickness of the Ni sheath was ∼30 nm and the content of Ni(0) and Ni (II) in the sheath were 70.2% and 29.8%, respectively. The responsive effects of BT/Ni particles filled in hydrogel elastomer were investigated by the viscoelastic properties. The results indicate that the BT/Ni particles exhibit electro and magneto coordinated responsive properties (E = 1 kV/mm, H = 0.1 T/mm), which is superior to BT particles with individual electro response.

A novel approach using powder metallurgy for strengthened RABiTS composite substrates for coated superconductors

International Nuclear Information System (INIS)

Suo Hongli; Zhao Yue; Liu Min; Ye Shuai; Zhu YongHua; He Dong; Ma Lingji; Ji Yuan; Zhou Meiling

2008-01-01

We report on the development of mechanically strengthened, highly textured Ni-5 at.%W/Ni-12 at.%W composite materials prepared by a powder metallurgical approach as promising weakly magnetic substrates for coated superconductors. The key configuration of this composite substrate consists of a thin, sharp cubic textured Ni-5 at.%W layer on a Ni-12 at.%W alloy core, thus providing a mechanical reinforcement while decreasing the saturation magnetization of the whole substrate. The composite substrates have a sharp cubic texture at the top Ni-5 at.%W outer layer and their yield strength reaches 272 MPa, exceeding that of the commercially used Ni5W substrates by a factor of 1.6. The saturation magnetization of the composite substrate Ni5W/Ni12W/Ni5W is substantially reduced when compared to that of pure Ni and Ni-5 at.%W substrates, respectively

Forming a structure of the CoNiFe alloys by X-ray irradiation

Science.gov (United States)

Valko, Natalia; Kasperovich, Andrey; Koltunowicz, Tomasz N.

The experimental data of electrodeposition kinetics researches and structure formation of ternary CoNiFe alloys deposited onto low-carbon steel 08kp in the presence of X-rays are presented. Relations of deposit rate, current efficiencies, element and phase compositions of CoNiFe coatings formed from sulfate baths with respect to cathode current densities (0.5-3A/dm2), electrolyte composition and irradiation were obtained. It is shown that, the CoNiFe coatings deposited by the electrochemical method involving exposure of the X-rays are characterized by more perfect morphology surfaces with less developed surface geometry than reference coatings. The effect of the X-ray irradiation on the electrodeposition of CoNiFe coatings promotes formatting of alloys with increased electropositive component and modified phase composition.

Microwave reflection properties of planar anisotropy Fe50Ni50 powder/paraffin composites

International Nuclear Information System (INIS)

Wei Jian-Qiang; Zhang Zhao-Qi; Han Rui; Wang Tao; Li Fa-Shen

2012-01-01

The reflection properties of planar anisotropy Fe 50 Ni 50 powder/paraffin composites have been studied in the microwave frequency range. The permeability of Fe 50 Ni 50 powder/paraffin composites is greatly enhanced by introducing the planar anisotropy, and can be further enhanced by using a rotational orientation method. The complex permeability can be considered as the superposition of two types of magnetic resonance. The resonance peak at high frequency is attributed to the natural resonance, while the peak at low frequency is attributed to the domain-wall resonance. The simulated results of the microwave reflectivity show that the matching thickness, peak frequency, permeability, and permittivity are closely related to the quarter wavelength matching condition. The Fe 50 Ni 50 powder/paraffin composites can be attractive candidates for thinner microwave absorbers in the L-band (1–2 GHz). (condensed matter: electronic structure, electrical, magnetic, and optical properties)

THE STRUCTURE AND PROPERTIES OF COMPOSITE LASER CLAD COATINGS WITH Ni BASED MATRIX WITH WC PARTICLES

Directory of Open Access Journals (Sweden)

Zita Iždinská

2010-09-01

Full Text Available In this work, the influence of the processing conditions on the microstructure and abrasive wear behavior of composite laser clad coatings with Ni based matrix reinforced with 50% WC particles is analyzed. Composite powder was applied in the form of coatings onto a mild steel substrate (Fe–0.17% C by different laser powers and cladding speeds. The microstructure of the coatings was analyzed by scanning electron microscopy (SEM. Tribological properties of coatings were evaluated by pin-on-disc wear test. It appeared that the hardness of the matrix of composite coatings decreases with increasing cladding speed. However, wear resistance of composite coatings with decreasing hardness of Ni based matrix increases. Significantly enhanced wear resistance of WC composite coatings in comparison with Ni based coatings is attributed to the hard phase structures in composite coatings.

Optimization of NiFe2O4/rGO composite electrode for lithium-ion batteries

Science.gov (United States)

Li, Chen; Wang, Xia; Li, Shandong; Li, Qiang; Xu, Jie; Liu, Xiaomin; Liu, Changkun; Xu, Yuanhong; Liu, Jingquan; Li, Hongliang; Guo, Peizhi; Zhao, Xiu Song

2017-09-01

The combination of carbon compositing and the proper choice of binders in one system offer an effective strategy for improving electrode performance for lithium ion batteries (LIBs). Here, we focus on the optimization of reduced graphene oxide content in NiFe2O4/reduced graphene oxide (abbreviated to NiFe2O4/rGO) composites and the proper choice of binders to enhance the cycling stability of the NiFe2O4 electrode. The NiFe2O4/rGO composites were fabricated by a hydrothermal-annealing method, in which the mean size of spinel NiFe2O4 nanoparticles was approximately 20 nm. When tested as anode materials for LIBs, the NiFe2O4/rGO electrodes with carboxymethylcellulose (CMC) binder exhibited excellent lithium-storage performance including high reversible capacity, good cycling durability and high-rate capability. The capacity could be retained as high as 1105 mAh g-1 at a current density of 100 mA g-1 for over 50 cycles, even cycled at higher current density of 1000 mA g-1, a capacity of 800 mAh g-1can be obtained, whereas the electrode with the polyvinylidene fluoride (PVDF) binder suffered from rapid capacity decay under the same test conditions. As a result, the NiFe2O4/rGO composites with CMC binder electrode in this work are promising as anodes for high-performance LIBs, resulting from the synergistic effect of optimal graphene content and proper choice of binder.

Sorption properties of new composite materials suitable for radioanalytical determination of 59-Ni and 63-Ni

International Nuclear Information System (INIS)

Fisera, O.; Sebesta, F.

2006-01-01

New composite materials for separation and radioanalytical determination of radionickel ( 59, 63 Ni) were prepared and their sorption properties were examined. Chelating agents dimethylglyoxime (DMG) and diphenylglyoxime (DFG) as active components were immobilized in porous matrix of binding polymer polyacrylonitrile (PAN). Sorption properties of these materials were compared with commercial Ni Resin (Eichrom Technologies, USA). Weight distribution ratios, sorption kinetics and operating capacities were investigated during experiments performed. The highest weight distribution ratios were found for the material DFG-PAN. The sorbent DMG-PAN has the highest operating capacity. The fastest kinetics of nickel sorption was determined for the commercial Ni Resin. Elution of nickel with nitric acid solution allows subsequent and direct determination of radionickel by liquid scintillation counting. (author)

Elaboration of modified poly(NiII-DHS films as electrodes by the electropolymerization of Ni(II-[5,5′-dihydroxysalen] onto indium tin oxide surface and study of their electrocatalytic behavior toward aliphatic alcohols

Directory of Open Access Journals (Sweden)

Ali Ourari

2017-11-01

Full Text Available Nickel(II-DHS complex was obtained from N,N′-bis(2,5-dihydroxybenzylidene-1,2-diaminoethane (H2DHS ligand and nickel acetate tetrahydrated in ethanolic solution with stirring under reflux. This complex, dissolved in an alkaline solution, was oxidized to form electroactive films strongly adhered on the ITO (indium tin oxide electrode surface. In this alkaline solution, the poly-[NiII-DHS]/ITO films showed the typical voltammetric response of (Ni2+/Ni3+ redox couple centers which are immobilized in the polymer-film. The modified electrodes (MEs obtained were also characterized by several techniques such as scanning electronic microscopy, atomic force microscopy and electrochemical methods. The electrocatalytic behavior of these MEs toward the oxidation reaction of some aliphatic alcohols such as methanol, ethanol, 2-Methyl-1-propanol and isopropanol was investigated. The voltammograms recorded with these alcohols showed good electrocatalytic efficiency. The electrocatalytic currents were at least 80 times higher than those obtained for the oxidation of methanol on electrodes modified with nickel hydroxide films in alkaline solutions. We noticed that these electrocatalytic currents are proportional to the concentration of methanol (0.050–0.30 μM. In contrast, those recorded for the oxidation of other aliphatic short chain alcohols such as ethanol, 2-methyl-1-propanol and isopropanol are rather moderately weaker. In all cases the electrocatalytic currents presented a linear dependence with the concentration of alcohol. These modified electrodes could be applied as alcohol sensors.

Synthesis and characterization of Ni-P-Ag composite coating as efficient electrocatalyst for alkaline hydrogen evolution reaction

International Nuclear Information System (INIS)

Elias, Liju; Hegde, A. Chitharanjan

2016-01-01

Highlights: • Electrocatalytic activity of Ni-P alloy is improved by Ag nanoparticle incorporation. • Ni-P-Ag electrode is developed through sol-enhanced electrodeposition. • Ni-P-Ag composite coating shows better electrocatalytic efficiency for HER. - Abstract: The effect of addition of silver nanoparticle sol (SNS) into Ni-P plating bath was studied in terms of the variation in electrocatalytic behavior of the developed coatings in 1.0 M KOH. Ni-P-Ag composite coating was achieved through direct electrolysis by adding a known quantity of the conventionally prepared SNS into Ni-P bath. Ni-P-Ag coatings electrodeposited galvanostatically on copper under different conditions of the bath was used as electrode material for alkaline hydrogen evolution reaction (HER). The optimal concentration of the SNS required for maximum electrocatalytic activity towards HER was obtained by adding different volumes of SNS (from 0 to 50 mL L −1 ) into the bath. The HER efficiency of the test electrodes in 1.0 M KOH medium was examined using cyclic voltammetry (CV) and chronopotentiometry (CP) techniques. The kinetics of HER on the alloy and composite electrodes were established through Tafel polarization and electrochemical impedance spectroscopy (EIS) analyses. Energy dispersive spectroscopy (EDS) was used to confirm the incorporation of Ag nanoparticles into the Ni-P alloy matrix. The microstructure and morphology of the alloy and composite coatings were analyzed by Scanning Electron Microscopy (SEM). A significant improvement in the electrocatalytic property of nano-Ag derived composite coatings was found, and was attributed to the enhanced electroactive sites of Ag particles. Deposition conditions to maximize the electrocatalytic activity of Ni-P-Ag nanocomposite coatings in relation to traditional Ni-P alloy coatings was arrived, and results are discussed.

Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

Science.gov (United States)

Xu, Jiang; Zhuo, Chengzhi; Tao, Jie; Jiang, Shuyun; Liu, Linlin

2009-01-01

In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO2 predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 °C) conditions, amorphous nano-SiO2 particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr6.5Ni2.5Si and Cr23C6. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO2 particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO2 particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix around the precipitated phase takes place by the chemical

Density of liquid NiCrAlMo quarternary alloys measured by a modified sessile drop method

International Nuclear Information System (INIS)

Fang, L.; Wang, Y.F.; Xiao, F.; Tao, Z.N.; MuKai, K.

2006-01-01

The densities of liquid NiCrAlMo quaternary alloys with a fixed molar ratio of Ni:Cr:Al (approximately as 73:14:13) and molybdenum concentration from 0 to 10 mass% were measured by a modified sessile drop method (MSDM). It was found that the density of the liquid NiCrAlMo quaternary alloys decreases with increasing temperature, but increases with the increase of molybdenum concentration. The molar volume of liquid NiCrAlMo quaternary alloys increases with the increase of temperature and molybdenum concentration. The density of liquid NiCrAlMo quaternary alloys calculated from the partial molar volumes of nickel, chromium, aluminum and molybdenum in the corresponding Ni-based binary alloys are in good agreement with the experimental results, means, within the error tolerance range the density of liquid Ni-based multi-component alloys can be predicted from the partial volumes of elements in Ni-based binary alloys in liquid state

Electroless Ni-P/Nano-SiO2 Composite Plating on Dual Phase Magnesium-Lithium Alloy

Science.gov (United States)

Zou, Y.; Zhang, Z. W.; Zhang, M. L.

The application of Mg-Li alloys is restricted in practice due to mainly poor corrosion resistance and wear resistance. Electroless nickel plating is one of the common and effective ways to protect alloys from corrosion. In this study, nano-SiO2 particles with Ni-P matrix have been successfully co-deposited onto dual phase Mg-8Li base alloy through electroless plating, generating homogeneously Ni-P/nano-SiO2 composite coating. The morphology, elemental composition and structures of coatings were investigated. Coating performances were evaluated using hardness tests and electrochemical analysis. The results indicate that the Ni-P/nano-SiO2 composite coating can significantly improve the wear and corrosion resistance.

Interaction of human endothelial cells and nickel-titanium materials modified with silicon ions

Energy Technology Data Exchange (ETDEWEB)

Lotkov, Aleksandr I., E-mail: lotkov@ispms.tsc.ru; Kashin, Oleg A., E-mail: okashin@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Kudryavtseva, Yuliya A., E-mail: yulia-k1970@mail.ru; Antonova, Larisa V., E-mail: antonova.la@mail.ru; Matveeva, Vera G., E-mail: matveeva-vg@mail.ru; Sergeeva, Evgeniya A., E-mail: sergeewa.ew@yandex.ru [Research Institute for Complex Issues of Cardiovascular Diseases, Kemerovo, 650002 (Russian Federation); Kudryashov, Andrey N., E-mail: kudryashov@angioline.ru [Angioline Interventional Device Ltd, Novosibirsk, 630090 (Russian Federation)

2015-10-27

The paper studies the influence of chemical and phase compositions of NiTi surface layers modified with Si ions by plasma immersion implantation on their interaction with endothelial cells. It is shown that certain technological modes of Si ion implantation enhance the adhesion, proliferation, and viability of endothelial cells. It is found that the Si-modified NiTi surface is capable of stimulating the formation of capillary-like structures in the cell culture.

Synthesis and Characterization of Electrodeposited C-PANI-Pd-Ni Composite Electrocatalyst for Methanol Oxidation

Directory of Open Access Journals (Sweden)

S. S. Mahapatra

2014-01-01

Full Text Available Electropolymerization of aniline at the graphite electrodes was achieved by potentiodynamic method. Electrodeposition of Pd (C-PANI-Pd and Ni (C-PANI-Ni and codeposition of Pd-Ni (C-PANI-Pd-Ni microparticles into the polyaniline (PANI film coated graphite (C-PANI were carried out under galvanostatic control. The morphology and composition of the composite electrodes were obtained using scanning electron microscopy (SEM and energy dispersive X-ray analysis (EDX techniques. The electrochemical behavior and electrocatalytic activity of the electrode were characterized using cyclic voltammetry (CV, electrochemical impedance spectroscopy (EIS, and chronoamperometric (CA methods in acidic medium. The C-PANI-Pd-Ni electrode showed an improved catalytic performance towards methanol oxidation in terms of lower onset potential, higher anodic oxidation current, greater stability, lower activation energy, and lower charge transfer resistance. The enhanced electrocatalytic activity might be due to the greater permeability of C-PANI films for methanol molecules, better dispersion of Pd-Ni microparticles into the polymer matrixes, and the synergistic effects between the dispersed metal particles and their matrixes.

Beneficial effects of laser irradiation on the deposition process of diamond/Ni60 composite coating with cold spray

Energy Technology Data Exchange (ETDEWEB)

Yao, Jianhua, E-mail: laser@zjut.edu.cn; Yang, Lijing; Li, Bo; Li, Zhihong

2015-03-01

Graphical abstract: - Highlights: • The hard Ni-based alloy powder as matrix in diamond composite coating was studied. • The influence of laser on diamond distribution of composite coating was analyzed. • The graphitization of diamond was prohibited in supersonic laser deposition process. • The abrasion mechanisms of diamond/Ni60 composite coating were discussed. - Abstract: Although cold spray process has many unique advantages over other coating techniques, it has difficulties in depositing hard materials. This article presents a study in the beneficial effects of laser irradiation on the fabrication process of diamond/Ni60 composite coating using cold spray. The focus of this research is on the comparison between the composite coatings produced with laser cladding (LC) and with supersonic laser deposition (SLD), with respect to diamond graphitization and tribological properties, thus to demonstrate the beneficial effects of laser irradiation on the cold spray process. The influence of deposition temperature on the coating characteristics, such as deposition efficiency, diamond volume fraction, microstructure and phase is also investigated. The tribological properties of the diamond/Ni60 composite coating produced with SLD are determined using a pin-on-disc tribometer, along with the diamond/Ni60 coating produced using LC with the optimal process parameters for comparison. The experimental results show that with the assistance of laser irradiation, diamond/Ni60 composite coating can be successfully deposited using cold spray; the obtained coating is superior to that processed with LC, because SLD can suppress the graphitization of the diamond particles. The diamond/Ni60 composite coating fabricated with SLD has much better tribological properties than the LC coating.

A visible-light-driven photocatalytic activity of vanadate garnet AgCa2Ni2V3O12 nanoparticles

International Nuclear Information System (INIS)

Lu, Yuting; Chen, Luyang; Li, Yuze; Huang, Yanlin; Cheng, Han; Seo, Hyo Jin

2015-01-01

A visible-light-driven photocatalyst of nanosized vanadate garnet AgCa 2 Ni 2 V 3 O 12 was prepared by a modified Pechini method. The nanoparticles were characterized with the measurements such as X-ray powder diffraction (XRD) and structural refinements, scanning electron microscope (SEM), and UV–visible (UV–Vis) absorption spectrum. The sample has an efficient absorption in the UV–Vis light region with a narrow band-gap energy of 2.16 eV and an indirect allowed electronic transition. Besides, the photocatalysis of AgCa 2 Ni 2 V 3 O 12 nanoparticles was evaluated by photo-degradation of methylene blue under visible-light irradiation, which shows excellent photocatalytic activity. The effective photocatalytic activity was discussed on the base of the garnet crystal structure such as the activated optical centers of Ni–O octahedron and V–O tetrahedral, highly distorted Ag–O dodecahedra, and long V–V distance in the lattices

The new ternary pnictides Er12Ni30P21 and Er13Ni25As19: Crystal structures and magnetic properties

International Nuclear Information System (INIS)

Oryshchyn, Stepan; Babizhetskyy, Volodymyr; Zhak, Olga; Zelinska, Mariya; Pivan, Jean-Yves; Duppel, Viola; Simon, Arndt; Kienle, Lorenz

2010-01-01

The new ternary pnictides Er 12 Ni 30 P 21 and Er 13 Ni 25 As 19 have been synthesized from the elements. They crystallize with hexagonal structures determined from single-crystal X-ray data for Er 12 Ni 30 P 21 (space group P6 3 /m, a=1.63900(3) nm, c=0.37573(1) nm, Z=1, R F =0.062 for 1574 F-values and 74 variable parameters), and for Er 13 Ni 25 As 19 (Tm 13 Ni 25 As 19 -type structure, space group P6-bar , a=1.6208(1) nm, c=0.38847(2) nm, Z=1, R F =0.026 for 1549 F-values and 116 variable parameters). These compounds belong to a large family of hexagonal structures with a metal-metalloid ratio of 2:1. HRTEM investigations were conducted to probe for local ordering of the disordered structure at the nanoscale. The magnetic properties of the phosphide Er 12 Ni 30 P 21 have been studied in the temperature of range 2 eff =9.59 μ B corresponds to the theoretical value of Er 3+ . - Graphical abstract: The new ternary pnictides Er 12 Ni 30 P 21 and Er 13 Ni 25 As 19 have been synthesized from the elements. They crystallize with hexagonal structures determined from single-crystal X-ray data. The compounds belong to a large family of structures with a metal-metalloid ratio of 2:1. HRTEM investigations were conducted to probe for local ordering of the disordered structure at the nanoscale. Display Omitted

Core-shell Ni0.5TiOPO4/C composites as anode materials in Li ion batteries

International Nuclear Information System (INIS)

Zhang, X.J.; Zhang, Y.; Zhou, Z.; Wei, J.P.; Essehli, R.; Bali, B. El

2011-01-01

Pristine Ni 0.5 TiOPO 4 was prepared via a traditional solid-state reaction, and then Ni 0.5 TiOPO 4 /C composites with core-shell nanostructures were synthesized by hydrothermally treating Ni 0.5 TiOPO 4 in glucose solution. X-ray diffraction patterns indicate that Ni 0.5 TiOPO 4 /C crystallizes in monoclinic P2 1 /c space group. Scanning electron microscopy and transmission electron microscopy show that the small particles with different sizes are coated with uniform carbon film of ∼3 nm in thickness. Raman spectroscopy also confirms the presence of carbon in the composites. Ni 0.5 TiOPO 4 /C composites presented a capacity of 276 mAh g -1 after 30 cycles at the current density of 42.7 mA g -1 , much higher than that of pristine Ni 0.5 TiOPO 4 (155 mAh g -1 ). The improved electrochemical performances can be attributed to the existence of carbon shell.

Structural and dielectric characteristics of double perovskite La2(NiFe)1/2MnO6

Science.gov (United States)

Nasir, Mohd.; Kandasami, Asokan; Sen, Somaditya

2018-05-01

Recently, La2NiMnO6 has drawn significant interest because large magnetic field induced changes in dielectric properties makes this compound a promising material for potential spintronic device applications. In the present study, the structural and dielectric characteristics of sol-gel prepared La2(Ni1/2Fe1/2)MnO6 double perovskite ceramics were evaluated. La2(Ni1/2Fe1/2)MnO6 was crystallized in the monoclinic P21/n structure with ordered Ni2+/Fe2+ and Mn4+ cations. A giant dielectric constant with relaxor-like behavior was observed, which was attributed to the dipolar effects arising from hopping between Ni2+/Fe2+ and Mn4+ ions.

Kinetic Studies on Ni-YSZ Composite Electrodes

DEFF Research Database (Denmark)

Njodzefon, Jean-Claude; Sudireddy, Bhaskar Reddy; Hjelm, Johan

2015-01-01

AC and DC techniques were applied to investigate the electrochemical reaction kinetics of porous composite Ni/8-mol% yttria-stabilized zirconia (Ni/8YSZ) solid oxide cell (SOC) electrodes using a novel pseudo-3-electrode cell geometry. From OCV impedance spectra an activation energy Ea of 1.13 e......V, prefactor yan of 3.7·105·T, hydrogen and steam partial pressure dependencies a and b respectively of -0.07 and 0.22 were determined. DC current density vs. overpotential curves compared with those predicted using the determined kinetic parameters. Apparent Butler-Volmer charge transfer coefficients α were...... branch and the need for different α values for each branch suggests that a simple BV model of the measured electrode kinetics is insufficient and/or different reaction mechanisms might be occurring in anodic vs cathodic polarization....

Strong composition-dependence on glass-forming ability in Ni-(Ti,Zr)-Si pseudo-ternary alloys

International Nuclear Information System (INIS)

Yang, H.; Wang, J.Q.; Li, Y.

2006-01-01

The glass formation in Ni-(Ti,Zr)-Si pseudo-ternary alloys was studied. For suction casting, by carefully adjusting the alloy composition and studying the microstructure changes, the best glass-forming alloy with a 2 mm diameter is pinpointed in a narrow composition region of 57.5-58.5 at.% Ni, 36.5-38.5 at.% (Ti + Zr) and 5-5.5 at.% Si. The main competing crystalline phases, identified by XRD and SEM, were Ni 10 (Zr,Ti) 7 , Ni(Ti,Zr) and an unidentified Si-containing phase. Our results indicate a clear need for monitoring the microstructure change in the cross section of the ingots to locate the best glass-forming alloys

Vastly Enhanced BiVO4 Photocatalytic OER Performance by NiCoO2 as Cocatalyst

KAUST Repository

Palaniselvam, Thangavelu

2017-08-07

Here, a simple and efficient preparation of NiCoO nanoparticle modified nanoporous bismuth vanadate (BiVO) thin film and its application in photoelectrocatalytic (PEC) oxygen evolution reaction (OER) is demonstrated. The role of NiCoO in the composite electrode (BiVO/NiCoO) is twofold: OER cocatalyst and band structure modifier. It improves surface reaction kinetics for PEC OER and enhances charge separation efficiency simultaneously, which is believed to be a determining factor for the unprecedentedly high PEC OER performance of this BiVO/NiCoO nanocomposite. The photocurrent density of 3.6 mA cm at 1.23 V versus RHE in 0.1 m potassium phosphate buffered (pH = 7) electrolyte by BiVO/NiCoO is three times that of BiVO and significantly higher than most literature values. The BiVO/NiCoO nanocomposite shows/possess a high charge separation efficiency (η) of ≈72% as compared to only 23% for pure nanoporous BiVO at 1.23 V versus RHE, which demonstrates convincing role of NiCoO in the composite electrode. Both the excellent photocurrent density and great operational stability of this BiVO/NiCoO nanocomposite makes it a promising photocatalytic material for practical applications.

Preparation and characterization of NiW-nHA composite catalyst for hydrocracking

Science.gov (United States)

Zhou, Gang; Hou, Yongzhao; Liu, Lei; Liu, Hongru; Liu, Can; Liu, Jing; Qiao, Huiting; Liu, Wenyong; Fan, Yubo; Shen, Shituan; Rong, Long

2012-11-01

The synthesis, characterization and catalytic capability of the NiW-nano-hydroxyapatite (NiW-nHA) composite were investigated in this paper. The NiW-nHA catalyst was prepared by a co-precipitation method. Then Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX) were used to analyze this material. In addition, the catalytic capacity of the NiW-nHA composite was also examined by FT-IR and gas chromatography (GC). The results of FT-IR analysis indicated that Ni, W and nHA combined closely. TEM observation revealed that this catalyst was needle shaped and the crystal retained a nanometer size. XRD data also suggested that a new phase of CaWO4 appeared and the lattice parameters of nHA changed in this system. nHA was the carrier of metals. The rates of Ni/W-loading were 73.24% and 65.99% according to the EDX data, respectively. Furthermore, the conversion of 91.88% Jatropha oil was achieved at 360 °C and 3 MPa h-1 over NiW-nHA catalyst. The straight chain alkanes ranging from C15 to C18 were the main components in the production. The yield of C15-C18 alkanes was up to 83.56 wt%. The reaction pathway involved hydrocracking of the C&z.dbd;C bonds of these triglycerides from Jatropha oil. This paper developed a novel non-sulfided catalyst to obtain a ``green biofuel'' from vegetable oil.

Density of Ni-Al Alloys in Liquid and Solid-Liquid Coexistence State Measured by a Modified Pycnometric Method

Institute of Scientific and Technical Information of China (English)

Liang FANG; Feng XIAO; Zushu LI; Zainan TAO

2004-01-01

The density of Ni-Al alloys in both liquid state and solid-liquid coexistence state was measured with a modified pycnometric method. It was found that the density of NI-Al alloys decreases with increasing temperature and Al concentration in the alloys. The molar volume of liquid Ni-Al binary alloys increases with the increase of temperature and Al concentration. The partial molar volume of Al in NI-Al binary alloy was calculated approximately. The molar volume of liquid NI-Al alloy determined in the present work shows a negative deviation from the ideal linear molar volume.

Sintering behavior and thermal conductivity of nickel-coated graphite flake/copper composites fabricated by spark plasma sintering

Science.gov (United States)

Xu, Hui; Chen, Jian-hao; Ren, Shu-bin; He, Xin-bo; Qu, Xuan-hui

2018-04-01

Nickel-coated graphite flakes/copper (GN/Cu) composites were fabricated by spark plasma sintering with the surface of graphite flakes (GFs) being modified by Ni-P electroless plating. The effects of the phase transition of the amorphous Ni-P plating and of Ni diffusion into the Cu matrix on the densification behavior, interfacial microstructure, and thermal conductivity (TC) of the GN/Cu composites were systematically investigated. The introduction of Ni-P electroless plating efficiently reduced the densification temperature of uncoated GF/Cu composites from 850 to 650°C and slightly increased the TC of the X-Y basal plane of the GF/Cu composites with 20vol%-30vol% graphite flakes. However, when the graphite flake content was greater than 30vol%, the TC of the GF/Cu composites decreased with the introduction of Ni-P plating as a result of the combined effect of the improved heat-transfer interface with the transition layer, P generated at the interface, and the diffusion of Ni into the matrix. Given the effect of the Ni content on the TC of the Cu matrix and on the interface thermal resistance, a modified effective medium approximation model was used to predict the TC of the prepared GF/Cu composites.

Microstructure of Vacuum-Brazed Joints of Super-Ni/NiCr Laminated Composite Using Nickel-Based Amorphous Filler Metal

Science.gov (United States)

Ma, Qunshuang; Li, Yajiang; Wu, Na; Wang, Juan

2013-06-01

Vacuum brazing of super-Ni/NiCr laminated composite and Cr18-Ni8 stainless steel was carried out using Ni-Cr-Si-B amorphous filler metal at 1060, 1080, and 1100 °C, respectively. Microstructure and phase constitution were investigated by means of optical and scanning electron microscopy, energy-dispersive spectroscopy, x-ray diffraction, and micro-hardness tester. When brazed at 1060-1080 °C, the brazed region can be divided into two distinct zones: isothermally solidified zone (ISZ) consisting of γ-Ni solid solution and athermally solidified zone (ASZ) consisting of Cr-rich borides. Micro-hardness of the Cr-rich borides formed in the ASZ was as high as 809 HV50 g. ASZ decreased with increase of the brazing temperature. Isothermal solidification occurred sufficiently at 1100 °C and an excellent joint composed of γ-Ni solid solution formed. The segregation of boron from ISZ to residual liquid phase is the reason of Cr-rich borides formed in ASZ. The formation of secondary precipitates in diffusion-affected zone is mainly controlled by diffusion of B.

A nano-structured Ni(II)-chelidamic acid modified gold nanoparticle self-assembled electrode for electrocatalytic oxidation and determination of methanol

Energy Technology Data Exchange (ETDEWEB)

Gholivand, Mohammad Bagher, E-mail: mbgholivand@yahoo.com [Department of Analytical Chemistry, Faculty of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Azadbakht, Azadeh [Department of Chemistry, Faculty of Basic Science, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-10-01

A nano-structured Ni(II)-chelidamic acid (2,6-dicarboxy-4-hydroxypyridine) film was electrodeposited on a gold nanoparticle-cysteine-gold electrode. The morphology of Ni(II)-chelidamic acid gold nanoparticle self-assembled electrode was investigated by scanning electron microscopy (SEM). Electrocatalytic oxidation of methanol on the surface of modified electrode was studied by cyclic voltammetry and chronoamperometry methods. The hydrodynamic amperometry at a rotating modified electrode at constant potential versus reference electrode was used for detection of methanol. Under optimized conditions the calibration plots are linear in the concentration range 0-50 mM with a detection limit of 15 {mu}M. The formed matrix in our work possessed a 3D porous network structure with a large effective surface area, high catalytic activity and behaved like microelectrode ensembles. The modified electrode indicated reproducible behavior and a high level stability during the experiments, making it particularly suitable for analytical purposes. - Highlights: Black-Right-Pointing-Pointer The Au electrode modified with thin Ni(II)/CHE-AuNP film shows stable and reproducible behavior. Black-Right-Pointing-Pointer Long stability and excellent electrochemical reversibility were observed. Black-Right-Pointing-Pointer This modified electrode shows excellent catalytic activity for methanol oxidation. Black-Right-Pointing-Pointer Combination of unique properties of AuNP and Ni(II)/CHE resulted in improvement of current responses.

Nanostructural and magnetic studies of virtually monodispersed NiFe2O4 nanocrystals synthesized by a liquid–solid-solution assisted hydrothermal route

International Nuclear Information System (INIS)

Li Xinghua; Tan Guoguo; Chen Wei; Zhou Baofan; Xue Desheng; Peng Yong; Li, Fashen; Mellors, Nigel J.

2012-01-01

This study presents a comprehensively and systematically structural, chemical and magnetic characterization of ∼9.5 nm virtually monodispersed nickel ferrite (NiFe 2 O 4 ) nanoparticles prepared using a modified liquid–solid-solution (LSS) assisted hydrothermal method. Lattice-resolution scanning transmission electron microscope (STEM) and converged beam electron diffraction pattern (CBED) techniques are adapted to characterize the detailed spatial morphology and crystal structure of individual NiFe 2 O 4 particles at nano scale for the first time. It is found that each NiFe 2 O 4 nanoparticle is single crystal with an fcc structure. The morphology investigation reveals that the prepared NiFe 2 O 4 nanoparticles of which the surfaces are decorated by oleic acid are dispersed individually in hexane. The chemical composition of nickel ferrite nanoparticles is measured to be 1:2 atomic ratio of Ni:Fe, indicating a pure NiFe 2 O 4 composition. Magnetic measurements reveal that the as-synthesized nanocrystals displayed superparamagnetic behavior at room temperature and were ferromagnetic at 10 K. The nanoscale characterization and magnetic investigation of monodispersed NiFe 2 O 4 nanoparticles should be significant for its potential applications in the field of biomedicine and magnetic fluid using them as magnetic materials.

Electrophoretic deposition of 9-YSZ solid electrolyte on Ni- YSZ composite

International Nuclear Information System (INIS)

Santos, F.S.; Yoshito, W.K.; Lazar, D.R.R.; Ussui, V.

2010-01-01

9-YSZ ceramic and Ni-YSZ metal/ceramic composite are the more commonly used materials for the fabrication of solid oxide fuel cell electrolyte and anode, respectively. The main challenges for these applications are the forming of both materials as superposed double thin layers. In the present work ceramic powder of 9- YSZ was synthesized by a coprecipitation technique and the Ni O-YSZ composite by a combustion technique. The later was formed by uniaxial pressing as cylindrical pellets of 15 mm diameter. Thin ceramic layers of 9-YSZ were deposited on composite pellets from a suspension with 10% solid content by an Electrophoretic Deposition technique. Applied voltage varied in the range of 30 to 200 V and deposition time from 15 to 90 seconds, evaluating the deposited mass, porosity on the interface and adhesion of layers. Resulted ceramics were characterized by X-ray diffraction and were observed in a scanning electron microscope. Results showed that deposited layers are thin (∼20μm), dense and have good adhesion on the surface of composite substrate. (author)

Magnetization reversal process and nonlinear magneto-impedance in Cu/NiFe and Nb/NiFe composite wires

Energy Technology Data Exchange (ETDEWEB)

Antonov, A.S.; Buznikov, N.A. E-mail: n_buznikov@mail.ru; Granovsky, A.B.; Iakubov, I.T.; Prokoshin, A.F.; Rakhmanov, A.L.; Yakunin, A.M

2002-08-01

The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors.

Magnetization reversal process and nonlinear magneto-impedance in Cu/NiFe and Nb/NiFe composite wires

International Nuclear Information System (INIS)

Antonov, A.S.; Buznikov, N.A.; Granovsky, A.B.; Iakubov, I.T.; Prokoshin, A.F.; Rakhmanov, A.L.; Yakunin, A.M.

2002-01-01

The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors

Fabrication of BaTiO{sub 3}/Ni composite particles and their electro-magneto responsive properties

Energy Technology Data Exchange (ETDEWEB)

Lu, Yaping [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Gao, Lingxiang, E-mail: gaolx@snnu.edu.cn [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Wang, Lijuan [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Xie, Zunyuan, E-mail: zyxie123@snnu.edu.cn [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China); Gao, Meixiang [Yulin Vocational and Technical College, Yulin 719000 (China); Zhang, Weiqiang [Key Laboratory of Applied Surface and Colloid Chemistry (Shaanxi Normal University), Ministry of Education, Xi’an 710119 (China); School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi’an 710119 (China)

2017-07-15

Graphical abstract: The spherical BaTiO{sub 3}/Ni particles with excellent structure were made by one-step method through fixing the metal Ni(0) reduced by a specific reducing agent (N{sub 2}H{sub 4}·H{sub 2}O) on the surface of the BaTiO{sub 3} particles with grain diameter of ∼500 nm. BaTiO{sub 3}/Ni particle has double responses of electric and magnetic field simultaneously. Consequentially, coating magnetic metal on BT particle is proposed an effective method to prepare novel electro-magneto responsive particles and one basis of electro-magneto responsive elastomers. - Highlights: • The BaTiO{sub 3}/Ni composite particles were fabricated. • The content of Ni(0) in nickel sheath is 70.2%. • The BaTiO{sub 3}/Ni particles have double responses of electric and magnetic field. - Abstract: BaTiO{sub 3} (BT)/Ni composite particles were made by one-step method through agglomerating the metal Ni(0) nanoparticles reduced by a specific reducing agent (N{sub 2}H{sub 4}·H{sub 2}O) on the surface of BT sphere with diameter of ∼500 nm. The BT/Ni composite particles were characterized by the means of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS). In BT/Ni particles, pure BT spherical particle was coated with Ni nanoparticles agglomerated on its surface. The average thickness of the Ni sheath was ∼30 nm and the content of Ni(0) and Ni (II) in the sheath were 70.2% and 29.8%, respectively. The responsive effects of BT/Ni particles filled in hydrogel elastomer were investigated by the viscoelastic properties. The results indicate that the BT/Ni particles exhibit electro and magneto coordinated responsive properties (E = 1 kV/mm, H = 0.1 T/mm), which is superior to BT particles with individual electro response.

The converse magnetoelectric coupling in asymmetric granule/matrix composite film with Ni/PZT component

Science.gov (United States)

Chen, Bo; Su, Ning-Ning; Cui, Wen-Li; Yan, Shi-Nong

2018-04-01

In this work, a type of asymmetric granule/matrix composite film is designed, where the Ni granule is dispersed in PZT matrix, meanwhile the top and bottom electrode is constituted by Au and SRO respectively. Predicted through the electrostatic screening model and mean field approximation, considerable electrostatic charge is induced on Ni granule surface by ferroelectric PZT polarization. Predicted through the spin splitting model and spherical shell approximation, both the magnetization and magnetic anisotropy of Ni granule are modulated by ferroelectric PZT polarization. As the volume fraction of Ni granule is increased, the electric modulation of magnetization and magnetic anisotropy is reduced and enhanced respectively. As the dimension of granule/matrix composite is varied, such modulation is retained. Due to the large area-volume ratio of nano-granule, this work benefits to realize the converse magnetoelectric coupling in nanoscale.

Microstructure and wear characteristics on Al alloy matrix composite reinforced with Ni perform

Energy Technology Data Exchange (ETDEWEB)

Park, Won Jo; Park, Cheol Hong; Kim, Hyung Jin; Huh, Sun Chul [Gyeongsang National University, Tongyeong, (Korea, Republic of)

2012-06-15

Al based composite reinforced with Nickel is used for diesel engine piston, because the thermal properties, strength and corrosion resistant are for better than Al alloy alone. For processing, the intermetallic compounds of Ni and Al improves wear resistance due to its high hardness. Existing process methods for MMC (metal matrix composite) using preform were manufactured under high-pressure. However, this causes deformation of the preform or weaknesses in the completed MMC. Low-pressure infiltration can prevent these problems, and there is an advantage of cost reduction in of production with small-scale of production equipment. In this study, the microstructure and wear characteristics of Al-based composite with Ni preform as reinforcement with low-pressure infiltration was analyzed.

The change of NiCrBSi alloys’ phase composition after plasma spraying

Directory of Open Access Journals (Sweden)

A. Dudek

2008-08-01

Full Text Available Material for investigations was NiCrBSi powder for components’ coatings which improve their corrosion resistance as well as resistance to friction wear and erosion. Plasma spraying method was used to produce a coating with thickness of 300 μm on low-alloy steel which was then remelted with the base material. Using X-ray quality analysis, phase composition was determined for: NiCrBSi powder, obtained coating and the alloyed surface layer. Crystallinity degree was also calculated for NiCrBSi layer sprayed on the base material.

Physico-Chemical and Electrochemical Properties of Nanoparticulate NiO/C Composites for High Performance Lithium and Sodium Ion Battery Anodes

Directory of Open Access Journals (Sweden)

Amaia Iturrondobeitia

2017-12-01

Full Text Available Nanoparticulate NiO and NiO/C composites with different carbon proportions have been prepared for anode application in lithium and sodium ion batteries. Structural characterization demonstrated the presence of metallic Ni in the composites. Morphological study revealed that the NiO and Ni nanoparticles were well dispersed in the matrix of amorphous carbon. The electrochemical study showed that the lithium ion batteries (LIBs, containing composites with carbon, have promising electrochemical performances, delivering specific discharge capacities of 550 mAh/g after operating for 100 cycles at 1C. These excellent results could be explained by the homogeneity of particle size and structure, as well as the uniform distribution of NiO/Ni nanoparticles in the in situ generated amorphous carbon matrix. On the other hand, the sodium ion battery (NIB with the NiO/C composite revealed a poor cycling stability. Post-mortem analyses revealed that this fact could be ascribed to the absence of a stable Solid Electrolyte Interface (SEI or passivation layer upon cycling.

Composition pathway in Fe–Cu–Ni alloy during coarsening

International Nuclear Information System (INIS)

Mukherjee, Rajdip; Nestler, Britta; Choudhury, Abhik

2013-01-01

In this work the microstructure evolution for a two phase Fe–Cu–Ni ternary alloy is studied in order to understand the kinetic composition paths during coarsening of precipitates. We have employed a quantitative phase-field model utilizing the CALPHAD database to simulate the temporal evolution of a multi-particle system in a two-dimensional domain. The paths for the far-field matrix and for precipitate average compositions obtained from simulation are found to be rectilinear. The trends are compared with the corresponding sharp interface theory, in the context of an additional degree of freedom for determining the interface compositions due to the Gibbs–Thomson effect in a ternary alloy. (paper)

Composition pathway in Fe-Cu-Ni alloy during coarsening

Science.gov (United States)

Mukherjee, Rajdip; Choudhury, Abhik; Nestler, Britta

2013-10-01

In this work the microstructure evolution for a two phase Fe-Cu-Ni ternary alloy is studied in order to understand the kinetic composition paths during coarsening of precipitates. We have employed a quantitative phase-field model utilizing the CALPHAD database to simulate the temporal evolution of a multi-particle system in a two-dimensional domain. The paths for the far-field matrix and for precipitate average compositions obtained from simulation are found to be rectilinear. The trends are compared with the corresponding sharp interface theory, in the context of an additional degree of freedom for determining the interface compositions due to the Gibbs-Thomson effect in a ternary alloy.

High-frequency permeability of electroplated CoNiFe and CoNiFe-C alloys

International Nuclear Information System (INIS)

Rhen, Fernando M.F.; McCloskey, Paul; O'Donnell, Terence; Roy, Saibal

2008-01-01

We have investigated CoNiFe and CoNiFe-C electrodeposited by pulse reverse plating (PRP) and direct current (DC) techniques. CoNiFe(PRP) films with composition Co 59.4 Fe 27.7 Ni 12.8 show coercivity of 95 A m -1 (1.2 Oe) and magnetization saturation flux (μ 0 M s ) of 1.8 T. Resistivity of CoNiFe (PRP) is about 24 μΩ cm and permeability remains almost constant μ r ' ∼475 up to 30 MHz with a quality factor (Q) larger than 10. Additionally, the permeability spectra analysis shows that CoNiFe exhibits a classical eddy current loss at zero bias field and ferromagnetic resonance (FMR) when biased with 0.05 T. Furthermore, a crossover between eddy current and FMR loss is observed for CoNiFe-PRP when baised with 0.05 T. DC and PRP plated CoNiFe-C, which have resistivity and permeability of 85, 38 μΩ cm, μ r '=165 and 35 with Q>10 up to 320 MHz, respectively, showed only ferromagnetic resonance losses. The ferromagnetic resonance peaks in CoNiFe and CoNiFe-C are broad and resembles a Gaussian distribution of FMR frequencies. The incorporation of C to CoNiFe reduces eddy current loss, but also reduces the FMR frequency

Preparation and mechanical properties of in situ TiC{sub x}–Ni (Si, Ti) alloy composites

Energy Technology Data Exchange (ETDEWEB)

Wang, Wenjuan [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhai, Hongxiang, E-mail: hxzhai@sina.com [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Chen, Lin; Huang, Zhenying [Institute of Materials Science and Engineering, School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Bei, Guoping; Baumgärtner, Christoph; Greil, Peter [Department of Materials Science (Glass and Ceramics), University of Erlangen-Nuernberg, Martensstr. 5, 91058 Erlangen (Germany)

2014-10-20

Novel in situ TiC{sub x} reinforced Ni (Si, Ti) alloy composites with superior mechanical properties were prepared at 1250 °C for 30 min by pressureless sintering Ti{sub 3}SiC{sub 2} (10 and 20 vol%) and Ni as precursors. The Ti{sub 3}SiC{sub 2} particles decomposed into substoichiometric TiC{sub x} phase, while the additional Si and partial Ti atoms derived from Ti{sub 3}SiC{sub 2} diffused into Ni matrix to form Ni (Si, Ti) alloy. The in situ formed TiC{sub x} phases are mainly dispersed on the grain boundaries of the Ni (Si, Ti) alloying, forming a strong skeleton and refining the microstructures of the metal matrix. The hardness, the yield stress σ{sub 0.2%} and ultimate compressive strength of 20.6 vol%TiC{sub x}–Ni(Si, Ti) composite can reach 2.15±0.04 GPa, 466.8±55.8 MPa and 733.3±78.4 MPa, respectively. The enhanced mechanical properties of TiC{sub x}–Ni(Si, Ti) composites are due to the in situ formation of TiC{sub x} skeleton, the refined microstructures of Ni (Si, Ti) alloys and solid solution effects as well as good wettability between TiC{sub x} and Ni (Si, Ti) matrix.

Hydrothermal Synthesis and Structural Characterization of NiO/SnO2 Composites and Hydrogen Sensing Properties

Directory of Open Access Journals (Sweden)

Chao Wei

2015-01-01

Full Text Available Pure SnO2 and NiO doped SnO2 nanostructures were successfully synthesized via a simple and environment-friendly hydrothermal method. X-ray powder diffraction (XRD, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS, and X-ray photoelectron spectra (XPS were used to investigate the crystalline structures, surface morphologies and microstructures, and element components and their valences of the as-synthesized samples. Furthermore, planar chemical gas sensors based on the synthesized pure SnO2 and NiO/SnO2 composites were fabricated and their sensing performances to hydrogen, an important fault characteristic gas dissolved in power transformer oil, were investigated in detail. Gas sensing experiments indicate that the NiO/SnO2 composites showed much higher gas response and lower working temperature than those of pure SnO2, which could be ascribed to the formation of p-n heterojunctions between p-type NiO and n-type SnO2. These results demonstrate that the as-synthesized NiO/SnO2 composites a promising hydrogen sensing material.

Shock response of Ni/Al reactive inter-metallic composites

Science.gov (United States)

Cherukara, Mathew; Germann, Timothy; Kober, Edward; Strachan, Alejandro

2014-03-01

Intermolecular reactive composites find diverse applications in defense, microelectronics and medicine, where strong, localized sources of heat are required. Motivated by experimental work which has shown that high-energy ball milling can significantly improve the reactivity as well as the ease of ignition of Ni/Al inter-metallic composites, we present large scale (~41 million atom) molecular dynamics simulations of shock-induced chemistry in porous, polycrystalline, lamellar Ni/Al nano-composites, which are designed to capture the microstructure that is obtained post milling. Shock propagation in these porous, lamellar materials is observed to be extremely diffuse, leading to substantial inhomogeneity in the local stress states of the material. We describe the importance of pores as sites of initiation, where local temperatures can rise to several thousands of degrees, and chemical mixing is accelerated by vortex formation and jetting in the pore. We also follow the evolution of the chemistry after the shock passage by allowing the sample to ``cook'' under the shock induced pressures and temperatures for up to 0.5 ns. Multiple ``tendril-like'' reaction fronts, born in the cauldron of the pores, propagate rapidly through the sample, consuming it within a nanosecond. US Defense Threat Reduction Agency, Contract No. HDTRA1-10-1-0119.

Microstructure of a Ni Matrix Composite Coating Reinforced by In-situ TiC Particles Using Plasma Cladding

Institute of Scientific and Technical Information of China (English)

WUYu-ping; WANGZe-hua; LINPing-hua

2004-01-01

Plasma cladding process was used to prepare the TiC/Ni composite coating on the mild steel substrates. The TiC particles were synthesized in-situ. Microstructure and properties of the coating were investigated by optical microscopy, X-Ray diffraction, SEM, TEM and microhardness tester. The results show that the interface between the coating and the substrate is metallurgically bonded. The coating was uniform and almost defect-free when [Ti+C] varied from 10% to 20% after ball milling. The microstructure of the coating is mainly composed of γ-Ni dendrite, interdendritic eutectic (γ-Ni austenite, M23C6 and CrB) and TiC particles. Most of the TiC particles are spherical and a small fraction is blocky in size of 1-2μm. The TiC particles are smaller at the bottom than near the top of the coating. The coating has a gradient microstructure and a highest hardness of 1000Hv0.1.

Post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin

International Nuclear Information System (INIS)

Yap, A.U.J.

1997-01-01

This study examined the post-irradiation hardness of resin-modified glass ionomer cements and a polyacid-modified composite resin using a digital microhardness tester. Change in hardness of these materials over a period of 6 months was compared to that of conventional glass ionomer cements and a composite resin. With the exception of the composite resin, all materials showed a significant increase in hardness over 24 h after their initial set. Dual-cure resin-modified glass ionomer cements showed decreased hardness with increased storage time in saline at 37 o C. Results suggest that the addition of resins to glass ionomer cements does not improve initial hardness and does not negate the acid-base reaction of conventional cements. Resin addition may, however, lead to increased water sorption and decreased hardness. (author)

Strong and anisotropic magnetoelectricity in composites of magnetostrictive Ni and solid-state grown lead-free piezoelectric BZT–BCT single crystals

Directory of Open Access Journals (Sweden)

Haribabu Palneedi

2017-03-01

Full Text Available Aimed at developing lead-free magnetoelectric (ME composites with performances as good as lead (Pb-based ones, this study employed (001 and (011 oriented 82BaTiO3-10BaZrO3-8CaTiO3 (BZT–BCT piezoelectric single crystals, fabricated by the cost-effective solid-state single crystal growth (SSCG method, in combination with inexpensive, magnetostrictive base metal Nickel (Ni. The off-resonance, direct ME coupling in the prepared Ni/BZT–BCT/Ni laminate composites was found to be strongly dependent on the crystallographic orientation of the BZT–BCT single crystals, as well as the applied magnetic field direction. Larger and anisotropic ME voltage coefficients were observed for the composite made using the (011 oriented BZT–BCT single crystal. The optimized ME coupling of 1 V/cm Oe was obtained from the Ni/(011 BZT–BCT single crystal/Ni composite, in the d32 mode of the single crystal, when a magnetic field was applied along its [100] direction. This performance is similar to that reported for the Ni/Pb(Mg1/3Nb2/3O3-Pb(Zr,TiO3 (PMN–PZT single crystal/Ni, but larger than that obtained from the Ni/Pb(Zr,TiO3 ceramic/Ni composites. The results of this work demonstrate that the use of lead-free piezoelectric single crystals with special orientations permits the selection of desired anisotropic properties, enabling the realization of customized ME effects in composites.

Catalytic upgrading of oleic acid into biofuel using Mo modified zeolite supported Ni oxalate catalyst functionalized with fluoride ion

International Nuclear Information System (INIS)

Ayodele, O.B.; Abbas, Hazzim F.; Daud, Wan Mohd Ashri Wan

2014-01-01

Highlights: • Modification of zeolite with freshly prepared molybdenum oxalate. • Functionalization of Ni oxalate with HF and incorporation into Mo modified zeolite. • Characterization of synthesized Mo modified zeolite supported Ni oxalate catalyst. • Deoxygenation of oleic acid with the synthesized zeolite supported catalyst. • Reusability study on the synthesized zeolite supported catalyst. - Abstract: In this study, fluoride ion functionalized nickel oxalate supported on molybdenum modified zeolite (NiMoFOx/Zeol) catalyst was synthesized, characterized and tested on the hydrodeoxygenation (HDO) of oleic acid (OA) into paraffinic fuel. The NiMoFOx/Zeol characterization results confirmed the presence of both Ni and Mo as well as the formation of NiMoO 4 which is a highly HDO reactive specie at 2θ value of 43.6° according to the XRD result. NiMoFOx/Zeol also showed loss in crystallinity and reduction in the average particle size leading to increase in the pore volume and specific surface area due to the combined effects of fluoride ion presence, oxalic acid functionalization and calcination. The effect of temperature, pressure and NiMoFOx/Zeol loading studied showed that initial increase in their values increased the yield of the target fractions until some points where reduction was observed. The best observed experimental conditions to hydrodeoxygenate 40 g (∼45 mL) of OA into 75% n-C 18 and 23% i-C 18 were 360 °C, 30 mg NiMoFOx/Zeol loading and 20 bar using 100 mL H 2 /min. The presence of i-C 18 was due to the functionalization of the catalyst with fluoride ion. The catalyst reusability result displayed excellent qualities with marginal loss of only 2% in activity after third reuse due to the improved synthesis protocol that employed organometallic precursor. The results are strongly encouraging for further studies toward industrialization of HDO process

Investigation of protein adsorption performance of Ni2+-attached diatomite particles embedded in composite monolithic cryogels.

Science.gov (United States)

Ünlü, Nuri; Ceylan, Şeyda; Erzengin, Mahmut; Odabaşı, Mehmet

2011-08-01

As a low-cost natural adsorbent, diatomite (DA) (2 μm) has several advantages including high surface area, chemical reactivity, hydrophilicity and lack of toxicity. In this study, the protein adsorption performance of supermacroporous composite cryogels embedded with Ni(2+)-attached DA particles (Ni(2+)-ADAPs) was investigated. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic composite cryogel column embedded with Ni(2+)-ADAPs was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N'-methylene-bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for affinity purification of human serum albumin (HSA) both from aqueous solutions and human serum. The chemical composition and surface area of DA was determined by XRF and BET method, respectively. The characterization of composite cryogel was investigated by SEM. The effect of pH, and embedded Ni(2+)-ADAPs amount, initial HSA concentration, temperature and flow rate on adsorption were studied. The maximum amount of HSA adsorption from aqueous solution at pH 8.0 phosphate buffer was very high (485.15 mg/g DA). It was observed that HSA could be repeatedly adsorbed and desorbed to the embedded Ni(2+)-ADAPs in poly(2-hydroxyethyl methacrylate) composite cryogel without significant loss of adsorption capacity. The efficiency of albumin adsorption from human serum before and after albumin adsorption was also investigated with SDS-PAGE analyses. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dilute NiO/carbon nanofiber composites derived from metal organic framework fibers as electrode materials for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Yang, Ying; Yang, Feng; Hu, Hongru; Lee, Sungsik; Wang, Yue; Zhao, Hairui; Zeng, Dehong; Zhou, Biao; Hao, Shijie

2017-01-01

A new type of carbon nanofiber (CNF) dominated electrode materials decorated with dilute NiO particles (NiO/CNF) has been in situ fabricated by direct pyrolysis of Ni, Zn-containing metal organic framework fibers, which are skillfully constructed by assembling different proportional NiCl2·6H2O and Zn(Ac)2·2H2O with trimesic acid in the presence of N,N-dimethylformamide. With elegant combination of advantages of CNF and evenly dispersed NiO particles, as well as successful modulation of conductivity and porosity of final composites, our NiO/CNF composites display well-defined capacitive features. A high capacitance of 14926 F g–1 was obtained in 6 M KOH electrolyte when the contribution from 0.43 wt% NiO was considered alone, contributing to over 35% of the total capacitance (234 F g–1 ). This significantly exceeds its theoretical specific capacitance of 2584 F g–1. It has been established from the Ragone plot that a largest energy density of 33.4 Wh kg–1 was obtained at the current density of 0.25 A g–1. Furthermore, such composite electrode materials show good rate capability and outstanding cycling stability up to 5000 times (only 10% loss). The present study provides a brand-new approach to design a high capacitance and stable supercapacitor electrode and the concept is extendable to other composite materials. Keywords: Metal organic framework; Nickel oxide; Carbon nanofiber; In situ synthesis; Capacitance

Laser cladding Ni-base composite coating on titanium alloy with pre-placed B4C+NiCoCrAlY

International Nuclear Information System (INIS)

Qingwu Meng; Lin Geng; Zhenzhu Zheng

2005-01-01

Using a CO 2 laser, a process of cladding Ni-base composite coating on Ti6Al4V with pre-placed B 4 C and NiCoCrAlY was studied. A good metallurgical bonding coating without cracks and pores was obtained in reasonable ratio of components and low energy laser process. Morphology and microstructure of the coating were analyzed with OM, XRD, SEM and EDS. It is certain that there was a reaction between B 4 C and Ti during in-situ producing TiB 2 and TiC. The Ni-base composite coating is strengthened with TiB 2 and TiC reinforcement phases. Vickers hardness tester measured that the average microhardness of the coating is HV1200 and it is 3.5 times of the Ti6Al4V substrate. The high hard coating containing several reinforcement phases greatly enhances wear resistance of titanium alloy. (orig.)

Understanding micro-diffusion bonding from the fabrication of B4C/Ni composites

Science.gov (United States)

Wang, Miao; Wang, Wen-xian; Chen, Hong-sheng; Li, Yu-li

2018-03-01

A Ni-B4C macroscopic diffusion welding couple and a Ni-15wt%B4C composite fabricated by spark plasma sintering (SPS) were used to understand the micro-scale diffusion bonding between metals and ceramics. In the Ni-B4C macroscopic diffusion welding couple a perfect diffusion welding joint was achieved. In the Ni-15wt%B4C sample, microstructure analyses demonstrated that loose structures occurred around the B4C particles. Energy dispersive X-ray spectroscopy analyses revealed that during the SPS process, the process of diffusion bonding between Ni and B4C particles can be divided into three stages. By employing a nano-indentation test, the room-temperature fracture toughness of the Ni matrix was found to be higher than that of the interface. The micro-diffusion bonding between Ni and B4C particles is quite different from the Ni-B4C reaction couple.

Large energy absorption in Ni-Mn-Ga/polymer composites

International Nuclear Information System (INIS)

Feuchtwanger, Jorge; Richard, Marc L.; Tang, Yun J.; Berkowitz, Ami E.; O'Handley, Robert C.; Allen, Samuel M.

2005-01-01

Ferromagnetic shape memory alloys can respond to a magnetic field or applied stress by the motion of twin boundaries and hence they show large hysteresis or energy loss. Ni-Mn-Ga particles made by spark erosion have been dispersed and oriented in a polymer matrix to form pseudo 3:1 composites which are studied under applied stress. Loss ratios have been determined from the stress-strain data. The loss ratios of the composites range from 63% to 67% compared to only about 17% for the pure, unfilled polymer samples

Studies on SiC(p) reinforced Al-Al sub 3 Ni eutectic matrix composites

International Nuclear Information System (INIS)

Masrom, A.K.; Foo, L.C.; Ismail, A.B.

1996-01-01

An investigation on processing of Al-5.69wt% Ni eutectic with SiC particulate composites is reported. The intermetallic composites are prepared by elemental powder metallurgy route and sintered at two different temperatures, i.e., 600 degree C and 620 degree C. Results show that the metal matrix was Al-Al sub 3 Ni eutectic. The phase analysis by XRD identified the presence of Al sub 3 Ni and Al as dominant phases together with silicon and Al sub 4 C sub 3 phase as minor phases. The Al sub 4 C sub 3 and Si phases are formed during sintering due to SiC-Al interface reaction. SEM micrographs also reveal the formation of microvoid surrounding the SiC particle

Microstructure evolution and shear strength of vacuum brazed joint for super-Ni/NiCr laminated composite with Ni–Cr–Si–B amorphous interlayer

International Nuclear Information System (INIS)

Wu, Na; Li, Yajiang; Ma, Qunshuang

2014-01-01

Highlights: • Divorced eutectic of γ-Ni and Ni 3 B formed in the brazed region. • The detailed isothermal solidification mechanism was proposed. • Borides formed at the interfaces at different temperatures were identified. • Effect of brazing temperatures on microstructure and shear strength was investigated. • Excellent joint with shear strength of 191 MPa was obtained at 1100 °C for 20 min. - Abstract: Vacuum brazing of super-Ni/NiCr laminated composite and Cr18–Ni8 steel was carried out with Ni–Cr–Si–B amorphous interlayer at different temperatures (1060–1150 °C). The effects of brazing temperature on the microstructure evolution and shear strength of the joints were investigated. Microstructure, chemical composition and microhardness of the joints were studied using field emission scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction and microsclerometer. Shear strength of the joints were measured by the electromechanical universal testing machine. Diffusion of B was the controlling factor for microstructure evolution. The detailed isothermal solidification mechanism was proposed in this study. The fracture morphology of the joint made at 1100 °C exhibited plastic feature and the shear strength reached 191 MPa. Bulky Ni 3 B formed in super-Ni cover layer near the brazed region when performed at 1060–1100 °C while Ni–B eutectic formed instead at 1150 °C

NiTi-polyimide composites prepared using thermal imidization process

Czech Academy of Sciences Publication Activity Database

Vokoun, David; Sysel, P.; Heller, Luděk; Kadeřávek, L.; Svatuška, Michal; Goryczka, T.; Kafka, Vratislav; Šittner, Petr

2016-01-01

Roč. 25, č. 5 (2016), 1993-1999 ISSN 1059-9495 R&D Projects: GA ČR GC15-13174J; GA ČR GA14-15264S Institutional support: RVO:68378271 ; RVO:68378297 Keywords : actuator * composite * model * NiTi * polyimide * residual * stress Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.331, year: 2016

Processing of composites based on NiO, samarium-doped ceria and carbonates (NiO-SDCC as anode support for solid oxide fuel cells

Directory of Open Access Journals (Sweden)

Lily Siong Mahmud

2017-09-01

Full Text Available NiO-SDCC composites consisting of NiO mixed with Sm-doped ceria (SDC and carbonates (Li2CO3 and Na2CO3 were sintered at different temperatures and reduced at 550 °C. The influence of reduction on structure of the NiO-SDCC anode support for solid oxide fuel cells (SOFCs was investigated. Raman spectra of the NiO-SDCC samples sintered at 500, 600 and 700 °C showed that after reducing at 550 °C NiO was reduced to Ni. In addition, SDC and carbonates (Li2CO3 and Na2CO3 did not undergo chemical transformation after reduction and were still detected in the samples. However, no Raman modes of carbonates were identified in the NiO-SDCC pellet sintered at 1000 °C and reduced at 550 °C. It is suspected that carbonates were decomposed at high sintering temperature and eliminated due to the reaction between the CO32– and hydrogen ions during reduction in humidified gases at 550 °C. The carbonate decomposition increased porosity in the Ni-SDCC pellets and consequently caused formation of brittle and fragile structure unappropriated for SOFC application. Because of that composite NiO-SDC samples without carbonates were also analysed to determine the factors affecting the crack formation. In addition, it was shown that the different reduction temperatures also influenced the microstructure and porosity of the pellets. Thus, it was observed that Ni-SDC pellet reduced at 800 °C has higher electrical conductivity of well-connected microstructures and sufficient porosity than the pellet reduced at 550 °C.

Preparation, characteristics and electrochemical properties of surface-modified LiMn2O4 by doped LiNi0.05Mn1.95O4

International Nuclear Information System (INIS)

Yuan, Y.F.; Wu, H.M.; Guo, S.Y.; Wu, J.B.; Yang, J.L.; Wang, X.L.; Tu, J.P.

2008-01-01

The surface-modified spinel LiMn 2 O 4 by doped LiNi 0.05 Mn 1.95 O 4 was prepared by a tartaric acid gel method. Transmission electron microscope (TEM) images indicated that some small particles with 100-200 nm in diameter modified the surface of large particle LiMn 2 O 4 . Energy dispersive spectrometry (EDS) showed that the particles were LiNi 0.05 Mn 1.95 O 4 . Electrochemical properties of LiNi 0.05 Mn 1.95 O 4 -modified spinel LiMn 2 O 4 were intensively investigated by the galvanostatic charge-discharge tests, cyclic voltammetry (CV) and AC impedance measurements. The doped LiNi 0.05 Mn 1.95 O 4 -modified LiMn 2 O 4 cathode delivered the same initial discharge capacity as the unmodified LiMn 2 O 4 , but its cyclic stability was evidently improved, the capacity retention ratio reached 96% after 20 cycles, being higher than 89% of the unmodified LiMn 2 O 4 . Cyclic voltammograms of the LiNi 0.05 Mn 1.95 O 4 -modified LiMn 2 O 4 did not markedly change while the semicircle diameter of AC impedance spectra evidently decreased after 20 cycles, which showed that the surface modification with LiNi 0.05 Mn 1.95 O 4 improved the electrochemical activity and cycling stability of LiMn 2 O 4 .

Understanding the effect of compositions on electronegativity, atomic radius and thermal stability of Mg-Ni-Y amorphous alloy

Science.gov (United States)

Deshmukh, A. A.; Kuthe, S. A.; Palikundwar, U. A.

2018-05-01

In the present paper, the consequences of variation in compositions on the electronegativity (ΔX), atomic radius difference (δ) and the thermal stability (ΔTx) of Mg-Ni-Y bulk metallic glasses (BMGs) are evaluated. In order to understand the effect of variation in compositions on ΔX, δ and ΔTx, regression analysis is performed on the experimentally available data. A linear correlation between both δ and ΔX with regression coefficient 0.93 is observed. Further, compositional variation is performed with δ and then it is correlated to the ΔTx by deriving subsequent equations. It is observed that concentration of Mg, Ni and Y are directly proportional to the δ with regression coefficients 0.93, 0.93 and 0.50 respectively. The positive slope of Ni and Y stated that ΔTx will increase if it has more contribution from both Ni and Y. On the other hand negative slope stated that composition of Mg should be selected in such a way that it will have more stability with Ni and Y. The results obtained from mathematical calculations are also tested by regression analysis of ΔTx with the compositions of individual elements in the alloy. These results conclude that there is a strong dependence of ΔTx of the alloy on the compositions of the constituting elements in the alloy.

Rapid microwave-assisted synthesis of mesoporous NiMoO_4 nanorod/reduced graphene oxide composites for high-performance supercapacitors

International Nuclear Information System (INIS)

Liu, Ting; Chai, Hui; Jia, Dianzeng; Su, Ying; Wang, Tao; Zhou, Wanyong

2015-01-01

Graphical abstract: Mesoporous NiMoO_4-rGO shows high specific capacitance of 1274 F/g at 1 A/g and ultrahigh energy density of 30.3 Wh/kg at a power density of 187 W/kg. - Abstract: Mesoporous NiMoO_4 nanorods grown on the surface of reduced graphene oxide composites (NiMoO_4-rGO) were synthesized via a simple, rapidly, and environment-friendly microwave-solvothermal method. The structure and morphology of the composites were characterized by X-ray diffraction, Raman spectra, scanning electron microscopy, and transmission electron microscopy. The NiMoO_4-rGO composite exhibited high performance as an electrode material for supercapacitors. At a current density of 1 A g"−"1, the specific capacitance reached 1274 F g"−"1, which is higher than that of pure NiMoO_4 (800 F g"−"1). NiMoO_4-rGO can retain about 81.1% of its initial capacitance after 1000 charge/discharge cycles. Remarkably, NiMoO_4-rGO composites can be applied in asymmetric supercapacitors with ultrahigh energy density of 30.3 Wh kg"−"1 at a power density of 187 W kg"−"1. The enhanced electrochemical performance of NiMoO_4-rGO is mainly ascribed to the mesoporous-NiMoO_4 nanorods with large specific surface area, as well as high coupling with conductive rGO.

Hydrogen storage behaviors of Ni-doped graphene Oxide/MIL-101 hybrid composites.

Science.gov (United States)

Lee, Seul-Yi; Park, Soo-Jin

2013-01-01

In this work, Ni-doped graphene oxide/MIL-101 hybrid composites (Ni--GO/MIL) were prepared to investigate their hydrogen storage behaviors. Ni--GO/MIL was synthesized by adding Ni--GO in situ during the synthesis of MIL-101 using a hydrothermal process, which was conducted by conventional convection heating with Cr(III) ion as a metal center and telephthalic acid as organic ligands. The crystalline structures and morphologies were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The specific surface area and micropore volume were investigated by N2/77 K adsorption isotherms using the Brunauer-Emmett-Teller (BET) method and Dubinin-Radushkevic (D-R) equation, respectively. The hydrogen storage capacity was investigated by BEL-HP at 77 K and 1 bar. The obtained results show that Ni--GO/MIL presents new directions for achieving novel hybrid materials with higher hydrogen storage capacity.

Fe-based soft magnetic composites coated with NiZn ferrite prepared by a co-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Peng, Yuandong; Yi, Yi; Li, Liya; Ai, Hengyu; Wang, Xiaoxu [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Chen, Lulu [Jiangsu Eagle-globe Group Co., Ltd., Nantong 226600 (China)

2017-04-15

Fe powder was coated with NiZn ferrite by a co-precipitation method using chlorate as the raw material. Soft magnetic composites were manufactured via compaction and heat treatment of the coated powder. The coated powder and heat treated powder were analysed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy. Their magnetic properties were determined using a Quantum Design-Vibrating Sample Magnetometer (QD-VSM). The composites were analysed with SEM and EDS. The permeability and magnetic loss of the composites were measured with a B-H curve analyzer. The results show that, using the co-precipitation method, the raw precipitate was successfully prepared and coated the pure Fe powder and turned into spinel NiZn ferrite treated at 600 ℃ for 1 h. After heat treatment at 500 ℃ under air, the insulation coating layer of soft magnetic composite (SMC) was not destroyed and containing Fe, Ni, Zn and oxygen. The permeabilities of the SMC are stable at edge of the 2–200 kHz frequency range and the total loss was lower. - Graphical abstract: Scanning electron microscopy (SEM) images of Fe/(NiZn)Fe{sub 2}O{sub 4} composite powder heated at 600 ℃ for 1 h. - Highlights: • Fe particles were coated with (NiZn)Fe{sub 2}O{sub 4} via a co-precipitation and calcined method. • Coating layers were uniform and dense. • The permeabilities of the SMC are stable at edge of the 2–200 kHz frequency range.

Nanoscale compositional analysis of NiTi shape memory alloy films deposited by DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Sharma, S. K.; Mohan, S. [Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore-560012 (India); Bysakh, S. [Central Glass and Ceramics Research Institute, Kolkata-700032 (India); Kumar, A.; Kamat, S. V. [Defence Metallurgical Research Laboratory, Hyderabad-500058 (India)

2013-11-15

The formation of surface oxide layer as well as compositional changes along the thickness for NiTi shape memory alloy thin films deposited by direct current magnetron sputtering at substrate temperature of 300 °C in the as-deposited condition as well as in the postannealed (at 600 °C) condition have been thoroughly studied by using secondary ion mass spectroscopy, x-ray photoelectron spectroscopy, and scanning transmission electron microscopy-energy dispersive x-ray spectroscopy techniques. Formation of titanium oxide (predominantly titanium dioxide) layer was observed in both as-deposited and postannealed NiTi films, although the oxide layer was much thinner (8 nm) in as-deposited condition. The depletion of Ti and enrichment of Ni below the oxide layer in postannealed films also resulted in the formation of a graded microstructure consisting of titanium oxide, Ni{sub 3}Ti, and B2 NiTi. A uniform composition of B2 NiTi was obtained in the postannealed film only below a depth of 200–250 nm from the surface. Postannealed film also exhibited formation of a ternary silicide (Ni{sub x}Ti{sub y}Si) at the film–substrate interface, whereas no silicide was seen in the as-deposited film. The formation of silicide also caused a depletion of Ni in the film in a region ∼250–300 nm just above the film substrate interface.

Metal organic frameworks-derived sensing material of SnO2/NiO composites for detection of triethylamine

Science.gov (United States)

Bai, Shouli; Liu, Chengyao; Luo, Ruixian; Chen, Aifan

2018-04-01

The SnO2/NiO composites were synthesized by hydrothermal followed by calcination using metal-organic framework (MOF) consisting of the ligand of p-benzene-dicarboxylic acid (PTA) and the Sn and Ni center ions as sacrificial templates. The structure and morphology of Sn/Ni-based MOF and SnO2/NiO composites were characterized by XRD, SEM, TEM, FT-IR, TG, XPS and Brunauer-Emmett-Teller analysis. Sensing experiments reveal that the SnO2/NiO composite with the molar ratio of 9:1 not only exhibits the highest response of 14.03 that is 3 times higher than pristine SnO2 to triethylamine at 70 °C, but also shows good selectivity. Such excellent performance is attributed to the MOF-driven strategy and the formation of p-n heterojunctions, because the metal ions can be highly dispersed and separated in the MOFs and can prevent the metal ions aggregation during the MOF decomposition process. The work is a novel route for synthesis of gas sensing material.

Solvothermal synthesis of Ni(HCO{sub 3}){sub 2}/graphene composites toward supercapacitors and the faradiac redox mechanism in KOH solution

Energy Technology Data Exchange (ETDEWEB)

Sun, Jinfeng [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100080 (China); Li, Zhangpeng [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Jinqing, E-mail: jqwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Zhaofeng [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Niu, Lengyuan; Gong, Peiwei [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100080 (China); Liu, Xiaohong; Wang, Honggang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yang, Shengrong, E-mail: sryang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2013-12-25

Highlights: •Ni(HCO{sub 3}){sub 2}/GS composites were prepared by a simple solvothermal method. •Ni(HCO{sub 3}){sub 2}/GS composites exhibited good supercapacitive performance. •Ni(HCO{sub 3}){sub 2}/GS2 presented the highest capacitance of 1200 F g{sup −1} at 4 A g{sup −1}. -- Abstract: In this work, a series of composites consisting of Ni(HCO{sub 3}){sub 2} and graphene nanosheets (GS) have been prepared by a facile solvothermal method, and then their application as electrode materials for supercapacitors has been investigated by cyclic voltammetry (CV) and galvanostatic charge–discharge tests. Morphological and structural analyses by field-emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy indicated that Ni(HCO{sub 3}){sub 2} particles deposited on the GS and formed a loosely packed microstructure, actualizing the successful combination of Ni(HCO{sub 3}){sub 2} particles with GS. Among the prepared composites, the sample of Ni(HCO{sub 3}){sub 2}/GS2 exhibited the highest capacitance of 1200 F g{sup −1} at a current density of 4 A g{sup −1}, illustrating that such composite is a promising candidate as electrode material for supercapacitors. Moreover, the Faradic redox mechanism of the Ni(HCO{sub 3}){sub 2}/GS composite was further studied in virtue of XRD analysis, which revealed that the Ni(HCO{sub 3}){sub 2} phase could be quickly transformed into Ni(OH){sub 2} phase by an electrochemically induced phase transformation process during the galvanostatic charge–discharge tests.

Facile Synthesis of A 3D Flower-Like Mesoporous Ni@C Composite Material for High-Energy Aqueous Asymmetric Supercapacitors.

Science.gov (United States)

Liu, Song; An, Cuihua; Zang, Lei; Chang, Xiaoya; Guo, Huinan; Jiao, Lifang; Wang, Yijing

2018-04-16

A 3D flower-like mesoporous Ni@C composite material has been synthesized by using a facile and economical one-pot hydrothermal method. This unique 3D flower-like Ni@C composite, which exhibited a high surface area (522.4 m 2  g -1 ), consisted of highly dispersed Ni nanoparticles on mesoporous carbon flakes. The effect of calcination temperature on the electrochemical performance of the Ni@C composite was systematically investigated. The optimized material (Ni@C 700) displayed high specific capacity (1306 F g -1 at 2 A g -1 ) and excellent cycling performance (96.7 % retention after 5000 cycles). Furthermore, an asymmetric supercapacitor (ASC) that contained Ni@C 700 as cathode and mesoporous carbon (MC) as anode demonstrated high energy density (60.4 W h kg -1 at a power density of 750 W kg -1 ). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and capacitance properties of N-doped porous carbon/NiO nanosheet composites using coal-based polyaniline as carbon and nitrogen source

Science.gov (United States)

Wang, Xiaoqin; Li, Qiaoqin; Zhang, Yong; Yang, Yufei; Cao, Zhi; Xiong, Shanxin

2018-06-01

A novel synthesis approach of N-doped porous carbon (NPC)/NiO composites possessing some honeycomb-shaped nanoporous carbon and plentiful NiO nanosheets is exploited. First NPC/Ni composites are achieved with NPC yield of 52.9% through a catalytic pyrolysis method, using coal-based polyaniline particles prepared by an in-situ polymerization method as a carbon and nitrogen source, and nickel particles as a catalyst, respectively. Next NPC/NiO composites are achieved unexpectedly with plentiful NiO nanosheets and N content of 1.00 wt% after a liquid oxidation process. In NPC/NiO composites, porous carbon mainly presents in the amorphous state, while the incorporated nitrogen mainly presents in the form of pyrrolic N (92.9 at.%) and oxidized N (7.1 at.%). Plentiful NiO nanosheets are embedded in the pores or on the NPC surface. 33.3 at.% Ni2O3 components exist in the surface of NiO nanosheets. NPC/NiO composites possess not only rich micropores, but also significant mesopores and nanoscale macropores. The BET specific surface area, BET average pore width and BJH adsorption average pore diameter are 627.5 m2/g, 2.0 nm and 5.1 nm, respectively. NPC/NiO composites demonstrate a high specific capacitance of 404.1 F/g at 1 A/g, and a good cycling stability maintaining high specific capacitance of 212.4 F/g (84.3% of the initial capacitance) at 5 A/g after 5000 cycles of charge and discharge, attributed to some honeycomb-shaped nanopores of carbon and large specific surface area of NiO nanosheets, and the synergistic effects between electric double-layer capacitance of NPC and pseudocapacitance of NiO. This study may provide a novel approach for the value-added applications of low-rank coal.

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

International Nuclear Information System (INIS)

Zhang Shitang; Zhou Jiansong; Guo Baogang; Zhou Huidi; Pu Yuping; Chen Jianmin

2008-01-01

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si 3 N 4 from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C

Friction and wear behavior of laser cladding Ni/hBN self-lubricating composite coating

Energy Technology Data Exchange (ETDEWEB)

Zhang Shitang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Jiansong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Guo Baogang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhou Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Pu Yuping [Central Iron and Steel Research Institute, Beijing 100081 (China); Chen Jianmin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: chenjm@lzb.ac.cn

2008-09-15

Ni/hBN coating was successfully prepared on 1Cr18Ni9Ti stainless steel substrate by means of laser cladding. The microhardness profile of the composite coating along the depth direction was measured, while its cross-sectional microstructures and phase compositions were analyzed by means of scanning electron microscopy and X-ray diffraction. Moreover, the friction and wear behavior of the composite coatings sliding against Si{sub 3}N{sub 4} from ambient to 800 deg. C was evaluated using a ball-on-disc friction and wear tester, and the worn surface morphologies of the composite coatings and counterpart ceramic balls were observed using a scanning electron microscope. At the same time, the worn surfaces of the ceramic balls were also analyzed using a 3D non-contact surface mapping profiler as well. It was found that the laser cladding Ni/hBN coating on the stainless steel substrate had high microhardness and good friction-reducing and antiwear abilities at elevated temperatures up to 800 deg. C. The composite coating registered slightly increased friction coefficient and wear rate as the temperature rose from ambient to 100 deg. C; then the friction coefficient and wear rate decreased with increasing temperature up to 800 deg. C (with the slight increase in the wear rate at 700 deg. C and 800 deg. C to be an exception). The laser cladding Ni/hBN coating was dominated by mixed adhesion and abrasive wear as it slid against the ceramic ball below 300 deg. C. With further increase in the test temperature up to 400 deg. C and above, it was characterized by mild adhesion wear and plastic deformation. Since the laser cladding Ni/hBN coating registered an increased wear rate at temperatures of 600 deg. C and above, it was not suggested to be used for wear prevention and protection of the stainless steel at elevated temperature above 800 deg. C.

Ordering in rapidly solidified Ni/sub 2/Mo

International Nuclear Information System (INIS)

Kulkarni, U.D.; Dey, G.K.; Banerjee, S.

1988-01-01

Ordering processes in the Ni-Mo system have been a subject of several investigations. Although the ordering behaviour of the Ni/sub 4/Mo and the Ni/sub 3/Mo has been examined in detail, no such study has been reported in the case of the Ni/sub 2/Mo alloy. The lack of experimental work on ordering transformations in Ni/sub 2/Mo is presumably due to the difficulty in obtaining a single phase fcc alloy of this composition. Enhanced solid solubility of Mo in Ni, which accompanies rapid solidification processing (RSP) makes the formation of such a phase possible. The ordering processes in Ni-Mo based alloys show several remarkable features. Firstly, the alloy (15 - 28 at % Mo) quenched from the α -phase filed exhibit a short range order (SRO) characterized by the presence of intensity maxima at /1 1/2 0/ fcc positions of the reciprocal space. This state of SRO has been attributed to the occurrence of 1 1/2 O spinodal ordering in the system. Secondly, the transformation from the state of SRO to the equilibrium/metastable coherent long range ordered (LRO) structures appears to take place in a continuous manner at relatively low temperatures of aging. Three different coherent LRO structures, namely: the equilibrium Ni/sub 4/Mo (prototype structure D1/sub a/) and the metastable Ni/sub 3/Mo (DO/sub 22/) and Ni/sub 2/Mo (Pt/sub 2/Mo) structures have reported to evolve from the SRO alloy, depending upon the aging treatment and the composition of the alloy

Active and inactive buffering effect on the electrochemical behavior of Sn–Ni/MWCNT composite anodes prepared by pulse electrodeposition for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Uysal, Mehmet, E-mail: mehmet_uys@yahoo.com; Cetinkaya, Tugrul; Alp, Ahmet; Akbulut, Hatem

2015-10-05

Highlights: • Sn–Ni/MWCNT anodes were produced by pulse electrodeposition. • The effect of MWCNT studied on electrochemical properties of composite electrodes. • A high reversible capacity, and good cyclability were achieved for Sn–Ni/MWCNT (10 g L{sup −1}). - Abstract: Cycling stability of pure tin electrodes was aimed to improve by using suitable combination of nickel and multiwalled carbon nanotubes (MWCNTs). Nanocrystalline Sn–Ni/MWCNT composite was prepared by ultrasonic-pulse electrodeposition on a copper substrate in a pyrophosphate bath containing different concentrations of multi-walled carbon nanotubes. Surface morphology of produced Sn–Ni/MWCNT composites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) was conducted to understand the elemental surface composition of composites. X-ray diffraction analysis was carried out to investigate structure of Sn–Ni/MWCNT composites. The electrochemical performances of Sn–Ni/MWCNT composite electrodes have been investigated by charge/discharge tests, cyclic voltammetric experiments and the ac impedance technique. These cells discharge capacity cyclically tested by a battery tester at a constant current in voltage range between 0.02 V and 1.5 V. The concentrations of MWCNTs were shown to be a crucial factor to improve Sn–Ni/MWCNT composite anodes for cyclability and reversible capacity.

Adhesion and removal kinetics of Bacillus cereus biofilms on Ni-PTFE modified stainless steel.

Science.gov (United States)

Huang, Kang; McLandsborough, Lynne A; Goddard, Julie M

2016-01-01

Biofilm control remains a challenge to food safety. A well-studied non-fouling coating involves codeposition of polytetrafluoroethylene (PTFE) during electroless plating. This coating has been reported to reduce foulant build-up during pasteurization, but opportunities remain in demonstrating its efficacy in inhibiting biofilm formation. Herein, the initial adhesion, biofilm formation, and removal kinetics of Bacillus cereus on Ni-PTFE-modified stainless steel (SS) are characterized. Coatings lowered the surface energy of SS and reduced biofilm formation by > 2 log CFU cm(-2). Characterization of the kinetics of biofilm removal during cleaning demonstrated improved cleanability on the Ni-PTFE coated steel. There was no evidence of biofilm after cleaning by either solution on the Ni-PTFE coated steel, whereas more than 3 log and 1 log CFU cm(-2) of bacteria remained on the native steel after cleaning with water and an alkaline cleaner, respectively. This work demonstrates the potential application of Ni-PTFE non-fouling coatings on SS to improve food safety by reducing biofilm formation and improving the cleaning efficiency of food processing equipment.

Preparation of Ni Doped ZnO-TiO2 Composites and Their Enhanced Photocatalytic Activity

Directory of Open Access Journals (Sweden)

Xiaowen Zou

2014-01-01

Full Text Available Herein, Ni doped ZnO-TiO2 composites were prepared by facile sol-gel approach and were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, UV-visible diffuse reflectance spectroscopy (UV-Vis DRS, X-ray photoelectron spectroscopy (XPS, and photoluminescence spectroscopy (PL. The results indicated that the Ni ions can be incorporated into the lattice of TiO2 structure and replace Ti. The introduction of Ni expanded light absorption of TiO2 to visible region, increased amount of surface hydroxyl groups and physically adsorbed oxygen (as the electronic scavenges, and then enhanced separation rate of photogenerated carriers. The photodegradation test of reactive brilliant blue (KN-R under simulated solar light indicated that Ni doped ZnO-TiO2 composites have better photocatalytic activities, as compared to those of TiO2 and ZnO-TiO2.

Behaviour of human endothelial cells on surface modified NiTi alloy.

Science.gov (United States)

Plant, Stuart D; Grant, David M; Leach, Lopa

2005-09-01

Intravascular stents are being designed which utilise the shape memory properties of NiTi alloy. Despite the clinical advantages afforded by these stents their application has been limited by concerns about the large nickel ion content of the alloy. In this study, the surface chemistry of NiTi alloy was modified by mechanical polishing and oxidising heat treatments and subsequently characterised using X-ray photon spectroscopy (XPS). The effect of these surfaces on monolayer formation and barrier integrity of human umbilical vein endothelial cells (HUVEC) was then assessed by confocal imaging of the adherens junctional molecule VE-cadherin, perijunctional actin and permeability to 42kDa dextrans. Dichlorofluoroscein assays were used to measure oxidative stress in the cells. XPS analysis of NiTi revealed its surface to be dominated by TiO(2). However, where oxidation had occurred after mechanical polishing or post polishing heat treatments at 300 and 400 degrees C in air, a significant amount of metallic nickel or nickel oxide species (10.5 and 18.5 at%) remained on the surface. Exposure of HUVECs to these surfaces resulted in increased oxidative stress within the cells, loss of VE-cadherin and F-actin and significantly increased paracellular permeability. These pathological phenomena were not found in cells grown on NiTi which had undergone heat treatment at 600 degrees C. At this temperature thickening of the TiO(2) layer had occurred due to diffusion of titanium ions from the bulk of the alloy, displacing nickel ions to sub-surface areas. This resulted in a significant reduction in nickel ions detectable on the sample surface (4.8 at%). This study proposes that the integrity of human endothelial monolayers on NiTi is dependent upon the surface chemistry of the alloy and that this can be manipulated, using simple oxidising heat treatments.

NiS(NPs)-PEDOT-PSS composite counter electrode for a high efficiency dye sensitized solar cell

Energy Technology Data Exchange (ETDEWEB)

Maiaugree, Wasan [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Center for Alternative Energy Research and Development, Khon Kaen University, Khon Kaen 40002 (Thailand); Pimparue, Pachara; Jarernboon, Wirat [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Pimanpang, Samuk [Department of Physics, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Amornkitbamrung, Vittaya [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Swatsitang, Ekaphan, E-mail: ekaphan@kku.ac.th [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Center for Alternative Energy Research and Development, Khon Kaen University, Khon Kaen 40002 (Thailand)

2017-06-15

Graphical abstract: Figure(a) and (b) represent models depict PEDOT-PSS counter electrodes of DSSC without and with NiS NPs modification, respectively. The active surface area of PEDOT-PSS polymer can be improved by combining with NiS(NPs). The I-V curves in figure (c) show the superior photovoltaic conversion efficiency of 8.18% for NiS(NPs)/PEDOT-PSS DSSC. - Highlights: • Active surface area of PEDOT-PSS CE can be improved by mixing with NiS(NPs). • Electrocatalytic activity of mixed NiS(NPs)/PEDOT-PSS polymer is also improved. • NiS(NPs)/PEDOT-PSS CE shows a very low charge transfer resistance of 0.46 Ω. • In this work, the high photovoltaic conversion efficiency of 8.18% is achieved. - Abstract: Nickel sulfide (NiS) nanoparticles (NPs) (NiS(NPs)) were prepared by the hydrothermal method. X-ray diffraction (XRD) results indicate the hexagonal structure of NiS(NPs). SEM micrographs reveal the agglomeration of irregular hexagonal – shaped NiS(NPs) with estimated particle size in the range of 50–150 nm. Counter electrodes (CEs) of dye-sensitized solar cells (DSSCs) were prepared by coating the composite slurry of different NiS(NPs) loadings and Poly (3, 4-Ethylendioxythiophene) – Poly (Styrene Sulfonate) (PEDOT-PSS) on fluoride-doped tin oxide (FTO) substrates using a doctor blading technique. Cyclic voltammetry (CV) results indicate that the composites of NiS(NPs) and PEDOT-PSS (NiS(NPs)/PEDOT-PSS) films could function as a catalyst for I{sub 3}{sup −} reduction with a maximum cell efficiency of 8.18% for a cell of 0.3 g NiS(NPs) loading.

Fabrication of a Textured Non-Magnetic Ni-12at.%V Alloy Substrate for Coated Conductors

DEFF Research Database (Denmark)

Gao, M. M.; Grivel, Jean-Claude; Suo, H. L.

2011-01-01

Ni-12at.%V alloy is a promising candidate for non-magnetic cube textured metallic substrates used for high temperature coated conductors. In this work, a textured Ni-12at.%V substrate has been fabricated by powder metallurgy route. After cold rolling and recrystallization annealing, a cube texture...

Resistance pressure sensor based on Ag/Cu/sub 2/O-PEPC-NiPc/Al composite

International Nuclear Information System (INIS)

Khan, A.; Karimov, K.S.; Shah, M.

2011-01-01

This work reports on the fabrication and investigation of pressure sensor based on Ag/Cu/sub 2/O-PEPC-NiPc/Al composite. The active layer of the composite was deposited by drop-casting of the blend Cu/sub 2/O-PEPC-NiPc on flexible substrate. The thin film of the blend consist of cuprous oxide (Cu/sub 2/O) micropowder, (5 wt. %), poly-N-epoxypropyl carbazole (PEPC), (2 wt. %) and nickel phthalocyanine (NiPc) micropowder, (3 wt. %) in benzol (1 ml). The film thickness of the composite is in the range of 20-30 mu m. It is found that the fabricated sensor is sensitive to pressure and showed good repeatability. The decrease in resistance of the sensor is observed 10 times by increasing the external uniaxial pressure up to 11.7 kNm/sup -2/. The experimentally obtained results are compared with the simulated results and showed reasonable agreement with each other. (author)

Stress-induced martensitic transformations in NiTi and NiTi-TiC composites investigated by neutron diffraction

International Nuclear Information System (INIS)

Vaidyanathan, R.; Dunand, D.C.

1999-01-01

Superelastic NiTi (51.0 at.% Ni) specimens reinforced with 0, 10 and 20 vol.% TiC particles were deformed under uniaxial compression while neutron diffraction spectra were collected. The experiments yielded in-situ measurements of the thermoelastic stress-induced transformation. The evolution of austenite/martensite phase fractions and of elastic strains in the reinforcing TiC particles and the austenite matrix were obtained by Rietveld refinement during the loading cycle as the austenite transforms to martensite (and its subsequent back transformation during unloading). Phase fractions and strains are discussed in terms of load transfer in composites where the matrix undergoes a stress-induced phase transformation. (orig.)

Interfacial evaluation and hydrophobicity of multi-functional Ni-nanopowder/epoxy composites for self-sensing and actuation

International Nuclear Information System (INIS)

Park, Joung-Man; Wang, Zuo-Jia; Kwon, Dong-Jun; Jang, Jung-Hoon; DeVries, K Lawrence

2010-01-01

Electrical and interfacial properties of Ni-nanopowder/epoxy composites were investigated for self-sensing and actuation. Contact resistance and electrical resistivity were measured using a micro-specimen with a gradient grid of electrical contact on its length. The specimens' self-sensing characteristics were monitored reasonably well under applied cyclic loading. Actuation in an electromagnetic field was evaluated by measurement of induced strain for three wavefunction voltages, i.e. sine, triangular and square. Due to the presence of hydrophobic domains on the heterogeneous surface, the static contact angle of Ni-nanopowder/epoxy composites exhibited hydrophobicity. The specimens responded well in both self-sensing and actuation tests, in electromagnetic fields, due to the intrinsic metallic property of Ni-nanopowder. Displacement of the actuator was evaluated to attain optimum performance as functions of wave type, frequency and voltage. The strain response followed the shape of the applied voltages better, and was much smoother and less erratic for applied voltages with sine and triangular waveforms than it was for voltages with a rectangular waveform. This is attributed to the sudden changes in voltage in the latter case. Such self-sensing and actuation, in conductive Ni-nanopowder/epoxy composites, might find uses in multi-functional composite devices such as biomimetic and micro-size generators

RF and microwave noise suppression in a transmission line using Fe-Si-Al/Ni-Zn magnetic composite films

International Nuclear Information System (INIS)

Lee, J. W.; Hong, Y. K.; Kim, K.; Joo, J.; Yoon, Y. W.; Kim, S. W.; Kim, Y. B.; Kim, K. Y.

2006-01-01

Radio-frequency (RF) and microwave noise suppression by using magnetic composite films on a microstrip line (MSL) was studied in the frequency range from 50 MHz to 13.5 GHz. The MSL was composed of a Cu transmission line, dielectric materials, and a Cu substrate. The Fe-Si-Al/Ni-Zn magnetic composite films were placed on the MSL, and the reflection and the transmission characteristics were investigated. We observed that RF and microwave noise suppression caused by the Fe-Si-Al/Ni-Zn magnetic composite films varied with the concentration ratio of the sendust (Fe-Si-Al) and the Ni-Zn ferrite. The frequency dependence of the power loss due to the composite films on the MSL was measured and the power loss increased at higher frequencies with increasing concentration of the sendust in the composites. The electromagnetic interference shielding efficiencies of the magnetic composite films in the far-field region are also discussed.

Synthesis of FeCoNi nanoparticles by galvanostatic technique

International Nuclear Information System (INIS)

Budi, Setia; Hafizah, Masayu Elita; Manaf, Azwar

2016-01-01

Soft magnetic nanoparticles of FeCoNi have been becoming interesting objects for many researchers due to its potential application in electronic devices. One of the most promising methods for material preparation is the electrodeposition which capable of growing nanoparticles alloy directly onto the substrate. In this paper, we report our electrodeposition studies on nanoparticles synthesis using galvanostatic electrodeposition technique. Chemical composition of the synthesized FeCoNi was successfully controlled through the adjustment of the applied currents. It is revealed that the content of each element, obtained from quantitative analysis using atomic absorption spectrometer (AAS), could be modified by the adjustment of current in which Fe and Co content decreased at larger applied currents, while Ni content increased. The nanoparticles of Co-rich FeCoNi and Ni-rich FeCoNi were obtained from sulphate electrolyte at the range of applied current investigated in this work. Broad diffracted peaks in the X-ray diffractograms indicated typical nanostructures of the solid solution of FeCoNi.

Synthesis of FeCoNi nanoparticles by galvanostatic technique

Energy Technology Data Exchange (ETDEWEB)

Budi, Setia, E-mail: setiabudi@unj.ac.id [Potgraduate Program of Materials Science Study, Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok 16424 (Indonesia); Department of Chemistry, Faculty of Mathematics and Sciences, Universitas Negeri Jakarta, Jl. Pemuda No.10, Rawamangun, Jakarta 13220 (Indonesia); Hafizah, Masayu Elita; Manaf, Azwar, E-mail: azwar@ui.ac.id [Potgraduate Program of Materials Science Study, Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok 16424 (Indonesia)

2016-06-17

Soft magnetic nanoparticles of FeCoNi have been becoming interesting objects for many researchers due to its potential application in electronic devices. One of the most promising methods for material preparation is the electrodeposition which capable of growing nanoparticles alloy directly onto the substrate. In this paper, we report our electrodeposition studies on nanoparticles synthesis using galvanostatic electrodeposition technique. Chemical composition of the synthesized FeCoNi was successfully controlled through the adjustment of the applied currents. It is revealed that the content of each element, obtained from quantitative analysis using atomic absorption spectrometer (AAS), could be modified by the adjustment of current in which Fe and Co content decreased at larger applied currents, while Ni content increased. The nanoparticles of Co-rich FeCoNi and Ni-rich FeCoNi were obtained from sulphate electrolyte at the range of applied current investigated in this work. Broad diffracted peaks in the X-ray diffractograms indicated typical nanostructures of the solid solution of FeCoNi.

Lanthanum and cerium co-modified Ni/SiO2 catalyst for CO methanation from syngas

Science.gov (United States)

Gong, Dandan; Li, Shuangshuang; Guo, Shaoxia; Tang, Honggui; Wang, Hong; Liu, Yuan

2018-03-01

Sintering of active metal nanoparticles (NPs) and carbon deposition is critical problems for many metal catalysts, such as nickel based catalysts for generating methane from syngas. To improve the resistance to the sintering and carbon deposition, a new scheme was proposed in this work. Lanthanum and cerium co-modified Ni/SiO2 catalysts were synthesized by using perovskite type oxide of La1-xCexNiO3 loaded on SiO2 as the precursor. In a nanocrystallite of La1-xCexNiO3, ions of nickel, lanthanum and cerium are evenly mixed at atomic level and confined in the nanocrystallite, therefore, Ni NPs and the two promoters of La2O3 and CeO2 should be in close contact and highly dispersed on SiO2 after reduction. The catalysts were characterized by using XRD, TEM, BET, H2-TPD, XPS, TG and Raman techniques. Compared with the mono-promoted catalysts, the bi-promoted La0.75Ce0.25NiO3/SiO2 showed much better resistance to carbon deposition, higher resistance to sintering and higher activity for CO methanation, which are attributed to co-eliminating effect of the two promoters for the deposited carbon, confinement of the interacted two promoters for Ni NPs and the higher dispersion of Ni NPs derived from the smaller size of La0.75Ce0.25NiO3.

High strength Ni based composite reinforced by solid solution W(Al) obtained by powder metallurgy

International Nuclear Information System (INIS)

Zhao Bo; Zhu Changjun; Ma Xianfeng; Zhao Wei; Tang Huaguo; Cai Shuguang; Qiao Zhuhui

2007-01-01

The solid-solution-particle reinforced W(Al)-Ni composites were successfully fabricated by using mechanical alloying (MA) and hot-pressing (HP) technique when the content of Ni is between 45 wt% and 55 wt%. Besides, samples of various original component ratio of Al 50 W 50 to Ni have been fabricated, and the corresponding microcomponents and mechanical properties such as microhardness, ultimate tensile strength and elongation were characterized and discussed. The optimum ultimate tensile strength under the experiment conditions is 1868 MPa with elongation of 10.21% and hardness of 6.62 GPa. X-ray diffraction (XRD), FE-SEM and energy dispersive analysis of X-rays (EDS) were given to analysis the components and morphology of the composite bulk specimens

Hierarchically structured Ni(3)S(2)/carbon nanotube composites as high performance cathode materials for asymmetric supercapacitors.

Science.gov (United States)

Dai, Chao-Shuan; Chien, Pei-Yi; Lin, Jeng-Yu; Chou, Shu-Wei; Wu, Wen-Kai; Li, Ping-Hsuan; Wu, Kuan-Yi; Lin, Tsung-Wu

2013-11-27

The Ni3S2 nanoparticles with the diameters ranging from 10 to 80 nm are grown on the backbone of conductive multiwalled carbon nanotubes (MWCNTs) using a glucose-assisted hydrothermal method. It is found that the Ni3S2 nanoparticles deposited on MWCNTs disassemble into smaller components after the composite electrode is activated by the consecutive cyclic voltammetry scan in a 2 M KOH solution. Therefore, the active surface area of the Ni3S2 nanoparticles is increased, which further enhances the capacitive performance of the composite electrode. Because the synergistic effect of the Ni3S2 nanoparticles and MWCNTs on the capacitive performance of the composite electrode is pronounced, the composite electrode shows a high specific capacitance of 800 F/g and great cycling stability at a current density of 3.2 A/g. To examine the capacitive performance of the composite electrode in a full-cell configuration, an asymmetric supercapacitor device was fabricated by using the composite of Ni3S2 and MWCNTs as the cathode and activated carbon as the anode. The fabricated device can be operated reversibly between 0 and 1.6 V, and obtain a high specific capacitance of 55.8 F/g at 1 A/g, which delivers a maximum energy density of 19.8 Wh/kg at a power density of 798 W/kg. Furthermore, the asymmetric supercapacitor shows great stability based on the fact that the device retains 90% of its initial capacitance after a consecutive 5000 cycles of galvanostatic charge-discharge performed at a current density of 4 A/g.

Preparation and microwave-infrared absorption of reduced graphene oxide/Cu-Ni ferrite/Al2O3 composites

Science.gov (United States)

De-yue, Ma; Xiao-xia, Li; Yu-xiang, Guo; Yu-run, Zeng

2018-01-01

Reduced graphene oxide (RGO)/Cu-Ni ferrite/Al2O3 composite was prepared by solvothermal method, and its properties were characterized by SEM, x-ray diffraction, energy-dispersive x-ray spectroscopy and FTIR. The electromagnetic parameters in 2-18 GHz and mid-infrared (IR) spectral transmittance of the composite were measured, respectively. The results show that Cu0.7Ni0.3Fe2O4 nanoparticles with an average size of tens nanometers adsorb on surface of RGO, and meanwhile, Al2O3 nanoparticles adhere to the surface of Cu0.7Ni0.3Fe2O4 nanoparticles and RGO. The composite has both dielectric and magnetic loss mechanism. Its reflection loss is lower than -19 dB in 2-18 GHz, and the maximum of -23.2 dB occurs at 15.6 GHz. With the increasing of Al2O3 amount, its reflection loss becomes lower and the maximum moves towards low frequency slightly. Compared with RGO/Cu-Ni ferrite composites, its magnetic loss and reflection loss slightly reduce with the increasing of Al2O3 amount, and the maximum of reflection loss shifts from a low frequency to a high one. However, its broadband IR absorption is significantly enhanced owing to nano-Al2O3. Therefore, RGO/Cu-Ni ferrite/Al2O3 composites can be used as excellent broadband microwave and IR absorbing materials, and maybe have broad application prospect in electromagnetic shielding, IR absorbing and coating materials.

Electrodes from carbon nanotubes/NiO nanocomposites synthesized in modified Watts bath for supercapacitors

Science.gov (United States)

Hakamada, Masataka; Abe, Tatsuhiko; Mabuchi, Mamoru

2016-09-01

A modified Watts bath coupled with pulsed current electroplating is used to uniformly deposit ultrafine nickel oxide particles (diameter < 4 nm) on multiwalled carbon nanotubes. The capacitance of the multiwalled carbon nanotubes/nickel oxide electrodes was as high as 2480 F g-1 (per mass of nickel oxide), which is close to the theoretical capacitance of NiO.

Characterization and properties of an advanced composite substrate for YBCO-coated conductors

DEFF Research Database (Denmark)

Gao, M.; Suo, H.; Zhao, Y.

2010-01-01

Thin, biaxially textured Ni5W/Ni12W/Ni5W composite substrates for coated conductor applications have been fabricated. The particularity of this three-layer composite configuration resides in the elemental diffusion between the outer layer and the core layer. Due to the migration of elemental W...

Development of modified release diltiazem HCl tablets using composite index to identify optimal formulation.

Science.gov (United States)

Gohel, M C; Patel, M M; Amin, A F

2003-05-01

This article reports the preparation of tartaric acid treated ispaghula husk powder for the development of modified release tablets of diltiazem HCl by adopting direct compression technique and a 32 full factorial design. The modified ispaghula husk powder showed superior swelling and gelling as compared to untreated powder. Addition of compaction augmenting agent such as dicalcium phosphate was found to be essential for obtaining tablets with adequate crushing strength. In order to improve the crushing strength of diltiazem HCl tablets, to modulate drug release pattern, and to obtain similarity of dissolution profiles in distilled water and simulated gastric fluid (pH 1.2), modified guar gum was used along with modified ispaghula husk powder and tartaric acid. A novel composite index, which considers a positive or a negative deviation from an ideal value, was calculated considering percentage drug release in 60, 300, and 540 min as dependent variables for the selection of a most appropriate batch. Polynomial equation and contour plots are presented. The concept of similarity factor (f2) was used to prove similarity of dissolution in water and simulated gastric fluid (pH 1.2).

Optical and structural properties of Mo-doped NiTiO{sub 3} materials synthesized via modified Pechini methods

Energy Technology Data Exchange (ETDEWEB)

Pham, Thanh-Truc; Kang, Sung Gu; Shin, Eun Woo, E-mail: ewshin@ulsan.ac.kr

2017-07-31

Highlights: • Mo-doped NiTiO{sub 3} materials were well prepared by a modified Pechini method. • Recombination rates of the materials were significantly inhibited by Mo doping. • Defect sites were generated by the substitution of Mo for Ni or Ti positions. • The generation of defect sites gradually decreased the grain sizes of the materials. • The surface areas of the materials were increased with decreasing the grain sizes. - Abstract: In this study, molybdenum (Mo)-doped nickel titanate (NiTiO{sub 3}) materials were successfully synthesized as a function of Mo content through a modified Pechini method followed by a solvothermal treatment process. Various characterization methods were employed to investigate the optical and structural properties of the materials. XRD patterns clearly showed that the NiTiO{sub 3} structure maintained a single phase with no observed crystalline structure transformations, even after the addition of 10 wt.% Mo. In the Raman spectra and XRD patterns, peak positions shifted with a change in Mo content, confirming that the NiTiO{sub 3} lattice was doped with Mo. On the other hand, Mo doping of NiTiO{sub 3} materials changed their optical properties. DRS-UV demonstrated that the addition of Mo increased photon absorption within the UV region. Relaxation processes were inhibited by Mo doping, which was evident in the PL spectra. Structural properties of the prepared materials were studied via FE-SEM and HR-TEM. The measured surface area increased proportionally with Mo content due to a reduction in grain size of the materials.

Performance of ethanol electro-oxidation on Ni-Cu alloy nanowires through composition modulation.

Science.gov (United States)

Tian, Xi-Ke; Zhao, Xiao-Yu; Zhang, Li-de; Yang, Chao; Pi, Zhen-Bang; Zhang, Su-Xin

2008-05-28

To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one.

Performance of ethanol electro-oxidation on Ni-Cu alloy nanowires through composition modulation

International Nuclear Information System (INIS)

Tian Xike; Zhao Xiaoyu; Yang Chao; Pi Zhenbang; Zhang Lide; Zhang Suxin

2008-01-01

To reduce the cost of the catalyst for direct ethanol fuel cells and improve its catalytic activity, highly ordered Ni-Cu alloy nanowire arrays have been fabricated successfully by differential pulse current electro-deposition into the pores of a porous anodic alumina membrane (AAMs). The energy dispersion spectrum, scanning and transmission electron microscopy were utilized to characterize the composition and morphology of the Ni-Cu alloy nanowire arrays. The results reveal that the nanowires in the array are uniform, well isolated and parallel to each other. The catalytic activity of the nanowire electrode arrays for ethanol oxidation was tested and the binary alloy nanowire array possesses good catalytic activity for the electro-oxidation of ethanol. The performance of ethanol electro-oxidation was controlled by varying the Cu content in the Ni-Cu alloy and the Ni-Cu alloy nanowire electrode shows much better stability than the pure Ni one

Nondestructive sensing and stress transferring evaluation of carbon nanotube, nanofiber, and Ni nanowire strands/polymer composites using an electro-micromechanical technique

Science.gov (United States)

Park, Joung-Man; Kim, Sung-Ju; Jung, Jin-Gyu; Hansen, George; Yoon, Dong-Jin

2006-03-01

Nondestructive damage sensing and load transfer mechanisms of carbon nanotube (CNT), nanofiber (CNF), and Ni nanowire strands/epoxy composites were investigated using electro-micromechanical technique. Electrospun PVDF nanofiber was also prepared as a piezoelectric sensor. High volume% CNT/epoxy composites showed significantly higher tensile properties than neat and low volume% CNT/epoxy composites. CNF /epoxy composites with smaller aspect ratio showed higher apparent modulus due to high volume content in case of shorter aspect ratio. Using Ni nanowire strands/silicone composites with different content, load sensing response of electrical contact resistivity was investigated under tensile and compression condition. The mechanical properties of Ni nanowire strands with different type and content/epoxy composites were indirectly measured apparent modulus using uniformed cyclic loading and electro-pullout test. CNT or Ni nanowire strands/epoxy composites showed humidity and temperature sensing within limited ranges, 20 vol% reinforcement. Thermal treated electrospun PVDF nanofiber showed higher mechanical properties than the untreated case due to increased crystallization, whereas load sensing decreased in heat treated case. Electrospun PVDF nanofiber web also responded the sensing effect on humidity and temperature. Nanocomposites using CNT, CNF, Ni nanowire strands, and electrospun PVDF nanofiber web can be applicable practically for multifunctional applications nondestructively.

The influence of Ni addition and hot-extrusion on the microstructure and tensile properties of Al–15%Mg2Si composite

International Nuclear Information System (INIS)

Emamy, M.; Khodadadi, M.; Honarbakhsh Raouf, A.; Nasiri, N.

2013-01-01

Highlights: ► Ni content on the microstructure and tensile properties of Al–Mg 2 Si composite. ► Ni changed the size of primary Mg 2 Si from 42 μm to 17 μm. ► Higher UTS and elongation values obtained by addition of 5 wt% Ni. ► Fracture behavior changed from brittle to ductile by Ni addition and extrusion. - Abstract: The effects of nickel addition and hot-extrusion on the microstructure and tensile properties of in situ Al–15%Mg 2 Si composite specimens have been investigated. Al–15%Mg 2 Si composite ingots were prepared by an in situ process and different amounts of nickel (0.1, 0.3, 0.5, 1.0, 3.0 and 5.0 wt% Ni) were added to the remelted composite. Optical microscopy (OM) and scanning electron microscopy (SEM) indicated that Ni addition changes the morphology of both primary and eutectic Mg 2 Si phases and decreases the size of primary Mg 2 Si particles from 42 μm to 17 μm. Hot-extrusion was found to be powerful in breaking the eutectic network and changing the size and morphology of pseudo-eutectic Mg 2 Si phase. The results obtained from tensile testing revealed that both Ni addition and hot-extrusion process improve ultimate tensile strength (UTS) and elongation values. Fracture surface examinations revealed a transition from brittle fracture mode in as-cast composite to ductile fracture in hot-extruded composite after Ni addition. This can be attributed to the changes in size and morphology of primary and eutectic Mg 2 Si phases and also the formation of more and finer α-Al phase

Interfacial characteristics and fracture behavior of spark-plasma-sintered TiNi fiber-reinforced 2024Al matrix composites

International Nuclear Information System (INIS)

Dong, Peng; Wang, Zhe; Wang, Wenxian; Chen, Shaoping; Zhou, Jun

2017-01-01

Embedding of shape memory alloy (SMA) fibers into materials to fabricate SMA composites has attracted considerable attention because of the potential applicability of these composites in smart systems and structures. In this study, 2024Al matrix composites reinforced by continuous TiNi SMA fibers were fabricated using spark plasma sintering (SPS). The interface between the fibers and matrix consisted of a bilayer. The layer close to the fiber consisted of a multiple phase mixture, and the other layer exhibited a periodic morphology resulting from the alternating phases of Al 3 Ti and Al 3 Ni. In addition, a small quantity of TiO 2 phases was also observed in the interface layer. Based on detailed interface studies of the orientation relationships between the Al 3 Ti, Al 3 Ni, and TiO 2 phases and the atomic correspondence at phase boundaries, the effects of the interface phases on the fracture behavior of the composites were demonstrated.

Interfacial characteristics and fracture behavior of spark-plasma-sintered TiNi fiber-reinforced 2024Al matrix composites

Energy Technology Data Exchange (ETDEWEB)

Dong, Peng, E-mail: dongpeng@tyut.edu.cn [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Shanxi Key Laboratory of Advanced Magnesium-Based Materials, Taiyuan 030024 (China); Wang, Zhe [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Wenxian [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Shanxi Key Laboratory of Advanced Magnesium-Based Materials, Taiyuan 030024 (China); Chen, Shaoping [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zhou, Jun [Department of Mechanical Engineering, Pennsylvania State University Erie, Erie, PA 16563 (United States)

2017-04-13

Embedding of shape memory alloy (SMA) fibers into materials to fabricate SMA composites has attracted considerable attention because of the potential applicability of these composites in smart systems and structures. In this study, 2024Al matrix composites reinforced by continuous TiNi SMA fibers were fabricated using spark plasma sintering (SPS). The interface between the fibers and matrix consisted of a bilayer. The layer close to the fiber consisted of a multiple phase mixture, and the other layer exhibited a periodic morphology resulting from the alternating phases of Al{sub 3}Ti and Al{sub 3}Ni. In addition, a small quantity of TiO{sub 2} phases was also observed in the interface layer. Based on detailed interface studies of the orientation relationships between the Al{sub 3}Ti, Al{sub 3}Ni, and TiO{sub 2} phases and the atomic correspondence at phase boundaries, the effects of the interface phases on the fracture behavior of the composites were demonstrated.

NiCrxFe2− xO4 ferrite nanoparticles and their composites with ...

Indian Academy of Sciences (India)

Half of the samples have been sintered at 620°C and the other at 1175°C. Then polypyrrole (PPy)–NiCrFe2-O4 composites have been synthesized by polymerization of pyrrole monomer in the presence of NiCrFe2-O4 nanoparticles. The structure, morphology and magnetic properties of the samples have been ...

Studying the Effect of the Concentration of PTFE Nanoparticles on the Tribological Behavior of Ni-P-PTFE Composite Coatings

Directory of Open Access Journals (Sweden)

Hamid Rahmati

2015-10-01

Full Text Available In the past 30 years, electroless nickel (EN plating has grown to such proportions that these coatings and their applications are now found underground, in outer space, and in a myriad of areas in between. Moreover, in order to further improve the mechanical and tribological properties of the nickel-phosphorous (Ni-P coatings, Ni-P/PTFE composite coatings can be obtained, which provides even greater friction behavior and lubricity than the one naturally occurring in the nickel-phosphorous alloy deposit. In this paper, The Ni-P-PTFE coating was deposited on mild carbon steel surface via electroless deposition process. The friction behavior and wear mechanisms of Ni-P-PTFE nanocomposite coating were studied at different concentrations of PTFE. Frictional behavior was examined using a pin on disk wear test method. Surface morphology and worn surface was evaluated using field emission scanning electron microscopy (FESEM and energy dispersive spectroscopy (EDS analysis. The results showed that the incorporation of PTFE nanoparticles can reduce the wear rate of Ni-P coating from 33.07×10-6 mm3/Nm to 12.46×10-6 mm3/Nm for the Ni-P PTFE containing 10 g/l PTFE and decrease the friction coefficient from 0.64 to 0.2. Thus the tribological behavior of Ni-P coating is much improved in the presence of PTFE nanoparticles and 10 g/l is the optimized concentration of PTFE in the electroless bath.

Development of graded Ni-YSZ composite coating on Alloy 690 by Pulsed Laser Deposition technique to reduce hazardous metallic nuclear waste inventory.

Science.gov (United States)

Sengupta, Pranesh; Rogalla, Detlef; Becker, Hans Werner; Dey, Gautam Kumar; Chakraborty, Sumit

2011-08-15

Alloy 690 based 'nuclear waste vitrification furnace' components degrade prematurely due to molten glass-alloy interactions at high temperatures and thereby increase the volume of metallic nuclear waste. In order to reduce the waste inventory, compositionally graded Ni-YSZ (Y(2)O(3) stabilized ZrO(2)) composite coating has been developed on Alloy 690 using Pulsed Laser Deposition technique. Five different thin-films starting with Ni80YSZ20 (Ni 80 wt%+YSZ 20 wt%), through Ni60YSZ40 (Ni 60 wt%+YSZ 40 wt%), Ni40YSZ60 (Ni 40 wt%+YSZ 60 wt%), Ni20YSZ80 (Ni 20 wt%+YSZ 80 wt%) and Ni0YSZ100 (Ni 0 wt%+YSZ 100 wt%), were deposited successively on Alloy 690 coupons. Detailed analyses of the thin-films identify them as homogeneous, uniform, pore free and crystalline in nature. A comparative study of coated and uncoated Alloy 690 coupons, exposed to sodium borosilicate melt at 1000°C for 1-6h suggests that the graded composite coating could substantially reduced the chemical interactions between Alloy 690 and borosilicate melt. Copyright © 2011 Elsevier B.V. All rights reserved.

Cavitation erosion resistance of AISI 316L stainless steel laser surface-modified with NiTi

International Nuclear Information System (INIS)

Chiu, K.Y.; Cheng, F.T.; Man, H.C.

2005-01-01

The present study is part of a project on the surface modification of AISI 316 stainless steel using various forms of NiTi for enhancing cavitation erosion resistance. In this study, NiTi powder was preplaced on the AISI 316L substrate and melted with a high-power CW Nd:YAG laser. With appropriate laser processing parameters, an alloyed layer of a few hundred micrometers thick was formed and fusion bonded to the substrate without the formation of a brittle interface. EDS analysis showed that the layer contained Fe as the major constituent element while the XRD patterns of the surface showed an austenitic structure, similar to that of 316 stainless steel. The cavitation erosion resistance of the modified layer (316-NiTi-Laser) could reach about 29 times that of AISI 316L stainless steel. The improvement could be attributed to a much higher surface hardness and elasticity as revealed by instrumented nanoindentation tests. Among various types of samples, the cavitation erosion resistance was ranked in descending order as: NiTi plate > 316-NiTi-Laser > 316-NiTi-TIG > AISI 316L, where 316-NiTi-TIG stands for samples surfaced with the tungsten inert gas (TIG) process using NiTi wire. Though the laser-surfaced samples and the TIG-surfaced samples had similar indentation properties, the former exhibited a higher erosion resistance mainly because of a more homogeneous alloyed layer with much less defects. In both the laser-surfaced and TIG-surfaced samples, the superelastic behavior typical of austenitic NiTi was only partially retained and the superior cavitation erosion resistance was thus still not fully attained

Edge geometry effects on resonance response of electroplated cylindrical Ni/PZT/Ni magnetoelectric composites

Science.gov (United States)

Yakubov, Vladislav; Xu, Lirong; Volinsky, Alex A.; Qiao, Lijie; Pan, De'an

2017-08-01

Trilayer Ni/PZT/Ni cylindrical magnetoelectric (ME) composites were prepared by electrodeposition, a process, which creates sub-millimeter raised edges due to current concentration near sharp points. The ME response in both axial and vertical modes was measured with the edges, with only outer edges removed, and with both outer and inner edges removed. The ME voltage coefficient improved at resonance by 40% and 147% without the edges in the vertical and axial modes, respectively. The observed improvements in three different samples were only present at the ME resonance and no changes were detected outside of the ME resonance. Mechanical quality factor at resonance also improved with no effect on the resonant frequency. Experimentally demonstrated minor geometry changes resulted in substantial ME improvement at resonant frequency. This study demonstrates device performance optimization. The observed effects have been attributed to improved vibrations in terms of decreased damping coefficient and enhanced vibration amplitude at resonance.

Edge geometry effects on resonance response of electroplated cylindrical Ni/PZT/Ni magnetoelectric composites

Directory of Open Access Journals (Sweden)

Vladislav Yakubov

2017-08-01

Full Text Available Trilayer Ni/PZT/Ni cylindrical magnetoelectric (ME composites were prepared by electrodeposition, a process, which creates sub-millimeter raised edges due to current concentration near sharp points. The ME response in both axial and vertical modes was measured with the edges, with only outer edges removed, and with both outer and inner edges removed. The ME voltage coefficient improved at resonance by 40% and 147% without the edges in the vertical and axial modes, respectively. The observed improvements in three different samples were only present at the ME resonance and no changes were detected outside of the ME resonance. Mechanical quality factor at resonance also improved with no effect on the resonant frequency. Experimentally demonstrated minor geometry changes resulted in substantial ME improvement at resonant frequency. This study demonstrates device performance optimization. The observed effects have been attributed to improved vibrations in terms of decreased damping coefficient and enhanced vibration amplitude at resonance.

Study of the influence of volume fraction of ceramic inclusions in NiCr-TiC composite with columnar structure on its mechanical behavior

Science.gov (United States)

Eremina, Galina M.; Smolin, Alexey Yu.; Shilko, Evgeny V.

2017-12-01

Metal-ceramic materials are characterized by high mechanical and tribological properties. The surface treatment of the composite by an electron beam in inert gas plasma leads to a qualitative and quantitative change in its microstructure as well as to a change in mechanical properties of the components: a columnar structure forms in the modified layer. Different treatment regimes result in different concentrations of inclusions in the surface layer. In this paper, the effect of the volume concentration of inclusions on the integral mechanical properties of a dispersion-strengthened NiCr-TiC composite is studied on the basis of 3D numerical simulation. The results of computer simulation show that the change in concentration significantly affects the integral mechanical characteristics of the composite material as well as the nature of the nucleation and development of damages in it.

Data on the synthesis processes optimization of novel β-NiS film modified CdS nanoflowers heterostructure nanocomposite for photocatalytic hydrogen evolution.

Science.gov (United States)

Zhang, Yu; Peng, Zhijian; Guan, Shundong; Fu, Xiuli

2018-02-01

The data presented in this article are related to a research article entitled 'Novel β-NiS film modified CdS nanoflowers heterostructure nanocomposite: extraordinarily highly efficient photocatalysts for hydrogen evolution' (Zhang et al., 2018) [1]. In this article, we report original data on the synthesis processes optimization of the proposed nanocomposite on the basis of their optimum photocatalytic performance together with the comparison on the results of literatures and comparative experiments. The composition, microstructure, morphology, photocatalytic hydrogen evolution and photocatalytic stability of the corresponding samples are included in this report. The data are presented in this format in order to facilitate comparison with data from other researchers in the field and understanding the mechanism of similar catalysts.

Microstructures and mechanical properties of directionally solidified Ni-25%Si full lamellar in situ composites

International Nuclear Information System (INIS)

Zhang, Binggang; Li, Xiaopeng; Wang, Ting; Liu, Zheng

2016-01-01

Directional solidification experiments have been performed on Ni-25 at% Si alloy using electron beam floating zone method. A fully regular eutectic microstructures consisting of Ni, γ-Ni 31 Si 12 and β 1 -Ni 3 Si have been obtained. The influences of the directional solidification rate on the microstructures and properties of the full lamellar structures have been studied. The results show that the relationship between the mean interphase spacing (λ) and withdrawal rate (v) meets λ=29.9v −0.65 . The hardness increases with the increasing of growth rate (v) and decreasing of the interlamellar spacing (λ) which meets the relationship of H V =445.2v 0.14 and H V =910λ −0.21 . The maximum compressive strength, 2576 MPa, for DS samples is obtained by 10 mm/h. The average fracture toughness value found for 5 mm/h, 7 mm/h, 10 mm/h is 28.3 MPa m 1/2 , 29.1 MPa m 1/2 and 35.9 MPa m 1/2 , respectively. The crack bridging and crack deflection/interface debonding are the main toughening mechanism of Ni-25 at% Si with full lamellar structures.

Magnetic properties of Mg12O12 nanocage doped with transition metal atoms (Mn, Fe, Co and Ni): DFT study

Science.gov (United States)

Javan, Masoud Bezi

2015-07-01

Binding energy of the Mg12O12 nanocage doped with transition metals (TM=Mn, Fe, Co and Ni) in endohedrally, exohedrally and substitutionally forms were studied using density functional theory with the generalized gradient approximation exchange-correlation functional along 6 different paths inside and outside of the Mg12O12 nanocage. The most stable structures were determined with full geometry optimization near the minimum of the binding energy curves of all the examined paths inside and outside of the Mg12O12 nanocage. The results reveal that for all stable structures, the Ni atom has a larger binding energy than the other TM atoms. It is also found that for all complexes additional peaks contributed by TM-3d, 4s and 4p states appear in the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) gap of the host MgO cluster. The mid-gap states are mainly due to the hybridization between TM-3d, 4s and 4p orbitals and the cage π orbitals. The magnetic moment of the endohedrally doped TM atoms in the Mg12O12 are preserved to some extent due to the interaction between the TM and Mg12O12 nanocage, in contrast to the completely quenched magnetic moment of the Fe and Ni atoms in the Mg11(TM)O12 complexes. Furthermore, charge population analysis shows that charge transfer occurs from TM atom to the cage for endohedrally and substitutionally doping.

Numerical simulation of shock initiation of Ni/Al multilayered composites

Energy Technology Data Exchange (ETDEWEB)

Sraj, Ihab; Knio, Omar M., E-mail: omar.knio@duke.edu [Department of Mechanical Engineering and Materials Science, Duke University, 144 Hudson Hall, Durham, North Carolina 27708 (United States); Specht, Paul E.; Thadhani, Naresh N. [School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332 (United States); Weihs, Timothy P. [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218 (United States)

2014-01-14

The initiation of chemical reaction in cold-rolled Ni/Al multilayered composites by shock compression is investigated numerically. A simplified approach is adopted that exploits the disparity between the reaction and shock loading timescales. The impact of shock compression is modeled using CTH simulations that yield pressure, strain, and temperature distributions within the composites due to the shock propagation. The resulting temperature distribution is then used as initial condition to simulate the evolution of the subsequent shock-induced mixing and chemical reaction. To this end, a reduced reaction model is used that expresses the local atomic mixing and heat release rates in terms of an evolution equation for a dimensionless time scale reflecting the age of the mixed layer. The computations are used to assess the effect of bilayer thickness on the reaction, as well as the impact of shock velocity and orientation with respect to the layering. Computed results indicate that initiation and evolution of the reaction are substantially affected by both the shock velocity and the bilayer thickness. In particular, at low impact velocity, Ni/Al multilayered composites with thick bilayers react completely in 100 ms while at high impact velocity and thin bilayers, reaction time was less than 100 μs. Quantitative trends for the dependence of the reaction time on the shock velocity are also determined, for different bilayer thickness and shock orientation.

A visible-light-driven photocatalytic activity of vanadate garnet AgCa{sub 2}Ni{sub 2}V{sub 3}O{sub 12} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Lu, Yuting; Chen, Luyang; Li, Yuze; Huang, Yanlin [Soochow University, College of Chemistry, Chemical Engineering and Materials Science (China); Cheng, Han; Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Pukyong National University, Department of Physics and Interdisciplinary Program of Biomedical, Mechanical and Electrical Engineering (Korea, Republic of)

2015-10-15

A visible-light-driven photocatalyst of nanosized vanadate garnet AgCa{sub 2}Ni{sub 2}V{sub 3}O{sub 12} was prepared by a modified Pechini method. The nanoparticles were characterized with the measurements such as X-ray powder diffraction (XRD) and structural refinements, scanning electron microscope (SEM), and UV–visible (UV–Vis) absorption spectrum. The sample has an efficient absorption in the UV–Vis light region with a narrow band-gap energy of 2.16 eV and an indirect allowed electronic transition. Besides, the photocatalysis of AgCa{sub 2}Ni{sub 2}V{sub 3}O{sub 12} nanoparticles was evaluated by photo-degradation of methylene blue under visible-light irradiation, which shows excellent photocatalytic activity. The effective photocatalytic activity was discussed on the base of the garnet crystal structure such as the activated optical centers of Ni–O octahedron and V–O tetrahedral, highly distorted Ag–O dodecahedra, and long V–V distance in the lattices.

Microstructure of bonding zones in laser-clad Ni-alloy-based composite coatings reinforced with various ceramic powders

International Nuclear Information System (INIS)

Pei, Y.T.; Ouyang, J.H.; Lei, T.C.

1996-01-01

Microstructure of the bonding zones (BZs) between laser-clad Ni-alloy-based composite coatings and steel substrates was studied by means of scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. Observations indicate that for pure Ni-alloy coating the laser parameters selected for good interface fusion have no effect on the microstructure of the BZ except for its thickness. However, the addition of ceramic particles (TiN, SiC, or ZrO 2 ) to the Ni alloy varies the compositional or constitutional undercooling of the melt near the solid/liquid interface and consequently leads to the observed changes of microstructure of the BZs. For TiN/Ni-alloy coating the morphology of γ-Ni solid solution in the BZ changes from dendritic to planar form with increasing scanning speed. A colony structure of eutectic is found in the BZ of SiC/Ni-alloy coating in which complete dissolution of SiC particles takes place during laser cladding. The immiscible melting of ZrO 2 and Ni-alloy powders induces the stratification of ZrO 2 /Ni-alloy coating which consists of a pure ZrO 2 layer fin the upper region and a BZ composed mainly of γ-Ni dendrites adjacent to the substrate. All the BZs studied in this investigation have good metallurgical characteristics between the coatings and the substrates

Modified variational iteration method for an El Niño Southern Oscillation delayed oscillator

International Nuclear Information System (INIS)

Cao Xiao-Qun; Song Jun-Qiang; Zhu Xiao-Qian; Zhang Li-Lun; Zhang Wei-Min; Zhao Jun

2012-01-01

This paper studies a delayed air—sea coupled oscillator describing the physical mechanism of El Niño Southern Oscillation. The approximate expansions of the delayed differential equation's solution are obtained successfully by the modified variational iteration method. The numerical results illustrate the effectiveness and correctness of the method by comparing with the exact solution of the reduced model. (general)

Effective reduction in the nanoparticle sizes of NiO obtained via the pyrolysis of nickel malonate precursor modified using oleylamine surfactant

Energy Technology Data Exchange (ETDEWEB)

Lontio Fomekong, Roussin, E-mail: lonforou@yahoo.fr [Chemistry Department, Higher Teacher Training College, University of Yaoundé I, B.P. 47, Yaoundé (Cameroon); Institut de la Matière Condensée et des Nanosciences, Université Catholique de Louvain, Croix du Sud 1, 1348 Louvain-La-Neuve (Belgium); Ngolui Lambi, John; Ebede, Guy Roland [Chemistry Department, Higher Teacher Training College, University of Yaoundé I, B.P. 47, Yaoundé (Cameroon); Kenfack Tsobnang, Patrice [Chemistry Department, University of Dschang, PO Box 96, Dschang (Cameroon); Tedjieukeng Kamta, Hypolite Mathias; Ngnintedem Yonti, Cedrik [Chemistry Department, Higher Teacher Training College, University of Yaoundé I, B.P. 47, Yaoundé (Cameroon); Delcorte, Arnaud [Institut de la Matière Condensée et des Nanosciences, Université Catholique de Louvain, Croix du Sud 1, 1348 Louvain-La-Neuve (Belgium)

2016-09-15

Nickel oxide nanoparticles were synthesized via thermal decomposition of two precursors, the first, a simple nickel malonate and the second, a nickel malonate modified by oleylamine, a surfactant, both having been synthesized by precipitation. While FTIR, TGA and ToF-SIMS were used to characterize the two precursors and to show the presence of oleylamine in the modified precursor, XRD, SEM, TEM and BET were employed to investigate the structure, the morphology and the specific surface area of the decomposition products obtained after pyrolysis. The results showed that the modification of nickel malonate by oleylamine was effective. The XRD results, which showed a cubic structure for the NiO obtained, suggest with SEM an important particle size reduction (at least 54%) when oleylamine was used to modify the nickel malonate precursor. The SEM images also showed a well-defined spherical nanoparticle morphology in both cases, not affected by the presence of oleylamine. The TEM also confirmed the reduction of particle size and their spherical nature but at the same time showed that, in the presence of oleylamine, there was no agglomeration resulting in a more uniform particle size distribution. The specific surface area of the NiO obtained by the oleylamine-modified precursor was 4.7 times larger than that obtained with the regular precursor. This again confirms the particle size reduction. - Highlights: • Nickel malonate precursor has been synthesized by precipitation method. • This precursor was successfully modified by a surfactant (oleylamine). • NiO was identified as the decomposition products of the previous precursors. • Oleylamine has provoked around 54% of particle size reduction of the NiO.

Effect of sintering time on structural, microstructural and chemical composition of Ni-doped lanthanum gallate perovskites

International Nuclear Information System (INIS)

Colomer, M.T.; Kilner, J.A.

2015-01-01

This work reports the effect of two different sintering times, 6 and 48 h on the structural, microstructural, and chemical features of Ni-doped La 0.90 Sr 0.10 GaO 3.00−δ . Independently of the sintering time, La 0.90 Sr 0.10 Ga 1−x Ni x O 3.00−δ (where x=0.10, and 0.20 (mol)) presents a rhombohedral symmetry with a lattice volume that decreases when NiO dopant increases. Besides the perovskite, LaSrGa 3.00 O 7.00 (nominal composition) is present as second phase in all cases. When the samples are doped with NiO, the peaks of this second phase are shifted with respect to the peaks of the pure phase. These shifts suggest that this second phase could admit some Ni ions in its structure. According to the XRD patterns, the amount of the latter phase is larger when sintering time is increased. Electron probe microanalysis (EPMA) indicated that the matrix of the samples sintered for 6 h is constituted by a perovskite with an experimental composition very close to the nominal one. However, when the samples are sintered for 48 h the matrix of each sample is constituted by two perovskites; both with compositional deviations with respect to their nominal one. In particular, a significant Sr depletion compensated by a La increment in the A site is observed. Those compositional deviations could be mainly due to the diffusion of the cations in the bulk and/or from the bulk to the surface of the samples. That diffusion can favour the formation, not only, of a second perovskite with a different composition in relation with the first one formed, but also, the formation of second phases. In addition, a very slight broadening of Bragg peaks of the perovskites sintered for 48 h is observed by XRD and can be related to the presence of two different perovskites in each sample according to EPMA results. By BSEM and EPMA analyses La 4.00 Ga 2.00 O 9.00 (nominal composition) is also observed as second phase when samples are treated for 48 h. - Graphical abstract: Typical

Effect of sintering time on structural, microstructural and chemical composition of Ni-doped lanthanum gallate perovskites

Energy Technology Data Exchange (ETDEWEB)

Colomer, M.T., E-mail: tcolomer@icv.csic.es [Instituto de Cerámica y Vidrio, CSIC, C/ Kelsen no. 5, 28049 Madrid (Spain); Kilner, J.A. [Department of Materials, Imperial College, Prince Consort Road, London SW7 2BP (United Kingdom)

2015-08-15

This work reports the effect of two different sintering times, 6 and 48 h on the structural, microstructural, and chemical features of Ni-doped La{sub 0.90}Sr{sub 0.10}GaO{sub 3.00−δ}. Independently of the sintering time, La{sub 0.90}Sr{sub 0.10}Ga{sub 1−x}Ni{sub x}O{sub 3.00−δ} (where x=0.10, and 0.20 (mol)) presents a rhombohedral symmetry with a lattice volume that decreases when NiO dopant increases. Besides the perovskite, LaSrGa{sub 3.00}O{sub 7.00} (nominal composition) is present as second phase in all cases. When the samples are doped with NiO, the peaks of this second phase are shifted with respect to the peaks of the pure phase. These shifts suggest that this second phase could admit some Ni ions in its structure. According to the XRD patterns, the amount of the latter phase is larger when sintering time is increased. Electron probe microanalysis (EPMA) indicated that the matrix of the samples sintered for 6 h is constituted by a perovskite with an experimental composition very close to the nominal one. However, when the samples are sintered for 48 h the matrix of each sample is constituted by two perovskites; both with compositional deviations with respect to their nominal one. In particular, a significant Sr depletion compensated by a La increment in the A site is observed. Those compositional deviations could be mainly due to the diffusion of the cations in the bulk and/or from the bulk to the surface of the samples. That diffusion can favour the formation, not only, of a second perovskite with a different composition in relation with the first one formed, but also, the formation of second phases. In addition, a very slight broadening of Bragg peaks of the perovskites sintered for 48 h is observed by XRD and can be related to the presence of two different perovskites in each sample according to EPMA results. By BSEM and EPMA analyses La{sub 4.00}Ga{sub 2.00}O{sub 9.00} (nominal composition) is also observed as second phase when samples are

Facile synthesis and lithium storage properties of a porous NiSi2/Si/carbon composite anode material for lithium-ion batteries.

Science.gov (United States)

Jia, Haiping; Stock, Christoph; Kloepsch, Richard; He, Xin; Badillo, Juan Pablo; Fromm, Olga; Vortmann, Britta; Winter, Martin; Placke, Tobias

2015-01-28

In this work, a novel, porous structured NiSi2/Si composite material with a core-shell morphology was successfully prepared using a facile ball-milling method. Furthermore, the chemical vapor deposition (CVD) method is deployed to coat the NiSi2/Si phase with a thin carbon layer to further enhance the surface electronic conductivity and to mechanically stabilize the whole composite structure. The morphology and porosity of the composite material was evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption measurements (BJH analysis). The as-prepared composite material consists of NiSi2, silicon, and carbon phases, in which the NiSi2 phase is embedded in a silicon matrix having homogeneously distributed pores, while the surface of this composite is coated with a carbon layer. The electrochemical characterization shows that the porous and core-shell structure of the composite anode material can effectively absorb and buffer the immense volume changes of silicon during the lithiation/delithiation process. The obtained NiSi2/Si/carbon composite anode material displays an outstanding electrochemical performance, which gives a stable capacity of 1272 mAh g(-1) for 200 cycles at a charge/discharge rate of 1C and a good rate capability with a reversible capacity of 740 mAh g(-1) at a rate of 5C.

Presence of a monoclinic (Pm) phase in the morphotropic phase boundary region of multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution: A Rietveld study

Energy Technology Data Exchange (ETDEWEB)

Pandey, Rishikesh, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in; Singh, Akhilesh Kumar, E-mail: akhilesh-bhu@yahoo.com, E-mail: aksingh.mst@itbhu.ac.in [School of Materials Science and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2014-07-28

We present here the results of structural studies on multiferroic (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} solid solution using Rietveld analysis on powder x-ray diffraction data in the composition range 0.35 ≤ x ≤ 0.55. The stability region of various crystallographic phases at room temperature for (1 − x)Bi(Ni{sub 1/2}Ti{sub 1/2})O{sub 3}-xPbTiO{sub 3} is determined precisely. Structural transformation from pseudo-cubic (x ≤ 0.40) to tetragonal (x ≥ 0.50) phase is observed via phase coexistence region demarcating the morphotropic phase boundary. The morphotropic phase boundary region consists of coexisting tetragonal and monoclinic structures with space group P4mm and Pm, respectively, stable in composition range 0.41 ≤ x ≤ 0.49 as confirmed by Rietveld analysis. The results of Rietveld analysis completely rule out the coexistence of rhombohedral and tetragonal phases in the morphotropic phase boundary region reported by earlier workers. A comparison between the bond lengths for “B-site cations-oxygen anions” obtained after Rietveld refinement, with the bond length calculated using Shannon-Prewitt ionic radii, reveals the ionic nature of B-O (Ni/Ti-O) bonds for the cubic phase and partial covalent character for the other crystallographic phases.

Electrolytically exfoliated graphene-loaded flame-made Ni-doped SnO2 composite film for acetone sensing.

Science.gov (United States)

Singkammo, Suparat; Wisitsoraat, Anurat; Sriprachuabwong, Chakrit; Tuantranont, Adisorn; Phanichphant, Sukon; Liewhiran, Chaikarn

2015-02-11

In this work, flame-spray-made SnO2 nanoparticles are systematically studied by doping with 0.1-2 wt % nickel (Ni) and loading with 0.1-5 wt % electrolytically exfoliated graphene for acetone-sensing applications. The sensing films (∼12-18 μm in thickness) were prepared by a spin-coating technique on Au/Al2O3 substrates and evaluated for acetone-sensing performances at operating temperatures ranging from 150 to 350 °C in dry air. Characterizations by X-ray diffraction, transmission/scanning electron microscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy and Raman spectroscopy demonstrated that Ni-doped SnO2 nanostructures had a spheriodal morphology with a polycrystalline tetragonal SnO2 phase, and Ni was confirmed to form a solid solution with SnO2 lattice while graphene in the sensing film after annealing and testing still retained its high-quality nonoxidized form. Gas-sensing results showed that SnO2 sensing film with 0.1 wt % Ni-doping concentration exhibited an optimal response of 54.2 and a short response time of ∼13 s toward 200 ppm acetone at an optimal operating temperature of 350 °C. The additional loading of graphene at 5 wt % into 0.1 wt % Ni-doped SnO2 led to a drastic response enhancement to 169.7 with a very short response time of ∼5.4 s at 200 ppm acetone and 350 °C. The superior gas sensing performances of Ni-doped SnO2 nanoparticles loaded with graphene may be attributed to the large specific surface area of the composite structure, specifically the high interaction rate between acetone vapor and graphene-Ni-doped SnO2 nanoparticles interfaces and high electronic conductivity of graphene. Therefore, the 5 wt % graphene loaded 0.1 wt % Ni-doped SnO2 sensor is a promising candidate for fast, sensitive and selective detection of acetone.

GC electrode modified with carbon nanotubes and NiO for the simultaneous determination of bisphenol A, hydroquinone and catechol

International Nuclear Information System (INIS)

Goulart, Lorena Athie; Mascaro, Lucia Helena

2016-01-01

This work reports the electrochemical determination of bisphenol A (BPA), hydroquinone (HQ) and catechol (CC) using glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNT) and nickel oxide nanoparticles (NiO). MWCNT were functionalized with sulfonitric solution (3H 2 SO 4 :1HNO 3 ) and dispersed in dimethylformamide for the MWCNT/GCE manufacturing. The MWCNT/GCE was modified with NiO using cyclic potential in pH 4 maintained by an acetate buffer solution containing 0.008 mol L −1 of nickel nitrate. The concentration of the nickel solution and the number of cycles in the electrodeposition were studied. Morphological characterization of NiO/MWCNT/GCE was carried out by scanning electron microscopy and the presence of NiO was observed. The electrochemical behavior was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy using BPA solution and the results were compared with those of GCE. The NiO/MWCNT/GCE presented the lowest charge transfer resistance. The electrochemical detection of BPA, HQ and CC was developed using differential pulse voltammetry. The analytical curves showed an excellent linear response and the detection limits for the simultaneous determination of BPA, HQ and CC were 2.8 × 10 −8 mol L −1 , 2.70 × 10 −8 mol L −1 and 5.9 × 10 −8 mol L −1 , respectively.

Nial and Nial-Based Composites Directionally Solidified by a Containerless Zone Process. Ph.D. Thesis

Science.gov (United States)

Joslin, Steven M.

1995-01-01

A containerless electromagnetically levitated zone (CELZ) process has been used to directionally solidify NiAl and NiAl-based composites. The CELZ processing results in single crystal NiAl (HP-NiAl) having higher purity than commercially pure NiAl grown by a modified Bridgman process (CP-NiAl). The mechanical properties, specifically fracture toughness and creep strength, of the HP-NiAl are superior to binary CP-NiAl and are used as a base-line for comparison with the composite materials subsequently studied. Two-phase composite materials (NiAl-based eutectic alloys) show improvement in room temperature fracture toughness and 1200 to 1400 K creep strength over that of binary HP-NiAl. Metallic phase reinforcements produce the greatest improvement in fracture toughness, while intermetallic reinforcement produces the largest improvement in high temperature strength. Three-phase eutectic alloys and composite materials were identified and directionally solidified with the intent to combine the improvements observed in the two-phase alloys into one alloy. The room temperature fracture toughness and high temperature strength (in air) serve as the basis for comparison between all of the alloys. Finally, the composite materials are discussed in terms of dominant fracture mechanism observed by fractography.

Investigating Planetesimal Evolution by Experiments with Fe-Ni Metallic Melts: Light Element Composition Effects on Trace Element Partitioning Behavior

Science.gov (United States)

Chabot, N. L.

2017-12-01

As planetesimals were heated up in the early Solar System, the formation of Fe-Ni metallic melts was a common occurrence. During planetesimal differentiation, the denser Fe-Ni metallic melts separated from the less dense silicate components, though some meteorites suggest that their parent bodies only experienced partial differentiation. If the Fe-Ni metallic melts did form a central metallic core, the core eventually crystallized to a solid, some of which we sample as iron meteorites. In all of these planetesimal evolution processes, the composition of the Fe-Ni metallic melt influenced the process and the resulting trace element chemical signatures. In particular, the metallic melt's "light element" composition, those elements present in the metallic melt in a significant concentration but with lower atomic masses than Fe, can strongly affect trace element partitioning. Experimental studies have provided critical data to determine the effects of light elements in Fe-Ni metallic melts on trace element partitioning behavior. Here I focus on combining numerous experimental results to identify trace elements that provide unique insight into constraining the light element composition of early Solar System Fe-Ni metallic melts. Experimental studies have been conducted at 1 atm in a variety of Fe-Ni systems to investigate the effects of light elements on trace element partitioning behavior. A frequent experimental examination of the effects of light elements in metallic systems involves producing run products with coexisting solid metal and liquid metal phases. Such solid-metal-liquid-metal experiments have been conducted in the Fe-Ni binary system as well as Fe-Ni systems with S, P, and C. Experiments with O-bearing or Si-bearing Fe-Ni metallic melts do not lend themselves to experiments with coexisting solid metal and liquid metal phases, due to the phase diagrams of these elements, but experiments with two immiscible Fe-Ni metallic melts have provided insight into

Synthesis of microporous Ni/NiO nanoparticles with enhanced microwave absorption properties

International Nuclear Information System (INIS)

Liu, Tong; Pang, Yu; Xie, Xiubo; Qi, Wen; Wu, Ying; Kobayashi, Satoru; Zheng, Jie; Li, Xingguo

2016-01-01

The fabrication of microporous metal materials with many potential applications is challenging due to their high chemical activities and the difficulty in controlling the pore size. By adjusting the reaction condition and the composition of the Ni–Al nanoparticle precursor, we have successfully produced the microporous Ni nanoparticles (NPs) of 22 nm by chemical dealloying method. During the passivation process, the microporous Ni NPs covered with NiO shell are generated as the result of surface oxidation. The micropores range from 0.6 to 1.2 nm in diameter with a large surface area of 68.9 m"2/g. Due to the elimination of Al atoms during dealloying process, the crystalline size of the microporous Ni NPs is sharply decreased to 2–5 nm. The specific architecture offers the microporous Ni/NiO NPs a small microwave reflection coefficient (RC) and a wide absorption bandwidth (RC ≤ −10 dB) of −49.1 dB and 5.8 GHz, much better than the nonporous counterpart of −24.1 dB and 3.7 GHz. The enhanced microwave absorption performance has been interpreted in terms of the micropore structure, core/shell structure and nanostructure effects. - Highlights: • Microporous Ni/NiO nanoparticles are prepared by chemical dealloying method. • They possess micropores of 0.6–1.2 nm with a surface area of 68.9 m"2/g. • They show minimum microwave reflection coefficient of −49.1 dB and bandwidth of 5.8 GHz. • Microwave absorption mechanism is explained by micropore and core/shell structures.

Synthesis of microporous Ni/NiO nanoparticles with enhanced microwave absorption properties

Energy Technology Data Exchange (ETDEWEB)

Liu, Tong, E-mail: tongliu@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, No.37 Xueyuan Road, Beijing, 100191 (China); Pang, Yu; Xie, Xiubo [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, No.37 Xueyuan Road, Beijing, 100191 (China); Qi, Wen; Wu, Ying [China Iron & Steel Research Institute Group, Advanced Technology & Materials Co., Ltd, No.76 Xueyuannanlu, Haidian District, Beijing, 100081 (China); Kobayashi, Satoru [Faculty of Engineering, Iwate University, Ueda, Morioka, 020-8551 (Japan); Zheng, Jie; Li, Xingguo [Beijing National Laboratory for Molecular Sciences (BNLMS), The State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871 (China)

2016-05-15

The fabrication of microporous metal materials with many potential applications is challenging due to their high chemical activities and the difficulty in controlling the pore size. By adjusting the reaction condition and the composition of the Ni–Al nanoparticle precursor, we have successfully produced the microporous Ni nanoparticles (NPs) of 22 nm by chemical dealloying method. During the passivation process, the microporous Ni NPs covered with NiO shell are generated as the result of surface oxidation. The micropores range from 0.6 to 1.2 nm in diameter with a large surface area of 68.9 m{sup 2}/g. Due to the elimination of Al atoms during dealloying process, the crystalline size of the microporous Ni NPs is sharply decreased to 2–5 nm. The specific architecture offers the microporous Ni/NiO NPs a small microwave reflection coefficient (RC) and a wide absorption bandwidth (RC ≤ −10 dB) of −49.1 dB and 5.8 GHz, much better than the nonporous counterpart of −24.1 dB and 3.7 GHz. The enhanced microwave absorption performance has been interpreted in terms of the micropore structure, core/shell structure and nanostructure effects. - Highlights: • Microporous Ni/NiO nanoparticles are prepared by chemical dealloying method. • They possess micropores of 0.6–1.2 nm with a surface area of 68.9 m{sup 2}/g. • They show minimum microwave reflection coefficient of −49.1 dB and bandwidth of 5.8 GHz. • Microwave absorption mechanism is explained by micropore and core/shell structures.

High Electrocatalytic Performance of CuCoNi@CNTs Modified Glassy Carbon Electrode towards Methanol Oxidation in Alkaline Medium

Directory of Open Access Journals (Sweden)

Amina A. Hamza

2017-01-01

Full Text Available A novel non-precious multiwalled carbon nanotubes (CNTs—supported metal oxide electrocatalyst was developed for methanol electrooxidation in alkaline medium. The catalyst was fabricated by simultaneous electrodeposition of copper-cobalt-nickel ternary nanostructures (CuCoNi on a glassy carbon electrode (GCE modified with CNTs. The proposed electrode was characterized using X-ray diffraction (XRD, energy dispersive X-ray (EDX, and scanning electron microscopy (SEM. The electrochemical behavior and the electrocatalytic performance of the suggested electrode towards the oxidation of methanol were evaluated by cyclic voltammetry (CV, linear sweep voltammetry (LSV, and chronoamperometry (CA in alkaline medium. Several parameters were investigated, e.g., deposition time, potential scan rate, etc. Compared to Cu, Co, or Ni mono electrocatalysts, the electrode based on ternary-metals exhibited superior electrocatalytic activity and stability towards methanol electrooxidation. For instance, CuCoNi@CNTs/GCE has shown at least 2.5 times electrocatalytic activity and stability compared to the mono eletrocatalysts. Moreover, the present study found that the optimized loading level is 1500 s of simultaneous electrodeposition. At this loading level, it was found that the relation between the Ip/ν1/2 function and scan rate gives the characteristic features of a catalytic process. The enhanced activity and stability of CuCoNi@CNTs/GCE was attributed to (i a synergism between three metal oxides coexisting in the same structure; (ii the presence of CNTs as a support for the metal oxides, that offers high surface area for the deposited tertiary alloy and suppresses the aggregation and sintering of the metals oxide with time; as well as (iii the increase of the conductivity of the deposited semiconducting metal oxides.

One-Pot Synthesis of Size- and Composition-Controlled Ni-Rich NiPt Alloy Nanoparticles in a Reverse Microemulsion System and Their Application

KAUST Repository

Biausque, Gregory

2017-08-16

Bimetallic nanoparticles have been the subject of numerous research studies in the nanotechnology field, in particular for catalytic applications. Control of the size, morphology, and composition has become a key challenge due to the relationship between these parameters and the catalytic behavior of the particles in terms of activity, selectivity, and stability. Here, we present a one-pot air synthesis of 2 nm NiPt nanoparticles with a narrow size distribution. Control of the size and composition of the alloy particles is achieved at ambient temperature, in the aqueous phase, by the simultaneous reduction of nickel and platinum precursors with hydrazine, using a reverse microemulsion system. After deposition on an alumina support, this Ni-rich nanoalloy exhibits unprecedented stability under the harsh conditions of methane dry reforming.

One-Pot Synthesis of Size- and Composition-Controlled Ni-Rich NiPt Alloy Nanoparticles in a Reverse Microemulsion System and Their Application

KAUST Repository

Biausque, Gregory; Laveille, Paco; Anjum, Dalaver H.; Zhang, Bei; Zhang, Xixiang; Caps, Valerie; Basset, Jean-Marie

2017-01-01

Bimetallic nanoparticles have been the subject of numerous research studies in the nanotechnology field, in particular for catalytic applications. Control of the size, morphology, and composition has become a key challenge due to the relationship between these parameters and the catalytic behavior of the particles in terms of activity, selectivity, and stability. Here, we present a one-pot air synthesis of 2 nm NiPt nanoparticles with a narrow size distribution. Control of the size and composition of the alloy particles is achieved at ambient temperature, in the aqueous phase, by the simultaneous reduction of nickel and platinum precursors with hydrazine, using a reverse microemulsion system. After deposition on an alumina support, this Ni-rich nanoalloy exhibits unprecedented stability under the harsh conditions of methane dry reforming.

Magnetic properties of Mg{sub 12}O{sub 12} nanocage doped with transition metal atoms (Mn, Fe, Co and Ni): DFT study

Energy Technology Data Exchange (ETDEWEB)

Javan, Masoud Bezi, E-mail: javan.masood@gmail.com

2015-07-01

Binding energy of the Mg{sub 12}O{sub 12} nanocage doped with transition metals (TM=Mn, Fe, Co and Ni) in endohedrally, exohedrally and substitutionally forms were studied using density functional theory with the generalized gradient approximation exchange-correlation functional along 6 different paths inside and outside of the Mg{sub 12}O{sub 12} nanocage. The most stable structures were determined with full geometry optimization near the minimum of the binding energy curves of all the examined paths inside and outside of the Mg{sub 12}O{sub 12} nanocage. The results reveal that for all stable structures, the Ni atom has a larger binding energy than the other TM atoms. It is also found that for all complexes additional peaks contributed by TM-3d, 4s and 4p states appear in the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) gap of the host MgO cluster. The mid-gap states are mainly due to the hybridization between TM-3d, 4s and 4p orbitals and the cage π orbitals. The magnetic moment of the endohedrally doped TM atoms in the Mg{sub 12}O{sub 12} are preserved to some extent due to the interaction between the TM and Mg{sub 12}O{sub 12} nanocage, in contrast to the completely quenched magnetic moment of the Fe and Ni atoms in the Mg{sub 11}(TM)O{sub 12} complexes. Furthermore, charge population analysis shows that charge transfer occurs from TM atom to the cage for endohedrally and substitutionally doping. - Highlights: • Binding energy of the Mg{sub 12}O{sub 12} nanocage doped with transition metals was studied. • The most stable structures were determined near the minimum of the binding energy. • The encapsulated Ni atom has a larger binding energy than the other TM atoms. • Magnetic moment of the endohedrally doped TM atoms in the Mg{sub 12}O{sub 12} are preserved.

Fracture frequency and longevity of fractured resin composite, polyacid-modified resin composite, and resin-modified glass ionomer cement class IV restorations: an up to 14 years of follow-up

DEFF Research Database (Denmark)

van Dijken, Jan W V; Pallesen, Ulla

2010-01-01

The aim of this study was to evaluate the fracture frequency and longevity of fractured class IV resin composite (RC), polyacid-modified resin composite (compomer; PMRC), and resin-modified glass ionomer cement (RMGIC) restorations in a longitudinal long-term follow-up. Eighty-five class IV RC (43...

Structure and composition of layers of Ni-Co-Mn-In Heusler alloys obtained by pulsed laser deposition

International Nuclear Information System (INIS)

Wisz, Grzegorz; Sagan, Piotr; Stefaniuk, Ireneusz; Cieniek, Bogumil; Maziarz, Wojciech; Kuzma, Marian

2017-01-01

In present work we were analysing thin layers of Ni-Co-Mn-In alloys, grown by pulsed laser deposition method (PLD) on Si, NaCl and glass substrates. For target ablation the second harmonics of YAG:Nd 3+ laser was used. The target had the composition Ni 45 Co 5 Mn 34.5 In 14.5 . The morphology of the layers and composition were studied by electron microscopy TESCAN Vega3 equipped with microanalyzer EDS – Easy EdX system working with Esprit Bruker software. The X-ray diffraction measurements (XRD), performed on spectrometer Bruker XRD D8 Advance system, reveals Ni 2 -Mn-In cubic phase having lattice constant a = 6.02Å.

mwnts composite film modified glassy carbon electrode

African Journals Online (AJOL)

Preferred Customer

ABSTRACT: A poly p-aminosalicylic acid (Poly(p-ASA)) and multiwall carbon nanotubes. (MWCNTs) composite modified glassy carbon (GC) electrode was constructed by casting the MWNTs on the GC electrode surface followed by electropolymerization of the p-ASA on the MWCNTs/GCE. The electrochemical behaviours ...

Evolution Of Lattice Structure And Chemical Composition Of The Surface Reconstruction Layer In Li1.2Ni0.2Mn0.6O2 Cathode Material For Lithium Ion Batteries

Energy Technology Data Exchange (ETDEWEB)

Yan, Pengfei; Nie, Anmin; Zheng, Jianming; Zhou, Yungang; Lu, Dongping; Zhang, Xiaofeng; Xu, Rui; Belharouak, Ilias; Zu, Xiaotao; Xiao, Jie; Amine, Khalil; Liu, Jun; Gao, Fei; Shahbazian-Yassar, Reza; Zhang, Jiguang; Wang, Chong M.

2015-01-14

Voltage and capacity fading of layer structured lithium and manganese rich (LMR) transition metal oxide is directly related to the structural and composition evolution of the material during the cycling of the battery. However, understanding such evolution at atomic level remains elusive. Based on atomic level structural imaging, elemental mapping of the pristine and cycled samples and density functional theory calculations, it is found that accompanying the hoping of Li ions is the simultaneous migration of Ni ions towards the surface from the bulk lattice, leading to the gradual depletion of Ni in the bulk lattice and thickening of a Ni enriched surface reconstruction layer (SRL). Furthermore, Ni and Mn also exhibit concentration partitions within the thin layer of SRL in the cycled samples where Ni is almost depleted at the very surface of the SRL, indicating the preferential dissolution of Ni ions in the electrolyte. Accompanying the elemental composition evolution, significant structural evolution is also observed and identified as a sequential phase transition of C2/m →I41→Spinel. For the first time, it is found that the surface facet terminated with pure cation is more stable than that with a mixture of cation and anion. These findings firmly established how the elemental species in the lattice of LMR cathode transfer from the bulk lattice to surface layer and further into the electrolyte, clarifying the long standing confusion and debate on the structure and chemistry of the surface layer and their correlation with the voltage fading and capacity decaying of LMR cathode. Therefore, this work provides critical insights for designing of cathode materials with both high capacity and voltage stability during cycling.

Hydrocracking of ethyl laurate on bifunctional micro-/mesoporous composite materials

Energy Technology Data Exchange (ETDEWEB)

Adam, M.; Busse, O.; Reschetilowski, W. [Technische Univ. Dresden (Germany). Inst. for Industrial Chemistry

2011-07-01

Hydrocracking of ethyl laurate (dodecanoic acid ethyl ester) as a representative model compound of vegetable oil has been investigated in a fixed bed reactor under integral conditions. A synthesized micro-/mesoporous composite support material Al-MCM-41/ZSM-5 modified by different metal loadings (NiMo, NiW, PtNiW) was used as catalyst system. It could be demonstrated that the metal loading and reducibility influence product selectivity as well as deactivation behavior of catalyst samples. (orig.)

Ternary Pt-Ru-Ni catalytic layers for methanol electrooxidation prepared by electrodeposition and galvanic replacement

Directory of Open Access Journals (Sweden)

Athanasios ePapaderakis

2014-06-01

Full Text Available Ternary Pt-Ru-Ni deposits on glassy carbon substrates, Pt-Ru(Ni/GC, have been formed by initial electrodeposition of Ni layers onto glassy carbon electrodes, followed by their partial exchange for Pt and Ru, upon their immersion into equimolar solutions containing complex ions of the precious metals. The overall morphology and composition of the deposits has been studied by SEM microscopy and EDS spectroscopy. Continuous but nodular films have been confirmed, with a Pt÷Ru÷Ni % bulk atomic composition ratio of 37÷12÷51 (and for binary Pt-Ni control systems of 47÷53. Fine topographical details as well as film thickness have been directly recorded using AFM microscopy. The composition of the outer layers as well as the interactions of the three metals present have been studied by XPS spectroscopy and a Pt÷Ru÷Ni % surface atomic composition ratio of 61÷12÷27 (and for binary Pt-Ni control systems of 85÷15 has been found, indicating the enrichment of the outer layers in Pt; a shift of the Pt binding energy peaks to higher values was only observed in the presence of Ru and points to an electronic effect of Ru on Pt. The surface electrochemistry of the thus prepared Pt-Ru(Ni/GC and Pt(Ni/GC electrodes in deaerated acid solutions (studied by cyclic voltammetry proves the existence of a shell consisting exclusively of Pt-Ru or Pt. The activity of the Pt-Ru(Ni deposits towards methanol oxidation (studied by slow potential sweep voltammetry is higher from that of the Pt(Ni deposit and of pure Pt; this enhancement is attributed both to the well-known Ru synergistic effect due to the presence of its oxides but also (based on the XPS findings to a modification effect of Pt electronic properties.

Facile synthesis of CoNi2S4/Co9S8 composites as advanced electrode materials for supercapacitors

Science.gov (United States)

Zhao, Fenglin; Huang, Wanxia; Zhang, Hongtao; Zhou, Dengmei

2017-12-01

In this paper, a facile chemical bath deposition method was utilized to synthesize three-dimensional nanostructured CoNi2S4/Co9S8 (CNSCS) composites as advanced electrode materials for high performance supercapacitors. CNSCS composites showed remarkable electrochemical performance owing to the high porosity, appropriate pore size distribution, novel architecture and synergistic effect of Ni/Co ions. The electrochemical tests revealed that CNSCS composites exhibited high specific capacitance (1183.3 Fg-1 at the current density of 2 Ag-1), excellent rate performance (74.9% retention with tenfold current density increase) and outstanding cycle life stability. Moreover, the effect of temperature on electrochemical performance of CNSCS composites was investigated and the results indicated the specific capacitance of CoNi2S4/Co9S8 can keep relatively stable in a wide temperature from 0 °C to 50 °C. These results indicated that the synthesized CNSCS composites can be a promising electrode materials candidate for supercapacitors and chemical bath deposition is a promising processing route for CNSCS composites production.

Structural and compositional optimization of the LiNi0.8Co0.2O2 electrode by new synthesis conditions

International Nuclear Information System (INIS)

Mosqueda L, Y.; Milian P, C. R.; Pomares A, M.; Rodriguez H, J.; Perez C, E.

2012-01-01

The optimization of citrate precursor method to obtain the LiNi 0.8 Co 0.2 O 2 oxide from the thermal decomposition of the citrate precursor (NH 4 ) 3 LiNi 0.8 Co 0.2 (C 6 H 5 O 7 ) is presented. The optimization procedure consists of both the lithium atmosphere and the reaction time control during the decomposition of the citrate precursor. Were obtained and characterized two kind of the (Li l-x Ni x )(Ni 0.8 Co 0.2 )O 2 oxides, with and without optimized synthesis conditions, identified as A and B oxides, respectively. The A and B oxides are characterized by compositional, structural and electrochemical studies. The results showed that is possible to reach the ordered oxide phase at smaller reaction time if the lithium atmosphere is controlled. From the combination of the chemical analysis by Icp and the DRX Rietveld structural refinement it is possible to establish the Li, Ni(II), Ni(III) and Co(III) composition with great accuracy. The resulted structural and compositional transformations have a close relation with technological parameters of the rechargeable lithium battery using Li Ni 0.8 Co 0.2 O 2 oxide as cathode. (Author)

Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers

International Nuclear Information System (INIS)

Monier, M.; Ayad, D.M.; Sarhan, A.A.

2010-01-01

The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

An Asymmetric Supercapacitor with Mesoporous NiCo2O4 Nanorod/Graphene Composite and N-Doped Graphene Electrodes

Science.gov (United States)

Mao, J. W.; He, C. H.; Qi, J. Q.; Zhang, A. B.; Sui, Y. W.; He, Y. Z.; Meng, Q. K.; Wei, F. X.

2018-01-01

In the present work, mesoporous NiCo2O4 nanorod/graphene oxide (NiCo2O4/GO) composite was prepared by a facile and cost-effective hydrothermal method and meanwhile, N-doped graphene (N-G) was fabricated also by a hydrothermal synthesis process. NiCo2O4/GO composite and N-G were used as positive and negative electrodes for the supercapacitor, respectively, which all displayed excellent electrochemical performances. The NiCo2O4/GO composite electrode exhibited a high specific capacitance of 709.7 F g-1 at a current density of 1 A g-1 and excellent rate capability as well as good cycling performance with 84.7% capacitance retention at 6 A g-1 after 3000 cycles. A high-voltage asymmetric supercapacitor (ASC) was successfully fabricated using NiCo2O4/GO composite and N-G as the positive and negative electrodes, respectively, in 1 M KOH aqueous electrolyte. The ASC delivered a high energy density of 34.4 Wh kg-1 at a power density of 800 W kg-1 and still maintained 28 Wh kg-1 at a power density of 8000 W kg-1. Furthermore, this ASC showed excellent cycling stability with 94.3% specific capacitance retained at 5 A g-1 after 5000 cycles. The impressive results can be ascribed to the positive synergistic effects of the two electrodes. Evidently, our work provides useful information for assembling high-performance supercapacitor devices.

Electrochemical properties of the ball-milled LaMg10NiMn alloy with Ni powders

International Nuclear Information System (INIS)

Wang Yi; Wang Xin; Gao Xueping; Shen Panwen

2008-01-01

The electrochemical characteristics of the ball-milled LaMg 10 NiMn alloys with Ni powders were investigated. It was found that the ball-milled LaMg 10 NiMn + 150 wt.% Ni composite exhibited higher first discharge capacity and better cycle performance. By means of the analysis of electrochemical impedance spectra (EIS), it was shown that the existence of manganese in LaMg 10 NiMn alloy increased the electrocatalytic activity due to its catalytic effect, and destabilized metal hydrides, and so reduced the hydrogen diffusion resistance. These contributed to the higher discharge capacity of the ball-milled LaMg 10 NiMn-Ni composite. According to the analytical results of X-ray diffraction (XRD), EIS and steady-state polarization (SSP) experiments, the inhibition of metal corrosion is not the main reason for the better cycle performance. The main reason is that the electrochemical reaction resistance of the ball-milled LaMg 10 NiMn-Ni composite is always lower than that of the ball-milled LaMg 10 Ni 2 -Ni composite because the former one contains manganese, which is a catalyst for the electrode reaction

Electrophoretic deposition of 9-YSZ solid electrolyte on Ni- YSZ composite; Estudos de deposicao eletroforetica de ceramicas de 9-YSZ sobre Ni-YSZ

Energy Technology Data Exchange (ETDEWEB)

Santos, F.S.; Yoshito, W.K.; Lazar, D.R.R.; Ussui, V., E-mail: vussui@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

2010-07-01

9-YSZ ceramic and Ni-YSZ metal/ceramic composite are the more commonly used materials for the fabrication of solid oxide fuel cell electrolyte and anode, respectively. The main challenges for these applications are the forming of both materials as superposed double thin layers. In the present work ceramic powder of 9- YSZ was synthesized by a coprecipitation technique and the Ni O-YSZ composite by a combustion technique. The later was formed by uniaxial pressing as cylindrical pellets of 15 mm diameter. Thin ceramic layers of 9-YSZ were deposited on composite pellets from a suspension with 10% solid content by an Electrophoretic Deposition technique. Applied voltage varied in the range of 30 to 200 V and deposition time from 15 to 90 seconds, evaluating the deposited mass, porosity on the interface and adhesion of layers. Resulted ceramics were characterized by X-ray diffraction and were observed in a scanning electron microscope. Results showed that deposited layers are thin ({approx}20{mu}m), dense and have good adhesion on the surface of composite substrate. (author)

Characterisation of electrodeposited and heat-treated Ni-Mo-P coatings

Energy Technology Data Exchange (ETDEWEB)

Melo, Regis L.; Casciano, Paulo N.S.; Correia, Adriana N.; Lima-Neto, Pedro de, E-mail: pln@ufc.br [Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, Fortaleza, CE (Brazil)

2012-07-01

The electrodeposition, hardness and corrosion resistance properties of Ni-Mo-P coatings were investigated. Characterisations of the electrodeposited coatings were carried out using scanning electron microscopy, X-ray diffraction and energy dispersive X-ray analysis techniques. Corrosion tests were performed at room temperature in 10-1 mol dm-3 NaCl solutions and by potentiodynamic linear polarisation. Amorphous Ni-Mo-P coatings were successfully obtained by electrodeposition using direct current. The coating composition showed to be dependent on the bath composition, current density and bath temperature. Both P and Mo contents contribute for the hardness properties of the Ni-Mo-P coatings and the absence of cracks is a requirement to produce electrodeposited Ni-Mo-P coatings with good hardness properties. The hardness values increase with heat-treatment temperature due to the precipitation of Ni, Ni{sub 3}P and NiMo phases during the heat treatment. The corrosion resistance of the electrodeposited Ni-Mo-P amorphous coatings increases with P content in the layer. Among the electrodeposited Ni-Mo-P amorphous coatings, Ni{sub 78}Mo{sub 10}P{sub 12} presented the best hardness and corrosion-resistance properties. The results showed that the addition of P is beneficial for the hardness and corrosion resistance properties of the Ni-Mo-based coatings. (author)

Thermal and electronic charge transport in bulk nanostructured Zr0.25Hf0.75NiSn composites with full-Heusler inclusions

International Nuclear Information System (INIS)

Makongo, Julien P.A.; Misra, Dinesh K.; Salvador, James R.; Takas, Nathan J.; Wang, Guoyu; Shabetai, Michael R.; Pant, Aditya; Paudel, Pravin; Uher, Ctirad; Stokes, Kevin L.; Poudeu, Pierre F.P.

2011-01-01

Bulk Zr 0.25 Hf 075 NiSn half-Heusler (HH) nanocomposites containing various mole fractions of full-Heusler (FH) inclusions were prepared by solid state reaction of pre-synthesized HH alloy with elemental Ni at 1073 K. The microstructures of spark plasma sintered specimens of the HH/FH nanocomposites were investigated using transmission electron microscopy and their thermoelectric properties were measured from 300 K to 775 K. The formation of coherent FH inclusions into the HH matrix arises from solid-state Ni diffusion into vacant sites of the HH structure. HH(1-y)/FH(y) composites with mole fraction of FH inclusions below the percolation threshold, y∼0.2, show increased electrical conductivity, reduced Seebeck coefficient and increased total thermal conductivity arising from gradual increase in the carrier concentration for composites. A drastic reduction (∼55%) in κ l was observed for the composite with y=0.6 and is attributed to enhanced phonon scattering due to mass fluctuations between FH and HH, and high density of HH/FH interfaces. - Graphical abstract: Large reduction in the lattice thermal conductivity of bulk nanostructured half-Heusler/full-Heusler (Zr 0.25 Hf 075 NiSn/ Zr 0.25 Hf 075 Ni 2 Sn) composites, obtained by solid-state diffusion at 1073 K of elemental Ni into vacant sites of the half-Heusler structure, arising from the formation of regions of spinodally decomposed HH and FH phases with a spatial composition modulation of ∼2 nm. Highlights: → Bulk composites from solid state transformation of half-Heusler matrix through Ni diffusion. → Formation of coherent phase boundaries between half-Heusler matrix and full-Heusler inclusion. → Alteration of thermal and electronic transports with increasing full-Heusler inclusion. → Enhanced phonon scattering at half-Heusler/ full-Heusler phase boundaries.

Characterization of Ni-P-SiO2 nano-composite coating on magnesium

Science.gov (United States)

Sadreddini, S.; Salehi, Z.; Rassaie, H.

2015-01-01

In this study, the effects of SiO2 nanoparticles added to the electroless Ni-P coating were studied. The surface morphology, corrosion behavior, hardness and porosity of Ni-P-SiO2composite were investigated. The related microstructure was investigated through field emission scanning electron microscopy (FESEM) and the amount of SiO2 was examined by Energy Dispersive Analysis of X-ray (EDX). The corrosion behavior was evaluated through electrochemical impedance spectroscopy (EIS) and polarization techniques. The results illustrated that with increasing the quantity of the SiO2 nanoparticles, the corrosion rate decreased and the hardness increased.

Electrical conductivity of Ni–YSZ composites: Degradation due to Ni particle growth

DEFF Research Database (Denmark)

Pihlatie, Mikko; Kaiser, Andreas; Mogensen, Mogens Bjerg

2011-01-01

The short-term changes in the electrical conductivity of Ni–YSZ composites (cermets) suitable for use in Solid Oxide Fuel Cells (SOFC) were measured by an in-situ 4-point DC technique. The isothermal reduction was carried out in dry, humidified or wet hydrogen at temperatures from 600 to 1000°C...... modelled using two different semi-empirical approaches. Thermodynamic calculations were carried out to assess the vaporisation of Ni in the conditions tested. The rate and mechanisms of conductivity degradation due to Ni particle growth are discussed in light of the measurements, modelling and literature...

Effect of pulse frequency and current density on anomalous composition and nanomechanical property of electrodeposited Ni-Co films

Energy Technology Data Exchange (ETDEWEB)

Chung, C.K., E-mail: ckchung@mail.ncku.edu.t [Department of Mechanical Engineering, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan 701 (China); Chang, W.T. [Department of Mechanical Engineering, and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan, Taiwan 701 (China)

2009-07-01

Effect of pulse frequency and current density on the anomalous cobalt content and nanomechanical property of the electrodeposited nickel-cobalt (Ni-Co) films has been investigated. The composition, morphology, phase and hardness of the Ni-Co alloy films were examined by scanning electron microscope with an attached energy dispersive X-ray spectroscope, X-ray diffraction and nanoindentation techniques, respectively. The different Co composition of the Ni-Co films codeposited from the fixed sulfamate-chloride bath is subject to the pulse frequencies and current densities. The frequencies varied from 0 to 100 Hz and current densities varied from 1 to 20 ASD (ampere per square decimeter). The Co composition has no significant variation in pulse electrodeposition but it is greatly influenced by current densities from 22.53% at 1 ASD decreased to 13.39% at 20 ASD under DC codeposition. The mean hardness of Ni-Co films has no eminent change at a pulse frequency of 10-100 Hz but it decreases with current densities from 8.72 GPa (1 ASD) to 7.13 GPa (20 ASD). The smoother morphology can be obtained at higher pulse frequency or lower current density. Good Ni-Co films with high hardness and smooth morphology can be obtained by reducing current density and increasing pulse frequency.

FeNi3/indium tin oxide (ITO) composite nanoparticles with excellent microwave absorption performance and low infrared emissivity

International Nuclear Information System (INIS)

Fu, Li-Shun; Jiang, Jian-Tang; Zhen, Liang; Shao, Wen-Zhu

2013-01-01

Highlights: ► Electrical conductivity and infrared emissivity can be controlled by ITO content. ► The infrared emissivity is the lowest when the mole ratio of In:Sn in sol is 9:1. ► The permittivity in microwave band can be controlled by the electrical conductivity. ► EMA performance is significantly influenced by the content of ITO phase. ► FeNi 3 /ITO composite particles are suitable for both infrared and radar camouflage. - Abstract: FeNi 3 /indium tin oxide (ITO) composite nanoparticles were synthesized by a self-catalyzed reduction method and a sol–gel process. The dependence of the content of ITO phase with the mole ratios of In:Sn of different sols was investigated. The relation between the electrical conductivity, infrared emissivity of FeNi 3 /ITO composite nanoparticles and the content of ITO phase was discussed. Electromagnetic wave absorption (EMA) performance of products was evaluated by using transmission line theory. It was found that EMA performance including the intensity and the location of effective band is significantly dependent on the content of ITO phase. The low infrared emissivity and superior EMA performance of FeNi 3 /ITO composite nanoparticles can be both achieved when the mole ratio of In:Sn in sol is 9:1.

The Effect of adding pore formers on the microstructure of NiO-YSZ ceramic composite

International Nuclear Information System (INIS)

Silva, F.S.; Santos, F.S.; Medeiros, L.M.; Yoshito, W.K.; Lazar, D.R.R.; Ussui, V.

2011-01-01

The ceramic composite of nickel oxide (NiO) with zirconium stabilized with 8 mol% yttria (8-YSZ) is the most employed material for use as anode for solid oxide fuel cells (SOFC). The nickel oxide in the composite is reduced to metallic nickel and this result in a 15% of porosity although the porosity needed to a proper function of an anode is about 30%, demanding the use of a pore former. In this work, NiO-YSZ composite powders were synthesized by a combustion process with urea as fuel, and the effect of the addition of carbon black and corn and rice starch as pore former were investigated. Powders were pressed as cylindrical pellets, sintered at 1350 °C for 60 minutes and density were measured by an immersion method and microstructure were observed by scanning electron microscopy. Results showed that ceramic composite has homogeneous microstructure and pores have different morphology and size depending on the kind of the pore former employed. (author)

Internal carbonitriding behavior of Ni-V, Ni-Cr, and Ni-3Nb alloys

International Nuclear Information System (INIS)

Allen, A.T.; Douglass, D.L.

1999-01-01

Ni-2V, Ni-5V, Ni-12V, Ni-10Cr, Ni-20Cr, and Ni-3Nb alloys were carbonitrided in C 3 H 6 and NH 3 gas mixtures (bal H 2 ) over the range 700--1,000 C. Carbonitridation of Ni-12V and Ni-20Cr in C 3 H 6 /NH 3 /H 2 (1.5/1.5/97 v/o) and (1.5/10/88.5 v/o) produced duplex subscales consisting of near-surface nitrides with underlying carbides. Growth of each zone obeyed the parabolic rate law under most conditions. The presence of carbon generally did not effect the depth of the nitride zones compared to nitriding the alloys in NH 3 /H 2 (10/90 v/o). However, at 700 C, the nitride zones were deeper in the carbonitrided Ni-V alloys and Ni-20Cr. The presence of nitrogen generally increased the depth of the carbide zones in Ni-12V and Ni-20Cr compared to carburizing these alloys in C 3 H 6 /H 2 (1.5/98.5 v/o). VN, CrN, and NbN formed in Ni-V, Ni-Cr, and Ni-Nb alloys, respectively, whereas the underlying carbide layers contained V 4 C 3 in Ni-12V, Cr 3 C 2 above a zone of Cr 7 C 3 in Ni-20Cr, and NbC in Ni-3Nb. The solubilities and diffusivities of nitrogen and carbon in nickel were determined. Nitrogen and carbon each exhibited retrograde solubility with temperature in pure Ni in both carbonitriding environments. Nitrogen diffusion in nickel was generally lower in each carbonitriding mixture compared to nitrogen diffusion in a nitriding environment, except at 700 C when nitrogen diffusion was higher. Carbon diffusion in nickel was generally higher in the carbonitriding environments compared to carbon diffusion in a carburizing environment

Martensitic transformation and magnetic properties of manganese-rich Ni-Mn-In and Ni-Mn-Sn Heusler alloys

International Nuclear Information System (INIS)

Krenke, T.

2007-01-01

In the present work, the martensitic transition and the magnetic properties of Manganese rich Ni 50 Mn 50-x Sn x and Ni 50 Mn 50-y In y alloys with 5 at%≤x(y)≤25 at% were investigated. Calorimetry, X-ray and neutron diffraction, magnetization, and strain measurements were performed on polycrystalline samples. It was shown that alloys close to the stoichiometric composition Ni 50 Mn 25 Sn 25 and Ni 50 Mn 25 Sn 25 do not exhibit a structural transition on lowering of the temperature, whereas alloys with x≤15 at% Tin and y≤16 at% Indium transform martensitically. The structural transition temperatures increase linearly with decreasing Tin or Indium content. The crystal structures of the low temperature martensite are modulated as well as unmodulated. Alloys with compositions close to stoichiometry are dominated by ferromagnetic interactions, whereas those close to the binary composition Ni 50 Mn 50 order antiferromagnetically. Ferromagnetic order and structural instability coexist in a narrow composition range between 13 at%≤x≤15 at% and 15 at%≤x≤16 at% for Ni 50 Mn 50-x Sn x and Ni 50 Mn 50-y In y respectively. As a consequence, interesting magnetoelastic effects are observed. The Ni 50 Mn 34 In 16 alloy shows a magnetic field-induced structural transition, whereby application of an external magnetic field in the martensitic state stabilizes the high temperature L2 1 structure. Evidence for this was given by neutron diffraction experiments in external magnetic fields. Moreover, the structural transition temperatures of this alloy show large magnetic field dependencies. By use of calorimetry, M(T), and strain measurements, changes in M s up to -11 K/Tesla are observed. Such large values have, until now, not been observed in Heusler alloys. Since during transformation the volume changes reversibly, magnetic field-induced strains of about 0.12 % appear. Additionally, the alloys Ni 50 Mn 35 Sn 15 , Ni 50 Mn 37 Sn 13 , Ni 50 Mn 34 In 16 , Ni 51.5 Mn 33 In

Particle reinforced composites from acrylamide modified blend of styrene-butadiene and natural rubber

Science.gov (United States)

Blends of styrene-butadiene rubber and natural rubber that provide balanced properties were modified with acrylamide and reinforced with soy protein particles. The rubber composites show improved mechanical properties. Both modified rubber and composites showed a faster curing rate. The crosslinking...

Amperometric detection of hydrogen peroxide at nano-nickel oxide/thionine and celestine blue nanocomposite-modified glassy carbon electrodes

International Nuclear Information System (INIS)

Noorbakhsh, Abdollah; Salimi, Abdollah

2009-01-01

A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with nickel oxide (NiOx) nanoparticles and water-soluble dyes. By immersing the GC/NiOx modified electrode into thionine (TH) or celestine blue (CB) solutions for a short period of time (5-120 s), a thin film of the proposed molecules was immobilized onto the electrode surface. The modified electrodes showed stable and a well-defined redox couples at a wide pH range (2-12), with surface confined characteristics. In comparison to usual methods for the immobilization of dye molecules, such as electropolymerization or adsorption on the surface of preanodized electrodes, the electrochemical reversibility and stability of these modified electrodes have been improved. The surface coverage and heterogeneous electron transfer rate constants (k s ) of thionin and celestin blue immobilized on a NiOx-GC electrode were approximately 3.5 x 10 -10 mol cm -2 , 6.12 s -1 , 5.9 x 10 -10 mol cm -2 and 6.58 s -1 , respectively. The results clearly show the high loading ability of the NiOx nanoparticles and great facilitation of the electron transfer between the immobilized TH, CB and NiOx nanoparticles. The modified electrodes show excellent electrocatalytic activity toward hydrogen peroxide reduction at a reduced overpotential. The catalytic rate constants for hydrogen peroxide reduction at GC/NiOx/CB and GC/NiOx/TH were 7.96 (±0.2) x 10 3 M -1 s -1 and 5.5 (±0.2) x 10 3 M -1 s -1 , respectively. The detection limit, sensitivity and linear concentration range for hydrogen peroxide detection were 1.67 μM, 4.14 nA μM -1 nA μM -1 and 5 μM to 20 mM, and 0.36 μM, 7.62 nA μM -1 , and 1 μM to 10 mM for the GC/NiOx/TH and GC/NiOx/CB modified electrodes, respectively. Compared to other modified electrodes, these modified electrodes have many advantages, such as remarkable catalytic activity, good reproducibility, simple preparation procedures and long-term stabilities of signal responses during

Interphase Constituent of Laminated Composites Ti46Zr26Cu17Ni11

Directory of Open Access Journals (Sweden)

XU Bingtong

2017-10-01

Full Text Available Thermal analysis of the Ti46Zr26Cu17Ni11 amorphous ribbon prepared by melt spinning was conducted by using DSC. Accordingly the amorphous alloy was treated by vacuum heat treatment at 693 K (Tg, 753 K (Tg-Tx1 and 813 K (> Tx1 for different time to analyze the crystallization behavior. Taking Ti46Zr26Cu17Ni11 amorphous alloy, TA2 and pure Al as raw materials, laminated composites were fabricated by Gleeble-3500 thermal simulator at 873 K, 10 MPa and 8 h. The phase composition, precipitation order and properties of interface layers were investigated by SEM, TEM, micro hardness tester, combined thermodynamics and element diffusion theory. The results indicate that the glass transition temperature Tg of Ti46Zr26Cu17Ni11 amorphous is 720 K and the initial crystallization temperature Tx1 is 788 K. The I phase is crystallized from the amorphous at first, followed by a ternary or quaternary Laves phase and a TiNi phase precipited. After hot pressing, the interface between pure Al and crystallization layer is divided into two parts, which are Al3Ni with small thickness and Al3(Ti0.6Zr0.4 with fine grain and uniform microstructure. The interfaces are straight and there are no defects, with a thickness ratio of about 6.5:1 compared with interface layer between pure Ti with Al. The hardness of Al3(Ti0.6Zr0.4 and Al3Ti are 564.2HV and 579.8HV respectively. The plasticity of Al3(Ti0.6Zr0.4 layer is better.

Mechanical and thermal properties of polypropylene (PP) composites filled with modified shell waste

Energy Technology Data Exchange (ETDEWEB)

Yao, Z.T., E-mail: sxyzt@126.com [College of Materials Science and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Chen, T. [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China); Li, H.Y. [Zhoushan Ocean Research Institute, Zhejiang University, Zhoushan 316021 (China); Xia, M.S., E-mail: msxia@zju.edu.cn [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China); Ye, Y.; Zheng, H. [Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058 (China)

2013-11-15

Highlights: • Adding modified shell powder could significantly increase the properties of PP. • The modified shell powder could act as a nucleating agent in PP matrix. • The modified shell powder has a potential to be used as a bio-filler. -- Abstract: Shell waste, with its high content of calcium carbonate (CaCO{sub 3}) plus organic matrix, has a potential to be used as a bio-filler. In this work, shell waste was modified by furfural and then incorporated to reinforce polypropylene (PP). The shell waste and modified powder were characterized by means of X-ray diffraction (XRD), scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS), X-ray photoelectronic spectroscopy (XPS), and Fourier transformed infrared spectroscopy (FTIR). The mechanical and thermal properties of neat PP and PP composites were investigated as well. Thermal gravimetric (TG) analyses confirmed the reinforcing role of modified powder in PP composites. The mechanical properties studied showed that adding modified powder could significantly increase the impact strength, elongation at break point and flexural modulus of composites. The maximum incorporation content could reach 15 wt.% with a good balance between toughness and stiffness of PP composites. Differential scanning calorimetry (DSC) results showed that the modified powder could act as a nucleating agent and thus increase the crystallization temperature of PP. Polarized optical microscopy (POM) observation also indicated that the introduction of modified powder could promote the heterogeneous nucleation of PP matrix.

Facile Synthesis of Graphene@NiO/MoO3 Composite Nanosheet Arrays for High-performance Supercapacitors

International Nuclear Information System (INIS)

Zeng, Wei; Zhang, Guanhua; Hou, Sucheng; Wang, Taihong; Duan, Huigao

2015-01-01

Graphene@NiO/MoO 3 composite nanosheet arrays (CSAs) were grown on the nickel foam via a one-step hydrothermal way. The composite of NiO and MoO 3 showed a promising synergistic effect for capacitors. Graphene had been integrated to the composite nanosheets to further enhance the electrochemical performance. The prepared samples were characterized by scanning electron microscopy and transmission electron microscopy, X-ray diffraction spectroscopy and Raman spectroscopy. A possible growth mechanism was proposed to explain the formation of the composite nanosheets by carrying out a series of time-dependent experiments. Benefiting from the improved electron conductivity and effective buffering of the volume variation induced by redox reactions, the composite exhibited a high area capacitance of 1.372 F cm −2 even at a high current density of 42 mA cm −2 , and showed excellent cycle stability (62.7% of the initial capacitance after 7500 cycles, while 87.9% remained in the latter 7000 cycles)

X-ray diffraction characterization of epitaxial CVD diamond films with natural and isotopically modified compositions

Energy Technology Data Exchange (ETDEWEB)

Prokhorov, I. A., E-mail: igor.prokhorov@mail.ru [Russian Academy of Sciences, Space Materials Science Laboratory, Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics”, Kaluga Branch (Russian Federation); Voloshin, A. E. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Scientific Research Centre “Crystallography and Photonics” (Russian Federation); Ralchenko, V. G.; Bolshakov, A. P. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Romanov, D. A. [Bauman Moscow State Technical University, Kaluga Branch (Russian Federation); Khomich, A. A. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Sozontov, E. A. [National Research Centre “Kurchatov Institute” (Russian Federation)

2016-11-15

Comparative investigations of homoepitaxial diamond films with natural and modified isotopic compositions, grown by chemical vapor deposition (CVD) on type-Ib diamond substrates, are carried out using double-crystal X-ray diffractometry and topography. The lattice mismatch between the substrate and film is precisely measured. A decrease in the lattice constant on the order of (Δa/a){sub relax} ∼ (1.1–1.2) × 10{sup –4} is recorded in isotopically modified {sup 13}C (99.96%) films. The critical thicknesses of pseudomorphic diamond films is calculated. A significant increase in the dislocation density due to the elastic stress relaxation is revealed by X-ray topography.

Polypropylene-modified kaolinite composites: Effect of chemical ...

African Journals Online (AJOL)

PP/kaolinite compounds were prepared by the melt intercalation method. The effects of modified clay on properties of the prepared composites were studied. The XRD results showed that the treatment with the ammonium salt caused the return to the initial state of the clay. The thermogravimetric analysis thermograms (TGA) ...

Fabrication and Properties of Iron-based Soft Magnetic Composites Coated with NiZnFe2O4

Directory of Open Access Journals (Sweden)

WU Shen

2017-07-01

Full Text Available This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing the sol-gel method prepared Ni-Zn ferrite particles as insulating compound to coat iron powder, and the influence of NiZnFe2O4 content and molding pressure on the magnetic properties was studied. The morphology, magnetic properties and density of Ni-Zn ferrite insulated compacts were investigated. Scanning electron microscope,line-scan EDX analysis and distribution maps show that the iron particle surface is covered with a thin layer of uniform Ni-Zn ferrites. The existing of the insulating layer can effectively improve the electrical resistivity of soft magnetic composites. Magnetic measurements show that the real part of permeability decreases with the increase of the Ni-Zn ferrite content, and the sample with 3%(mass fraction, the same below Ni-Zn ferrite has an acceptable real part and minimum imaginary part of permeability in comparison with other samples. Results show that the addition of NiZnFe2O4 can dramatically decrease the internal magnetic loss, the magnetic loss of coated samples decreases by 83.8% as compared with that of uncoated samples at 100kHz. The density of the Fe-3%NiZnFe2O4 compacts reaches 7.14g/cm3 and the saturation magnetization is 1.47T when the molding pressure is 1000MPa.

Microstructure evolution during annealing of TiAl/NiCoCrAl multilayer composite prepared by EB-PVD

Energy Technology Data Exchange (ETDEWEB)

Zhang, Rubing, E-mail: zrb86411680@126.com [Department of Mechanics, School of Civil Engineering, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Deming [Beijing General Research Institute of Mining and Metallurgy, Beijing 100044 (China); Chen, Guiqing [Center for Composite Materials, Harbin Institute of Technology, Harbin 150001 (China); Wang, Yuesheng [Department of Mechanics, School of Civil Engineering, Beijing Jiaotong University, Beijing 100044 (China)

2014-07-01

TiAl/NiCoCrAl laminate composite sheet with a thickness of 0.4–0.6 mm as well as a dimension of 150 mm × 100 mm was fabricated successfully by using electron beam physical vapor deposition (EB-PVD) method. The annealing treatment was processed at 1123 and 1323 K for 3 h in a high vacuum atmosphere, respectively. The phase composition and microstructure of TiAl/NiCoCrAl microlaminated sheet have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Based on the sheet characterization and results of the microstructure evolution during annealing treatment process, the diffusion mechanism of interfacial reaction in TiAl/NiCoCrAl microlaminate was investigated and discussed.

Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers

Energy Technology Data Exchange (ETDEWEB)

Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Drexel University, Philadelphia, PA (United States); Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Ayad, D.M.; Sarhan, A.A. [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt)

2010-04-15

The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers.

Science.gov (United States)

Monier, M; Ayad, D M; Sarhan, A A

2010-04-15

The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction. 2009 Elsevier B.V. All rights reserved.

Dual functions of zirconium modification on improving the electrochemical performance of Ni-rich LiNi0.8Co0.1Mn0.1O2

Energy Technology Data Exchange (ETDEWEB)

Li, Xing; Zhang, Kangjia; Wang, Mingshan; Liu, Yang; Qu, Meizhen; Zhao, Wengao; Zheng, Jianming

2018-02-28

Trace amount of Zirconium (Zr) has been adopted to modify the crystal structure and surface of the Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material. During cycling at 1.0C, the Zr-modified NCM811 shows an improved capacity retention of 92% after 100 cycles, higher than 75% for pristine NMC811. In addition, the Zr-modified NCM811 is capable of delivering a discharge capacity of 107 mAh g-1 at 10.0C rate, much higher than 28 mAh g-1 delivered by pristine material. These improved electrochemical performances are ascribed to the dual functions of Zr modification. On one hand, part of the Zr enters the crystal lattice, which is beneficial for reducing the Li/Ni cation mixing and enhancing the crystal stability of the cathode. On the other hand, the rest of the Zr forms a 1~2 nm thick coating layer on the surface of the NCM811 cathode, which effectively prevents the direct contact between NCM and the electrolyte, thus suppressing the detrimental interfacial reactions. Therefore, the Zr-modified LiNi0.8Co0.1Mn0.1O2 exhibited significantly enhanced cycling stability and charging/discharging rate capability in comparison with the untreated counterpart.

Effect of amorphous Mg50Ni50 on hydriding and dehydriding behavior of Mg2Ni alloy

International Nuclear Information System (INIS)

Guzman, D.; Ordonez, S.; Fernandez, J.F.; Sanchez, C.; Serafini, D.; Rojas, P.A.; Aguilar, C.; Tapia, P.

2011-01-01

Composite Mg 2 Ni (25 wt.%) amorphous Mg 50 Ni 50 was prepared by mechanical milling starting with nanocrystalline Mg 2 Ni and amorphous Mg 50 Ni 50 powders, by using a SPEX 8000 D mill. The morphological and microstructural characterization of the powders was performed via scanning electron microscopy and X-ray diffraction. The hydriding characterization of the composite was performed via a solid gas reaction method in a Sievert's-type apparatus at 363 K under an initial hydrogen pressure of 2 MPa. The dehydriding behavior was studied by differential thermogravimetry. On the basis of the results, it is possible to conclude that amorphous Mg 50 Ni 50 improved the hydriding and dehydriding kinetics of Mg 2 Ni alloy upon cycling. A tentative rationalization of experimental observations is proposed. - Research Highlights: → First study of the hydriding behavior of composite Mg 2 Ni (25 wt.%) amorphous Mg 50 Ni 50 . → Microstructural characterization of composite material using XRD and SEM was obtained. → An improved effect of Mg 50 Ni 50 on the Mg 2 Ni hydriding behavior was verified. → The apparent activation energy for the hydrogen desorption of composite was obtained.

Structural and textural study of Ni and/or Co in a common molybdate lattice as catalysts

Directory of Open Access Journals (Sweden)

Boukhlouf H.

2013-09-01

Full Text Available This work deals with the search for new molybdate catalyst formulations, which are known to be active in light alkane oxidative dehydrogenation, a process which could be replace in the near future the common steam cracking and pure dehydrogenation processes currently used for the production of alkenes. Co, Ni and mixed Ni-Co molybdates of various compositions are prepared by a modified coprecipitation procedure from metal nitrates and ammonium heptamolybdate. Their structural and textural properties were studied by XRD, Raman, B.E.T and XPS. Textural and structural properties of the materials are correlated to the composition.

Electrochemical vs X-ray Spectroscopic Measurements of NiFe(CN)6 Crystals

Science.gov (United States)

Peecher, Benjamin; Hampton, Jennifer

Pseudocapacitive materials like hexacyanoferrate have greater energy storage capabilities than standard capacitors while maintaining an ability to charge and discharge quickly. We modify the surface of an electrodeposited Ni thin film with a layer of hexacyanoferrate. Charging and discharging these modified films using cyclic voltammetry (CV) allows us to measure the electrochemically active Fe in the film. To determine how closely this resembles the full amount of Fe in the film, we measure the films' composition using particle-induced x-ray emission (PIXE). We also vary the amount of Ni deposited, both to compare the electrolysis value of charge deposited to the PIXE measurement of Ni in the film, and also to measure how varying the thickness of the Ni surface affects the presence of Fe in the film. Comparisons of the CV and PIXE measurements show agreement in Ni levels but disagreement in Fe levels. PIXE measurements of Fe in the film have positive correlation with Ni in the film. This correlation between PIXE measurements of Ni and Fe suggests that PIXE provides a reliable measure of Fe in the film. This implies that a variable proportion of total Fe in a given film is electrochemically active. This research was made possible by the Hope College Department of Physics Frissel Research Fund and the National Science Foundation under Grants RUI-DMR-1104725, MRI-CHE-0959282, and MRI/RUI-PHY-0319523.

Enthalpies of formation of layered LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} (0 ≤ x ≤ 0.5) compounds as lithium ion battery cathode materials

Energy Technology Data Exchange (ETDEWEB)

Masoumi, Maryam; Cupid, Damian M.; Reichmann, Thomas L.; Seifert, Hans J. [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany). Inst. for Applied Materials - Applied Materials Physics; Chang, Keke; Music, Denis; Schneider, Jochen M. [RWTH Aachen Univ. (Germany). Materials Chemistry

2017-11-15

Layer-structured mixed transition metal oxides with the formula LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} (0 ≤ x ≤ 0.5) are considered as important cathode materials for lithium-ion batteries. In an effort to evaluate the relative thermodynamic stabilities of individual compositions in this series, the enthalpies of formation of selected stoichiometries are determined by high temperature oxide melt drop solution calorimetry and verified by ab-initio calculations. The measured and calculated data are in good agreement with each other, and the results show that LiCoO{sub 2}-LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} solid solution approaches ideal behavior. By increasing x, i.e. by equimolar substitution of Mn{sup 4+} and Ni{sup 2+} for Co{sup 3+}, the enthalpy of formation of LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} from the elements becomes more exothermic, implying increased energetic stability. This conclusion is in agreement with the literature results showing improved structural stability and cycling performance of Ni/Mn-rich LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} compounds cycled to higher cut-off voltages.

Facile Electrodeposition of Flower-Like PMo12-Pt/rGO Composite with Enhanced Electrocatalytic Activity towards Methanol Oxidation

Directory of Open Access Journals (Sweden)

Xiaoying Wang

2015-07-01

Full Text Available A facile, rapid and green method based on potentiostatic electrodeposition is developed to synthesize a novel H3PMo12O40-Pt/reduced graphene oxide (denoted as PMo12-Pt/rGO composite. The as-prepared PMo12-Pt/rGO is characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and X-ray photoelectron spectroscopy (XPS. The results reveal that graphene oxide (GO is reduced to the rGO by electrochemical method and POMs clusters are successfully located on the rGO as the modifier. Furthermore, the PMo12-Pt/rGO composite shows higher electrocatalytic activity, better tolerance towards CO and better stability than the conventional pure Pt catalyst.

Investigation on Wire Electrochemical Micro Machining of Ni-based Metallic Glass

International Nuclear Information System (INIS)

Meng, Lingchao; Zeng, Yongbin; Zhu, Di

2017-01-01

Highlights: • WECMM with nanosecond pulses is proposed firstly for fabricating micro complex components based on metallic glasses. • Applicable electrolyte for WECMM of the Ni-based MG is discussed. • Significantly uniform machined surface is achieved in H_2SO_4 solution. • High machining efficiency and stability are obtained experimentally by modifying pulse waveforms and electrolyte compositions. • Complex microstructures of Ni-based MG are fabricated by WECMM with optimized parameters. - Abstract: Metallic glasses (MGs) have been recognized as promising materials for realizing high-performance micro devices in micro electromechanical systems (MEMS) due to their excellent functional and structural characteristics. However, the applications of MGs are currently limited because of the difficulty of shaping them on the microscale. Wire electrochemical micro machining (WECMM) is increasingly recognized as a flexible and effective method to fabricate complex-shaped micro metal components with many advantages relative to the thermomechanical processing, which appears to be well suitable for micro shaping of MGs. We consider the example of a Ni-based MG, Ni_7_2Cr_1_9Si_7B_2, which has a typical passivation characteristic in 0.1 M H_2SO_4 solution. The transpassive process can be used for localized material removal when combined with nanosecond pulsed WECMM technique. In present work, the applicable electrolyte for WECMM of the Ni-based MG was discussed firstly. Then the voltage pulse waveform and electrolyte composition were modified to improve machining efficiency and stability. Several complex microstructures such as micro curved cantilever beam, micro gear, and micro square helix were machined with different optimized parameters.

TEM Studies of Boron-Modified 17Cr-7Ni Precipitation-Hardenable Stainless Steel via Rapid Solidification Route

Science.gov (United States)

Gupta, Ankur; Bhargava, A. K.; Tewari, R.; Tiwari, A. N.

2013-09-01

Commercial grade 17Cr-7Ni precipitation-hardenable stainless steel has been modified by adding boron in the range 0.45 to 1.8 wt pct and using the chill block melt-spinning technique of rapid solidification (RS). Application of RS has been found to increase the solid solubility of boron and hardness of 17Cr-7Ni precipitation-hardenable stainless steel. The hardness of the boron-modified rapidly solidified alloys has been found to increase up to ~280 pct after isochronal aging to peak hardness. A TEM study has been carried out to understand the aging behavior. The presence of M23(B,C)6 and M2(B,C) borocarbides and epsilon-carbide in the matrix of austenite and ferrite with a change in heat treatment temperature has been observed. A new equation for Creq is also developed which includes the boron factor on ferrite phase stability. The study also emphasizes that aluminum only takes part in ferrite phase stabilization and remains in the solution.

Ultrathin NiO/NiFe2O4 Nanoplates Decorated Graphene Nanosheets with Enhanced Lithium Storage Properties

International Nuclear Information System (INIS)

Du, Dejian; Yue, Wenbo; Fan, Xialu; Tang, Kun; Yang, Xiaojing

2016-01-01

Highlights: • Ultrathin NiO/NiFe 2 O 4 nanoplates derived from NiFe layered double hydroxides are fabricated on the graphene. • NiO/NiFe 2 O 4 nanoplates on the graphene show superior electrochemical performance compared to pure NiO/NiFe 2 O 4 aggregates. • The effects of the content and the particle size/component of NiO/NiFe 2 O 4 on the electrochemical performances are studied. • Graphene-encapsulated NiO/NiFe 2 O 4 is prepared and shows slightly decreased performance compared to graphene-based composite. - Abstract: As anode materials for lithium-ion batteries, bicomponent metal oxide composites show high reversible capacities; but the morphology and particle size of the composites are hardly controllable, which may reduce their electrochemical properties. In this work, ultrathin NiO/NiFe 2 O 4 nanoplates with a diameter of 5 ∼ 7 nm and a thickness of ∼2 nm are controllably fabricated on the graphene derived from NiFe layered double hydroxides (NiFe-LDHs), and exhibit superior electrochemical performance compared to pure NiO/NiFe 2 O 4 aggregates without graphene. The nanosized NiO and NiFe 2 O 4 plates are separated from each other and the graphene substrate can prevent the aggregation of NiO/NiFe 2 O 4 as well as enhance the electronic conductivity of the composite, which is beneficial to improving the electrochemical performance. Moreover, the effects of the content and the particle size/component of NiO/NiFe 2 O 4 on the electrochemical performances are also studied in order to achieve optimal performance. Ultrathin NiO/NiFe 2 O 4 nanoplates are further encapsulated by graphene nanosheets and show slightly decreased performance compared to those supported by graphene nanosheets. The different electrochemical behaviors of graphene-containing composites may be attributed to the different interactions between graphene nanosheets and NiO/NiFe 2 O 4 nanoplates.

Surface modification of AISI H13 tool steel by laser cladding with NiTi powder

Science.gov (United States)

Norhafzan, B.; Aqida, S. N.; Chikarakara, E.; Brabazon, D.

2016-04-01

This paper presents laser cladding of NiTi powder on AISI H13 tool steel surface for surface properties enhancement. The cladding process was conducted using Rofin DC-015 diffusion-cooled CO2 laser system with wavelength of 10.6 µm. NiTi powder was pre-placed on H13 tool steel surface. The laser beam was focused with a spot size of 90 µm on the sample surface. Laser parameters were set to 1515 and 1138 W peak power, 18 and 24 % duty cycle and 2300-3500 Hz laser pulse repetition frequency. Hardness properties of the modified layer were characterized by Wilson Hardness tester. Metallographic study and chemical composition were conducted using field emission scanning electron microscope and energy-dispersive X-ray spectrometer (EDXS) analysis. Results showed that hardness of NiTi clad layer increased three times that of the substrate material. The EDXS analysis detected NiTi phase presence in the modified layer up to 9.8 wt%. The metallographic study shows high metallurgical bonding between substrate and modified layer. These findings are significant to both increased hardness and erosion resistance of high-wear-resistant components and elongating their lifetime.

Copper separation using modified active carbon before the polarographic determination of Pb, Cd, Ni, Zn and Fe in wastes

International Nuclear Information System (INIS)

Rubel, S.; Lada, Z.M.; Golimowski, J.

1977-01-01

The investigations on the selective separation of Pb 2+ , Cd 2+ , Ni 2+ , Zn 2+ and Fe 3+ ions from the excess of copper were carried out. For this purpose active carbon modified by Na-diethyldithiocarbamate was used. The manner of DDTK-Na deposition on active carbon has been elaborated. The influence of pH was investigated and it was found that at pH 1(HNO 3 ) copper ions are quantitavely bound on modified carbon whereas other ions (Pb 2+ , Cd 2+ , Ni 2+ , Zn 2+ and Fe 3+ ) remain in the solution and can be determined polarographically. The elaborated method was applied to the determination of mentioned ions in the samples of wastes containing even 100-fold excess of copper. The concentration of copper can not exceed 100 mg/dm 3 . (author)

Anchor of Ni2+ on the Agmatine Sulfate-Modified Electrodes for the Determination of H2O2 in Food

Science.gov (United States)

Yan, Yuhua; Zhang, Zhonghui; Xiao, Mingshu; Zhou, Hualan

2017-07-01

A method was developed to conveniently and rapidly determine hydrogen peroxide (H2O2) in food. The glassy carbon electrode (GCE) modified with agmatine sulfate (AS) easily anchoring nickel ion was attached to AS with polyamine structure. As a result, more Ni2+ was obtained and transformed to Ni(OH)2/NiOOH on the AS-GCE, which caused the electrode to own much better electrocatalytic performance on H2O2. Based on these, the content of H2O2 in thin sheet of bean curd sample was detected with standard addition method, by which good results were obtained.

Rietveld refinement of the orthorhombic Pbca structures of Rb2CdSi5O12, Cs2MnSiO5O12, Cs2CoSi5O12 and Cs2NiSi5O12 leucites by synchrotron X-ray powder diffraction

International Nuclear Information System (INIS)

Bell, A.M.T.; Henderson, C.M.B.

1996-01-01

Analysis of high-resolution synchrotron X-ray powder diffraction patterns for hydrothermally synthesized Rb 2 CdSi 5 O 12 and Cs 2 MnSi 5 O 12 leucite analogues, and dry-synthesized Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite analogues showed that they have an orthorhombic Pbca structure. The structures have been refined by the Rietveld method, showing that the tetrahedrally coordinated atoms (Si, Cd, Mn, Co and Ni) are ordered on separate sites. The Cs 2 MnSi 5 O 12 , Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite samples are unusual in containing SiO 4 tetrahedra which are more distorted, on average, than the larger MnO 4 , CoO 4 and NiO 4 tetrahedra. The JCPDS file numbers for Rb 2 CdSi 5 O 12 , Cs 2 MnSi 5 O 12 and Cs 2 CoSi 5 O 12 are 46-1491, 46-1492 and 46-1493, respectively. (orig.)

Characteristics and in vitro biological assessment of (Ti, O, N)/Ti composite coating formed on NiTi shape memory alloy

International Nuclear Information System (INIS)