scholarly journals Electrochemical deposition and characterization of zinc-nickel alloys deposited by direct and reverse current

2005 ◽  
Vol 70 (12) ◽  
pp. 1427-1439 ◽  
Author(s):  
Jelena Bajat ◽  
Aleksandra Petrovic ◽  
Miodrag Maksimovic
Keyword(s):  
Reverse Current ◽  
Rotating Disc ◽  
Time Duration ◽  
Corrosion Properties ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Electrochemically Deposited ◽  
Chemical Content ◽  
Current Densities

Zn-Ni alloys electrochemically deposited on steel under various deposition conditions were investigated. The alloys were deposited on a rotating disc electrode and on a steel panel from chloride solutions by direct and reverse current. The influence of reverse plating variables (cathodic and anodic current densities and their time duration) on the composition, phase structure and corrosion properties were investigated. The chemical content and phase composition affect the anticorrosive properties of Zn-Ni alloys during exposure to a corrosive agent (3%NaCl solution). It was shown that the Zn-Ni alloy electrodeposited by reverse current with a full period T = 1 s and r=0.2 exhibits the best corrosion properties of all the investigated alloys deposited by reverse current.

scholarly journals Electrochemical deposition and characterization of zinc-nickel alloys deposited by direct and pulse current

2002 ◽  
Vol 67 (8-9) ◽  
pp. 625-634 ◽  
Author(s):  
Jelena Bajat ◽  
Miodrag Maksimovic ◽  
Goran Radovic
Keyword(s):  
Electrochemical Deposition ◽  
Phase Structure ◽  
Nickel Alloys ◽  
Pulse Current ◽  
Rotating Disc ◽  
Corrosion Properties ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Off Time

Chemical composition and phase structure of Zn-Ni alloys obtained by electrochemical deposition under various conditions were investigated. The alloys were deposited on a rotating disc electrode and steel panel from chloride solutions by direct and pulse current. The influence of the pulse plating variables (on-time, off-time, relation of off- and on-time) on the composition, phase structure and corrosion properties were investigated. The phase composition affects the anticorrosive properties of Zn-Ni alloys during exposure to a corrosive agent (3% NaCl solution). It was shown that a Zn-Ni alloy electrodeposited by pulse current with a pulse time of 1 ms and an off- and on-time ratio of 1 exhibits the best corrosion properties.

Revelation of solid solubility limit Fe/Ni = 1/12 in corrosion resistant Cu-Ni alloys and relevant cluster model

2010 ◽  
Vol 25 (2) ◽  
pp. 328-336 ◽  
Author(s):  
Jie Zhang ◽  
Qing Wang ◽  
Yingmin Wang ◽  
Chunyan Li ◽  
Lishi Wen ◽  
...  
Keyword(s):  
Solid Solubility ◽  
Solubility Limit ◽  
Corrosion Performance ◽  
Corrosion Properties ◽  
Solid Solubility Limit ◽  
Corrosion Resistant ◽  
Ni Alloys ◽  
Alloy Series ◽  
Fe Content ◽  
Ni Alloy

Minor Fe additions are necessary to enhance the corrosion resistance of commercial Cu-Ni alloys. The present paper aims at optimizing the Fe content in three alloy series Cu90(Ni,Fe)10, Cu80(Ni,Fe)20, and Cu70(Ni,Fe)30 (at.%) from the viewpoint of their corrosion performance in a 3.5% NaCl solution. An Fe/Ni = 1/12 solid solubility limit line was revealed in the Cu-Ni-Fe phase diagram. Three Fe/Ni = 1/12 alloys, Cu90Ni9.23Fe0.77 (at.%) = Cu-8.6Ni-0.7Fe (wt.%), Cu80Ni18.46Fe1.54 = Cu-17.3Ni-1.4Fe, and Cu70Ni27.7Fe2.3 = Cu-26.2Ni-2.1Fe, show the best corrosion performances in their respective alloy series. The Fe/Ni = 1/12 solubility limit is explained by assuming isolated Fe-centered FeNi12 cuboctahedral clusters embedded in a Cu matrix. The three Fe/Ni = 1/12 alloys can be respectively described by cluster formulas [Fe1Ni12]Cu117, [Fe1Ni12]Cu52, and [Fe1Ni12]Cu30.3. The Fe/Ni = 1/12 rule may serve an important guideline in the industrial Cu-Ni alloy selection because above this limit, easy precipitation would negate the corrosion properties of the Cu-Ni-based alloys.

Microstructural Evolution and Corrosion Behavior of Carburized α-Fe Plates by Glucose

2013 ◽  
Vol 203-204 ◽  
pp. 94-98
Author(s):  
Eleftheria Maria Pechlivani ◽  
Fani Stergioudi ◽  
Christos Vogiatzis ◽  
Stefanos Skolianos ◽  
Danuta Stróż
Keyword(s):  
Room Temperature ◽  
Experimental Characterization ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
X Ray ◽  
Electrochemical Tests ◽  
Corrosion Rates ◽  
Current Densities ◽  
Scanning Electron

The aim of this paper is to obtain an experimental characterization of glucose-carburized substrates of α-Fe. The carburization process was achieved under vacuum condition using glucose as a carburizing medium. The process was carried out at several temperatures keeping the duration constant at 2h. The samples were treated at 400°C, 650°C and 900°C. The microstructure of the as produced coatings was observed by Scanning Electron Microscopy (SEM) and the formed phases were analyzed by X-Ray Diffraction (XRD). To investigate the corrosion properties of the carburized iron specimens, electrochemical tests were conducted. The samples were exposed to a solution of 3.5% wt. NaCl electrolyte, under quiescent conditions at room temperature and open to the air. The corroded samples were observed with use of Optical Microscopy in order to evaluate the corrosion effect on their surfaces. Carburization of iron samples at temperatures up to 650°C resulted in a shift of the polarization curves to lower current densities. Smaller corrosion rates were measured indicating higher corrosion resistance for these specimens.

scholarly journals Nuclear Gamma Resonance Study of the Ir —Fe and Ir —Ni Alloy Systems

1971 ◽  
Vol 26 (3) ◽  
pp. 343-352 ◽  
Author(s):  
R.L. Mössbauer ◽  
M. Lengsfeld ◽  
W. Von Lieres ◽  
W. Potzel ◽  
T. Teschner ◽  
...  
Keyword(s):  
Composition Range ◽  
Magnetic Hyperfine Field ◽  
Band Model ◽  
Hyperfine Fields ◽  
Ni Alloys ◽  
Dilute Alloys ◽  
Ni Alloy ◽  
Bulk Magnetization ◽  
Bcc Phase ◽  
Alloy Systems

Abstract The Ir-Fe and Ir-Ni alloy systems were studied over the whole composition range by means of the nuclear resonance absorption of the 73 keV y-rays of 193Jr and of the 14.4 keV y-rays of 57Fe. The magnetic hyperfine field at the Ir-nuclei in Ir-Ni alloys decreases approximately linearly with the Ir concentration from - 460 kOe at 4.2 K in very dilute alloys to zero at about 20 at.-% Ir. This behaviour is paralleled by the decrease of the magnetic moment per Ni atom as determined from bulk magnetization measurements. The hyperfine fields at both Ir and Fe were measured for the ferromagnetic bcc phase of the Ir-Fe system. They turned out to be virtually independent of concentration with values of about -1400 kOe and - 330 kOe, respectively. Linewidths increasing with the Ir concentration indicate a distribution of hyperfine fields. The fee phase of the Ir-Fe system has been found to be paramagnetic at 4.2 K throughout the range of its existence. The dependence of the hyperfine fields on concentration is discussed in terms of a rigid 3d-band model combined with local shielding. A discussion of the concentration dependence of the 193Ir and 57Fe isomer shifts has to take into account lattice expansion as well as band repopulation effects.

Structural Characterization and Corrosion Properties of BTESPT Silane Films on Surface of 2024-T6 Aluminium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1111-1116 ◽  
Author(s):  
Ming An Chen ◽  
Xuan Xie ◽  
Guo Fu Xu ◽  
Hui Zhong Li ◽  
Xin Ming Zhang
Keyword(s):  
Structural Characterization ◽  
Water Solution ◽  
Corrosion Current ◽  
Immersion Test ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Entire Surface ◽  
Corrosion Properties ◽  
The Matrix

2024-T6 Al alloy sheet s were modified by bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) silane film to improve the corrosion resistance. Fourier-Transform Reflection Absorption (FTIR-RA) spectroscopy was used for structural characterization of BTESPT silane film formed on surface of the sheet. Potentiodynamic polarization and immersion test in 3.5% NaCl solution were used for evaluating the corrosion performances of the silane film. The results showed that the film formed after curing at 120 °C for 40 min was cross-linked through Si-O-Si and that it was covered on the entire surface of the sheet. The content of elements S and Si on the Al2CuMg particles is a little higher that of on the matrix. The strong peak at 1032 cm-1 indicated that the film was linked to the sheet by Si-O-Al. Compared to the untreated case, the corrosion current density of the sheet treated with the silane film was reduced by close to 2 orders. Treatment of BTESPT silane can provide about 670 h protection of corrosion for the sheet in 3.5% NaCl water solution.

Synthesis and Magnetic Properties of Nanocrystalline Co-Ni Alloys: A Review

2012 ◽  
Vol 736 ◽  
pp. 229-240 ◽  
Author(s):  
Sudhakar Panday ◽  
P. Jeevanandam ◽  
B.S. Sunder Daniel
Keyword(s):  
Magnetic Properties ◽  
Binary Alloys ◽  
Synthesis Method ◽  
Surface Oxidation ◽  
Alloy Nanoparticles ◽  
Ni Alloys ◽  
Alloy Particles ◽  
Ni Alloy ◽  
Co Concentration ◽  
Potential Applications

This review article deals with the synthesis, characterization and magnetic properties of Co-Ni nanoalloys. The various physical and chemical methods for the synthesis of Co-Ni alloy nanoparticles are discussed. Co-Ni alloy nanoparticles with different size and shape such as spherical, rods, wires chain-like assembly are found to depend on the synthesis method and experimental condition. The structure of Co-Ni alloys is eitherfcc,hcpor mixedfccandhcpphase and found to depends on size, shape and concentration of Co in the Co-Ni alloys. Sodium hydroxide (NaOH) concentration and Co to Ni ratio influence the shape of bimetallic Co-Ni nanoparticles. Pt nucleating agents produced smaller size of Co-Ni alloy particles compared to Ru and Ag. Higher Co concentration in the Co-Ni alloys also influences the size alloy particles. The magnetic properties of Co-Ni nanoalloys depend on the size, shape and composition of the binary alloys. Surface oxidation of Co-Ni alloy nanoparticles decrease the saturation magnetization and increases with Co concentration in the alloys. The shape of Co-Ni alloy nanoparticles has an influence on coercivity. The microwave absorption properties of the Co-Ni alloys found to depend on the shape, size and composition of the binary alloys. The absorbance peaks shifts to higher frequency with decrease in size of the alloy particles. Potential applications of Co-Ni alloys in various fields are highlighted.

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