scholarly journals Characterization and corrosion properties of electrodeposited Ni-W alloys

2001 ◽  
Vol 66 (11-12) ◽  
pp. 899-912 ◽  
Author(s):  
M. Obradovic ◽  
J. Stevanovic ◽  
A. Despic ◽  
R. Stevanovic ◽  
J. Stoch
Keyword(s):  
Solid Solution ◽  
Surface Layer ◽  
Complex Structure ◽  
Deposition Process ◽  
Corrosion Process ◽  
Cathodic Deposition ◽  
Corrosion Properties ◽  
Corrosion Rates ◽  
Pure Metals ◽  
Preferential Dissolution

Ni-W alloys electrodeposited from citrate solution consist of three different phases, which are all present in high W-content alloys: a solid solution of W in a Ni matrix; an intermetallic compound Ni4W, as well as another solid solution of Win Ni with a W content higher than 20 mol.%. XPS analysis revealed that the alloys were covered with a surface layer of complex structure containing the pure metals Ni and W, Ni(OH)2 andWO3, on the very surface as well as some partially reduced oxideWO2.72 (most probably a solid solution of WO2.72 in Ni) and tungsten carbide in the layer underneath. It is highly likely that some of the oxide species in the layer act as intermediates in the cathodic deposition process. Identifying these species should be the clue to a more detailed understanding of the mechanism of induced deposition of W than has been achieved so far. Corrosion of Ni-W alloys in sulfuric acid solution at OCP, occurs by the preferential dissolution of nickel from the surface layer. The longer the corrosion process lasts, the more the surface behaves like pure W. The lowest initial corrosion rates were recorded with alloys rich in W, but after aging at OCP the lowest corrosion c.d. was found for the Ni-W alloy with the most homogenous phase structure, consisting of the solid solution only.

Corrosion behavior of new type Co-based superalloys with different Ni contents

2017 ◽  
Vol 35 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Bo Gao ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Shu-Yu Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Corrosion Properties ◽  
Oxidation Processes ◽  
Ni Content ◽  
Ni Addition ◽  
New Type

AbstractThe corrosion properties of γ′-strengthened Co-xNi-Al-W-Cr (where x=15, 20, 25, and 30 at.%) superalloys were investigated in the mixture of 75 wt.% Na2SO4+25 wt.% NaCl at 900°C. The results showed that the corrosion behavior is associated with both sulfuration and oxidation processes. It was demonstrated that increasing the addition of Ni effectively promoted the formation of continuous Al2O3 scales, so that the hot corrosion resistance could be improved. When Ni content is more than 20 at.%, a large amount of Ni3S2 precipitates during the corrosion process. Sulfuration can destroy the integrity of the corrosion layer and increase the activity of oxygen. In this way, the internal oxidation of the alloys becomes more serious. Therefore, it is recommended that the optimum Ni addition is about 20 at.% for new type Co-Ni-Al-W-Cr superalloys.

Changes in Residual Stress in Worked Surface Layer of Type 304 Austenitic Stainless Steel Due to Tensile Deformation

2000 ◽  
Vol 123 (1) ◽  
pp. 130-134
Author(s):  
Makoto Hayashi ◽  
Kunio Enomoto
Keyword(s):  
Solid Solution ◽  
Residual Stress ◽  
Stainless Steel ◽  
Surface Layer ◽  
Residual Stresses ◽  
Tensile Deformation ◽  
End Mill ◽  
Heat Treated ◽  
304 Austenitic Stainless Steel ◽  
Type 304

Changes in the residual stress in a worked surface layer of type 304 austenitic stainless steel due to tensile deformation were measured by the X-ray diffraction residual stress measuring method. The compressive residual stresses introduced by end-mill, end-mill side cutter, and grinder were easily changed into tensile stresses when the plate specimens were subjected to tensile stress greater than the yield stress of the solid solution heat-treated material. The residual stresses after the tensile deformation depend on the initial residual stresses and the degree of preliminary working. The behavior of the residual stress changes can be interpreted if the surface-worked material is regarded as a composite made of solid solution heat-treated material and work-hardened material.

scholarly journals Corrosion Behavior of Al in Ethanol–Gasoline Blends

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5544
Author(s):  
Alfredo Brito-Franco ◽  
Jorge Uruchurtu ◽  
Isai Rosales-Cadena ◽  
Roy Lopez-Sesenes ◽  
Sergio Alonso Serna-Barquera ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Sugar Cane ◽  
Electrochemical Noise ◽  
Electrochemical Impedance ◽  
Pure Aluminum ◽  
Electrochemical Techniques ◽  
Intermediate Compound ◽  
Corrosion Process ◽  
Corrosion Rates ◽  
Adsorption Desorption

The corrosion behavior of pure aluminum (Al) in 20 v/v% ethanol–gasoline blends has been studied using electrochemical techniques. Ethanol was obtained from different fruits including sugar cane, oranges, apples, or mangos, whereas other techniques included lineal polarization resistance, electrochemical noise, and electrochemical impedance spectroscopy for 90 days. Results have shown that corrosion rates for Al in all the blends were higher than that obtained in gasoline. In addition, the highest corrosion rate was obtained in the blend containing ethanol obtained from sugar cane. The corrosion process was under charge transfer control in all blends; however, for some exposure times, it was under the adsorption/desorption control of an intermediate compound. Al was susceptible to a localized, plotting type of corrosion in all blends, but they were bigger in size and in number in the blend containing ethanol obtained from sugar cane.

scholarly journals Atomistic Simulations of Surface Relaxations in Ni, Al, and Their Ordered Alloys

1986 ◽  
Vol 82 ◽  
Author(s):  
S. P. Chen ◽  
A. F. Voter ◽  
D. J. Srolovitz
Keyword(s):  
Surface Layer ◽  
Atomistic Simulations ◽  
Atomic Diameter ◽  
Ordered Alloys ◽  
Pure Metals

ABSTRACTWe have performed a series of simulations to examine the atomistic nature of surface relaxations in pure metals and ordered alloys. The surface relaxations (∆dn, n+1) are shown to be oscillatory and to decay rapidly into the bulk. The period and form of the oscillation may be determined by simple geometrical arguments. The oscillation wavelength is always of the order of an atomic diameter. In pure metals, the surface layer of atoms always displaces inward. However, in the ordered alloys the larger atom may displace outward. On planes composed of more than one atom types, rippling occurs.

Effect of Nitrogen Diffusion in Ti and TiTiN Films for Future DRAM Bit Line Interconnects and Plugs

1996 ◽  
Vol 429 ◽  
Author(s):  
John M. Drynan ◽  
Kuniaki Koyama
Keyword(s):  
Solid Solution ◽  
Gas Phase ◽  
Sheet Resistance ◽  
Solid Phase ◽  
Deposition Process ◽  
Thermal Treatments ◽  
Nitrogen Diffusion ◽  
Materials Properties ◽  
Post Deposition

AbstractThe effects of nitrogen diffusion from both N2 gas phase and TiN solid phase sources on the characteristics of Ti/TiN bilayer and TiN/Ti/TiN trilayer films have been investigated in terms of both materials properties such as resistance, coloration, composition, and crystallinity, and prospective applications such as for DRAM bit line interconnections and contact-hole plugs. Using blank films it has been found, in coincidence with other work, that at the onset of N diffusion and hence low N concentrations within a Ti film, the sheet resistance increases and the Ti layer becomes a solid solution of N in hexagonal Ti. As the concentration increases, the sheet resistance reaches a maximum, after which it decreases abruptly and the structure becomes primarily tetragonal Ti2N phase. At higher concentrations the resistance stabilizes or increases slightly and the structure becomes more cubic TiN phase. Sheet resistances calculated from resistance measurements of Ti and TiN mono- and multilayer conductor lines with and without RTN and RTAr thermal treatments have shown that the conductor lines exhibit similar behavior to the blank films. In comparison with the mon-olayer lines, the multilayer ones are generally lower in resistance and more stable over a wider range of post-deposition process temperatures.

Liquidus Curves and Corrosion of Fe, Cr, Ni, Co, V, Cb, Ta, Ti, Zr, in 500–750 C Mercury

CORROSION ◽  
1967 ◽  
Vol 23 (4) ◽  
pp. 98-106 ◽  
Author(s):  
JOHN R. WEEKS
Keyword(s):  
Grain Boundaries ◽  
Selective Leaching ◽  
Corrosion Rates ◽  
Pure Metals

Abstract Liquldus curves of Fe, Cr, Ni, Co, V, Cb, Ta, Ti and Zr with Hg have been investigated at temperatures from 500 to 750 C (932–1382 F). From the results, relative corrosion rates have been estimated for each of these pure metals at 600 C (1112 F) in Hg which is saturated at 500 C. Predicted corrosion rates increase in the sequence: Ta, Cb, Fe, Co, V, Cr, Zr, Ti, Ni„ A stress-sensitive penetration of grain boundaries of Cb-lZr by Hg was shown to be associated with selective leaching of Zr from the alloy. Annealing the alloy before stressing it reduced but did not eliminate this attack.

In-situSpectroscopic Ellipsometry of the Cu Deposition Process from Supercritical Fluids: Evidence of an Abnormal Surface Layer Formation

2012 ◽  
Vol 51 (5S) ◽  
pp. 05EA02 ◽  
Author(s):  
Takuya Sasaki ◽  
Yukihiro Tamegai ◽  
Takahiro Ueno ◽  
Mitsuhiro Watanabe ◽  
Lianhua Jin ◽  
...  
Keyword(s):  
Surface Layer ◽  
Supercritical Fluids ◽  
Deposition Process ◽  
Layer Formation ◽  
Surface Layer Formation

Corrosion Properties of 20# Pipelines Steel in Near-Neutral Soils

2010 ◽  
Vol 129-131 ◽  
pp. 312-316
Author(s):  
Wen He Wang ◽  
Jun Yi ◽  
Shi Ming Shen
Keyword(s):  
Open Circuit Potential ◽  
Low Carbon Steel ◽  
Open Circuit ◽  
Corrosion Mechanism ◽  
Low Carbon ◽  
Corrosion Properties ◽  
Corrosion Rates ◽  
Cathode Area ◽  
Neutral Soil ◽  
Anode Area

Corrosion law and mechanism of 20# low-carbon steel in near-neutral soil along Yangtze River in Nanjing are studied by experiments of buried specimens in laboratory. In three kinds of soils, the corrosion features and products are analyzed by EDS and XRD, and the relation of corrosion rates, open-circuit potential and polarization curve with times are tested. The results indicated that corrosion rates changed incessantly along. On the condition of the same times, specimens and different soil samples, the corrosive degree of 1# and 2# specimens are serious, but 3# specimen is serious lightly. The corrosion products are main non-crystalloid, Fe (OH) 3 and Fe2O3.The changing tendency of different times and soils is different, and accordant with that of corrosion rates. The corrosion mechanism is discussed lastly, in near-neutral soils, oxygen is deoxidized and OH- ions are created in cathode area, iron is oxidized and the hydration of Fe2+ ions is created with water from soil in anode area, and Fe2+ are converted into more steady products Fe（OH）3 and Fe2O3.

scholarly journals Formation of Al-alloyed Layer on Magnesium with Use of Casting Techniques

2016 ◽  
Vol 16 (1) ◽  
pp. 112-116 ◽  
Author(s):  
R. Mola ◽  
T. Bucki ◽  
A. Dziadoń
Keyword(s):  
Solid Solution ◽  
Surface Layer ◽  
Casting Process ◽  
Outer Zone ◽  
Intermetallic Phases ◽  
Deep Penetration ◽  
Alloyed Layer ◽  
Molten Magnesium ◽  
Magnesium Melt ◽  
Steel Mould

Abstract Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al, Al3Mg2, Mg17Al12 and a solid solution of Mg in Al. When the temperature of the melt and the mould was lower (variant 1 – 670°C and 310°; variant 2 – 680°C and 310°C, respectively) the unreacted thin layer of aluminium was observed in the outer zone. Applying higher temperatures of the melt (685°C) and the mould (325°C) resulted in deep penetration of aluminium into the magnesium substrate. Areas enriched in aluminium were locally observed. The Al-enriched layers composed mainly of Mg-Al intermetallic phases have hardness from 187-256 HV0.1.

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