scholarly journals Corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey)

2021 ◽  
Vol 7 (1) ◽  
pp. 21-30
Author(s):  
Izatullo N. Ganiev ◽  
Firdavs A. Aliev ◽  
Haydar O. Odinazoda ◽  
Ahror M. Safarov ◽  
Rakhmazhon Usmonov
Keyword(s):  
Electrical Conductivity ◽  
High Temperature ◽  
Oxidation Rate ◽  
Copper Wire ◽  
Electrochemical Corrosion ◽  
Aluminum Wire ◽  
Temperature Oxidation ◽  
Alloy Oxidation ◽  
Temperature Exposure ◽  
Almgsi Alloy

The effect of impurities on the electrical conductivity of aluminum has been studied in detail. The electrical conductivity of aluminum is 65.45% of that of copper. The tensile strength of aluminum wire is 150–170 MPa which, at equal conductivity, is about 65% of the strength of copper wire. This strength of aluminum wire is sufficient for bearing the wire’s own weight but may be too low in case of snow, ice or wind overloads. One way to improve the strength of aluminum wire is to use aluminum alloys having higher strength combined with sufficiently high electrical conductivity, e.g. the E-AlMgSi alloy (Aldrey). The key strengthening agent of the E-AlMgSi alloy (Aldrey) is the Mg2Si phase which imparts high mechanical strength to aluminum. In this work we present experimental data on the kinetics of high-temperature oxidation and electrochemical corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey). Thermal gravimetric study has shown that indium doping and high temperature exposure increase the oxidation rate of E-AlMgSi alloy (Aldrey), with the apparent alloy oxidation activation energy decreasing from 120.5 to 91.8 kJ/mole. Alloy oxidation rate data determined using a potentiostatic technique in NaCl electrolyte media have shown that the corrosion resistance of the indium doped alloy is 20–30% superior to that of the initial alloy. With an increase in NaCl electrolyte concentration the electrochemical potentials of the alloys decrease whereas the corrosion rate increases regardless of alloy composition.

scholarly journals HIGH TEMPERATURE AND ELECTROCHEMICAL CORROSION OF Zn0.5Al ALLOY DOPED WITH CALCIUM IN VARIOUS MEDIA

2020 ◽  
Vol 63 (11) ◽  
pp. 21-26
Author(s):  
Ziyodullo R. Obidov ◽  
Jamshed Kh. Dzhailoev ◽  
Izatullo N. Ganiev ◽  
Odiljon N. Nazarov ◽  
Rakhmatjon Usmanov ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Atmospheric Oxygen ◽  
Electrochemical Corrosion ◽  
Oxidation Products ◽  
Alkaline Media ◽  
Potential Sweep ◽  
Temperature Oxidation

The article presents the results of a study of high-temperature and electrochemical corrosion of Zn0.5Al alloy doped with calcium in the various media. The thermogravimetric method was used to study the interaction of the Zn0.5Al alloy doped with calcium with atmospheric oxygen in the temperature range 523–623 K in the solid state. The kinetic and energy parameters of the process of high-temperature oxidation of alloys are determined. The process of high-temperature oxidation of Zn-Al-Ca alloys system is characterized by a monotonic decrease in the true oxidation rate and an increase in the effective activation energy when the alloying component in the initial Zn0.5Al alloy is up to 1.0 wt% doping with zinc-aluminum alloy 0.5 and 1.0 wt%. Calcium shows a slight increase in the oxidation rate of alloys. It was revealed that the oxidation process of the studied alloys with oxygen of the gas phase obeys the hyperbolic law. It was found that calcium supplements in the range of 0.01 - 0.1 wt%. The oxidizability of the initial Zn0.5Al alloy is reduced significantly, and the oxidation products of the alloys were ZnO, Al2O3, Al2O3 ∙ ZnO, CaO, Al2O3 ∙ CaO. By potentiostatic methods in the potentiodynamic mode with a potential sweep speed of 2 mV/s, it has been shown that for all samples of the Zn0.5Al-Ca alloys system in the acidic, neutral, and alkaline media, electrochemical potentials of corrosion, pitting formation, and repassivation are shifted to the region of negative values. It was revealed that zinc-aluminum alloys doped with calcium are most resistant to pitting corrosion in all studied media, respectively, in acidic (0.01n.), neutral (0.03-, 0.3-, 3.0 wt%) and alkaline (0.01n.) electrolytes of HCl, NaCl and NaOH. It has been established that calcium additions in the range of 0.01 - 0.1 wt.% reduce the corrosion rate of zinc-aluminum alloy Zn0.5Al by a factor of 2–3. Calcium alloys are recommended as anodic coatings and protectors for corrosion protection of steel products and structures operating at high temperatures.

scholarly journals Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2104 ◽  
Author(s):  
Hediyeh Dabbaghi ◽  
Keyvan Safaei ◽  
Mohammadreza Nematollahi ◽  
Parisa Bayati ◽  
Mohammad Elahinia
Keyword(s):  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Early Stage ◽  
Niti Alloy ◽  
Temperature Oxidation ◽  
X Ray ◽  
Rate Law ◽  
Parabolic Rate

In this study, the effect of the addition of Hf on the oxidation behavior of NiTi alloy, which was processed using additive manufacturing and casting, is studied. Thermogravimetric analyses (TGA) were performed at the temperature of 500, 800, and 900 °C to assess the isothermal and dynamic oxidation behavior of the Ni50.4Ti29.6Hf20 at.% alloys for 75 h in dry air. After oxidation, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to analyze the oxide scale formed on the surface of the samples during the high-temperature oxidation. Two stages of oxidation were observed for the NiTiHf samples, an increasing oxidation rate during the early stage of oxidation followed by a lower oxidation rate after approximately 10 h. The isothermal oxidation curves were well matched with a logarithmic rate law in the initial stage and then by parabolic rate law for the next stage. The formation of multi-layered oxide was observed for NiTiHf, which consists of Ti oxide, Hf oxide, and NiTiO3. For the binary alloys, results show that by increasing the temperature, the oxidation rate increased significantly and fitted with parabolic rate law. Activation energy of 175.25 kJ/mol for additively manufactured (AM) NiTi and 60.634 kJ/mol for AM NiTiHf was obtained.

High Temperature Resistance of Selected HVOF Coatings

2015 ◽  
Vol 662 ◽  
pp. 111-114 ◽  
Author(s):  
Šárka Houdková ◽  
Jan Černý ◽  
Zdeněk Pala ◽  
Petr Haušild
Keyword(s):  
High Temperature ◽  
Thermal Spraying ◽  
High Velocity Oxygen Fuel ◽  
Temperature Oxidation ◽  
Ni Alloys ◽  
The Stability ◽  
Temperature Exposure ◽  
Oxygen Fuel ◽  
Hardness Values ◽  
Composition Changes

The HVOF (high velocity oxygen fuel) thermal spraying technology is widely used for creation of coatings notable for their resistance against various kinds of loading. Depending on the sprayed material, the coatings suitable for high temperature applications can be sprayed as well. The coatings, based on CrC or Co/Ni alloys, offer the advantageous combination of high temperature oxidation resistance and the wear resistance. In the paper, the attention is paid to the evaluation of the influence of the high temperature on the coatings microstructure and mechanical properties, namely hardness. The stability of the hardness values in respect to the time of the high temperature exposure is presented and related to the phase composition changes.

Microstructure Features of Cold-Sprayed NiCoCrAlTaY Coating and its High Temperature Oxidation Behavior

2011 ◽  
Vol 686 ◽  
pp. 595-602 ◽  
Author(s):  
Chang Jiu Li ◽  
Yong Li ◽  
Lu Kuo Xing ◽  
Guan Jun Yang ◽  
Cheng Xin Li
Keyword(s):  
High Temperature ◽  
Oxidation Behavior ◽  
Cold Spraying ◽  
Thermal Exposure ◽  
Isothermal Treatment ◽  
Temperature Oxidation ◽  
The Matrix ◽  
High Temperature Oxidation Behavior ◽  
Temperature Exposure ◽  
Sprayed Coating

Superalloy coating was deposited by cold-spraying using a commercial NiCoCrAlTaY powder. The coating microstructure was investigated by scanning electron microscopy and X-ray diffraction to reveal the change of the b-NiAl phase in the as-received powder particle during coating deposition. The oxidation behavior of the cold-sprayed MCrAlY coating and its microstructural evolution during the isothermal treatment were examined. The results show that significant microstructural change occurred to NiCoCrAlTaY superalloy during cold spraying and the thermal exposure. The intensive plastic deformation upon high velocity impact of spray particles results in transformation of b-NiAl to the matrix phase, forming metaltable b-NiAl depletion zones (b-PDZs) which are distributed around the boundaries of deposited particles in the coating. The central part of the deposited particles with limited deformation retained the original phase constitutions of the starting powder. The b-phase with fine grains is re-precipitated uniformly in the areas in b-PDZs in the as-sprayed coating during high temperature exposure. A stable Al2O3 scale was formed on cold-sprayed NiCoCrAlTaY during oxidation possibly due to active b-PDZs on the top surface of the coating.

Influence of the Third Element on the High Temperature Oxidation Behavior of γ'-Ni3Al Alloys

2006 ◽  
Vol 522-523 ◽  
pp. 617-624 ◽  
Author(s):  
Shinya Mikuni ◽  
Shigenari Hayashi ◽  
Toshio Narita
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Al Alloys ◽  
Temperature Oxidation ◽  
The Third ◽  
Alloy Oxidation ◽  
Oxidation Performance ◽  
Fe Alloys ◽  
High Temperature Oxidation Behavior

The effects of the third element on the high temperature oxidation of γ'-Ni3Al with 5at%X (X=Ti, Ta, Nb, Cu, Co and Fe) alloys were investigated at 1173K in air, and oxidation behavior could be classified into three groups. The first group, comprised of alloys with Cu and Co, showed good oxidation performance with Al2O3 formation. A second group contains Ti, Ta, and Nb as alloying elements, and showed poor oxidation performance. With Fe or Mn addition the alloy oxidation performance was intermediate between the first and second group. The effects of these elements are discussed associate with partitioning factors for each element in the γ'-phase.

Influence of Ru, Mo and Ir on the Behavior of Ni-Based MCrAlY Coatings in High Temperature Oxidation

2014 ◽  
Author(s):  
Kang Yuan ◽  
Ru Lin Peng ◽  
Xin-Hai Li ◽  
Sten Johansson ◽  
Yan-Dong Wang
Keyword(s):  
High Temperature ◽  
Microstructural Evolution ◽  
Structure Study ◽  
Micro Structure ◽  
Temperature Oxidation ◽  
Coating Surface ◽  
Mcraly Coating ◽  
Mcraly Coatings ◽  
Oxidation Performance ◽  
Temperature Exposure

To improve the oxidation/corrosion resistance of MCrAlY coatings (M for Ni and/or Co), elements like Y, Si and Ta have been added into the coatings in past decades. In this study the oxidation performance of a Ni-based MCrAlY coating with small proportion of Ru, Mo and/or Ir were investigated after high-temperature exposure. The oxidation tests were carried out at 900°C, 1000°C or 1100°C. The micro structure study showed that the addition of Ru, Mo and/or Ir had significant influence on the oxidation behavior at the coating surface and the microstructural evolution in the material. The microstructural evolution was quantitatively evaluated by measuring the phase degradation of β-NiAl in the coating and γ′-Ni3Al in the substrate of superalloy. Since no oxides of Ru, Mo and Ir were found on the coating surface, it was believed that the effects by those elements were mainly due to their dissolution in the metallic phases in the coatings.

Formation of Protective Cr2O3 Scale at High Temperature and the Effect of Mass Transport in the Presence of Water Vapor

2011 ◽  
Vol 402 ◽  
pp. 412-420 ◽  
Author(s):  
Hanafi Ani Mohd ◽  
Raihan Othman
Keyword(s):  
Water Vapor ◽  
High Temperature ◽  
Mass Transport ◽  
Oxidation Rate ◽  
Oxygen Permeability ◽  
Critical Concentration ◽  
Alloy Oxidation ◽  
Permeability Increase ◽  
Cr Concentration ◽  
Wagner’S Theory

The formation of protective Cr2O3scale at high temperature was evaluated using Wagner’s theory of binary alloy oxidation. The results show that at 1073 K, around 9.8 wt% of Cr is required to form external Cr2O3scale, and 3.5wt% of Cr is needed to maintain the scale. Introduction of water vapor has shifted the critical Cr concentration to higher value. The effects of water vapor in increasing Cr critical concentration to form external Cr2O3scale was disscussed from view of oxygen permeablility and Cr diffusivity in the alloy. It is concluded that Cr diffusivity has negligible effect, while oxygen permeability increase with the presence of water vapor, thus increase the oxidation rate.

Effect of Yttrium Addition on High Temperature Oxidation Resistance of Co-10Cr-5Al Alloys

2011 ◽  
Vol 391-392 ◽  
pp. 606-610 ◽  
Author(s):  
Huai Shu Zhang ◽  
Hong Hua Zhang ◽  
Jun Huai Xiang ◽  
Shan Wang ◽  
Di Wu
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Temperature Oxidation ◽  
Linear Rate ◽  
Rate Law ◽  
Yttrium Addition ◽  
Parabolic Rate

The oxidation behavior of Co-10Cr-5Al-0.3Y alloy in 1 atm of pure O2 at 700°C was investigated. The addition of 0.3 at.%Y significantly increased the oxidation rate of the alloy and changed the oxidation behavior from the approximate parabolic rate law to linear rate law. The scale grown on the surface at 700°C was porous with many small voids and cracks, and was composed of an outer CoO layer and an inner complex layer rich in Al2O3 and Cr2O3 which were intermingled with yttric oxide and spinel Co(Cr, Al)2O4.

The Effect of Yttrium Ion Implantation on the High Temperature Oxidation Properties of NiAl

1990 ◽  
Vol 213 ◽  
Author(s):  
B.A. Pint ◽  
A. Jain ◽  
L.W. Hobbs
Keyword(s):  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Aluminum Content ◽  
Cyclic Testing ◽  
Cation Diffusion ◽  
Temperature Oxidation ◽  
Oxidation Properties ◽  
Yttrium Ion ◽  
Very High

ABSTRACTNiAl was ion implanted with yttrium (2×1016 cm−2) in order to study its effect on the very high temperature (1000–1500°C) oxidation properties. At 1000°C, implanted Y stabilizes the faster growing θ-Al2O3 phase, thus slightly increasing the oxidation rate. At 1200°C, where predominantly α-Al2 O3 is formed with and without Y, there is a factor of 4 reduction in the oxidation rate. However at higher than 1200°C, there is little effect by Y on the oxidation rate. Cyclic testing showed that the Y implant had an imperfect and short-lived improvement on adherence relative to other Y-containing alloys. Variations in aluminum content from 23.5 to 36.0wt%(40–55at%) had little effect on the oxidation properties. Initial experiments at 1500°C with a novel Rh marker indicate that alumina grows at least partially by outward cation diffusion both with and without Y.

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