scholarly journals Corrosion of the Welded Aluminium Alloy in 0.5 M NaCl Solution. Part 2: Coating Protection

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2177 ◽  
Author(s):  
Andrey Gnedenkov ◽  
Sergey Sinebryukhov ◽  
Dmitry Mashtalyar ◽  
Igor Vyaliy ◽  
Vladimir Egorkin ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Welded Joint ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Weld Interface ◽  
Open Circuit ◽  
Al Alloy ◽  
Protective Properties ◽  
Coating Formation ◽  
Electrode Technique

The high electrochemical activity of the aircraft 1579 aluminium alloy with a welded joint and the necessity of the coating formation to protect this material against corrosion as well as to increase the stability of the weld interface in the corrosive medium has been previously established. In this work, two suggested methods of protective coating formation based on plasma electrolytic oxidation (PEO) in tartrate-fluoride electrolyte significantly increased the protective properties of the welded joint area of the 1579 Al alloy. The electrochemical properties of the formed surface layers have been investigated using SVET (scanning vibrating electrode technique) and SIET (scanning ion-selective electrode technique), EIS (electrochemical impedance spectroscopy), OCP (open circuit potential), and PDP (potentiodynamic polarization) in 0.5 M NaCl. The less expressed character of the local electrochemical processes on the welded 1579 Al alloy with the composite coating in comparison with the base PEO-layer has been established. Polymer-containing coatings obtained using superdispersed polytetrafluoroethylene (SPTFE) treatment are characterized by the best possible protective properties and prevent the material from corrosion destruction. Single SPTFE treatment enables one to increase PEO-layer protection by 5.5 times. The results of this study indicate that SVET and SIET are promising to characterize and to compare corrosion behaviour of coated and uncoated samples with a welded joint in chloride-containing media.

Corrosion Behaviour of a Laser-MIG hybrid welding-brazing Joint of 6061 Aluminium Alloy to SUS304 Stainless Steel

CORROSION ◽  
10.5006/3866 ◽  
2021 ◽  
Author(s):  
ruilin liu ◽  
Yunqi Liu ◽  
Zheng Lei ◽  
Hui Tang ◽  
Shaoxiong He ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Weld Metal ◽  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Salt Spray ◽  
Chemical Properties ◽  
Open Circuit ◽  
Hybrid Welding

Lightweight steel-aluminium structures have broad application prospects because of their lowering weight characteristics, however, the corrosion of welding-brazing joints in steel-aluminium structures is less concerned or studied. In this paper, the corrosion behaviour of the Laser-MIG hybrid welding-brazing joints of steel-aluminium is investigated through the tests and analysis of salt spray, immersion and electrochemistry. The salt spray and immersion tests show that obvious galvanic corrosion occurs at the welded joints, in which the aluminium side is seriously corroded while the steel side is not corroded. The OCP values of the aluminium alloy and the weld metal are similar (approximately -0.48 V), and the stainless steel has a higher OCP value of -0.33 V. The corrosion resistance of the weld metal is lower than aluminium- as well as steel-base materials. The corrosion resistance of the joints is controlled by the aluminium alloy part of the two metals based on the open-circuit potential and EIS analysis. A possible corrosion process schematic for the physical/chemical properties of a welding-brazing joint immersed in a sodium chloride solution is proposed according to electrochemical impedance spectroscopy.

scholarly journals Corrosion of the Welded Aluminium Alloy in 0.5 M NaCl Solution. Part 1: Specificity of Development

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2053 ◽  
Author(s):  
Andrey Gnedenkov ◽  
Sergey Sinebryukhov ◽  
Dmitry Mashtalyar ◽  
Igor Vyaliy ◽  
Vladimir Egorkin ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Process Development ◽  
Morphological Structure ◽  
Weld Interface ◽  
Al Alloy ◽  
Alloy Sample ◽  
Nacl Solution ◽  
Corrosive Media ◽  
The Stability ◽  
Electrode Technique

This work consists of two parts. In the first part, the kinetics and mechanism of corrosion on the surface of the welded joint area of the aircraft 1579 aluminium alloy have been studied using SVET (scanning vibrating electrode technique) and SIET (scanning ion-selective electrode technique) in 0.5 M NaCl. The results have revealed the corrosion process development within the weld interface due to the presence of microdefects in the morphological structure. Features of the 1579 Al alloy corrosion have also been investigated through immersion experiments, quantitative analysis of dissolved alloying elements by means of atomic absorption spectroscopy, and corrosion products characterization using XRD (X-ray diffraction) analysis. The presence of Mg as an alloying element in the 1579 Al alloy sufficiently increases the bulk pH values as a result of the intensive dissolution of Mg. These factors accelerate the corrosion activity of the studied material in the 0.5 M NaCl solution. Corrosion evolution analysis of the 1579 Al alloy sample showed the importance of the coating formation to protect this alloy against corrosion and to increase the stability of this system in the corrosive media.

Joint Strength and its Improvement of Friction Welded Joint Between Ductile Cast Iron and 5052 Al Alloy

2020 ◽  
Author(s):  
Masaaki Kimura ◽  
Akira Yoneda ◽  
Masahiro Kusaka ◽  
Koichi Kaizu ◽  
Kazuhiro Hayashida ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Cast Iron ◽  
Base Metal ◽  
Joint Strength ◽  
Welded Joint ◽  
Weld Interface ◽  
Ductile Cast Iron ◽  
Al Alloy ◽  
High Tensile Strength ◽  
Graphite Particles

Abstract To obtain dissimilar joint for easily making multi-material structures, the characteristics of friction welded joint between ductile cast iron (FCD400) and 5052 Al alloy (A5052) was investigated. The relatively high tensile strength of joint was obtained when that was made with a friction speed of 27.5 s−1, a friction pressure of 20 MPa, a friction time of 1.5 s, and a forge pressure of 270 MPa, respectively. However, this joint had approximately 77% in the tensile strength of the A5052 base metal and that was fractured at the weld interface. Although the weld interface had no intermetallic compound layer, the fractured surface at the A5052 side had some graphite particles that were supplied from the FCD400 side. To improve the joint strength, the graphite particles were reduced from the weld faying surface at the FCD400 side by decarburization treatment. The joint had approximately 96% in the tensile strength of the A5052 base metal and that was fractured between the A5052 side and the weld interface. The joint with high tensile strength as well as the possibility improving the fractured point of that were obtained when those were made with opportune friction welding condition and no graphite particles at the weld faying surface of the FCD400 side.

scholarly journals Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

2001 ◽  
Vol 66 (11-12) ◽  
pp. 871-880 ◽  
Author(s):  
Vesna Miskovic-Stankovic ◽  
Zorica Lazarevic ◽  
Zorica Kacarevic-Popovic
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Charge Transfer Resistance ◽  
Epoxy Coatings ◽  
Transfer Resistance ◽  
Protective Properties ◽  
Chemically Modified ◽  
Thermal Stability Of

The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA) were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS) smaller amount of absorbed water inside the coating (From TGA). On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium.

Electrochemical Determination of the Corrosion Resistance of Ag-Pd Dental Alloys

2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Daniel Mareci ◽  
Igor Cretescu ◽  
Neculai Aelenei ◽  
Julia Claudia Mirza Rosca
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Artificial Saliva ◽  
Surface Film ◽  
Electrochemical Determination ◽  
Open Circuit ◽  
Electrochemical Characteristics

The electrochemical behavior of a three Ag-Pd alloys used in dental prosthetics construction for crowns and bridges was studied in artificial saliva using the polarization curves and electrochemical impedance spectroscopy (EIS). The corrosion resistance was evaluated by means of the corrosion currents value and by coulometric analysis. The open circuit potential of Ag-Pd are attributed to dealloying followed by surface enrichment with Ag and the possible formation of an insoluble AgCl surface film on the respective alloy surfaces. Our results have shown that these alloys have a somewhat good corrosion resistance in artificial saliva. When increasing the content of Cu, corrosion resistance decreases. The passivation of all samples occurred spontaneously at the open circuit potential. The electrochemical properties of the spontaneously passivated electrodes at the open circuit potential were studied by EIS. The polarization resistance (Rp) and the electrode capacitance (Cdl) were determined. The polarisation resistance of all the samples increases with the immersion time. The polarization resistances are largest and decrease when increasing the content of Cu. Cu reduces the Ag-Pd alloy corrosion resistance. The present study, thought limited, has shown that electrochemical characteristics can be use to identify such alloys. Knowledge of the in vitro corrosion behaviour of these alloys may lead to better understanding of any biologically adverse effects in vitro.

Characterisation of Reinforced BTSE Films Deposited on Anodized Aluminium Substrate

2018 ◽  
Vol 69 (11) ◽  
pp. 2964-2968
Author(s):  
Ioana Alina Ciobotaru ◽  
Oana Claudia Ciobotea Barbu ◽  
Florin Mihai Benga ◽  
Danut Ionel Vaireanu
Keyword(s):  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Substrate Surface ◽  
Electrochemical Techniques ◽  
Surface Characteristics ◽  
Open Circuit ◽  
Point Of View ◽  
Aluminium Substrate ◽  
Anodised Aluminium ◽  
Deposited Films

This paper discusses the improvements achieved in the anticorrosive properties of some silane films by pretreating the metallic substrate prior to films deposition and by reinforcement with some reinforcement agents. One has compared the behaviour of silane films, deposited on aluminium substrate, and the reinforced silane films deposited on anodised aluminium substrate. The use of scanning electron microscopy highlighted the modifications of substrate surface characteristics prior and after the anodisation process, while electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization were employed in order to characterize the deposited films from the corrosion behaviour point of view.

Corrosion Behavior of Sealed Films on Anodized Al Alloy

2011 ◽  
Vol 233-235 ◽  
pp. 1498-1501
Author(s):  
Qi Zhou ◽  
Chun Lin He ◽  
Qing Kui Cai
Keyword(s):  
Potentiodynamic Polarization ◽  
Open Circuit Potential ◽  
Corrosion Behaviour ◽  
Sol Gel ◽  
Open Circuit ◽  
Green Technology ◽  
Al Alloy ◽  
Corrosion Mechanism ◽  
Pitting Potential ◽  
Corrosive Solution

Alumina sol sealing is one of new green technology for anodized Al alloy. The corrosion mechanism of films sealed by sol and corrosion behaviour of films sealed by sol, Na2Cr2O7, boiling water were analyzed by their curves of open circuit voltage-time (E-T) and potentiodynamic polarization curve. It is found that corrosion tendency of sol sealing film is less than other sealed films by E-T inspection. Fluctuation of open-circuit potential is furious in the immersing prophase and slows down in the anaphase for anodized sealed films. At this time corrosive reactions gradually reach steady state. Open-circuit potential greatly waves for the rough sealed films. Potentiodynamic polarization curves of sealed films show that passive area is the longest for films sealed by sol which has the minimum corrosive current , the passivate current, anodic current and cathode current, but the maximum pitting potential and open-circuit potential. Corrosion parameters are the second for the film sealed by dichromate. Anodic reactions are strongly inhibited by sol sealing films in Cl- corrosive solution. Sol sealing films weaken cathode O2 depolarize reaction. Cl- ions erode anodized Al material on which covered with sol film and produce corrosion. The corrosion of sol-gel film goes through two periods: pitting induced phase and pitting corrosion period.

Investigation of corrosion behavior on plastically deformed aa 7075 t651 by shot peening process

2021 ◽  
Author(s):  
Abeens M ◽  
R Murugananthan
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Dislocation Density ◽  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
X Ray ◽  
Transmission Electron ◽  
Aa 7075 ◽  
Micro Structures

Abstract As AA 7075 T651 comprehensively is used in the marine naval vessels, the factor of corrosion performance always plays a significant role. In this work, an investigation is carried out to study the effect of corrosion behaviour of shot peened AA 7075 T651 in 3.5% solution. From the potentiodynamic polarization study, a 27.72% decrease is ascertained in the Icorr in shot peened specimen in correlation to unpeened aluminium alloy. A drop in Icorr from 1.883 to 1.480 mA/cm2 in shot peened specimen, indicates enhanced pitting corrosion resistance. An electrochemical impedance spectroscopy reveals a surge in the oxide layer formation on the peened surface aiding the drop in corrosion rate. Resistance to pit formations and improvement in oxygen deposition in the peened specimen is observed availing a Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray analysis (EDX). The micro structures of the peened and unpeened specimen are captured using optical microscopy and Transmission electron microscopy (TEM). Micro-strain, dislocation density is also calculated from the X- ray diffraction analysis (XRD), in which grain size reduces by 28.07%, dislocation density surges by 38.65% and micro strain increases by 21.95% in peened specimen in correlation to unpeened AA 7075 T651, resulting in a surge in corrosion resistance by 27.92% in the peened specimen in correlation to unpeened aluminium alloy.

scholarly journals The Effects of Heat Treatment on the Electrochemical Properties and Corrosion of Aluminium Alloy AA8011 in an Aqueous Acid Media

2013 ◽  
Vol 24 ◽  
pp. 17-31 ◽  
Author(s):  
B. Okeoma Kelechukwu ◽  
O. Owate Israel ◽  
E. Oguzie Emeka ◽  
M. Mejeha Ihebrodike ◽  
Nnanna Lebe ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloy ◽  
Lattice Distortion ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Defect Size ◽  
Active Dissolution ◽  
Acid Media ◽  
Transfer Resistance ◽  
Positive Effects

Effects of heat treatment and quenching regimen on the electrochemical corrosion behaviour of aluminium alloy AA8011 in 0.1M H2SO4 was studied by open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Three different specimens (untreated/control, air -quenched oven- quenched) were investigated. Polarization results show that all the specimens underwent active dissolution, with no distinctive transition to passivation, heat treatment was observed to shift the corrosion potential towards low anodic values and decreased the rates of anodic partial reactions of the corrosion process. Electrochemical investigations reveal that heat treatment techniques have positive impacts on the alloy as indicated in increase in charge transfer resistance, polarization resistance and decrease in double layer capacitance. These positive effects are attributed to decrease in mean defect size and increase in lattice distortion of the crystallites in the heat treated specimens of the alloy. Studies of X-ray diffraction (XRD) spectra, scanning electron microscopy (SEM) morphologies of control, air and oven quenched samples of AA8011 aluminium alloy indicate decrease in mean defect size of 18.97% and 40.44%; increase in the lattice distortion of 11.07% and 20.04% for air and oven quenched specimens respectively.

The Manipulation of Properties of Ti Bioalloys at Micro and Nanoscale Using Etching Procedures

2008 ◽  
Vol 396-398 ◽  
pp. 393-396 ◽  
Author(s):  
D. Ionita ◽  
Doina Raducanu ◽  
Mariana Prodana ◽  
Ioana Demetrescu
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Simulated Body Fluid ◽  
Body Fluid ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Open Circuit ◽  
Electrochemical Study ◽  
Acid Etching ◽  
Equivalent Circuits

The paper is an electrochemical study regarding the influence of different acid etching conditions on the corrosion behaviour of a new Ti based bioalloy with Nb, Ta and Zr. Open circuit, potentiodynamic and electrochemical impedance spectroscopy were the methods performed in a simulated body fluid (SBF) and a stability mechanism was discussed in terms of equivalent circuits.

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