Electrochemical Characterization of Different Variants of a Commercial Trivalent Chromium Process (TCP) Coating on Aluminum Alloy 7075-T6

CORROSION ◽  
10.5006/2517 ◽  
2017 ◽  
Vol 74 (1) ◽  
pp. 50-65 ◽  
Author(s):  
Catherine A. Munson ◽  
Paulo Zutim ◽  
Greg M. Swain
Keyword(s):  
Aluminum Alloy ◽  
Electrochemical Properties ◽  
Rotating Disk ◽  
Open Circuit ◽  
Trivalent Chromium ◽  
Cathodic Polarization Curve ◽  
Aluminum Alloy 7075 ◽  
High Chloride ◽  
Made In

The electrochemical properties (open-circuit potentials, anodic and cathodic polarization curve currents, and polarization resistances) were evaluated for AA7075-T6 alloys coated with three variants of a commercial trivalent chromium process (TCP) pretreatment coating. The coatings were formed on degreased and deoxidized aluminum alloy specimens. Measurements were made in oxygenated 0.5 M Na2SO4 and 3.5% NaCl. Comparison of coatings formed by immersion and spray was undertaken. The three coating variants were 650 chromitAL, versions E, V, and C. Similar concentrations of Cr were in all three coating baths but there were differences in Zr, Zn, S (likely as sulfate), and Fe among the three. TCP coatings formed by immersion exhibited electrochemical properties similar to those formed by spray. Overall, the greatest level of corrosion protection was provided by 650 E based on electrochemical data and results from a 14 d thin-layer mist (3.5% NaCl, 55°C) accelerated degradation test. The coating provides both anodic and cathodic protection in low-chloride electrolytes and functions as more of a cathodic inhibitor in high-chloride electrolytes. Rotating disk voltammetric data revealed the coating inhibits the reduction of dissolved oxygen by providing a diffusional barrier and possibly blocking sites for O2 chemisorption on the cathodically-active intermetallic phases.

scholarly journals Soldering of 7075 Aluminum Alloy Using Ni-P and Cu-Cr Electrodeposited Interlayers

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4100
Author(s):  
Zbigniew Mirski ◽  
Ireneusz Ciepacz ◽  
Tomasz Wojdat
Keyword(s):  
Electron Microscopy ◽  
Shear Strength ◽  
Aluminum Alloy ◽  
Light And Electron Microscopy ◽  
7075 Aluminum Alloy ◽  
7075 Alloy ◽  
Aluminum Alloy 7075 ◽  
Soldered Joint ◽  
Measured Hardness ◽  
Made In

Direct soldering of the aluminum alloy 7075 is very difficult or even impossible. In order to make it possible, galvanic coatings and the procedures for their application on alloy surfaces were developed. The paper presents structures and mechanical properties of soldered joints of the 7075 alloy, made in indirect way with use of electrolytically deposited Ni-P and Cu-Cr coatings. Application of the newly developed Ni-P and Cu-Cr coatings on base surfaces of the 7075 alloy is described. The results of wettability examination of the S-Sn97Cu3 solder in the droplet test and by spreading on the coatings applied on the 7075 substrates are presented. The wettability angle of both coatings was lower than 30°. The results of metallographic examinations with use of light and electron microscopy are presented. It was shown that adhesion of metallic coatings to the aluminum alloy is good, exceeding shear strength of the S-Sn97Cu3 solder. Shear strength of soldered joint was equal to 35 ± 3 MPa. Measured hardness of the Ni-P interlayer reached high value of 471 HV 0.025.

scholarly journals CHARACTERIZATION OF OXIDE LAYERS MADE ON ALUMINUM ALLOY 7075 BY DIFFERENT METHODS

2016 ◽  
Vol 42 (3) ◽  
pp. 187
Author(s):  
Mateusz Jędrusik ◽  
Aleksandra Dębowska ◽  
Agnieszka Kopia ◽  
Paweł Petrzak ◽  
Damian Koclęga ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Oxide Layers ◽  
Aluminum Alloy 7075

scholarly journals Electrochemical Impedance Spectroscopy (EIS) Characterization of Kitchen Utensils Used as Materials for Local Cooking in Two Culinary Media

2020 ◽  
Author(s):  
Jacques Sawadogo ◽  
Jean Boukari Legma
Keyword(s):  
Aluminum Alloy ◽  
Electrochemical Impedance Spectroscopy ◽  
Chemical Composition ◽  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Open Circuit ◽  
Important Place ◽  
Traditional Production

This study is inscribed in the framework of the valorization of traditional kitchen utensils recycled from aluminum waste in Burkina Faso. In fact, these traditional kitchen utensils made of recycled aluminum alloys occupy a very important place in Burkina Faso’s kitchen. The effect of foods for consumption on its local utensils was studied using the non-stationary technique and electrochemical impedance spectroscopy. For this purpose, a sample of utensil has been deducted on traditional production site. The corrosion behavior of the recycled aluminum alloy ok know chemical composition was evaluated by analyzing the impedance spectra obtained at the open circuit potential, in the salt media titrated at 3 g·L−1 and rice. Modeling electrical properties by using of a simple equivalent circuit made it possible to interpret the results obtained by impedance spectroscopy. The results showed a susceptibility to pitting corrosion and were confirmed by the electrochemical impedance spectroscopy method.

Deposition and characterization of cerium oxide conversion coatings on aluminum alloy 7075-T6

2004 ◽  
Vol 176 (3) ◽  
pp. 349-356 ◽  
Author(s):  
Berny F. Rivera ◽  
Benedict Y. Johnson ◽  
Matthew J. O'Keefe ◽  
William G. Fahrenholtz
Keyword(s):  
Aluminum Alloy ◽  
Cerium Oxide ◽  
Conversion Coatings ◽  
Aluminum Alloy 7075 ◽  
Oxide Conversion

Fabrication and Characterization of Nife Thin Film Composition Modulated Alloys

1996 ◽  
Vol 451 ◽  
Author(s):  
S. D. Leith ◽  
D. T. Schwartz
Keyword(s):  
Rotation Rate ◽  
Stripping Voltammetry ◽  
Rotating Disk ◽  
Oscillation Period ◽  
Rotating Disk Electrode ◽  
Disk Rotation ◽  
Rate Oscillation ◽  
Composition And Structure ◽  
Spatially Periodic

ABSTRACTDescribed are results showing that an oscillating flow-field can induce spatially periodic composition variations in electrodeposited NiFe films. Flow-induced NiFe composition modulated alloys (CMA's) were deposited on the disk of a rotating disk electrode by oscillating the disk rotation rate during galvanostatic plating. Deposit composition and structure were investigated using potentiostatic stripping voltammetry and scanning probe microscopy. Results illustrate a linear relationship between the composition modulation wavelength and the flow oscillation period. CMA's with wavelengths less than 10 nm can be fabricated when plating with a disk rotation rate oscillation period less than 3 seconds.

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