Corrosion inhibition of Cu in nitrate solution

The effect of ethylenediamine [ED] and acetic acid on the corrosion inhibition of copper in 0.1 M NaNO] was studied. The study involved electrochemical polarization methods, gravimetric measurements and scanning electron microscopy investigations [SEM]. Both of ED and concentrated solutions of acetic acid >/= 10[-3] M act as a promoter while diluted concentrations of acetic acid

Cu redeposition and surface enrichment during the dissolution of Al-Cu Alloy in 0.1 M HCI

The enrichment of Cu on the surface of Al - 3.84% Cu alloy during the dissolution in 0.1 M HCI has been examined using open circuit potential [OCP] accompanied by scanning electron microscopy [SEM], Auger electron spectroscopy [AES] and X-ray photoelectron spectroscopy [XPS]. Results obtained during this study show that there are two types of Cu enrichment, one of them is in the form of Cu clusters, which is formed due to the outer diffusion or segregation of Cu to the alloy surface. The second type is more uniform deposition as a result of copper redeposition from solution, this data is confirmed by the AES survey point analysis, which show that the detection of Cu peak beside the disappearance of Al peak occurred at the whole surface. It is also indicated that the Cu released from the alloy surface is due to two different sources. The first occurred due to the severe galvanic attack, around the breifery of the clusters. This attack can be extended under the cluster and released. The other was attributed to the uniform redeposition of Cu on pure Al, where the disproportionation reaction of Cu[+] ions takes place on the surface, which can produce Cu[++] ions to the solution. The higher resolution multiplex of Cu using XPS analysis shows that the appearance of three peaks corresponding to Cu[°] [metallic copper], CuCI, CuCI[2] and devoid of any Al species. Accordingly the redeposit Cu on pure Al can behaves as Cu metal and dissolves also as dichlorocoprate [CuCI[2]] soluble complex beside CuCI[2]

Effect of argon ion sputtering on the surface composition of some metals and alloys

The effect of argon ion sputtering [Ar[+]] on the composition of Cu, Zn, Ag, Fe, Zr, Al, brass, C-steel, Al alloys and different types of stainless steels were studied using Auger Electron Spectroscopy [AES] and X-ray Photoelectron Spectroscopy surface analytical techniques. Argon ion bombardment with an accelerating voltage of 4.5kV causes the formation of new interstitial compounds in case of Al, Fe, Zr and their alloys, while there are no changes for other metals. The peaks corresponding to the new interstitial compounds are overlapping with the peaks related to nitrogen species either in the case of AES or XPS analysis. The produced interstitial compound shows different species which depends on the metal

study of the behaviour of AI, Cu and AI-Cu couple in sodium carbonate solutions.

In case of copper, oxide film thickening occurred and the open circuit steady state potential shifted slightly towards more negative values; while in case of Al, either alone or coupled with copper, oxide film thickening occurred at lower concentrations <10-3 but at higher than 10-3 M; dissolution of the oxide took place and the potential was shifted to more negative values. Potentiostatic polarization confirmed the above results. The galvanic potential measurements of Al-Cu couple in different aerated or oxygenated carbonate solutions indicated that at concentrations <10-3 M, the potential shifted to less negative values; while at higher concentrations, a more negative shift was recorded and Al anode was severely attacked. Addition of 3.5% NaCl shifted the potential to more negative values at lower carbonate concentrations. Galvanic current Ig measurements indicated a decrease in the current strength values at the moment of contact followed by a steady state value. The steady state galvanic current Ist against logarithm of carbonate concentration showed a more or less regular increase of Ist with increase of electrolyte concentration