Corrosion Behavior of Some Titanium Base Alloys in Acid Solutions

Popa, Mónica; Vasilescu, Ecaterina; Drob, Paula; Vasilescu, Cora; Rosca, Julia Claudia Mirza; López, Alfonso

doi:10.1081/amp-200041602

Cited by 12 publications

(4 citation statements)

References 29 publications

(19 reference statements)

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“…The last puzzle is to understand the origin of the accelerated dissolution of base metals especially of Mo in the presence of ILs. In aqueous medium, an insoluble passive oxide film tends to form on surfaces of transition metals including Ni and Mo − under anodic polarization conditions . The passive oxide film can prevent further oxidation or dissolution of these metals even in acidic electrolyte as observed on pristine PtNiMo/C, on which the dissolution amounts of both Ni and Mo are less than 10% after the ADT.…”

Section: Resultsmentioning

confidence: 99%

Effect of Ionic Liquid Modification on the ORR Performance and Degradation Mechanism of Trimetallic PtNiMo/C Catalysts

et al. 2019

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Ionic liquids (ILs) modification, following the concept of “solid catalyst with ionic liquid layer (SCILL)”, has been demonstrated to be an effective approach to improving both activity and stability of Pt-based catalysts for the oxygen reduction reaction. In this work, the SCILL concept has been applied to a trimetallic PtNiMo/C system, which has been documented recently to be significantly advantageous over the benchmark PtNi-based catalysts for oxygen reduction. To achieve this, two hydrophobic ILs ([BMIM][NTF2] and [MTBD][BETI]) were used to modify PtNiMo/C with four IL-loading amounts between 7 and 38 wt %. We found that the Pt mass activity (@0.9 V) could be improved by up to 50% with [BMIM][NTF2] and even 70% when [MTBD][BETI] is used. Exceeding a specific IL loading amount, however, leads to a mass transport related activity drop. Moreover, it is also disclosed that both ILs can effectively suppress the formation of nonreactive oxygenated species, while at the same time imposing little effect on the electrochemical active surface area. For a deeper understanding of the degradation mechanism of pristine and IL modified PtNiMo/C, we applied identical location transmission electron microscopy and in situ scanning flow cell coupled to inductively coupled plasma mass spectrometry techniques. It is disclosed that the presence of ILs has selectively accelerated the dissolution of Mo and eventually results in a more severe degradation of PtNiMo/C. This shows that future research needs to identify ILs that prevent the Mo dissolution to leverage the potential of the IL modification of PtNiMo catalysts.

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Section: Resultsmentioning

confidence: 99%

Effect of Ionic Liquid Modification on the ORR Performance and Degradation Mechanism of Trimetallic PtNiMo/C Catalysts

et al. 2019

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“…Evidence of that is in the reduced cathodic activity of the alloy near E corr and in the increased voltage required during anodising. According to Popa and co-workers, [11] the TiO 2 film formed on the surface of titanium alloys in the presence of aluminium is highly protective and possesses a high corrosion resistance in 20% nitric acid. This is attributed to the fact that titanium undergoes transpassive dissolution with Ti 4+ from TiO 2 oxidises to Ti 6+ at potentials above 2 V (SCE) only.…”

Section: Discussionmentioning

confidence: 99%

Anodic film formation on binary AlMg and AlTi alloys in nitric acid

García‐García

Королева

Thompson

et al. 2009

Surface & Interface Analysis

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Nitric acid is commonly used for surface treatments of aluminium alloys. It is used to clean the surfaces after alkaline etching; it has application in chemical polishing and is also used for electrograining. The majority of these treatments undergo the application of anodic polarisation that results in formation of anodic oxide film. However, little is known about the behaviour of aluminium containing magnesium or titanium in solid solution under such conditions. To reveal the effects of magnesium and titanium alloying additions on anodic film formation in nitric acid, Al-1800 ppm Mg and Al-800 ppm Ti alloys were investigated. It was found that porous alumina film developed on the surfaces with reduced efficiency of 40%, due to the reactive nature of nitric acid to alumina. The presence of magnesium and titanium in aluminium had little influence on the efficiency of film growth, as confirmed by the relatively similar thicknesses of oxide formed on binary alloys and aluminium. However, incorporation of magnesium ions into the alumina film led to development of a high-population density of localised voids near the alloy/film interface. An increased titanium content was found in the film regions close to the alloy/film interface, indicating its oxidation.

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“…The comparatively uniform attack of the surface of the Al–0.18%Mg alloy suggests that oxide thinning is enhanced or that the oxide detaches in the presence of magnesium. In respect of the latter, detachment of anodic films is known to occur from solid‐solution Al–Mg alloys, whereas anodic films remain adherent on solid‐solution Al–Ti alloys . For both types of alloys, the alloying element is oxidized and incorporated into the alumina, where the respective species migrate outward.…”

Section: Discussionmentioning

confidence: 99%

Effect of magnesium and titanium on the cathodic behaviour of aluminium in nitric acid

García‐García

Chiu

Skeldon

et al. 2014

Surf. Interface Anal.

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Cathodic polarization of aluminium and Al-0.18 wt.% Mg and Al-0.08 wt.% Ti alloys in 0.24 mol dm À3 nitric acid solution at 38°C has been employed to assist understanding of the roles of alloying elements in electrograining. The findings indicate that additions of magnesium and titanium to aluminium accelerate the corrosion of the substrate under the alkalization caused by the cathodic reactions. The accelerated dissolution and the consequent formation of hydrated alumina result in a decreased net cathodic current density in potentiostatic and potentiodynamic polarization conditions relative to the behaviour of aluminium.

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Corrosion Behavior of Some Titanium Base Alloys in Acid Solutions

Cited by 12 publications

References 29 publications

Effect of Ionic Liquid Modification on the ORR Performance and Degradation Mechanism of Trimetallic PtNiMo/C Catalysts

Effect of Ionic Liquid Modification on the ORR Performance and Degradation Mechanism of Trimetallic PtNiMo/C Catalysts

Anodic film formation on binary AlMg and AlTi alloys in nitric acid

Effect of magnesium and titanium on the cathodic behaviour of aluminium in nitric acid

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