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The influence of chloride deposition on the formation, evolution and barrier properties of the patina formed on Cu5Zn5Al1Sn used for architectural cladding is explored via long-term marine field exposures and laboratory investigations. The presence of Cu 2 O, ZnO, Al 2 O 3 and SnO 2 within the inner part of the patina and intercalation of SnO 2 , Zn 5 (CO 3 ) 2 (OH) 6 , Zn 6 Al 2 (OH) 16 CO 3 ·4H 2 O, Zn 5 (OH) 8 Cl 2 ·H 2 O within its outer part, predominantly composed of Cu 2 (OH) 3 Cl, significantly reduce the chloride-induced corrosion compared with Cu metal. The intercalation of zinc-rich corrosion products within the patina and not at the top-surface explain their marginal influence on the runoff process that mainly occurs at the outmost surface. [ABSTRACT FROM AUTHOR]

The golden alloy Cu-5Zn-5Al-1Sn has found many applications because of its appearance and resistance to tarnishing. The microstructure and multi-component surface oxide of Cu-5Zn-5Al-1Sn have been investigated through a multi-analytical approach. Compared to commercial Cu metal, Cu-5Zn-5Al-1Sn has significantly smaller grains and higher fraction of coherent twin boundaries. The 5–10 nm thick oxide formed after diamond polishing has four identified sub-oxides all contributing to the overall corrosion resistance. Cu 2 O is mainly located in the outer part, followed by ZnO, SnO 2 and Al 2 O 3 closer to the alloy substrate. The latter three possess barrier properties, while Cu 2 O exhibits a more complex structure. [ABSTRACT FROM AUTHOR]

• Local electrochemical properties of fusion boundary were studied by combining capillary and photolithographic mask technique. • Martensite in fusion boundary area shows passivation behavior and better corrosion resistance in 3.5 wt% NaCl solution. • A controversy was demonstrated between the nobility prediction through SKPFM test and local electrochemical measurements. The 309 L-SA508 fusion boundary (FB) in a SA508−309 L/308 L overlay cladding weldment was characterized by multi-analytical approaches. Local electrochemical properties around the FB region were investigated in 3.5 wt% NaCl solution by utilizing a self-developed microcell setup combining lithography and capillary techniques. The corrosion resistances follow the order: P1 (little austenite + martensite)>P2 (martensite + little coarse ferrite)>P3 (martensite + numerous coarse ferrite)>P4 (coarse ferrite). A better corrosion resistance of P1 is attributed to its higher Cr, Ni content and larger proportion of Σ3 boundaries. The controversy between results of scanning Kelvin probe force microscopy and local electrochemical measurements was demonstrated. [ABSTRACT FROM AUTHOR]

Potential dependent mechanism of the composition and electrochemical properties of oxide films formed on Ti-6Al-3Nb-2Zr-1Mo in 0.5 M H 2 SO 4 at potential ranging within −0.80–5.00 V was studied. The quantitative calculation and qualitative analysis of thicknesses of oxide films and valence states of Ti and Al, Nb, Mo increase with potential increasing to 3.00 V, whereas surface roughness illustrates the opposite trend. The corrosion resistances and semiconductor properties results indicate better protection effect and uniformity of oxide film at higher potential in passive region. A schematic considering alloying elements effect within oxide films formed at different applied potential on Ti-6Al-3Nb-2Zr-1Mo is established. • The thickness of oxide film and valence state of Ti, Al, Nb, Zr, Mo are quantitatively calculated and qualitatively analyzed. • Schematic model of the oxide films formed on Ti80 at different potentials is proposed. • The composition for most corrosion resistant oxide film formed at applied potential of 3.0 V is declared. [ABSTRACT FROM AUTHOR]

The present work investigated the localized corrosion of 304 stainless steel triggered by MnS in 3.5 wt% NaCl solution via multi-analytical approaches including in-situ and ex-situ techniques. The results suggested that the dissolution of MnS starts from boundary areas and directly releases elemental sulfur. The reoccurrence and disappearance of elemental sulfur during MnS dissolution indicated that sulfur was continuously consumed and converted. Copper-containing compounds were found deposited on residual MnS in the corrosion pit, whilst a thin Cr 2 O 3 film covered the pit and thickened over time. Based on the evidence obtained, a more comprehensive MnS-induced localized corrosion mechanism was proposed. [Display omitted] • Sulfur is first released in the form of elemental sulfur during MnS dissolution. • Copper-containing compounds are found in the pits induced by MnS dissolution. • A transparent film covering the pit thickens over time by accumulating corrosion products. [ABSTRACT FROM AUTHOR]