Search results for "CORROSION"

Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes

2011

Abstract The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of…

Local electrochemical methods in corrosion research

2007

Image analysis of corrosion pit damage

1999

Matter Transport and Corrosion Kinetics of Metals and Alloys at High Temperature

1992

Microstructural corrosion of aluminium alloys: a predictive finite element model based on corrosion-mimicking experiments

2013

The purpose of this study is to implement the basis of a finite element model (FEM) based on the resolution of the Nernst–Planck equation in order to progress in the predictive simulation of microstructural corrosion on aluminium alloys. Certain constituent intermetallic particles at the surface of aluminium alloys are considered as preferential sites for the initiation of structural corrosion resulting in localised trenching around the particles and the surrounding Al matrix. In this work, a modified scanning electrochemical microscope (SECM) experiment was used to induce such phenomena via a local alkalinization on 200 nm thick aluminium coatings, promoting their local dissolution in an a…

Grain-boundary modelling of hydrogen assisted intergranular stress corrosion cracking

2018

Abstract A novel hybrid strategy for modelling intergranular hydrogen embrittlement in polycrystalline microstructures is proposed. The technique is based on a grain-boundary integral representation of the polycrystalline micro-mechanics, numerically solved by the boundary element method, coupled with an explicit finite element model of the intergranular hydrogen diffusion. The intergranular interaction between contiguous grains in the aggregate is modelled through extrinsic cohesive-frictional traction-separation laws, whose parameters depend on the concentration of intergranular hydrogen, which diffuses over the interface according to the Fick’s second law, inducing the weakening of the i…

Effect of microstructure and chemical composition on localized corrosion resistance of a AISI 304L stainless steel after nanopulsed-laser surface mel…

2015

Abstract Changes induced in the surface properties of AISI 304L stainless steel when it is treated with a nanopulsed ytterbium-doped fiber laser were investigated to determine the microscale distribution of its physico-chemical properties. A Gaussian energy distribution was created with a radius of 71 μm (1/e2) at the focal point. Local investigations were carried out using transmission electron microscopy to consider the effect of overlapping individual laser impacts. The results obtained reveal that laser surface melting leads to changes in the crystallographic structure of the steel through the formation of a δ-ferritic phase. It also results in the creation of an oxide layer that increa…

Corrosion Behaviour of Ti6Al4V and TiMo10Zr4 Alloys in the Ringer’s Solution: Effect of pH and Plastic Strain

2015

The corrosion behaviour of titanium alloys is not well understood – especially the role of the microstructure and plastic strain. In this paper, the influence of the microstructure and plastic strain on the corrosion resistance of TiMo10Zr4 and Ti6Al4V alloys was studied in the Ringer’s solution at 37 °C. Measurements were performed for different pH values and in aerated and de-aerated solutions using potentiodynamic polarization techniques. Results obtained on the two alloys were compared. It was shown that in the absence of plastic strain TiMo10Zr4 shows better corrosion resistance than Ti6Al4V (especially for pH = 8). By contrast, the current density in the passive range measured after 8…

The effects of metal implants on inflammatory and healing processes

2007

Abstract Metal implants are known for their superior mechanical properties. However, cases of implant failure mainly due to aseptic loosening do occur. The formation of particulate wear debris and corrosion products, such as metal ions and reactive oxygen species, are considered to be crucial factors leading to the failure of metal implants. These metal degradation and corrosion products can induce inflammatory responses, mediated among others by neutrophils, macrophages and endothelial cells. Furthermore, these degradation products may affect blood vessel formation, one of the central processes in wound healing after implantation. Such events can lead to the aseptic loosening of implants c…

Corrosion resistance of the vacuum arc deposited Ti, TiN and TiO2 coatings on large area glass substrates

2000

An industrial installation for vacuum arc deposition is presented. Its potential in the field of decorative coatings for large area glass sheets is demonstrated. In particular it is possible to deposit patterned coatings through a polymeric textile mask. The ability to deposit uniform multilayer coatings having interference colours onto large silicate glass sheets is shown. Titanium, titanium nitride and titanium dioxide coatings on silicate glass have been characterized in terms of composition and corrosion resistance. Depth profiling was achieved with the aid of Auger electron spectroscopy. The corrosion resistance of TiN coatings is higher than that of TiO 2 . The corrosion resistance of…