Search results for "Copper alloy"

A compositional analysis by energy dispersive X-ray fluorescence of Iberian copper-alloy votive figurines from southern Spain (fourth-third centuries…

2018

Density functional theory description of random Cu-Au alloys

2019

Density functional alloy theory is used to accurately describe the three core effects controlling the thermodynamics of random Cu-Au alloys. These three core effects are exchange correlation (XC), local lattice relaxations (LLRs), and short-range order (SRO). Within the real-space grid-based projector augmented-wave (GPAW) method based on density functional theory (DFT), we adopt the quasinonuniform XC approximation (QNA), and take into account the LLR and the SRO effects. Our approach allows us to study the importance of all three core effects in a unified way within one DFT code. The results demonstrate the importance of the LLR term and show that going from the classical gradient level a…

Insight on bacteria communities in outdoor bronze and marble artefacts in a changing environment

2022

Epilithic bacteria play a fundamental role in the conservation of cultural heritage (CH) materials. On stones, bacterial communities cause both degradation and bioprotection actions. Bronze biocorrosion in non-burial conditions is rarely studied. Only few studies have examined the relationship between bacteria communities and the chemical composi- tion of patinas (surface degradation layers). A better comprehension of bacterial communities growing on our CH is fundamental not only to understand the related decay mechanisms but also to foresee possible shifts in their compo- sition due to climate change. The present study aims at (1) characterizing bacterial communities on bronze andmarble s…

Electrochemical behaviour of copper-nickel alloys as immobilisation matrices for the storage of fission products in CO2-enriched synthetic groundwater

2013

International audience; The surface properties of nickel and copper alloys exposed to simulated French Callovo-Oxfordien ground-water (aerated and CO2-saturated solutions) have been evaluated from electrochemical impedance spectroscopy in conjunction with X-ray photoelectron spectroscopy. The kinetic reactions and physical properties of the layers grown on the alloy's surfaces, change versus the Ni content in the alloys and the presence of CO2 in the solution. Nickel alloys retain favourable passive properties in such environments, whereas oxide products on copper alloys are insufficiently protective when formed in the absence of dissolved oxygen in the electrolyte. A maximum addition of 30…