Êtes-vous un étudiant de l'EPFL à la recherche d'un projet de semestre?
Travaillez avec nous sur des projets en science des données et en visualisation, et déployez votre projet sous forme d'application sur Graph Search.
Concept
Osmiridium
Résumé
Osmiridium and iridosmine are natural alloys of the elements osmium and iridium, with traces of other platinum-group metals.
Osmiridium has been defined as containing a higher proportion of iridium, with iridosmine containing more osmium. However, as the content of the natural Os-Ir alloys varies considerably, the constituent percentages of specimens often reflects the reverse situation of osmiridium describing specimens containing a higher proportion of osmium and iridosmine specimens containing more iridium.
In 1963, M. H. Hey proposed using iridosmine for hexagonal specimens with 32% < Os < 80%, osmiridium for cubic specimens with Os < 32% and native osmium for specimens Os > 80% (the would-be mineral native iridium of >80% purity was not known at that time).
In 1973, Harris and Cabri defined the following names for Os-Ir-Ru alloys: ruthenosmiridium was applied to cubic Os-Ir-Ru alloys, where Ir < 80% of (Os+Ir+Ru) and Ru > 10% of (Os+Ir+Ru) with no single other element >10% of the total; Rutheniridosmine was applied to cubic Os-Ir-Ru alloys, where Os < 80% of (Os+Ir+Ru) and Ru is 10–80% of (Os+Ir+Ru) with no single other element >10% of the total; the Ru-Os alloys be known as ruthenian osmium (>50% Os), osmian ruthenium (>50% Ru); the Ru-Ir alloys be known as iridian ruthenium and ruthenian iridium where the boundary between them is defined by the alloy's miscibility gap (a minimum 57% Ir for ruthenian iridium and a minimum of 55% Ru for iridian ruthenium).
The nomenclature of Os-Ir-Ru alloys were revised again by Harris and Cabri in 1991. Afterwards, only four names were applied to minerals whose compositions lie within the ternary Os-Ir-Ru system: osmium (native osmium) for all hexagonal alloys with Os the major element; iridium (native iridium) for all cubic alloys with iridium the major element; rutheniridosmine for all hexagonal alloys with Ir the major element; and ruthenium (native ruthenium) for all hexagonal alloys with Ru the major element.
Source officielle
À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.