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Nomenclature of platinum-group-element alloys: Review and revision
... Due to these differences, PGE usually form binary, rarely triple solid solutions represented by PGM. These include Pt-Fe alloys and intermediate intermetallic compounds [14], minerals of the Os-Ru-Ir system [15], as well as hexagonal Fe compounds with Ru, Os and Ir [16]. ...
The Inagli massif is a concentric-zonal ring massif consisting of a dunite core bordered by a sequential series of peridotites, pyroxenites and shonkinites. In dunites, there are densely disseminated accumulations of chromspinelides, as well as schlieren and veined particles of massive chromitites, to which polyphase growths of platinum-group minerals (PGM) are confined. The Inagli intrusive, like the well-known Konder massif, belongs to an independent "Aldan" type of platinum-bearing deposits. The Aldan type of ring intrusions is a platform analogue of the "Ural-Alaskan" zonal dunite-gabbro massifs of orogenic regions. In placers, dunites and chromitites of the Inagli massif, PGM are mainly represented by isoferroplatinum (Pt3Fe) with an admixture of iridium up to 8 wt %. In isoferroplatinum, symplektitic iridium particles and small inclusions of osmium, laurite, ehrlichmanite, malanite, as well as other sulfides and arsenides of platinum-group elements (PGE) are often observed. The bulk composition of such polymineral aggregates can be calculated based on the volume ratios and chemical composition of individual phases. The results obtained in this way show that the compositions of the initial polycomponent solid solutions vary from Pt-Ir-Fe to Ir-Os-Ru-Rh-Pt-Pd-Fe alloys. Polycomponent homogeneous solid solutions, which composition gradually changes from Ru-Rh-Ir-Os minerals to Fe-Pt alloys, are known in the Witwatersrand placers. A similar series of solid solutions of PGE is identified in the placers of the Guli massif on the Siberian platform. Unlike the placers of the Witwatersrand and Guli massif, where PGM are mainly represented by Os-Ir alloys, Inagli minerals have mainly a Pt-Ir-Fe composition with a low proportion of Os. The structures of most natural polyphase PGM aggregates are similar to those of artificial alloys, therefore, the former are also products of crystallization of multicomponent metal melts and their subsequent solid-phase transformations. The limits of solubility between PGE differ significantly, therefore, depending on the initial composition of metal alloys, both polycomponent solid solutions and polymineral aggregates can be formed. Based on the analysis of combined double and triple diagrams of PGE systems, the author considers possible ways of evolution of phase transformations of alloys of different composition.
... technique [45][46][47][48] using the following equations: 11 12 2 3 [51]. Therefore, in this paper, we use the Tian's equation (10) [49] to calculate the hardness of the transition metal X-Ru alloys. Furthermore, while the Vickers hardness procedure is used frequently for testing metallic systems and other hard materials, we note that its primary design targets softer materials like plastics, assessing their resistance to deformation under constant stress. ...
We use first-principles density functional theory calculations to study the properties of X–Ru alloys (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) in the B2 crystallographic phase for high-temperature structural applications. Specifically, we study their structural, mechanical, phonon and electronic properties and assess their applicability in high-temperature environments. All the X–Ru alloys show good mechanical stability with Sc–Ru, Ti–Ru, V–Ru, and Mn–Ru being highly ductile and relatively hard. Furthermore, these specific alloys have negative heat of formation, indicating that they are thermodynamically stable, and hence making experimental synthesis plausible. Phonon dispersion analysis of these alloys also shows dynamic stability. Their band structures and density of states reveal a metallic nature with dominant covalent bonds. These results make Sc–Ru, Ti–Ru, V–Ru, and Mn–Ru alloys suitable candidates for next-generation high-temperature structural applications.
... However, RMs based on Mo, Nb, Ta, and W suffer intense oxidation in the air above 500 • C (normally referred to as pesting [9]), while the strength of titanium alloys deteriorates with increasing temperature. Although the PGMs (consisting of Pt, Ru, Os, Rh, Pd, and Ir) have comparable chemical properties and similar mineral deposits to NBSAs [10], their use is hampered by weight and cost. ...
Citation: Mnisi, B.O.; Benecha, M.E.; Tibane, M.M. First-Principles Study on Thermodynamic, Structural, Mechanical, Electronic, and Phonon Properties of tP16 Ru-Based Alloys. Alloys 2024, 3, 126-139. https:// Abstract: Transition metal-ruthenium alloys are promising candidates for ultra-high-temperature structural applications. However, the mechanical and electronic characteristics of these alloys are not well understood in the literature. This study uses first-principles density functional theory calculations to explore the structural, electronic, mechanical, and phonon properties of X 3 Ru (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) binary alloys in the tP16 crystallographic phase. We find that Mn 3 Ru, Sc 3 Ru, Ti 3 Ru, V 3 Ru, and Zn 3 Ru have negative heats of formation and hence are thermo-dynamically stable. Mechanical analysis (C ij) indicates that all tP16-X 3 Ru alloys are mechanically stable except, Fe 3 Ru and Cr 3 Ru. Moreover, these compounds exhibit ductility and possess high melting temperatures. Furthermore, phonon dispersion curves indicate that Cr 3 Ru, Co 3 Ru, Ni 3 Ru, and Cu 3 Ru are dynamically stable, while the electronic density of states reveals all the X 3 Ru alloys are metallic, with a significant overlap between the valence and conduction bands at the Fermi energy. These findings offer insights into the novel properties of the tP16 X 3 Ru intermetallic alloys for the exploration of high-temperature structural applications.
... The Platinum group metals (PGMs), such as Pt, Ru, Os, Rh, Pd, and Ir, for high-temperature structural applications has been investigated [9][10][11][12]. Despite their chemical properties resembling those of Nickel-based super-alloys (NBSAs) [13], some PGMs are inherently brittle and face challenges related to weight and cost. This limits their potential use in high-temperature applications. ...
We present the structural, elastic, electronic, magnetic, and phonon properties of D0c X3Ru (X = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) alloys in their respective ground-states at zero pressure using first-principles density functional theory (DFT). The calculated heat of formation for Sc3Ru, Ti3Ru, V3Ru, Mn3Ru, and Zn3Ru are negative, signifying their thermodynamic stability. Meanwhile, we find that Sc3Ru, V3Ru, Mn3Ru, Co3Ru, Ni3Ru, Cu3Ru and Zn3Ru alloys are mechanically stable. The electronic properties indicate a metallic nature in all the X3Ru alloys due to valence-conduction band overlap at the Fermi energy. Additionally, the phonon dispersion curves suggest that Cr3Ru, Fe3Ru, Ni3Ru, Cu3Ru, and Zn3Ru are dynamically stable. These results provide a comprehensive overview of the stability, electronic, and mechanical properties of D0c Zn3Ru structures, suggesting their suitability for engineering novel alloys in high-temperature structural applications.
... It is one of six in the platinum-group metals (PGMs) which all share similar physical and chemical properties, such as being inert to most other elements of the Periodic Table. It is for this reason that Ru is usually found in the same mineral deposits as other PGMs (9), and it is easily alloyed with them for industrial applications. For example, Ru can be alloyed with platinum and palladium in order to increase their hardness (10). ...
... The studied Os-Ir alloys of the Guli massif (Figs. 4a, b and 5a-d, f) are formed by crystals and mineral aggregates referred to as Os minerals (osmium and Ir-containing osmium) according to the classification by Harris and Cabri (1991). Ru-Os sulfides of the Guli massif were identified within three mineral assemblages and were divided respectively into three types. ...
Understanding the main events of platinum-group element (PGE) ore formation is impossible without analysis of the sources and behavior of major ore-forming components, namely, platinum, osmium, sulfur, and copper, which are important indicators of magmatic and hydrothermal processes. In contrast to the Re–Os isotope system, the radiogenic Pt–Os isotope system, as well as stable isotopes of Cu and S in PGE deposits, are still relatively understudied. Our comprehensive research is aimed at filling this gap. The article presents data for the Guli massif of ultramafic and alkaline rocks and carbonatites in Polar Siberia and for the zoned-type Nizhny Tagil and Svetly Bor clinopyroxenite–dunite massifs in the Middle Urals, which include: (1) the contents of the highly siderophile elements (HSE) in whole-rocks and platinum-group minerals (PGM), (2) the Re–Os and Pt–Os isotope systematics of chromitite, Os–Ir alloys, and Ru–Os sulfides, (3) the sulfur isotope composition in Ru–Os and Ir–Rh sulfides in primary and secondary PGM assemblages, and (4) the copper isotope composition of Pt–Fe minerals from chromitites and placers. The research was performed using scanning electron microscopy, electron probe microanalysis, and high-precision isotope-geochemical analysis. The high-precision Re–Os and Pt–Os isotope data show that the HSE contents in chromitites and PGM of the Guli massif were controlled by the composition of the mantle source that evolved with near-chondritic time-integrated Re/Os and Pt/Os ratios, which are also typical of the sources of most komatiites and abyssal peridotites. The δ65Cu values of the studied samples of ferroan platinum and isoferroplatinum are identical within the analytical uncertainty and are close to 0‰, which is typical of high-temperature Cu-containing minerals. The sulfur isotope compositions of the Ir–Rh sulfides of the kashinite–bowieite series and of the Ru–Os sulfides of the laurite–erlichmanite series in the primary PGM assemblages indicate that the source of sulfur has a chondritic isotope composition, which is in agreement with the osmium isotope composition of the Ru–Os sulfides and Os–Ir alloys. The heavy sulfur isotope composition (δ34S = 5.6 ± 1.5‰) of As-containing erlichmanite is consistent with its secondary origin. The new data on the isotope compositions of osmium, copper, and sulfur can be used as new important parameters that characterize the sources of PGE mineralization.
... Изученные Os-Ir сплавы по классификации Д. Харриса и Л. Кабри [9] относятся к самородному осмию. Ru-Os сульфиды выявлены в составе трёх минеральных ассоциаций и подразделены соответственно на три типа. ...
Description, analysis and interpretation of PGE-element minerals in beach sands from Waratah Bay, Victoria, Australia.
A Cu- and Rh-enriched magmatic ore system is defined by abundant PGM (platinum group mineral) inclusions in forty-four Pt-Fe alloy nuggets from the Camumbi River gold placer, northwest Ecuador. Isoferroplatinum is depleted in Rh, Os, and Ru compared with native platinum, suggesting most crystallized after Os-(Ir) alloy, laurite, and some Rh-PGM. Two Pt-Fe alloy nuggets have zoned hydrothermal alteration rinds, and an UM (unnamed mineral) is (Rh,Pd)4As3. Our previous work shows that silicate glass inclusions define a fractionated co-magmatic compositional series related to primitive hydrous ferrobasalt, and trace element chemistry matches their Late Cretaceous accreted volcanic arc terrane. Here we report exceptional Cr-spinel (Ural-Alaskan type) inclusions coexisting with primitive ferrobasaltic glass crystallized at highest T. Laurite inclusions also indicate high T and S saturation of early melt. Os-(Ir) inclusions are Ru-depleted while two discrete Ir-enriched osmium crystals have remarkable, extreme Ru enrichment and depletion, confirming crystallization before and after laurite. Laurite and osmium inclusions in one Pt-Fe alloy reflect concomitant crystallization and fluctuating low fS2 melt conditions. In experimental primitive Cu-bearing Pt-Pd-S-(As) melt (cf. exsolved from primitive basalt), first Cu-PGM-sulfide crystallization generates a Cu-depleted, Pt-Pd-As-(S) residual melt. At lower T immiscible melts Pt-As-(S) and later Pd-As-(S) crystallize distinctive PGM. We report analogous natural multiphase PGM inclusion assemblages in separate isoferroplatinum nuggets: (1) zoned sulfarsenides, sperrylite, and genkinite, with rare resorbed cognate xenocrystic cooperite (captured from primary sulfide melt) define a high T, Pt-enriched sub-system [Pt > Rh(Pd,Ir,Ru)As,S ≫ Sb,Bi] and (2) zoned sulfarsenides, arsenopalladinite, sperrylite, törnroosite, and gold define a lower T, fractionated Pd-enriched sub-system [(Pd > Rh ≃ Pt > Ir > Au)As,S > Te ≫ Sb,Bi]. The previously undocumented natural S-rich sperrylite (formerly “platarsite”) solid solution series and later crystallized irarsite series are discriminated in terms of Pt-Ir-Rh. Both trends fractionate toward increasing Rh (hollingworthite). The discrete PGM assemblage, sperrylite-telluropalladinite (with exsolved palladium and electrum) defines an IPGE-depleted Pd > Pt(Au > Ag)As ≥ Te ≥ Sb sub-system and records extreme fractionation. Cu-bearing multiphase PGM inclusions (some coexisting with silicate glass) derived from the fraction of Cu-bearing exsolved Pt-Pd-S-(As) melt will be reported separately.
Eluvial material from this stream, presumed to be derived from the Freetown anorthositic gabbro, has been examined by SEM and electron microprobe. In addition to Pt-Fe and Os-Ir alloys, distinctive pyritohedra of laurite (RuS2) and erlichmanite (OsS2) occur with tulameenite (Pt2FeCu). Although some of the material is rounded by transport, many of the minerals preserve their original euhedral form and are large (0.5-1 mm) compared with those normally found. Representative microprobe analyses are given for all these phases. -R.A.H.
The phase behavior of the quaternary Mo-Ru-Rh-Pd system and that of the four ternary Mo-Ru-Rh, Mo-Ru-Pd, Mo-Rh-Pd, and Ru-Rh-Pd systems has been investigated at 1700 degree C. The quaternary system is characterized by the hcp epsilon -Ru(Mo,Rh,Pd) solid solution which can dissolve up to 48 at. % bcc Mo, 60 at. % fcc Rh and 15 at. % fcc Pd, respectively. The intermediate hcp phases in the binary Mo-Rh and Mo-Pd systems are stabilized in the range from 43 to 82 at. % Rh and 51 to 53 at. % Pd, and from continuous solid solutions with epsilon -Ru(Mo,Rh,Pd). Up to 5 at. % Rh and 5 at. % Pd, respectively, can be dissolved in the sigma -phase Mo//5Ru//3. Fcc alpha -Rh(Mo,Ru,Pd) can dissolve up to 14 at. % Mo, 34 at. % Ru, and 47 at. % Pd in the respective binary boundary systems. Complete miscibility exists between Rh and the fcc alpha region of the binary Mo-Pd system (approx. 60 to 70 at. % Pd at 1700 degree C), whereas Rh can dissolve up to 80 at. % Ru//0//. //5Pd//0//. //5. Lattice parameter and Vickers hardness results of the solid solution regions and pseudoternary sections of the quarternary system are given.
Terrestrial alloys of osmium-iridium-ruthenium occur in places from depleted mantle of obducted ophiolites. Some specimens consist of intergrown metal phases having textures and compositions consistent with formation by crystallization from a melt at temperatures greater than various proposed geotherms of the earth's mantle. It is proposed that these specimens were subjected to melting in the lower mantle when the earth had temperatures higher than at present or that they melted at depths greater than 2900 km before that region was occupied by the core or that they once resided within the core. The alloys were probably transported in convecting mantle material and were subsequently incorporated into depleted mantle of lithosphere, now exposed as obducted ophiolites. It is further proposed that the alloys were originally primitive material that has remained essentially intact since accretion of the earth from the solar nebula.
An historical review of the nomenclature of the natural Os-Ir alloys suggests that the most suitable names are: For the cubic alloys, osmiridium (Steffens, 1824), i.e. osmian iridium; and for the hexagonal alloys, iridosmine (Breithaupt, 1827), i.e. iridian osmium, for alloys with 20% or more Ir, and native osmium for the very rare alloys with little or no Ir. Iridosmine may, if desired, be divided into two varieties, nevyanskite and sysertskite , following Rose and Haidinger.
Electron microprobe and scanning electron microscopy. The platinum-group minerals found in the chromitites are laurite, porous
Ru-rich alloys, Os-Ir- and Pt-rich alloys with highly variable compositions, an Ir-Cu-rich sulfide, a Pt arsenide, and three
relatively rare platinum-group sulfides. The platinum-group minerals are 1 to 30 mu m in diameter and occur as inclusions
in chromite grains; some of these inclusions also contain silicates and millerite. Base metal alloys (largely Ni-Fe) occur
in cracks in the chromitites, along with magnetite, ferritchromite, chromian chlorite, and serpentine. The primary platinum-group
mineral assemblage is interpreted to have formed before or during crystallization of the chromite grains and not as a result
of exsolution from the chromite.--Modified journal abstract.