Mitrofanovite, Pt3Te4, a new mineral from the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia

2018 ◽  
Vol 83 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Victor V. Subbotin ◽  
Anna Vymazalová ◽  
František Laufek ◽  
Yevgeny E. Savchenko ◽  
Chris J. Stanley ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Electron Backscatter Diffraction ◽  
New Mineral ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Identity ◽  
Polarised Light ◽  
Fe Alloys ◽  
Backscatter Diffraction

AbstractMitrofanovite, Pt3Te4, is a new telluride discovered in low-sulfide disseminated ore in the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia. It forms anhedral grains (up to ~20 μm × 50 μm) commonly in intergrowths with moncheite in aggregates with lukkulaisvaaraite, kotulskite, vysotskite, braggite, keithconnite, rustenburgite and Pt–Fe alloys hosted by a chalcopyrite–pentlandite–pyrrhotite matrix. Associated silicates are: orthopyroxene, augite, olivine, amphiboles and plagioclase. Mitrofanovite is brittle; it has a metallic lustre and a grey streak. Mitrofanovite has a good cleavage, along {001}. In plane-polarised light, mitrofanovite is bright white with medium to strong bireflectance, slight pleochroism, and strong anisotropy on non-basal sections with greyish brown rotation tints; it exhibits no internal reflections. Reflectance values for the synthetic analogue of mitrofanovite in air (Ro, Re’ in %) are: 58.4, 54.6 at 470 nm; 62.7, 58.0 at 546 nm; 63.4, 59.1 at 589 nm; and 63.6, 59.5 at 650 nm. Fifteen electron-microprobe analyses of mitrofanovite gave an average composition: Pt 52.08, Pd 0.19, Te 47.08 and Bi 0.91, total 100.27 wt.%, corresponding to the formula (Pt2.91Pd0.02)Σ2.93(Te4.02Bi0.05)Σ4.07 based on 7 atoms; the average of eleven analyses on synthetic analogue is: Pt 52.57 and Te 47.45, total 100.02 wt.%, corresponding to Pt2.94Te4.06. The density, calculated on the basis of the formula, is 11.18 g/cm3. The mineral is trigonal, space group R$\overline 3 $m, with a = 3.9874(1), c = 35.361(1) Å, V = 486.91(2) Å3 and Z = 3. The crystal structure was solved and refined from the powder X-ray-diffraction data of synthetic Pt3Te4. Mitrofanovite is structurally and chemically related to moncheite (PtTe2). The strongest lines in the powder X-ray diffraction pattern of synthetic mitrofanovite [d in Å (I) (hkl)] are: 11.790(23)(003), 5.891(100)(006), 2.851(26)(107), 2.137(16)(1013), 2.039(18)(0114), 1.574(24)(0120), 1.3098(21)(0027). The structural identity of natural mitrofanovite with synthetic Pt3Te4 was confirmed by electron backscatter diffraction measurements on the natural sample. The mineral name is chosen to honour Felix P. Mitrofanov, a Russian geologist who was among the first to discover platinum-group element mineralisation in the Fedorova–Pana complex.

Maletoyvayamite, Au3Se4Te6, a new mineral from Maletoyvayam deposit, Kamchatka peninsula, Russia

2020 ◽  
Vol 84 (1) ◽  
pp. 117-123 ◽  
Author(s):  
Nadhezda D. Tolstykh ◽  
Marek Tuhý ◽  
Anna Vymazalová ◽  
Jakub Plášil ◽  
František Laufek ◽  
...  
Keyword(s):  
Kamchatka Peninsula ◽  
Structure Type ◽  
Van Der Waals Interactions ◽  
New Mineral ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Triclinic Space Group ◽  
Structural Identity ◽  
Polarised Light

AbstractMaletoyvayamite, Au3Se4Te6, is a new mineral discovered in a heavy-mineral concentrate from the Gaching occurrence of the Maletoyvayam deposit, Kamchatka, Russia (60°19′51.87″N, 164°46′25.65″E). It forms anhedral grains (10 to 50 μm in size) and is found in intergrowths with native gold (Au–Ag), Au tellurides (calaverite), unnamed phases (AuSe, Au2TeSe and Au oxide), native tellurium, sulfosalts (tennantite, tetrahedrite, goldfieldite and watanabeite) and supergene tripuhyite. Maletoyvayamite has a good cleavage on {010} and {001}. In plane-polarised light, maletoyvayamite is grey, has strong bireflectance (grey to bluish grey), and strong anisotropy; it exhibits no internal reflections. Reflectance values for maletoyvayamite in air (Rmin,Rmax in %) are: 38.9, 39.1 at 470 nm; 39.3, 39.5 at 546 nm; 39.3, 39.6 at 589 nm; and 39.4, 39.7 at 650 nm. Sixteen electron-microprobe analyses of maletoyvayamite gave an average composition: Au 34.46, Se 16.76, Te 47.23 and S 0.84, total 99.29 wt.%, corresponding to the formula Au2.90(Se3.52S0.44)Σ3.96Te6.14 based on 13 atoms; the average of eleven analyses on synthetic analogue is: Au 34.20, Se 19.68 and Te 45.42, total 99.30 wt.%, corresponding to Au2.90Se4.16Te5.94. The calculated density is 7.98 g/cm3. The mineral is triclinic, space group P1, with a = 8.901(2), b = 9.0451(14), c = 9.265(4) Å, α = 97.66(3), β = 106.70(2), γ = 101.399(14)°, V = 685.9(4) Å3 and Z = 2. The crystal structure of maletoyvayamite represents a unique structure type resembling a molecular structure. There are cube-like [Au6Se8Te12] clusters linked via van der Waals interactions. The structural identity of maletoyvayamite with the synthetic Au3Se4Te6 was confirmed by powder X-ray diffraction and Raman spectroscopy.

Viteite, Pd5InAs, a new mineral from the Monchetundra layered intrusion, Kola Peninsula, Russia

2020 ◽  
Vol 58 (3) ◽  
pp. 395-402
Author(s):  
A. Vymazalová ◽  
F. Laufek ◽  
T.L. Grokhovskaya ◽  
C.J. Stanley
Keyword(s):  
Kola Peninsula ◽  
Empirical Formula ◽  
Polarized Light ◽  
Layered Intrusion ◽  
Structure Type ◽  
New Mineral ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygenated Compounds

ABSTRACT Viteite, Pd5InAs, is a new mineral discovered in the Monchetundra layered intrusion, Kola Peninsula, Russia. It forms euhedral grains about 0.5 to 10 μm in size intergrown with irarsite (IrAsS), hollingworthite (RhAsS), zvyagintsevite (Pd3Pb), Au-Ag alloys, and tulameenite (Pt2CuFe), that are replaced by Pt-Pd-Fe-Cu alloys and Pt-Pd-Fe-Cu oxygenated compounds, all of which are embedded in chalcocite, goethite, and covellite. Viteite is brittle and has a metallic luster. In plane-polarized light, viteite is bright pinkish-white. The mineral is weakly anisotropic with rotation tints blue to pinkish brown; it exhibits no internal reflections. Reflectance values of viteite in air (R1, R2 in %) are 55.7, 54.0 at 470 nm; 59.2, 58.4 at 546 nm; 60.0, 60.4 at 589 nm; and 60.0, 62.6 at 650 nm. Eight electron-microprobe analyses of viteite give an average composition of Pd 71.90, Pt 1.60, Fe 0.98, Cu 0.59, In 11.48, Hg 1.42, Pb 0.40, As 10.70, total 99.07 wt.%, corresponding to the empirical formula (Pd4.92Pt0.06)Σ4.98(In0.73Fe0.12Cu0.07Hg0.05Pb0.01)Σ0.98As1.04 based on 7 atoms; the average of 12 analyses of its synthetic analogue is: Pd 73.72, In 16.37, As 9.80, total 99.90 wt.%, corresponding to Pd5.02In1.03As0.95. The density, calculated on the basis of the empirical formula, is 10.78 g/cm3. The mineral is tetragonal, space group P4/mmm, with a 3.98600(3), c 6.98385(8) Å, V 110.961(2) Å3, and Z = 1. The crystal structure of synthetic Pd5InAs was solved and refined using powder X-ray-diffraction data from synthetic Pd5InAs. Viteite crystallizes with the Pd5TlAs structure type. The strongest lines in the X-ray powder diffraction pattern of synthetic Pd5InAs [d in Å (I) (hkl)] are: 2.3281(45)(003), 2.1932(100)(112), 1.9928(33)(020), 1.2515(17)(115), 1.1857(25)(132). The mineral is named for the Vite river, which flows near the Monchetundra intrusion.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

Sergevanite, Na15(Ca3Mn3)(Na2Fe)Zr3Si26O72(OH)3·H2O, a new eudialyte-group mineral from the Lovozero alkaline massif, Kola Peninsula

2020 ◽  
Vol 58 (4) ◽  
pp. 421-436 ◽  
Author(s):  
Nikita V. Chukanov ◽  
Sergey M. Aksenov ◽  
Igor V. Pekov ◽  
Dmitriy I. Belakovskiy ◽  
Svetlana A. Vozchikova ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Structural Data ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
Eudialyte Group ◽  
Group Mineral ◽  
X Ray ◽  
Mohs Hardness ◽  
Alkaline Massif

ABSTRACT The new eudialyte-group mineral sergevanite, ideally Na15(Ca3Mn3)(Na2Fe)Zr3Si26O72(OH)3·H2O, was discovered in highly agpaitic foyaite from the Karnasurt Mountain, Lovozero alkaline massif, Kola Peninsula, Russia. The associated minerals are microcline, albite, nepheline, arfvedsonite, aegirine, lamprophyllite, fluorapatite, steenstrupine-(Ce), ilmenite, and sphalerite. Sergevanite forms yellow to orange-yellow anhedral grains up to 1.5 mm across and the outer zones of some grains of associated eudialyte. Its luster is vitreous, and the streak is white. No cleavage is observed. The Mohs' hardness is 5. Density measured by equilibration in heavy liquids is 2.90(1) g/cm3. Calculated density is equal to 2.906 g/cm3. Sergevanite is nonpleochroic, optically uniaxial, positive, with ω = 1.604(2) and ε = 1.607(2) (λ = 589 nm). The infrared spectrum is given. The chemical composition of sergevanite is (wt.%; electron microprobe, H2O determined by HCN analysis): Na2O 13.69, K2O 1.40, CaO 7.66, La2O3 0.90, Ce2O3 1.41, Pr2O3 0.33, Nd2O3 0.64, Sm2O3 0.14, MnO 4.15, FeO 1.34, TiO2 1.19, ZrO2 10.67, HfO2 0.29, Nb2O5 1.63, SiO2 49.61, SO3 0.77, Cl 0.23, H2O 4.22, –O=Cl –0.05, total 100.22. The empirical formula (based on 25.5 Si atoms pfu, in accordance with structural data) is H14.46Na13.64K0.92Ca4.22Ce0.27La0.17Nd0.12Pr0.06Sm0.02Mn1.81Fe2+0.58Ti0.46Zr2.67Hf0.04Nb0.38Si25.5S0.30Cl0.20O81.35. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is trigonal, space group R3, with a = 14.2179(1) Å, c = 30.3492(3) Å, V = 5313.11(7) Å3, and Z = 3. In the structure of sergevanite, Ca and Mn are ordered in the six-membered ring of octahedra (at the sites M11 and M12), and Na dominates over Fe2+ at the M2 site. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 7.12 (70) (110), 5.711 (43) (202), 4.321 (72) (205), 3.806 (39) (033), 3.551 (39) (220, 027), 3.398 (39) (313), 2.978 (95) (), 2.855 (100) (404). Sergevanite is named after the Sergevan' River, which is near the discovery locality.

scholarly journals Effects of Annealing Temperature on Recrystallization Texture and Microstructure Uniformity of High Purity Tantalum

Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 75 ◽  
Author(s):  
Jialin Zhu ◽  
Chao Deng ◽  
Yahui Liu ◽  
Nan Lin ◽  
Shifeng Liu
Keyword(s):  
Low Temperature ◽  
Electron Backscatter Diffraction ◽  
Stored Energy ◽  
X Ray Diffraction ◽  
Center Layer ◽  
X Ray ◽  
Texture Intensity ◽  
Low Temperature Annealing ◽  
Transmission Electron ◽  
Backscatter Diffraction

One hundred and thirty-five degree clock rolling significantly improves the texture homogeneity of tantalum sheets along the thickness, but a distinctly fragmented substructure is formed within {111} (<111>//normal direction (ND)) and {100} (<100>//ND) deformation grains, which is not suitable to obtain a uniform recrystallization microstructure. Thus, effects of different annealing temperatures on the microstructure and texture heterogeneity of tantalum sheets along the thickness were investigated by X-ray diffraction (XRD), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Results show that the texture distribution along θ-fiber and γ-fiber is irregular and many large grains with {111} orientation develop during annealing at high temperature. However, low-temperature annealing can not only weaken the texture intensity in the surface and the center layer but also introduce a more uniform grain size distribution. This result can be attributed to the subgrain-nucleation-dominated recrystallization mechanism induced by recovery at low temperature, and moreover, a considerable decline of recrystallization driving force resulting from the release of stored energy in the deformation matrix.

scholarly journals Effect of TiO2-Nanoparticles on Ni Electrodeposition on Copper Wire

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 406
Author(s):  
Samiha Saad ◽  
Zakaria Boumerzoug ◽  
Anne Laure Helbert ◽  
François Brisset ◽  
Thierry Baudin
Keyword(s):  
Surface Morphology ◽  
Tio2 Nanoparticles ◽  
Vickers Microhardness ◽  
Electron Backscatter Diffraction ◽  
Copper Wire ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Backscatter ◽  
Electrodeposited Nickel ◽  
Backscatter Diffraction

The objective of this work is to study, on a copper wire, the effect of TiO2-nanoparticles on electrodeposited nickel. Both the microstructure and surface morphology (texture) of the coating were investigated. This deposit is obtained from baths of sulfated electroplating Watts. The Ni-TO2 composite coating is deposited at a temperature of 45 °C. The composite deposit is prepared by adding nanoparticles of TiO2 to the electrolyte. The characterization has been carried out by X-ray diffraction, scanning electron microscopy, microhardness measurements, and electron backscatter diffraction (EBSD). Vickers microhardness was used to characterize the mechanical properties of the electrodeposited nickel. The results showed the effects of the TiO2 on the composition, the surface morphology, and the hardness of the deposited layer. However, there was not an effect of TiO2 nanoparticles on texture.

scholarly journals Russoite, NH4ClAs23+O3(H2O)0.5, a new phylloarsenite mineral from Solfatara Di Pozzuoli, Napoli, Italy

2018 ◽  
Vol 83 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Italo Campostrini ◽  
Francesco Demartin ◽  
Marco Scavini
Keyword(s):  
Ammonium Cation ◽  
New Mineral ◽  
Water Molecules ◽  
Synthetic Analogue ◽  
Arsenic Sulfide ◽  
X Ray Diffraction ◽  
Calculated Density ◽  
X Ray ◽  
Synthetic Phase ◽  
Irregular Cleavage

AbstractThe new mineral russoite (IMA2015-105), NH4ClAs23+O3(H2O)0.5, was found at the Solfatara di Pozzuoli, Pozzuoli, Napoli, Italy, as a fumarolic phase associated with alacránite, dimorphite, realgar, mascagnite, salammoniac and an amorphous arsenic sulfide. It occurs as hexagonal plates up to ~300 µm in diameter and 15 µm thick, in rosette-like intergrowths. On the basis of powder X-ray diffraction measurements and chemical analysis, the mineral was recognised to be identical to the corresponding synthetic phase NH4ClAs2O3(H2O)0.5. Crystals are transparent and colourless, with vitreous lustre and white streak. Tenacity is brittle and fracture is irregular. Cleavage is perfect on {001}. The measured density is 2.89(1) g/cm3; the calculated density is 2.911 g/cm3. The empirical formula, (based on 4.5 anions per formula unit) is [(NH4)0.94,K0.06]Σ1.00(Cl0.91,Br0.01)Σ0.92As2.02O3(H2O)0.5. Russoite is hexagonal, space group P622, with a = 5.2411(7), c = 12.5948(25) Å, V = 299.62(8) Å3 and Z = 2. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 12.63(19)(001), 6.32(100)(002), 4.547(75)(100), 4.218(47)(003), 3.094(45)(103), 2.627(46)(110), 2.428(31)(112) and 1.820(28)(115). The structure, was refined to R = 0.0518 for 311 reflections with I > 2σ(I) and shows a different location of the ammonium cation and water molecules with respect to that reported for the synthetic analogue. The mineral belongs to a small group of phylloarsenite minerals (lucabindiite, torrecillasite and gajardoite). It contains electrically neutral As2O3 layers, topologically identical to those found in lucabindiite and gajardoite between which are ammonium cations and outside of which Cl– anions. Water molecules and additional ammonium cations are located in a layer between two levels of chloride anions.

X-ray diffraction contrast tomography: a novel technique for three-dimensional grain mapping of polycrystals. II. The combined case

2008 ◽  
Vol 41 (2) ◽  
pp. 310-318 ◽  
Author(s):  
Greg Johnson ◽  
Andrew King ◽  
Marcelo Goncalves Honnicke ◽  
J. Marrow ◽  
Wolfgang Ludwig
Keyword(s):  
Electron Backscatter Diffraction ◽  
Three Dimensional ◽  
Real Data ◽  
X Ray Diffraction ◽  
Data Set ◽  
Transmitted Beam ◽  
X Ray ◽  
Diffraction Contrast ◽  
Simultaneous Acquisition ◽  
Backscatter Diffraction

By simultaneous acquisition of the transmitted and the diffracted beams, the applicability of the previously introduced diffraction contrast tomography technique [Ludwig, Schmidt, Lauridsen & Poulsen (2008).J. Appl. Cryst.41, 302–309] can be extended to the case of undeformed polycrystalline samples containing more than 100 grains per cross section. The grains are still imaged using the occasionally occurring diffraction contribution to the X-ray attenuation coefficient, which can be observed as a reduction in the intensity of the transmitted beam when a grain fulfils the diffraction condition. Automating the segmentation of the extinction spot images is possible with the additional diffracted beam information, even in the presence of significant spot overlap. By pairing the corresponding direct (`extinction') and diffracted beam spots a robust sorting and indexing approach has been implemented. The analysis procedure is illustrated on a real data set and the result is validated by comparison with a two-dimensional grain map obtained by electron backscatter diffraction.

Surface Crystallization of Cordierite from Glass Studied by High-Temperature X-ray Diffraction and Electron Backscatter Diffraction (EBSD)

2011 ◽  
Vol 11 (10) ◽  
pp. 4660-4666 ◽  
Author(s):  
Wolfgang Wisniewski ◽  
Carlos André Baptista ◽  
Matthias Müller ◽  
Günter Völksch ◽  
Christian Rüssel
Keyword(s):  
High Temperature ◽  
Electron Backscatter Diffraction ◽  
Surface Crystallization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Backscatter ◽  
Backscatter Diffraction
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