High Ti Content Research Articles

Interfacial characteristics in CNTs-AgCuTi systems

AgCuTi-based composite fillers reinforced with Carbon Nanotubes (CNTs) were prepared by mechanical ball milling and ultrasonic agitation. The morphological features, chemical components, and melting characteristics of the composite fillers with different content of CNTs addition were investigated using Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD) and a Differential Scanning Calorimeter (DSC). After being heated at 900 ℃, the microstructure of the composite fillers was examined through FESEM and Transmission Electron Microscopy (TEM) to analyze the interfacial characteristics in the AgCuTi-CNTs system. The microstructures of the composite fillers with 0.5 wt% CNTs and 0.1 wt% CNTs were compared. It was found that 0.5 wt% CNTs were favorable for dispersive distribution of the structure. Nano-sized TiC particles formed in the reaction of CNTs with Ti, resulting in the transformation of TiCu2 with high Ti content and Ti2Cu3 phases to TiCu4 phase with low Ti content. Additionally, the microstructure evolution of the composite fillers was studied by changing the ratio of Ti/CNTs. Results showed that CNTs significantly influenced the wettability of the AgCuTi filler. After addition of 0.3 wt% of CNTs, the spreading area of the composite filler on the C/C composite increased by 146.0%.

Catching the Main Ethiopian Rift evolving towards plate divergence

Magmatism accompanies rifting along divergent plate boundaries, although its role before continental breakup remains poorly understood. For example, the magma-assisted Northern Main Ethiopian Rift (NMER) lacks current volcanism and clear tectono-magmatic relationships with its contiguous rift portions. Here we define its magmatic behaviour, identifying the most recent eruptive fissures (EF) whose aphyric basalts have a higher Ti content than those of older monogenetic scoria cones (MSC), which are porphyritic and plagioclase-dominated. Despite these differences, calculations highlight a similar parental melt for EF and MSC products, suggesting only a different evolutionary history after melt generation. While MSC magmas underwent a further step of storage at intermediate crustal levels, EF magmas rose directly from the base of the crust without contamination, even below older polygenetic volcanoes, suggesting rapid propagation of transcrustal dikes across solidified magma chambers. Whether this recent condition in the NMER is stable or transient, it indicates a transition from central polygenetic to linear fissure volcanism, indicative of increased tensile conditions and volcanism directly fed from the base of the crust, suggesting transition towards mature rifting.

Chlorite mineralogy, geochemistry and exploration implications: A case study of the Xiaokelehe porphyry Cu-Mo deposit in NE China

The recently discovered Xiaokelehe porphyry Cu-Mo deposit (PCD) is situated in the northern part of the Great Xing’an Range in NE China. At Xiaokelehe, chlorite-illite alteration is characterized by chlorite, illite, disseminated chalcopyrite and pyrite assemblages that are widely developed in the granodiorite porphyry. The illite is altered from plagioclase or K-feldspar, and the chlorite from both igneous and hydrothermal biotite. The chlorite can be divided into three types (Chl1, Chl2 and Chl3): Chl1 is locally developed in the deeper part of the granodiorite porphyry, and is altered from hydrothermal biotite; Chl2 is pervasively distributed in the deeper part of the granodiorite porphyry, and is altered from igneous biotite and associated with abundant disseminated Cu-Fe-sulfide mineralization; Chl3 is widely developed in the shallower part of the granodiorite porphyry, and is altered from igneous biotite. Chl3 is overprinted by phyllic alteration and associated with minor disseminated Cu-Fe-sulfide mineralization. These Xiaokelehe chlorites resemble the chlorites from typical sericite-chlorite-calcic alteration (SCC) in PCDs, and are the first reported SCC-related chlorites in the Great Xing’an Range.Mineral geochemical results show that Chl1 has relatively high FeO, Mn, Ti, Li and Zn contents. Chl2 has relatively high FeO, Mn, Co, Ni, Zn and Sr contents, and Chl3 has relatively high MgO, K and Ni contents. These geochemical differences are likely controlled by temperature (e.g., for Ti), precursor minerals (e.g., for FeO and MgO) and fluid compositions (e.g., for FeO, MgO, Mn, Co and Zn). All Chl1 to Chl3 are classified as trioctahedral chlorite. The Fe-Mg, Tschermark and di-trioctahedral substitution mechanisms may have controlled the chemical differences of the Xiaokelehe chlorites. Empirical thermometer yielded chlorite formation temperatures of 209–314 °C, indicating that the Xiaokelehe chlorites were formed from intermediate-high temperature hydrothermal fluids. Compared with the chlorites from propylitic zones in other PCDs, the Xiaokelehe chlorites have higher FeO, Ti, V, Zn and Ga contents and Fe/(Fe + Mg) ratio, as well as lower MgO, K, Co and Sr contents, which distinguish chlorites in the SCC zone from those in the propylitic zone. Such differences may have also been influenced by temperature, and the protolith and fluid compositions. Compared with typical metamorphic chlorites, the Xiaokelehe chlorites have lower FeO content but higher MgO and Zn contents, of which the Zn difference is likely influenced by the fluid chemistry. We propose that the presence of Chl3 can be used as an effective vector toward mineralized zone. In addition, chlorite Mn and Zn contents in the mineralized zone are clearly higher than those away from it, and thus the chlorite Mn and Zn contents can also be potential exploration vectors at Xiaokelehe.

Mixing of cognate magmas as a process for producing high-silica granites: Insights from Guanmenshan Complex in Liaodong Peninsula, China

Ascertaining how high-silica granites form is important for understanding why Earth has a high-silica continental crust and how the composition of the continental crust has evolved through time. This study presents a systematic dataset for the petrology, mineralogy, geochronology, and geochemistry of the granite porphyries and related microgranular enclaves and diabases from the Early Cretaceous Guanmenshan Complex (126–123 Ma) in Liaodong Peninsula, North China Craton, to reveal the complex, multi-stage, magmatic evolution in a shallow silicic magma system prior to and during emplacement of high-silica granites. Zircons from the granite porphyries and microgranular enclaves can be classified into two groups: those with dark-CL cores surrounded by light-CL rims, and those comprising entirely light-CL domains, without dark-CL cores. Our results indicate that dark-CL zircon domains with high Th (46–579 ppm), U (120–1274 ppm), and Hf (6709–12,493 ppm) contents and low Ti contents (1.52–7.85 ppm) and Ti-in-zircon temperatures (TTiZ = 622–751 °C) formed from highly evolved magmas, whereas light-CL zircon domains with low Th (14–157 ppm), U (24–236 ppm), and Hf (4749–10,474 ppm) contents and high Ti contents (7.59–29.36 ppm) and Ti-in-zircon temperatures (TTiZ = 748–885 °C) formed from low evolved magmas. These characteristics, combined with the similar UPb ages and Hf isotopic compositions of the dark-CL zircon cores and light-CL zircon domains and insignificant intra- or inter-grain (87Sr/86Sr)i variations of plagioclase from the granite porphyries and microgranular enclaves, reflect mixing between two cognate magma batches with contrasting evolved signatures. This study presents a model in which the highly evolved magmas were derived from initial interstitial melts that were extracted from a crystal mush leaving behind residual cumulates, whereas the less evolved magmas were the products of re-melting of the cognate cumulates. The diabases likely represent the mafic recharge magma that contributed necessary heat but limited mass to remobilize the cumulate mush, inducing the internal self-mixing and formation of the hybrid high-silica magmas. Feeder-dyke related emplacement of the hybrid magma generated more mafic rocks that became incorporated and dispersed into the high-silica granite porphyries as cognate microgranular enclaves. Our results lend new insights into the important role of cognate magma mixing induced by mafic recharge in generation of high-silica granites.

The genesis and mineralization process of Xiaobaliang VHMS Cu-Au deposit, Central Asian Orogenic Belt: Constraints from the pyrite geochemistry and zircon geochronology

The Xiaobaliang Cu-Au deposit is located in the Hegenshan ophiolite complex belt of the western Xing’an–Mongolia Orogenic Belt (XMOB). Strata-bound sulfide ores are discovered within the Carboniferous volcanic tuff, with the oxidized Au-Cu ores at the top and Cu (-Au) sulfide ores at the bottom. Zircon U-Pb dating on volcanic tuff has yielded a concordia age of 326 ± 3 Ma (n = 21, MSWD = 5.6). Four types of pyrite have been identified, including lamellar pyrite (Py1) in the wall rocks, framboidal pyrite (Py2) in the Zn-rich massive ores, colloform pyrite (Py3) in the massive Cu ores, and euhedral pyrite (Py4) in the fractured Cu ores. Chalcopyrite comprises two types: early massive chalcopyrite aggregates (Cp1) and late chalcopyrite veinlets (Cp2). Here we present the in situ trace elements and sulfur isotopes analyses of different sulfide generations. Elements like Se (44.1 ppm), Co (227 ppm) and Cu (3211 ppm) are enriched in pyrites from Cu ores (Py3&Py4), whereas the pyrites from altered rocks (Py1) take high Mn (5027 ppm), Ti (134 ppm), V (13.0 ppm), Ni (41.9 ppm) and Au (5.07 ppm) concentrations. Similar elemental patterns are observed in chalcopyrite analyses where Co (312 ppm), Se (566 ppm) and Te (31.5 ppm) are enriched in massive Cu ores (Cp1), but Mn (147 ppm), V (174 ppm) and Ti (42.2 ppm) contents are mainly concentrated in chalcopyrite veinlets (Cp2). In situ S isotope analyses exhibit a large variation in Py1 (−30.70 to −1.50‰) and Cp2 (−7.81 ∼ −4.50‰) but are constant in Py2, Py3, Py4 and Cp1 (0.44 to 3.15 ‰). The high Co/Ni ratios and relatively lower δ34S values in Py1 suggest a diagenetic environment where the lower-temperature and extremely reduced conditions facilitate the enrichment of Mn, V and Au. The progressive enrichment of Sn, Te, Bi, Se and Cu in hydrothermal Py3 and Py4 then points out the rising of temperature in the weakly reduced environment. The negative sulfur isotopes in altered rocks (Py1) and fractured ores (Cp2) point out the contribution of the volcanic-sedimentary sequence. These compositional features, combined with sulfur isotopes, have demonstrated that Cu was mainly derived from magmatic-hydrothermal fluids whereas Au was released from Au-rich sediments on the seafloor. The Xiaobaliang Cu-Au deposit belongs to a Cyprus-type VHMS deposit formed in the Carboniferous extensional setting.

Effects of titanium content on the large precipitates in 443 ultra-pure ferritic stainless steel

ABSTRACT The effects of titanium contents on the precipitates of 443 ultra-pure ferritic stainless steel during solidification were determined experimentally and compared with a thermodynamic simulation software, that is, Thermo-Calc. Ultra-pure ferritic stainless steel was cast in a vacuum. The experimental results demonstrated that two types of precipitates during solidification exist in the as-cast ingot according to the compositional characteristics, that is, Al2O3–TiN–NbC and TiN–NbC. The number density of TiN–NbC is larger than the Al2O3–TiN–NbC with the Al2O3 core. The number density of the precipitates increases with the Ti content increasing. These precipitates are generated during solidification. The precipitating process could be well predicted through Thermo-Calc software. The Al2O3 forms first in the liquid steel before solidification, TiN appears later in the solidification process, NbC lastly below 1000°C. The titanium content variation from 0.10% to 0.29% has no apparent effect on the liquidus and precipitation temperatures of TiN, but it distinctly reduces the solidus temperature from 1422°C to 1378°C. The higher Ti content in 443 steel leads to TiN precipitates and Al2O3–TiN particles amount increase during solidification. The disregistry theory and thermodynamic calculation indicate that the Al2O3 could act as the nucleus of TiN and the TiN could act as the nucleus of NbC.

Mapping salinization and trace element abundance (including As and other metalloids) in the groundwater of north-central Mexico using a double-clustering approach

This study aimed to determine the reliability of the double-clustering method to understand the spatial association and distribution of major and minor constituents in the groundwater of an arid endorheic basin in central Mexico (Comarca Lagunera Region). The results of the double-clustering approach were compared with well-known spatial statistics such as spatial autocorrelations (Moran index) and the local indicator of spatial association (LISA). Fifty-five groundwater samples were collected from diverse wells within the basin, and the major ions, metalloids, and trace elements were determined. Overall, the double-clustering analysis was an effective tool for identifying lithogenic/anthropogenic processes occurring in the basin and for establishing zones with high or low abundance of major ions and trace elements, even where processes affecting the groundwater quality were spatially dispersed. Although 89% of the samples showed As higher than the threshold value of 10 μg/L proposed by the World Health Organization for drinking water, both the double-clustering and LISA analyses identified As hotspots in the alluvial aquifer, where the extraction of deeper and warmer groundwater might promote the concomitant release of the metalloids As, Sb, and Ge and the trace elements V and W. Similarly, both statistical analyses identified mountainous sectors where the weathering of silicates and carbonates plays a key role in the abundance of HCO3−, Ga, and Ba. However, the LISA analysis failed to identify hotspots of carbonate-derived elements such as Ca, Mg, Sr, and U and silicate-derived elements such as Ca, Mg, K, Sr, Rb, Cs, Pb, Ni, and Y. Otherwise, the double-clustering analysis clearly defined high- and low-concentration zones for all these elements in the study region. Unlike the LISA analysis, the double-clustering approach was also successful in determining alluvial areas with high concentrations of Si and Ti and areas where the concentrations of Na, Cl−, SO42−, NO3−, B, Li, Cu, Re, and Se in groundwater were elevated, increasing the groundwater salinity. Overall, this study demonstrated that the double-clustering is an easy-to-apply approach, capable of visualizing disperse zones where specific anthropogenic processes may threaten the groundwater quality.

Glimmerite: A product of melt-rock interaction within a crustal-scale high-strain zone

The paradigm for hydrous high-strain zones that cut dry host rocks is for fluid-rock interaction to have involved aqueous fluids. However, the role of silicate melt is increasingly recognised. This contribution examines the formation of glimmerite (biotitite) bands during melt migration in the Gough Dam shear zone, a high-strain zone in central Australia that was active during the Alice Springs Orogeny (c. 450–300 Ma). The glimmerite bands cut and replace a range of quartzo-feldspathic protoliths, including granitic gneiss and quartzite. Melt that migrated through the high-strain zone is interpreted to have penetrated relict layers along a network of fractures, enhancing dissolution of the precursor rock and causing replacement by glimmerite crystallisation. Microstructures indicative of the former presence of melt in the high-strain zone include: pseudomorphs of former melt pockets of granitic composition; small dihedral angles of interstitial phases; elongate grain boundary melt pseudomorphs; neighbourhoods of grains connected in three dimensions; and localised static grain growth and recovery. Other microstructures indicative of melt-present deformation include randomly oriented neosome grains, and evidence of activation of multiple slip systems during deformation. The degree of quartzite modification to glimmerite is recorded by an increase in biotite mode, and correlated with higher Ti concentrations in biotite (higher apparent temperature) and changes to trace element and REE compositions. Melt-assisted coupled dissolution-precipitation reactions during melt flux are interpreted to partially reset Proterozoic monazite U-Pb ages inherited from the protolith (> 1630 Ma) to younger Palaeozoic ages, with a complex age pattern partially congruent with the Alice Springs Orogeny (apparent ages range from c. 606–371 Ma, with a dominant age peak at c. 451 Ma). We propose that the glimmerite formed during dynamic melt migration of an externally-derived hydrous peraluminous melt, driving reaction replacement of various felsic protoliths during this orogenic event.

Investigation of Ni/Al/Ti Ohmic Contact on N-Type 4H-SiC

In order to understand the contribution of various metals in the formation of ohmic contacts, Ni/Al/Ti ohmic contacts on n-type 4H-SiC in terms of a different annealing temperature and Ti composition are investigated, which is more difficult to form than p-type ohmic contact. The formation of the Ni/Al/Ti metal alloy system is much more sensitive to metal composition than annealing conditions. With the increase of metal composition, the contact with a high Ti content yields a lower specific contact resistivity compared with the low Ti contact. The annealed surface morphology and phase resultants were examined by scanning electron microscopy (SEM) and atomic force microscope (AFM), respectively. With the increase of Ti components, the surface morphology of the samples becomes more uniform and smoother, while the surface roughness remains unchanged. It implies that Ti metal can not only reduce the ohmic resistance, but also protect the surface of the sample and maintain the roughness.

Geology, geochronology, mineral chemistry and geochemistry of the Hongnieshan mafic–ultramafic complex in the Beishan area, southern Central Asian orogenic Belt, NW China: Implications for petrogenesis and regional Ni mineralization

In recent decades, new breakthroughs in Ni prospecting have been made in the Beishan area, southern Central Asian Orogenic Belt, NW China—more vein-type sulfide mineralization with high Ni tenor has been discovered. Here, novel discussions on the petrogenesis and sulfide immiscibility of the Permian mafic–ultramafic rock are presented based on petrological, geochronological, mineralogical, and Hf–S isotopic studies of the newly discovered Hongnieshan Ni occurrence. The complex is predominantly composed of dunite, wehrlite, olivine clinopyroxenite, olivine gabbro, gabbro and norite. The gabbro has a zircon age of 282.9 Ma and positive εHf(t) values (+5.5–+7.8). The complex may have originated from partial melting of the depleted mantle, which was metasomatized by subduction fluid in a post-orogenic extensional setting. The parental magma is characterized by high temperature (1396 ℃) and high Mg (picritic affinity, 14.4 wt% MgO) and Ti (2.3 wt%) contents, and an oxidized nature (FMQ + 0.59). The disseminated and vein-type sulfide mineralization are the results of multistage segregation. The first segregation was induced by the assimilation of Archean strata, as indicated by the presence of Δ33S of sulfide minerals (1.4‰ to 3.6‰), which is within the range of Archean crust (-2.5‰–+11‰) and is clearly beyond the range of post-Archean rocks (0 ± 0.1‰). The sulfide was removed at depth, leading to that the later segregated sulfide was poor in platinum group element. Vein-type high Ni tenor mineralization was ascribed to the second segregation before olivine crystallization and later injection of sulfide ore pulp. The third sulfide segregation was accompanied by fractional crystallization and gave rise to disseminated mineralization with a low Ni tenor. The δ34S in the Beishan Ni-Cu deposits ranges from-2.01 to 2.07‰, exhibiting a mantle-like variation and arguing against the incorporation of crustal S. Crustal assimilation, especially the addition of Si-rich components from country rocks is the main trigger factor. The Beishan area is still a favorable exploration target in future prospecting.

Geochemistry and genesis of the Nadun Nb-enriched arc basalt in the Duolong mineral district, western Tibet: Indication of ridge subduction

The Duolong mineral district in western Tibet is one of the largest porphyry Cu–Au deposit fields with significant metallogenic potential in China. Its tectonic environment relevant to Early Cretaceous Cu–Au mineralization remains controversial. Here we report new whole-rock major and trace element, and Sr-Nd-Hf-Pb isotopic data for the newly discovered basalt in the Nadun area, Duolong mineral district, to decipher their genesis and further constrain the tectonic environment. A contemporaneous rhyolite sample interbedded with the basalt in the lower part of the volcanic section in the Nadun area yields an LA-ICP-MS zircon U–Pb age of 122.5 ± 1.2 Ma. The basalt samples exhibit high-K calc-alkaline/shoshonite properties and are enriched in high field strength elements, e.g., high TiO2 (1.43–1.79 wt.%) and Nb (14.6–19.5 ppm) contents, with high Nb/La ratios (0.4–0.6), which are compositionally comparable to those of Nb-enriched arc basalts (NEABs). The (87Sr/86Sr)i ratios of 0.7052 to 0.7056, negative εNd(t) (− 0.7 to − 0.2) and εHf(t) values (+ 6.0 to + 6.5), and high (206Pb/204Pb)i, (207Pb/204Pb)i, (208Pb/204Pb)i and ratios (18.522 to 18.561, 15.641 to 15.645 and 38.679 to 38.730, respectively) suggest that the Nadun NEABs are more enriched than those of the island arc basalts (IABs) in the area. The slightly enriched radiogenic isotopes for the Nadun NEABs indicate that the subducting sediments play an important role in the source. Furthermore, their high Nb, Ti, and Cu contents indicate that the source mantle wedge was metasomatized by slab melts. The Nadun NEAB and other coeval magmatic rocks in the Duolong mineral district, including adakite, OIB-like basalt, MORB-type basalt, A-type rhyolite, and common IAB, are typical rock assemblages of ridge subduction. We infer that the Duolong mineral district were formed by ridge subduction in the Early Cretaceous.

Early Ediacaran two-mica granites marking the contractional stage of the Brasiliano Orogeny in the Pernambuco-Alagoas Domain, NE Brazil

The two-mica granitoids intrude metasedimentary rocks of the Pernambuco-Alagoas Domain in the Southern subprovince of the Borborema Province. They comprise biotite (<8 %) -muscovite (>10 %), ferroan, alkali-calcic leucogranites. Zircon, apatite, and opaque minerals are the accessory phases. Most of the muscovite grains show high Na, Ti, Alt, and low Si (3.08–3.10 apfu) contents, being considered primary muscovite. Biotite grains have high Fe and Al, and low Mg contents, and Fe# (FeOt/FeOt + MgO) values ranging from 0.68 to 0.79, typical of biotite crystallized from peraluminous magmas. Plagioclase grains show compositional variation within the albite to low oligoclase fields (Ab94An05Or01 - Ab88An11Or01), and the K-feldspar crystals have composition ranging from Or97Ab03 to Or92Ab08. Thermobarometric data point out crystallization at temperatures < 800 °C and pressures ranging from 4.2 to 5.0 kbar. High Rb/Ba, Rb/Sr ratios, CaO/Na2O < 0.3, and negative correlation between Rb/Sr with Ba and Sr contents suggest that the studied granitoids magmas were formed by partial melting of metasedimentary sources, through muscovite and biotite dehydration. Shear heating appears to be the main heating source, but radioactive heat and previous basalt underplating could also contribute to increase the crustal temperature. The best candidate to the source of the studied granitoids is the Palmares Sequence metasedimentary rocks, due to similar Nd isotopic signature. Magma evolution was dominated by fractional crystallization of K-feldspar, apatite, ilmenite, and small amount of biotite, under low to middle fO2 (between 0 and + 1 Δ QFM) conditions. The crystallization age, ca. 630 Ma for the studied granitoids, is likely correlated to the peak of the high-T regional metamorphism, that was associated with the contractional stage of the Brasiliano Orogeny.

Metals in Calluna vulgaris, Empetrum nigrum, Festuca vivipara and Thymus praecox ssp. arcticus in the geothermal areas of Iceland

This investigation was conducted to identify the content of metals in Calluna vulgaris (family Ericaceae), Empetrum nigrum (family Ericaceae), Festuca vivipara (family Poaceae) and Thymus praecox subsp. arcticus (family Lamiaceae), as well as in the soils where they were growing in eight geothermal heathlands in Iceland. Investigation into the vegetation of geothermal areas is crucial and may contribute to their proper protection in the future and bring more understanding under what conditions the plants respond to an ecologically more extreme situation. Plants from geothermally active sites were enriched with metals as compared to the same species from non-geothermal control sites (at an average from about 150 m from geothermal activity). The enriched metals consisted of Cd, Co, Cu, Fe and Ni in C. vulgaris; Cd, Mn and Ti in E. nigrum; Hg and Pb in F. vivipara; and Cd, Fe and Hg in T. praecox. Notably, C. vulgaris, E. nigrum, F. vivipara and T. praecox had remarkably high concentrations of Ti at levels typical of toxicity thresholds. Cd and Pb (except for C. vulgaris and F. vivipara) were not accumulated in the shoots of geothermal plants. C. vulgaris from geothermal and control sites was characterised by the highest bioaccumulation factor (BF) of Ti and Mn; E. nigrum and F. vivipara by the highest BF of Ti and Cr; and T. praecox by the highest BF of Ti and Zn compared to the other elements. In comparison with the other examined species, F. vivipara from geothermal sites had the highest concentration of Ti in above-ground parts at any concentration of plant-available Ti in soil.

Effects of Input Power Ratio of AlCr/Ti Target on the Microstructural and Mechanical Properties of AlTiCrN Coatings Synthesized by a High-Power Impulse Magnetron Sputtering Process

In this study, five AlTiCrN nitride coatings were deposited via high-power impulse magnetron sputtering (HiPIMS). The AlTiCrN coatings were synthesized with high contents of Al or Ti and a lower fraction of Cr, using Ti and Al70Cr30 targets with five different input power ratios. Electron probe microanalyzer results revealed that the increased rate of Ti contents in the coatings can be divided into two regions due to the difference of power densities for HiPIMS (&gt;0.5 kW/cm2) and modulated pulsed power (MPP) (&lt;0.5 kW/cm2). The deposition rate and thickness of the coatings depended on the sputtering yield of two metal targets under HiPIMS and MPP modes. The grain size of the coatings decreased from 60 to 40 nm as the input power ratios of the AlCr/Ti targets decreased due to their lower thickness values and lower Al content. Selected area electron diffraction patterns and X-ray diffraction results revealed that the TiN and AlTiN phases can be found in the coating containing higher Ti content, whereas the AlN, CrN, and AlCrN phases were observed in the coating with a higher Al concentration. Nevertheless, decreasing the concentration of Ti had a detrimental effect on the mechanical properties of AlTiCrN coatings, due to a promotion in grain size and the formation of AlN, which is softer than TiN. It is noticed that our results differed from those in previous reports, in which a grain refinement effect was observed due to increasing Al content. In this work, the effect of processing the parameters of the HiPIMS and MPP power systems on the grain size and the mechanical property of the coating was also discussed.

Deep subduction, melting, and fast cooling of metapelites from the Cima Lunga Unit, Central Alps

AbstractThe Cima Lunga unit in the Central Alps is dominated by quartzofeldspathic gneisses with subordinate mafic, ultramafic, and metacarbonate rocks. Only mafic and ultramafic lithologies were thought to preserve clear evidence of Alpine high‐P metamorphism. This led to the questions of whether the different rock types were subducted and exhumed as a coherent unit or underwent different pressure–temperature (P–T) histories. New petrological and geochemical data from a metapelite associated with garnet peridotite from Cima di Gagnone (Cima Lunga unit, Switzerland) were obtained using major and trace element mapping. Complex zoning patterns in garnet and white mica are observed. In particular, high Ti content in phengite and increasing P, Zr, and HREE contents in pyrope‐rich garnet indicate that this metapelite underwent high‐P and high‐T (HP–HT) metamorphism involving fluid‐fluxed partial melting. A P–T path is reconstructed by combining textural analysis with petrological–geochemical data and thermodynamic simulations. We show that the mineral record preserves an evolution from prograde to HP–HT peak conditions (2.7 ± 0.1 GPa and 800℃) followed by near‐isobaric cooling (~2.5 GPa and 700–750℃) prior to decompression (1.0 GPa and ~620℃). The reconstructed P–T path suggests that the studied metapelites were subducted to depths where the slab gets heated by proximity to asthenospheric mantle related to slab break‐off. This heating resulted in the dehydration of chlorite‐ to garnet peridotite and the liberated fluids triggered partial melting in the associated metapelites, which might have favoured the fast exhumation of the entire Cima Lunga unit. Metapelites and garnet peridotite from Cima di Gagnone underwent a common prograde to peak and retrograde P–T path without significant tectonic pressure difference between the different lithologies, and deviation from lithostatic pressure is excluded. Lastly, the peak metamorphic conditions of metapelite from Cima di Gagnone are comparable with P–T estimates of ultramafic lithologies from the southern Adula nappe and the Dascio Bellinzona zone, thus opening new scenarios for the geodynamic interpretation of the Central Alps.

ZIRCONS FROM ROCKS OF THE MURZINKA-ADUI METAMORPHIC COMPLEX: GEOCHEMISTRY, THERMOMETRY, POLYCHRONISM, AND GENETIC CONSEQUENCES

Transformation of the oceanic crust into the continental one in orogenic belts is an important problem in petrological studies. In the paleocontinental sector of the Urals, a key object for tracing the stages of metamorphism and investigating the origin of anatectic granites is the Murzinka-Adui metamorphic complex. We have analyzed trace elements in zircons and established their genesis, sources, crystallization conditions, and stages of metamorphic events and granite generation in this complex. Zircons compositions were determined by the LA-ICP-MS method. Temperatures were calculated from Ti contents in the zircons. We distinguish three geochemical types of zircons, which differ in the ratios of light and heavy REE, U, Th, Ti, Y and show different values of Ce- and Eu-anomalies and Zr/Hf ratios, which are indicative of different crystallization conditions, as follows. Type I: minimal total LREE content; clear negative Eu- and Ce- anomalies; features of magmatic genesis; crystallization temperatures from 629 to 782 °C. Type II: higher contents of Ti, La, and LREE; low Ce-anomaly; assumed crystallization from highly fluidized melts or solutions. Type III: low positive Eu-anomaly; high REE content; low Th/U-ratio; zircons are assumed to originate from a specific fluidized melt with a high Eu-concentration. Ancient relict zircons (2300–330 Ma) in gneisses and granites show features of magma genesis and belong to types I and II. Such grains were possibly inherited from granitoid sources with different SiO2 contents and different degrees of metamorphism. Based on the geological and petrogeochemical features and zircon geochemistry of the Murzinka-Adui complex, there are grounds to conclude that the material composing this complex was generated from the sialic crust. The main stages of metamorphism and/or granite generation, which are traceable from the changes in types and compositions of the zircons, are dated at 1639, 380–370, 330, and 276–246 Ma. Thus, transformation of the oceanic crust into the continental one was a long-term and complicated process, and, as a result, the thickness of the sialic crust is increased in the study area.

Semi-Automated Determination of Heavy Metals in Autopsy Tissue Using Robot-Assisted Sample Preparation and ICP-MS

The endoprosthetic care of hip and knee joints introduces multiple materials into the human body. Metal containing implant surfaces release degradation products such as particulate wear and corrosion debris, metal-protein complexes, free metallic ions, inorganic metal salts or oxides. Depending on the material composition of the prostheses, a systemic exposure occurs and may result in increasing metal concentrations in body fluids and tissues especially in the case of malfunctions of the arthroplasty components. High concentrations of Cr, Co, Ni, Ti and Al affect multiple organs such as thyroid, heart, lung and cranial nerves and may lead to metallosis, intoxications, poly-neuropathy, retinopathy, cardiomyopathy and the formation of localized pseudo tumors. The determination of the concentration of metals in body fluids and tissues can be used for predicting failure of hip or knee replacements to prevent subsequent severe intoxications. A semi-automated robot-assisted measurement system is presented for the determination of heavy metals in human tissue samples using inductively coupled plasma mass spectrometry (ICP-MS). The manual and automated measurement processes were similarly validated using certified reference material and the results are compared and discussed. The automation system was successfully applied in the determination of heavy metals in human tissue; the first results are presented.

Effects of microelements on the microstructure evolution and properties of ultrahigh strength Cu–Ti alloys

Modern electronics components require copper alloys to have higher strength and ductility for processing and forming. Cu–Ti alloys exhibit excellent mechanical properties while their plasticity is limited. In this work, high ductility Cu–Ti alloys were fabricated and investigated systematically, results indicated that the samples' strength and plasticity can be improved by adding high Ti and Cr content. The crystal relationship between the β′-Cu4Ti and Cu is that: [100] Cu//[011] β'-Cu4Ti, (020) Cu//(21‾1) β'-Cu4Ti. Further increase aging time, metastable β′-Cu4Ti particles started cellular reaction to be β-Cu3Ti phase, which were detected at the grain boundary. The crystal relationship between the β-Cu3Ti and Cu is that: [100] Cu//[011] β-Cu3Ti, (220) Cu//(400) β-Cu3Ti. The hardness, yield strength, elongation of the CuTiCrMg alloy after aging at 450°C for 30 min are 394 HV, 1057 MPa, and 1.6%, respectively. While, those of the CuTiCrMg–Fe alloy are 370 HV, 1160 MPa, and 10%, respectively. The precipitation strengthening is the primary strengthening mechanism. These findings are of great significance for developing Cu–Ti alloys with high strength and high plasticity.

Evidence of crustal disequilibrium melting, mingling processes, layering and deformation in UHT conditions: The marginal zone of the Egersund-Ogna massif-type anorthosite (S. Norway)

Septa of banded gneisses crop out along the margin of the Proterozoic Sveconorwegian Egersund-Ogna (EGOG) anorthosite pluton. They permit the observation of the effects of a diapiric intrusion of anorthosite on its envelope of gneisses. The rocks are mylonitic and result from a strong deformation in UHT granulite facies conditions due to contact metamorphism. Concordance of the foliations in the septa and in the leuconoritic margin of the anorthosite suggests that the deformation was linked to the ballooning of the anorthosite. The septa lithology is dominated by noritic gneisses interleaved with felsic gneisses and comprises minor amounts of mafic granofels, metaquartzites and metagreywackes. A charnockitic dyke is cutting across the foliated structure. Geochemical data (major and trace elements) indicate that the noritic gneisses did not result from the metamorphism of amphibolites belonging to the high-grade gneiss complex characteristic of the wall rocks of the Rogaland anorthosite province. Instead they have strong similarities with a high-alumina basalt that is the possible parental magma of the EGOG anorthosite. Slight variations from norite to leuconorite compositions were induced by metamorphic differentiation. The felsic rocks encompass a large interval of rock types from granite to tonalite and quartz diorite. They compare with leucogranitic enclaves occurring in the charnockitic upper part of the Bjerkreim-Sokndal layered intrusion. Most felsic lithologies show the signature (including high positive Eu anomalies) of anatectic processes in disequilibrium melting conditions and rapid extraction from the source rocks. Flowage differentiation in the emplacement process explains the various compositions, as commonly observed in migmatite leucosomes. The metaquartzites show a relatively high Ti concentration and the Ti-in-quartz geothermometer records a minimum temperature of 820 °C. The study brings evidence that the high-alumina basalt and the felsic magmas were aggregated but did not interacted to yield hybrid magmas, possibly because the time interval was too short. They mingled in various proportions to form the norito-felsic gneisses. The aggregated magmas were intimately linked to the EGOG intrusion in which they played a role as a lubricating agent. They were injected into the wall rocks and were deformed by ballooning from superheated UHT conditions down to subsolidus conditions where mylonitic structures developed. Finally, a charnockitic magma was still able to intrude at a lower temperature below the ductile-brittle transition.

Influence of Ti content on sensing performance of LaTixOy sensing membrane based electrolyte-insulator-semiconductor pH sensor

In this article, we explored the ability of inorganic LaTixOy (LTO) sensing materials grown on bare p-type substrate to be used as a pH electrolyte-insulator-semiconductor (EIS) sensor. Herein, we fabricated the LTO EIS sensors through the sol-gel synthesis technique under the 0.2 M condition with subsequent annealing at 800 °C in O2 ambient for 20 min. In order to avoid the generation of hydration layer of the gate insulator and reduce the formation of La-silicate, we doped Ti into the La2O3. The structural properties, surface morphologies, film micromorphologies, and chemical states of the sensing films have been investigated by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy analyses, respectively. The sol-gel derived La2Ti2O7 sensing film exhibited super Nernstian pH sensitivity of 68.17 mV/pH with a linearity of 0.999. From the reliability point of view, the La2Ti2O7 sensor showed the best long-term stability with a lower drift rate of 0.21 mV/h as well as a smaller hysteresis voltage of 0.7 mV, as compared with other combination of LTO films. This finding behavior might be due to the high Ti content into the La2Ti2O7 film reducing the silicate layer and increasing the surface sites.