HF Concentration Research Articles

Holey etching strategy of siloxene nanosheets to improve the rate performance of photo-assisted Li-O2 batteries.

Improving the rate performance is of great significance to achieve high-performance photo-assisted Li-O2 batteries for developing new optimized bifunctional photocatalysts. Herein, a holey etching strategy is developed to prepare porous siloxene nanosheets with a size of 10 nm and few layers (P-siloxene NSs) by a modified Ag+-assisted chemical etching method, and the optimized pore-forming conditions are: Ag+ ion concentration 0.01 mol dm-3, HF concentration 0.565 mol dm-3, and H2O2 concentration 0.327 mol dm-3. By using P-siloxene NSs with a bandgap of 2.77 eV as a novel bifunctional photo-assisted Li-O2 system, the rate performance of the assembled P-siloxene NSs photo-assisted Li-O2 batteries is clearly improved. At a current density of 0.1 mA cm-2, the system shows a low overpotential of 0.35 V, full discharge capacity of 3270 mA h g-1, and 69% round-trip efficiency at 100 cycles. In particular, at a current density of 0.8 mA cm-2, the P-siloxene NSs photo-assisted Li-O2 batteries still give a relatively good charge potential of 3.66 V and a discharge potential of 2.97 V. This work provides a new approach for improving the rate performance of photo-assisted Li-O2 systems and will open up opportunities for the high-efficiency utilization of solar energy in electric systems.

Oxidation of HF with KMnO4 and possible misconceptions about HF

Is hydrogen fluoride or its aqueous solution really incompatible with KMnO4? If so, in what respect (meaning why)? This contribution seeks to answer the previous question that was posed some 20 years ago on the pages of the Journal of Chemical Education. The previous conclusion was that KMnO4 cannot oxidize fluoride anions to elemental fluorine. However, this does not prevent the possibility of another type of reaction occurring between HF and KMnO4. In brief, the reaction of HF(aq) and KMnO4(s) cannot occur with concentrated HF(aq), where w(HF) ≈ 0.4. However, the reaction of liquefied hydrogen fluoride, HF(l) and KMnO4(s) appears to produce Mn2O7(l), which is explosive even at moderate temperatures. The same applies to aqueous solutions of HF where w(HF) ≥ 0.6. In this contribution, some details are further explained and the spreading of some misconceptions is, hopefully, hampered. In addition, some authors described HF as a "flammable and explosive" substance, which is even worse than claiming that "water is flammable and explosive".

Investigating the Role of Hydrofluoric Acid Concentration in Tailoring the Morphology and Enhancing the Photonic Properties of Nanoporous Silicon Wafers

At This research used an electrochemical method to convert bulk silicon wafers into porous silicon (PS). The wafers, chosen with a (100) orientation and (8-3) Ω.cm resistivity, the time of etching was 25 min and the current density of etching 25 mA/cm². It was carried out nanoscale surface morphology on the PS substrates by modify the hydrofluoric acid (HF) to ethanol ratio (1:3, 1:6, and 1:9). In the compositional aspect it was used (AFM) to show that higher hydrofluoric: ethanol concentricity augment the porosity and particles density of wafer surface. subsequently, the etching depth given changeful directions with changing HF concentration, and the nanodimensions were clearly showed within the porous silicon layers were they produced. The anatomy of Photo luminescence (PL) specified that the energy gap E.G. was widened with increasing the porosity of wafers and the density of particles, as seem by a shifting to the blue in the PL spectrum

Sedimentological and Geochemical Evaluation of the Lower Cretaceous Yamama Formation, Riyadh, Saudi Arabia: An Integrated Tool for Paleoenvironmental Interpretation

Geochemical proxies are a reliable tool in deciphering the paleoenvironment and diagenetic alteration in carbonate rock units. The Lower Cretaceous Yamama Formation (LCYF) is an important carbonate unit of the Saudi Arabia region which has been studied in detail to evaluate the paleoenvironment and diagenetic alteration through geochemical studies. This study presents new data on petrography, stable isotopes, and trace and rare-earth elements to enhance our understanding on paleoenvironments, redox conditions, and paleosalinity during the deposition of these carbonate units. Field studies show that the formation is composed of thick-to-thin-bedded limestone. Petrographic studies show that the formation is mostly composed of mudstone, wackestone, packstone, and grainstone facies. The stable isotopic values of carbon (δ13C V-PDB = +0.58‰ to +2.23‰) and oxygen (δ18O V-PDB = −6.38‰ to −4.48‰) are directly within the range of marine signatures. CaCO3’s dominance over SiO2 and Al2O3 indicates minimal detrital contribution during the LCYF precipitation. The REE pattern suggests coeval marine signatures which include (i) a slight LREE depletion compared to HREEs (av. Nd/YbN = 0.70), (ii) negative Ce anomalies (av. Ce/Ce* = 0.5), and (iii) a positive La anomaly (av. La/La* = 1.70). Micritic limestone has low Hf (bdl to 0.4 µg/g), Sc (bdl to 2.5 µg/g), and Th (bdl to 0.8 µg/g) content, which suggests negligible detrital influence. The Ce content of different facies (Ce = 1u.80 to 12.85 µg/g) suggests that their deposition took place under oxic to dysoxic conditions. However, there is moderate variation during the deposition of MF-I, with higher Ce values as compared to MF-II, MF-III, and MF-IV, which suggests that the deposition of MF-I mostly took place in anoxic to dysoxic conditions.

Leaching Kinetics of Iron Collector Containing PGMs

The leaching kinetics of an industrial iron collector containing PGMs (Pd, Pt, Rh) in HCl and HF solutions were investigated. The effects of the HCl concentration (2.74–6.86 mol/L), the HF concentration (1.46–7.50 mol/L), temperature (323–363 K), and leaching time (0–210 min) on the extraction of Fe into the solution and Si into the gas phase from the iron collector were studied. The HCl concentration had a negative effect on the extraction of Si, which decreased from 78.2% to 58.1% and from 97.4% to 87.2% in the time ranges of 0–30 min and 30–120 min, respectively. This occurred due to the accumulation of Fe2+ in the solution and its interaction with HF, which led to a reduction in both the HF concentration and the extraction of Si. In addition, there were diffusion difficulties of the Fe and Si extraction because Fe precipitated on the surface of the cakes in the form of thin-film conglomerates of FeF2. This was confirmed by the XRF and EDS results, indicating that F was present on the surface of the cakes. The processes of the Fe and Si extraction were diffusion-chemically controlled and diffusion controlled—the apparent activation energies decreased from 26.9 kJ/mol to 7.8 kJ/mol and from 2.2 kJ/mol to 2.0 kJ/mol in the time range of 0–120 min, respectively. Using the shrinking core model and the full factorial experiment model, the kinetic equations, the optimal parameters of iron collector leaching, and the extraction rates of Fe and Si were determined. These optimal parameters ensure the extraction of Fe and Si at the level of 95% with high leaching rates: the HCl concentration of 4.36 mol/L, the HF concentration of 6.93 mol/L, temperature of 363 K, and leaching time of 80 min.

Effects of Ti and Sn Substitutions on Magnetic and Transport Properties of the TiFe2Sn Full Heusler Compound

The synthesis of polycrystalline TiFe2Sn samples by a route including arc melting and spark plasma sintering with Hf, Y, and In substitutions at the Ti and Sn sites is investigated. For a reduced amount of substitution, around 2 at%, the samples are single phase, while for increased amounts, secondary phases segregate. As is characteristic of these compounds, the Fe-Ti atomic disorder generates a weak ferromagnetic ordering, which is also influenced by the type of substitutional atoms and the secondary phases in the samples with a higher Hf content. The Seebeck coefficient values show an increase for Ti0.98Hf0.02Fe2Sn and for samples with an adjusted Sn content, resulting in slightly increased power factor values. These values reach a maximum for Ti0.98Hf0.02Fe2Sn at approximately 300 K and for TiFe2Sn1.05 at approximately 325 K, namely, 2.69 × 10⁻4 Wm−1K−2 and 2.52 × 10⁻4 Wm−1K−2, respectively. The thermal conductivity of all the samples with substitutions increases with respect to the pristine sample. The highest figure of merit value of 0.016 is also obtained for Ti0.98Hf0.02Fe2Sn at 325 K.

First-principles investigation of oxygen repulsion behavior on the Ir–Hf alloy surface

Enhancing the oxidation resistance of hot-end components under extreme conditions is a key focus in aerospace equipment research. We used first-principles simulations to investigate a series of IrxHf100−x (at. %) coatings. By employing density functional theory and the local density approximation method, we studied the surface oxygen repulsion energy and estimated the optimal composition ratio of IrxHf100−x for the strongest oxidation resistance. The results indicate that as the Hf content increases, the oxygen repulsion energy first rises and then falls, reaching a maximum value of 3.04 eV at x = 10 at. %, with active oxygen adsorption occurring when X exceeds 45 at.%. To understand the mechanism of the oxygen repulsion process, we analyzed the electronic characteristics between Ir, Hf, and O. O preferentially hybridizes its atomic orbitals with Ir, and the improvement in oxidation resistance of the Ir–Hf coating is attributed to the reduction in Ir atomic spacing due to Hf doping, which reduces O–Ir orbital hybridization.

Dissolution Behavior of M5 Cladding in Hydrofluoric-Nitric Mixed Acid.

M5 cladding has emerged as a prominent fuel cladding material due to its excellent corrosion resistance. The dissolution behavior of M5 cladding is critical in both the initial cleaning stage and the reprocessing of spent fuel cladding. This study investigated the dissolution of M5 cladding in hydrofluoric-nitric (HF-HNO3) mixed acid at varying concentrations. When the HF concentration exceeds 0.5 mol/L, the addition of strong oxidizing HNO3 significantly reduces the dissolution rate. Moreover, HNO3 effectively inhibits the HF-induced corrosion pitting, lowering surface roughness to 0.812 μm at a 1:5 ratio of HF:HNO3. In addition, a surface structural analysis reveals the dissolution mechanism of M5 cladding. The β-Nb precipitated in the mixed acid was oxidized to stable Nb2O5 by HNO3 while the M5 matrix surface was continuously oxidized to ZrO2. This passivation layer inhibits further dissolution, slowing the process and enhancing the uniformity of M5 cladding.

Selective Etching of SiO2 over Si3N4 through Varying the Concentration of Fluorine Species

Silicon dioxide (SiO2) and silicon nitride (Si3N4) are widely used as an insulating layer to separate interconnection, due to the characteristic of their wide band gap. As the feature size of semiconductors has been continuously decreasing and their structures have become more complex recent years, SiO2 as an insulating layer is reaching its limit. One of the ways to overcome this limitation, next generation 3D structure semiconductors are developed. In order to manufacture these kinds of devices, a removal of SiO2 is required, however, as both SiO2 and Si3N4 layers are revealed, the highly selective SiO2 etching process over Si3N4 is needed. If the Si3N4 layers were etched during the SiO2 layer etching process, the Si3N4 layer could not be function as an insulating layer and an etch stop layer. As an etchant for the SiO2 layer, hydrofluoric acid (HF) and ammonium fluoride (NH4F) combining solution is mainly used. However, it is known that HF solution also causes the material loss of the Si3N4 layers. Therefore, the study of etching behaviors of SiO2 and Si3N4 in HF solution is needed. In HF solutions, main etching species of SiO2 and Si3N4 exists as fluorine species. The concentration of these fluorine species depends on various conditions, such as pH of the solution or the composition of HF and NH4F. Therefore, the dependence of SiO2 and Si3N4 etching rates on the conditions of HF solutions were investigated.To investigate the etching rates of SiO2 and Si3N4, the blanket SiO2 and Si3N4 wafer in which deposited on Si wafer by the low-pressured chemical vapor deposition method were used, respectively. A patterned SiO2/Si3N4 multi-stack structures were fabricated by plasma-enhanced chemical vapor deposition, to verify whether SiO2 was selectively etched over Si3N4 in HF solution. The HF solutions were prepared by adding various concentrations of HF to deionized water and NH4F was added in some cases. The pH of the HF solution was controlled by adding hydrochloric acid or ammonium hydroxide. The temperature maintained at 25 °C during the etching processes using a water bath. The blanket SiO2 and Si3N4 wafers were immersed in these solutions for 3 and 60 mins, respectively. The etching depth of the SiO2 and Si3N4 films was measured by spectroscopic ellipsometry. The morphology of patterned SiO2/Si3N4 multi-stack structures after etching process was observed using field-emission scanning electron microscopy (FE-SEM). The pH and the concentrations of each fluorine species of the prepared HF solutions were calculated based on the equilibrium constants, molar balance, and charge balance.To obtain the HF solution with the high SiO2 etching selectivity over Si3N4, blanket SiO2 and Si3N4 wafers were etched under various pH and initial concentrations of HF solution. As the pH of the HF solution was increased, at the same initial HF concentration, the SiO2/Si3N4 etching selectivity was increased. Meanwhile, the etching selectivity of SiO2 over Si3N4 was increased with the initial concentrations of HF increased, at a fixed pH of the solution. To investigate the reason for the dependencies of the SiO2 and Si3N4 etching rates on pH and initial concentrations of HF, the concentrations of each fluorine species were calculated. As a result, the etching mechanisms and the etching behaviors of SiO2 and Si3N4 in the HF solutions were suggested. Based on the etching kinetics of SiO2 and Si3N4, a patterned SiO2/Si3N4 multi-stack structure etching conditions were controlled to investigate the SiO2/Si3N4 selective etching ability of the HF solution. The cross-sectional FE-SEM images visually showed that high SiO2 etching selectivity compared to Si3N4 was achieved. As a result, highly selective SiO2 etching without loss of Si3N4 was obtained by adjusting only the concentrations of HF and NH4F, without any special additives through the suggested SiO2 and Si3N4 etching kinetics.

Anodic Dissolution Behavior of Si Electrode in HF Solution Containing H2O2

Silicon is expected to be as anode materials for lithium-ion batteries because the battery performance can be improved by increasing surface area1). Metal-assisted chemical etching (MACE) 2) is a low-cost method to form the nano-silicon structures on Si electrode, which is called silicon nanowires (SiNWs). Though this method enables the fabrication of SiNWs to increase the surface area on Si electrode, the mechanisms on MACE have not been clarified yet. This study aimed to investigate the anodic dissolution behavior of Si electrode to understand the effect of electrolyte concentrations on MACE by electrochemical methods in the HF solution containing H2O2.Electrochemical measurements were carried out by a three-electrode system. An electrochemical cell was made of a polypropylene (PP) to use HF as the electrolyte. The counter electrode was a platinum wire, and the reference electrode was a KCl-saturated Ag/AgCl electrode (SSE) fabricated by the polycarbonate that can be used in the HF solution. The Si, Ag, and Si with deposited Ag particles were used as working electrodes. The Si electrode was made from n-type silicon wafers with a (100) surface. The electrode of Si with deposited Ag particles was prepared using an electroless Ag plating. A mixture of HF and H2O2 was used as the electrolyte solution. To investigate MACE behavior, the measurements of the electrode potential, polarization curve, and electrochemical impedance were carried out at each electrode. The electrode potential of Si with deposited Ag particles was measured for arbitrary time in the electrolyte solution. The potentiostatic polarization of Si electrode was performed to investigate anodic dissolution behavior. The electrochemical impedance measurements were carried out with an AC potential amplitude of 10 mV at arbitrary DC potential. The frequency range was 100 kHz to 0.01 Hz at five frequencies per decade.In the electrolyte solution of HF containing H2O2, the electrode potential of the Si with deposited Ag particles shifted to the less noble potential at the initial stage during MACE regardless of the concentrations of electrolyte solution. The cathodic polarization curve of Ag indicated that the cathodic reactions on Ag electrode were affected by the H2O2 concentrations. The anodic polarization curve of Si electrode demonstrated that the dissolution and film formation may occur on Si electrode, which was depended on the HF concentrations. Based on these results, the electrochemical impedance measurement was performed on the Si electrode. The dissolution and oxide film formation as the anodic reactions and the reduction reactions as the cathodic reactions during MACE were discussed to determine the suitable conditions for fabrication of SiNWs on the Si electrode. References Haibin Li, Shinya Kato, Yosuke Ishii, Yasuyoshi Kurokawa and Tetsuo Soga, Nano Ex., 3, 045010 (2023).Ming-Liang Zhang et al, J. Phys. Chem. C, 112, 4444 (2008).

Notched Gate and Graded Gate Oxide Processing for Reduced Capacitance Application in RF MOSFETs

As the demands of RF applications are rising, optimization of internal MOSFETs capacitances is a key issue to improve the cut-off frequency. In this abstract we report the development of a novel N-MOS architecture processed on 8-inch SOI wafers. This architecture has a gate oxide with variable thickness along the channel and a reduced bottom gate length aiming at minimizing Gate to Drain/Source capacitance (1) (2). This improvement on Gate to Drain/Source capacitance mainly comes from a decrease in overlap capacitances as described in (3).The new process flow is composed as usual until Poly-Si gate etching. By controlling the species flow and process time during plasma etching steps, over etch at the bottom of the gate is performed (fig.1(a,b)). Poly-Si gate notching engineering is possible due to reduction of the passivation layer thickness at the bottom of the gate during plasma etch. As described in (4) the gate is first etched using a HBr/CL2/O2 chemistry until reaching close to the bottom of the gate, allowing the formation of a passivation layer made of SiOxCly and the anisotropy of the etch. To etch the remaining thickness HBr flow is augmented while CL2 and O2 flow are reduced, preventing formation of passivation layer. This leads to isotropic etch of the bottom gate and reduction of the gate length as regard to the top Poly-Si dimension. This over-etch reduces the physical gate length without changing the effective and the on-mask gate lengths, leading to overlap capacitance reduction.To produce gate oxide with variable thickness under gate sidewalls a two-steps process is performed. First, full plate oxide is grown before poly-Si deposition to act as middle gate thickness. Then undercut is performed, consisting of lateral etching of the gate oxide under gate sidewall after gate etch (fig.2.a). To achieve this undercut, hydrofluoric acid (HF) wet etch has been chosen. First trials with very low HF concentration become quickly saturated leading to small lengths under gate sidewalls (fig.2.b). Then more acidic solutions were used allowing satisfying undercut lengths (fig.2.c).Finally rapid thermal oxidation (RTO) is performed to obtain an oxide bird beak at both gate side as both Poly-Si gate and Si from the active region react with ambient O2 in the chamber. This leads to a gate oxide with variable thickness along the channel (fig.3(a.b)) which has both effects: to get smoother poly-Si foot and a down step in the active between channel and Source/Drain regions. During this process step, a built-in spacer on the gate sides for LDD implantation is formed. RTO process step has grown a thicker oxide over Source/Drain areas which has to be reduced to allow an accurate LDD implantation, this is done by anisotropic etching. After these new steps, the process goes back to a standard N-MOS process flow.Some early versions of the notched gate have been investigated (5), and these experiments and details on processing recipe seem promising for electrical results. As poly-Si foot has been smoothed and graded gate oxide (GGO) on top of overlaps region is formed. It would allow a reduction in parasitic capacitances improving cut-off frequency of RF applications.References RF LDMOSFET with Graded Gate Structure. Xu Shuming, Foo Pan Dow. Toronto : s.n., 2001. 1th International Symposium on Power Semiconductor Devices and ICs. ISPSD'99 Proceedings. pp. 221-224. DOI:10.1109. Notched-Gate pMOSFET with ALD TiN/High-κ Gate Stack Formed by Selective Wet Etching. Zhang, D. Wu and J. Lu and P.-E. Hellström and M. Östling and S.-L. s.l. : The Electrochemical Society, Inc., 2004, Electrochemical and Solid-State Letters, Vol. 7, p. 228. 10.1149/1.1795612. A simple efficient model of parasitic capacitances of deep-submicron LDD MOSFETs. Fabien Pregaldiny, Christophe Lallement,Daniel Mathiot. s.l. : Solid State Electronics, 2002, Vol. 46, pp. 2191–2198. https://doi.org/10.1016/S0038-1101(02)00248-4. Design of notched gate processes in high density plasmas. J. Foucher, G. Cunge, L. Vallier, and O. Joubert. s.l. : AVS: Science & Technology of Materials, Interfaces, and Processing, 2002, Vols. Journal of Vacuum Science & Technology B 20,. http://dx.doi.org/10.1116/1.1505959. Notched gate MOSFET for capacitance reduction in RF SOI technology. al, L. Antunes et. s.l. : 2023 IEEE International Conference on Design, Test and Technology of Integrated Systems (DTTIS), 2023. doi: 10.1109/DTTIS59576.2023.10348288. Figure 1

Surface Damage by Physical Cleans during Semiconductors Manufacturing

Keywords: physical damage, surface, cracks, defect revelation Introduction More than one third of process operations in integrated circuits manufacturing rely on Wet cleans. They’re used to remove contaminants such as particles which are a dies’ yield killer. This is achieved either by a chemical action lifting the particles at the cost of a significant materials loss and device performances. This can be also done with some physical cleans (acoustic wave [1], cryogeny [2], high velocity spray [3]) or a combination of both. Whereas features damage by physical cleans has been widely studied [4], surface damage is poorly documented [5] due to lack of evidence. Experimental and characterizations In this work, FDSOI wafers (12 nm Si on 20nm buried oxide) are used. Physical cleans consist in either bi fluidic (aqueous liquid and nitrogen) high velocity sprays, or nitrogen cryogeny methods. Defects inspection on bare wafers is performed on a SP3 Surfscan tool from KLA-Tencor at detection such as 53 nm. Results and discussion Several physical cleans are considered in this paper.First and foremost, high velocity sprays are considered. Their activation and deactivation are the most critical steps due to high risk of erratic behavior (figure 1). Therefore, only well stabilized sprays are hereby discussed. Surface damage on FDSOI surfaces has already been reported [6]. Nano cracks on hard surface can’t be directly detected. A revelation method is used to enlarge the defects, by etching the box (buried oxide) underneath the 12 nm Si layer, thanks to concentrated HF. The wet chemistry can’t penetrate the nano cracks (trapped air [7] and steric hindering [8]) until the path is slightly enlarged. Hence an oxidation step is performed either by ozonated water or plasma to oxidize the silicon along the nano crack and generate after HF step, a 5 nm hole for HF to etch µm wide cavities underneath the damaged silicon (figure 2). Other solid films have been characterized the same way, by changing the enlarging and revealing chemistry. Secondly, a direct characterization method has been developed to quicker compare physical cleaning methods. Indeed, the first method has one drawback, only cracks deep enough are revealed. Soft films are hence used to directly reveal surface damage. A relevant choice of the polymer has enabled to evidence various kind of defects [9] with the high velocity spray (figure 3) and also some alumina particles damaging the resist surface during a nitrogen cryogenic clean (figure 4). These latter weren’t detected on hard films. The various defects maps and tests are summarized in table 1. Eventually, nano indentation and nano scratch tests have been performed on the photo resist films to reproduce the behavior of high energy droplets. And consequences from surface damage will be discussed. Conclusions Physical cleans are widely used in semiconductors manufacturing and are mandatory to achieve a high yield. Whereas damage to features is well documented and easily detected, surface damage is not. Two methods are given to evidence these phenomena: either directly on soft matter or by indirect revelation on hard surfaces.Some new particles cleaning solutions like polymer coat and peel methods are emerging [10] [11]. They combine both an excellent cleaning performance without any damage.

Geochronological and geochemical constraints on the multistage magmatic processes of the Lianhuashan batholith, South China: Implications for the petrogenesis and polymetallic mineralization

The Lianhuashan batholith, which is a composite pluton located in the middle part of a world-class giant tungsten (W) polymetallic belt of South China, hosts a huge reserve of more than 50000 t of W. Despite this great economic significance, the petrogenesis of each phases of the Lianhuashan batholith, as well as its temporal and genetic relationships to the W polymetallic mineralization, is still unclear. To address these questions, we conducted a comprehensive study for the Lianhuashan batholith, including LA-ICP-MS zircon U-Pb dating, whole-rock geochemical and in-situ mineral trace element analyses. Different from previous studies, four main granitic phases (G1 to G4) were identified. The biotite granite (G1) formed from 168.6 to 165.3 Ma, has the lowest Si content and high Al and Fe contents, and is significantly depleted in Ba, Sr, Ti, P, and Nb whereas enriched in U, Hf, Zr, and Y contents. In contrast, the two-mica granite (G2) and fine-grained muscovite granite (G3), formed from 162.8 to 160.5 Ma, exhibit similar characteristics including enrichment in La, Y, Hf, Th, U, and depletion in Ba, Sr, and P. The porphyritic granite (G4) is the latest magmatic phase and formed at 158.3 Ma. It is characterized by high K, Si, Th, U, Zr, Hf contents but low Al, Fe, Sr, P, and Ti contents. These features support that four main phases of the Lianhuashan batholith belong to S-type granites that experienced significant fractional crystallization, and display reduced and low temperature features. Combined with previously published studies, we suggest that the Lianhuashan batholith formed in an intraplate extensional setting triggered by the high-angle rollback subduction of the paleo-Pacific plate. The three early phases (i.e., G1–G3) are in turn more oxidized and are responsible for the transition from Sn- to W-dominated mineralization. In contrast, the G4 granite, characterized by lower oxygen fugacity, is resposible for Pb-Zn-Ag-U polymetallic mineralization.

Hf atomically modulated grain refinement of FeCrAl alloys

Owing to strong corrosion, radiation resistance and excellent mechanical strength at high temperatures, FeCrAl alloys have attracted much attention in the field of the new generation of nuclear fuel casing materials. The fine and uniform grain organisation further improved the alloy performance. In this study, alloy grain refinement was promoted by adding different Hf contents to FeCrAl alloy. Because of the solute drag effect caused by the segregation of Hf atoms at the grain boundaries and the pinning effect of the highly thermally stable HfC precipitation phase, the grain size of the FeCrAl alloy gradually decreased with increasing Hf content. The dislocation motion process was hindered by HfC, which promoted the formation of dislocation walls and dislocation cells and further evolved into subgrain boundaries; additionally, the increase in the density of the grain boundaries further promoted the segregation of the Hf atoms. Through the coupled proliferation process, Hf atoms effectively promoted the grain refinement of the FeCrAl alloys.

Eliminating Hydrogen Fluoride through Piperidine-Doped Separators for Stable Li Metal Batteries with Nickel-Rich Cathodes.

Hydrofluoric acid (HF)-induced electrode and interfacial structure degeneration poses a significant challenge for high-voltage lithium metal batteries (LMBs). To address this issue, we propose a separator strategy that involves decorating a regular polyethylene (PE) separator with molecular sieves (TW) impregnated with piperidine (PI). The porous structure of the TW serves as a reaction chamber for PI and HF. As a result, the HF content in the controlled electrolyte with 500 ppm H2O (ELE-500) is notably reduced when using TW@PI-PE separators, thereby shielding nickel-rich cathodes from HF etching. Simultaneously, due to the hydrolysis of Li salts, and the inertness of PI towards H2O, a uniform lithium fluoride (LiF)-rich solid electrolyte interphase can form on the Li metal anode, further mitigating dendrite formation. The lifespan of the symmetric Li cell using the TW@PI-PE separator is doubled in ELE-500, exhibiting stable 500-hour cycles at 3 mA cm-2 and 3 mAh cm-2. Additionally, with the effective limitation of transition metal (TM) dissolution, the 4.6-V LMBs employing a LiNi0.8Co0.1Mn0.1O2 cathode maintain an 81 % capacity retention over 100 cycles, even in ELE-1000. The innovative TW@PI system presented here offers a fresh perspective for future research aimed at eliminating HF in LMBs.

Eliminating Hydrogen Fluoride through Piperidine‐Doped Separators for Stable Li Metal Batteries with Nickel‐Rich Cathodes

AbstractHydrofluoric acid (HF)‐induced electrode and interfacial structure degeneration poses a significant challenge for high‐voltage lithium metal batteries (LMBs). To address this issue, we propose a separator strategy that involves decorating a regular polyethylene (PE) separator with molecular sieves (TW) impregnated with piperidine (PI). The porous structure of the TW serves as a reaction chamber for PI and HF. As a result, the HF content in the controlled electrolyte with 500 ppm H2O (ELE‐500) is notably reduced when using TW@PI‐PE separators, thereby shielding nickel‐rich cathodes from HF etching. Simultaneously, due to the hydrolysis of Li salts, and the inertness of PI towards H2O, a uniform lithium fluoride (LiF)‐rich solid electrolyte interphase can form on the Li metal anode, further mitigating dendrite formation. The lifespan of the symmetric Li cell using the TW@PI‐PE separator is doubled in ELE‐500, exhibiting stable 500‐hour cycles at 3 mA cm−2 and 3 mAh cm−2. Additionally, with the effective limitation of transition metal (TM) dissolution, the 4.6‐V LMBs employing a LiNi0.8Co0.1Mn0.1O2 cathode maintain an 81 % capacity retention over 100 cycles, even in ELE‐1000. The innovative TW@PI system presented here offers a fresh perspective for future research aimed at eliminating HF in LMBs.

Zircon Typology: a Synthesis. Applications to Magmatic, Metamorphic and Sedimentary Rocks

Abstract The study of more than 101 000 zircon crystals from 1105 different magmatic rocks (anatectic crustal, calc-alkaline, alkaline or tholeiitic) enables a general synthesis to be established which is useful for arguments in petrology. Populations are defined in typological distributions, mean points and typological evolutionary trends according to genetic groups. The overall logic obtained confirms the essential factors (temperature, chemistry) responsible for typological variations. The Hf contents of zircons, in substitution for Zr, make it possible to refine their origins (crustal, hybrid or mantle-derived), in particular by considering the early phase of crystallization, in equilibrium with the initial magma. They support the typological arguments and underline the role of the fluid phase in the magmatic evolution. Zircon crystals first formed in a given environment and subsequently immersed in a new medium of different chemical composition, temperature and fluid content show a spectacular readjustment of their typology. All the data obtained from the magmatic rocks are directly usable on ortho-derived metamorphic rocks with preserved zircon populations. For migmatites affected by partial melting, inherited zircon nuclei provide evidence (morphology, geochemistry notably Hf, Y) to constrain the nature of the protolith. Synthetic tables are proposed to help in the search for the origin of zircons found in sedimentary or volcano-sedimentary rocks, with a special mention for the most significant types and subtypes.

Sustainable fluoride removal with scrap aluminum: Co-producing cryolite and hydrogen

This study presents a novel continuous process for fluoride removal and re- source recovery as cryolite, using a scrap aluminum-packed column. Efficient aluminum dissolution in hydrofluoric acid (HF) generates hydrogen gas and provides cost-saving alkalinity. The process achieves high efficiency (Al/F molar ratio of 2/6) within short Empty Bed Contact Times (15 min) and at low HF concentrations (500 mg/L). Solution pH plays a crucial role, with Al/F ratios above 1 achievable at pH below 4. The exothermic reaction requires temperature control, with a strong correlation (R²=0.99) between HF concentration and heat generation. Hydrogen production matches theoretical predictions. Cryolite synthesis was confirmed at optimized pH (5–5.5) with a 1:1 bypass ratio, achieving 98 % fluoride removal. XRD and SEM- EDS analyses verified cryolite formation. This approach offers a promising solution for industrial fluoride management, resource recovery, and clean hydrogen production.

The elemental variance between the "rice" and "non-rice" portions of Maifanitum and its health risk assessment

BackgroundMaifanitum, a mineral used in Chinese medicine, was first documented during the Song Dynasty (960–1279). Historical records suggest its multifaceted therapeutic properties, including detoxification and stasis resolution, necrosis removal and tissue regeneration, diuretic and calculi dissolution and prolonging life. The concentration of elements in Maifanitum may vary depending on its origin, different parts, which can affect its effectiveness in different fields of applications. Therefore, the analysis of elements in Maifanitum and the subsequent health risk assessment have been conducted. This provides an important basis for the quality control and application safety of Maifanitum. MethodThe analytical techniques employed in this study are inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES), utilized for the quantitative assessment of 60 elements (Refer to Appendix 1) within Maifanitum samples. Based on the test results, chemometric methods are employed to evaluate the characteristics and differences in elemental concentration from different sources and locations. Additionally, a preliminary health risk assessment is conducted for Maifanitum from different origins and various parts. ResultsWe have established a fingerprint of the elements within Maifanitum, demonstrating a commendable level of similarity. The findings from hierarchical cluster analysis（HCA） corroborated with those from principal component analysis (PCA), collectively unveiling a systematic profile of elemental disparities between Maifanitum samples of diverse origins and applications. It also revealed that there are differences in the concentration of Al, Ga, Be, Hf, Na, Sn, Ti, Zr, Gd, Tb, Sr, Pb, Ce, Ba and other elements in different parts of Maifanitum. While Cd, As, and Cu levels in all samples were within the permissible limits as defined by the Chinese Pharmacopeia, Pb concentrations in the majority of samples were found to surpass these standards, albeit slightly in the ''non-rice'' fraction. The assessment of both beneficial and deleterious elements indicates that the ''non-rice'' fraction of Maifanitum possesses superior quality attributes. Moreover, the overall concentration of rare earth elements in Maifanitum is substantially below the established lower threshold for daily human consumption, with no immediate evidence suggesting any adverse health risks. ConclusionThis study provides a basis for the quality control and safety evaluation of Maifanitum in clinical use.

Thermal atomic layer deposition-processed InHfZnO thin film transistors with excellent stability

In recent years, the downscaling of transistors has sparked considerable interest in the advancement of amorphous oxide semiconductors, particularly indium-hafnium-zinc oxide (IHZO) has remarkable potential in applications such as high-resolution displays and 3D NAND. For the first time, we propose the fabrication of IHZO thin film transistors (TFTs) via thermal atomic layer deposition (TH-ALD). The preparation, electrical properties, and stability of IHZO TFTs are investigated. The performance of TFT deposited at 250 °C and annealed in N2 atmosphere at 300 °C exhibits a high field-effect mobility (μ) of 22.53 cm2/Vs, a high Ion/Ioff of ∼107, a low threshold voltage (Vth) of 0.15 V, and a minimum subthreshold swing (SS) of 0.24 V/decade. Furthermore, the threshold voltage shifts (ΔVth) in TFTs annealed in N2 and O2 are 0.31 and 0.16 V, respectively. These enhancements are attributed to the defects suppression and remaining ionized oxygen vacancies result in increased electron concentration in N2-annealed films. In comparison, O2 annealing causes a reduction in field effect mobility but concurrently enhances stability due to the direct passivation of defects, which leads to fewer oxygen vacancies. Additionally, Hf content can also impact the performance of TFT devices, even a small addition of Hf also results in the effective reduction of the carrier concentration. These findings provide valuable insights into the device mechanism of IHZO TFTs, presenting a novel avenue for comprehending and augmenting their overall performance.