Experimental Determination of the Liquidus in the High-Basicity Region in the Al2O3(25?mass?pct)-CaO-MgO-SiO2 and Al2O3(35?mass?pct)-CaO-MgO-SiO2 Systems

Liquidus in the Al₂O₃(25 mass pct)-CaO-MgO-SiO₂(<20 mass pct) and Al₂O₃(35 mass pct)-CaO-MgO-SiO₂(<20 mass pct) systems were determined experimentally in the high-CaO-containing region at 1873 K (1600 °C). For the Al₂O₃(35 mass pct)-CaO-MgO-SiO₂(<20 mass pct) system, liquidus data were also determined for 1773 K (1500 °C). The equilibrating and quenching technique with subsequent electron probe microanalyzer (EPMA) microanalysis were employed. Based on the data, liquidus lines were constructed for the 25 and 35 mass pct alumina planes at silica contents generally below 20 mass pct. The current results showed a slightly lower solubility of CaO and a higher solubility of MgO at 1873 K (1600 °C) for the 25 mass pct Al₂O₃ section compared with the existing phase diagram. At 1773 K (1500 °C), the result showed a slightly lower solubility of both CaO and MgO in the 35 mass pct Al₂O₃ section compared with the existing phase diagram. In addition, the activities of MgO, CaO, and Al₂O₃ were estimated at 1773 K and 1873 K (1500 °C and 1600 °C) using the phase diagram information.     

Phase Relations in CaO-SiO2-Al2O3-15 mass pct CaF2 System at 1523 K (1250 °C)

CaO-SiO₂-Al₂O₃-CaF₂ is a base system of mold flux for high Al steels. Phase equilibrium in CaO-SiO₂-Al₂O₃-15 mass pct CaF₂ system at 1523 K (1250 °C) was investigated using quenching method followed by X-ray diffraction and Scanning electron microscopy equipped with energy dispersive X-ray spectroscopy. Isothermal section in this system at 1523 K (1250 °C) with Al₂O₃ being less than 25 mass pct and CaO/SiO₂ (mass pct) being between 0.43 and 1.25 was experimentally constructed. The liquidus composition and seven solid-liquid coexistence regions at 1523 K (1250 °C) were determined.     

Solubility of RE2O3 (RE = La and Nd) in light rare earth fluoride molten salts

The chemical reaction and dissolution processes of RE₂O₃ in REF₃-LiF (RE = La and Nd) molten salts were studied by X-ray diffraction, differential thermal analysis and chemical analysis. Firstly, RE₂O₃ disperses in molten salts and reacts with REF₃ and LiF, which lead to the generation of a new phase REOF, resulting in the dissociation or formation of complex ions by part of REOF, and the sedimentation of excessive REOF at the bottom. The RE contents in molten salts were used to determine the solubility of RE₂O₃. The results show that with 20 mol%–40 mol% of REF₃, the solubility ranges from 1.79 to 3.05 g RE₂O₃ per 100 g electrolyte and the corresponding mole concentration is 0.33%–0.87%. RE₂O₃ solubility increases with increasing temperature and REF₃ concentration. The natural logarithm of the RE₂O₃ solubility is plotted against 1/T and can be interpreted by linear relationship. The fitting parameters can be used to estimate the solubility of RE₂O₃ with minimized experimental efforts and difficult experiment conditions.     

Synthesis and Fluorescence of Tb~(3 ) and Eu~(3 ) Complexes with N, N', N

ＳｙｎｔｈｅｓｉｓａｎｄＦｌｕｏｒｅｓｃｅｎｃｅｏｆＴｂ~（３＋）ａｎｄＥｕ~（３＋）ＣｏｍｐｌｅｘｅｓｗｉｔｈＮ，Ｎ＇，Ｎ＂－１，３，５－ｔｒｉａｚｉｎｅ－２，４，６－ｔｒｉｙｌｔｒｉｓ－［Ｎ－（ｃａｒｂｏｘｙｍｅｔｈｙｌ）］－ｇｌｙｃｉｎｅ￥Ｇｏｎ...     

Photoluminescence and energy transfer in transparent glass-ceramics based on GdF3:RE3+ (RE = Tb,Eu) nanocrystals

In the present work,the transparent oxyfluoride glass-ceramic samples containing GdF_3:RE~(3+)(RE=Tb,Eu) nanocrystals(nGCs) were fabricated via controlled heat-treatment of precursor xerogels prepared using a sol-gel method.The formation of GdF_3 nanocrystalline phase from gadolinium(III) trifluoroacetate was verified based on XRD measurements.The average crystal sizes calculated from Scherrer formula were estimated to～10 nm as well as～6 nm for Tb~(3+)-and Eu~(3+)-doped samples,respectively.The optical behavior of prepared sol-gel samples was evaluated based on photoluminescence excitation(PLE) and emission spectra(PL) as well as luminescence decay analysis.Obtained samples exhibit the ~5D_4→~7F_J(J=6-3,Tb~(3+))and the ~5D_0→~7F_J(J=0-4,Eu~(3+)) emission bands recorded within the visible spectral area under excitation at near-UV(393 nm(Eu~(3+)),351,369,378 nm(Tb~(3+))) as well as middle-UV illumination(273 nm(Gd~(3+))).Additionally,based on recorded decay curves,the luminescence lifetimes(τ_m) for the ~5D_4(Tb3+) and the ~5D_0(Eu~(3+))excited states were also evaluated.In general,recorded luminescence spectra and double-exponential character of decay curves for nGCs indicate a successful migration of Tb~(3+) and Eu~(3+) dopant ions from amorphous silicate framework to lowphonon energy GdF_3 nanocrystal phase.     

Grain Size Effects on Primary,Secondary, and Tertiary Twin Development in Mg-4 wt pct Li (-1 wt pct Al) Alloys

Grain size effects on three generations of twins were investigated in extruded Mg-4 wt pct Li (-1 wt pct Al) alloys using electron-backscatter diffraction. Samples with three distinct grains sizes, yet the same texture and applied strain were analyzed. With these variables fixed, we show that compression and double twinning decrease substantially with decreasing grain size. We find that compression twinning exhibits a stronger grain size effect than tension twinning, whereas the compression twinning to double twinning transition is independent of grain size.     

Synthesis,Characterization and Crystal Structure of Ln(CCl_3COO)_3·(phen)_2·2H_2O

Coordination compounds of lanthanide trichloroacetates with 1,10-phenanthroline weresynthesized and characterized as Ln(CCl_3COO)_3·(phen)_2·2H_2O(phen=1,10-phenanthroline,Ln=Tb～Lu)by chemical analysis,IR spectra,thermal analysis and crystal X-ray structural analysis.The crystal ofEr(CCl_3COO)_3·(phen)_2·2H_2O belongs to monoclinic system,with space group P2_1/c,a=1.6969(6)nm,b=1.3776(5)nm,c=1.7563(9)nm,β=114.79(9)°,V=3.727(1)nm~3,Z=4.     

A Study on the Oxidation Behavior of Nb Alloy (Nb-1 pct Zr-0.1 pct C) and Silicide-Coated Nb Alloys

In the current work, silicide coatings were produced on the Nb alloy (Nb-1 pct Zr-0.1 pct C) using the halide activated pack cementation (HAPC) technique. Coating parameters (temperature and time) were optimized to produce a two-layer (Nb₅Si₃ and NbSi₂) coating on the Nb alloy. Subsequently, the oxidation behavior of the Nb alloy (Nb-1 pct Zr-0.1 pct C) and silicide-coated Nb alloy was studied using thermogravimetric analysis (TGA) and isothermal weight gain oxidation experiments. Phase identification and morphological examinations were carried out using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. TGA showed that the Nb alloy started undergoing accelerated oxidation at and above 773 K (500 °C). Isothermal weight gain experiments carried out on the Nb alloy under air environment at 873 K (600 °C) up to a time period of 16 hours exhibited a linear growth rate law of oxidation. In the case of silicide-based coatings, TGA showed that oxidation resistance of silicide coatings was retained up to 1473 K (1200 °C). Isothermal weight gain experiments on the silicide coatings carried out at 1273 K (1000 °C) in air showed that initially up to 8 hours, the weight of the sample increased, and beyond 8 hours the weight of the sample remained constant. The oxide phases formed on the bare samples and on the coated samples during oxidation were found to be Nb₂O₅ and a mixture of SiO₂ and Nb₂O₅ phases, respectively. SEM showed the formation of nonprotective oxide layer on the bare Nb alloy and a protective (adherent, nonporous) oxide layer on silicide-coated samples. The formation of protective SiO₂ layer on the silicide-coated samples greatly improved the oxidation resistance at higher temperatures.     

Phase Relationship of CaO-SiO2-FeO-5 mass pct P2O5 System with Low Oxygen Partial Pressure at 1673?K (1400?°C)

Dephosphorization by using multiphase flux could considerably decrease the consumption of CaO and prevent the addition of fluorite. However, the equilibrium phase relationship within this system, which is of significant importance for understanding the formation mechanism of multiphase flux, remains unclear. Thus, it is required to provide reliable phase diagrams of the basic slag system of multiphase flux. In this research, the phase relationship of the CaO-SiO₂-FeO-5 mass pct P₂O₅ system at 1673?K (1400?°C) with $ {P}_{{{\text{O}}_{2} }} $ of 9.24?×?10^?11 atm has been studied by using the chemical equilibration method. It has been found that solid solution consists mainly of 2CaO·SiO₂-3CaO·P₂O₅, but occasionally it contains 3CaO·SiO₂. Liquidus saturated with solid solution shrinks toward the FeO corner compared with the isothermal at 1673?K (1400?°C) of the CaO-SiO₂-FeO system equilibrated with metallic iron. Thermodynamically stable CaO-FeO phase is confirmed, which could promote the condensation of 3CaO·P₂O₅ into the solid solution and increase the phosphorus partition ratio between the solid solution and molten slag. Based on the regular solution model, the effect of T.Fe and CaO content in the liquid phase on the phosphorus partition ratio between the solid solution and molten slag is discussed.     

Photostimulated Luminescence and F-centers of Sr_3Ca_2(PO_4)_3X:Eu~(2+)(X=F,Cl,Br)

This paper reports the F-centers and photostimulated luminescence of Eu~(2+)-activated Sr_3Ca_2(PO_4)_3Xcrystals.The influence of various halide ions on the F-centers and their energy level is discussed.The mechanismfor the photostimulated luminescence and valence change of Eu ion in that process have been investigated.     

Microstructure and High Temperature Impression Creep Properties of Mg–3Ca–xZr (x = 0.3, 0.6, 0.9 wt%) Alloys

The current study has investigated the influence of zirconium (Zr) addition to Mg–3Ca–xZr (x = 0.3, 0.6, 0.9 wt%) alloys prepared using argon arc melting on the microstructure and impression properties at 448–498 K under constant stress of 380 MPa. Microstructural analysis of as-cast Mg–3Ca–xZr alloys showed grain refinement with Zr addition. The observed grain refinement was attributed to the growth restriction effect of Zr in hypoperitectic Mg–3Ca–0.3 wt% Zr alloys. Heterogeneous nucleation of α-Mg in properitectic Zr during solidification resulted in grain refinement of hyperperitectic Mg–3Ca–0.6 wt% Zr and Mg–3Ca–0.9 wt% Zr alloys. The hardness of Mg–3Ca–xZr alloys increased as the amount of Zr increased due to grain refinement and solid solution strengthening of α-Mg by Zr. Creep resistance of Mg–3Ca–xZr alloys increased with the addition of Zr due to solid solution strengthening of α-Mg by Zr. The calculated activation energy (Q_a) for Mg–3Ca samples (131.49 kJ/mol) was the highest among all alloy compositions. The Q_a values for 0.3, 0.6 and 0.9 wt% Zr containing Mg–3Ca alloys were 107.22, 118.18 and 115.24 kJ/mol, respectively.     

Effect of Cobalt on Phase Formation, Microstructure, and Mechanical Properties of Cu50?xCoxZr50 (x?=?2, 5, 10, 20?at.?pct) Alloys

In this work, the effect of cobalt on the phase formation and mechanical properties of rapidly solidified Cu_50?xCo_xZr₅₀ (x?=?2, 5, 10, and 20?at.?pct) alloys was investigated. CuZr martensite forms in the case of low Co contents (x?=?2 and 5?at.?pct), while in the alloys with 10 and 20?at.?pct Co, the B2 phase is stable even at room temperature. The deformation behavior of the rods under compressive loading depends strongly on the microstructure and, thus, on the alloy composition. Cobalt affects the fracture strength of the as-cast samples, and deformation is accompanied by two yield stresses for high Co-content alloys, which undergo deformation-induced martensitic transformation.     

Synthesis and Crystal Structure of RE[CH_2(CH_2)_4CONC_4H_9]_3(NO_3)_3(RE=Dy,La)

ＳｙｎｔｈｅｓｉｓａｎｄＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆＲＥ［ＣＨ２（ＣＨ２）４ＣＯＮＣ４Ｈ９］３（ＮＯ３）３（ＲＥ＝Ｄｙ，Ｌａ）ＷａｎｇＨａｎｚｈａｎｇ（王汉章），ＸｕＱｉｎｇｆｅｎｇ（徐庆锋），ＱｉａｎＰｕ（钱朴）ＳｕｎＪｉａｎｐｉｎｇ（孙建...     

Synthesis, Characterization and Crystal Structure of Neutral Homoleptic Lanthanide Amide Yb(NPh_2)_3(THF)

Ｌａｎｔｈａｎｉｄｅａｍｉｄｅｃｏｍｐｌｅｘｅｓａｒｅａｎｉｍ ｐｏｒｔａｎｔｃｌａｓｓｏｆｐｒｅｃｕｒｓｏｒｓｆｏｒｌａｎｔｈａｎｉｄｅｄｅｒｉｖａｔｉｖｅｓ .Ｉｔｃａｎｂｅｅａｓｉｌｙｔｒａｎｓｆｏｒｍｅｄｔｏｃｏｒ ｒｅｓｐｏｎｄｉｎｇｌａｎｔｈａｎｉｄｅｃｏｍｐｌｅｘｂｙｒｅａｃｔｉｎｇｗｉｔｈｉｎｖｏｌｖｉｎｇｐｒｏｔｉｃｒｅａｇｅｎｔｓ[1,2 ] .Ｔｈｅｌａｎｔｈａｎｉｄｅａｍｉｄｅｕｓｅｄａｓｓｙｎｔｈｅｔｉｃｐｒｅｃｕｒｓｏｒｉｓｎｅｕｔｒａｌｈｏｍｏｌｅｐｔｉｃｃｏｍｐｌｅｘ ,ｏｔｈ…     

Separation of Tb~(3 ) , Dy~(3 ) , Ho~(3 ) , Er~( 3 ) with Solvent Impregnated Resins Containing Di-(2,4,4-trimethylpentyl) Phosphinic Acid

Separation of Tb~(3 ) , Dy~(3 ) , Ho~(3 ) , Er~( 3 ) with Solvent Impregnated Resins Containing Di-(2,4,4-trimethylpentyl) Phosphinic Acid     

Synthesis and Structure of Polynuclear Complex [La(bphsb)2(NO3)3]n

Ｓｏｍｅｌａｎｔｈａｎｉｄｅｃｏｍｐｌｅｘｅｓｗｉｔｈｄｉｓｕｌｆｏｘｉｄｅｓｈａｖｅｂｅｅｎｓｔｕｄｉｅｄ［１，２］．Ｈｏｗｅｖｅｒ，ｒｅｌａｔｉｖｅｌｙｌｉｔｌｅｗｏｒｋｈａｓｂｅｅｎｄｏｎｅｏｎｃｒｙｓｔａｌｓｔｒｕｃｔｕｒｅｏｆｔｈｅｓｅｃｏ...     

Effect of Carbon on Microstructure and Mechanical Properties of Low C-1.6 pct Mn-0.1 pct Cr-0.3 pct Mo-0.0005 pct B Dual-Phase Steels

Effect of carbon on the microstructure and mechanical properties of 0.011 and 0.032 pct carbon dual-phase steels was investigated. r _m value was increased to 1.52 at around 400 MPa tensile strength level through the optimal design in the steel chemistry and proper control of phase transformation during continuous galvanizing cycle. The isolated martensite particles are expected to increase the strength but are expected not to be desirable for the deep drawability.     

Preparation and Long Persistence Red Luminescence of M_ (0.2)Ca_(0.8)TiO_3∶Pr ~(3 ) (M=Mg~(2 ), Sr~(2 ), Ba~(2 ), Zn ~(2 )

Inthe 1990s ,newaluminatelongafterglowphos phorswerereported ,theluminescenceintensityandtheafterglowpersistencearemuchhigherthanthatofthetraditionalsulfide .Moreover ,theydonotcontainradiativeelementandhasgoodstructuralstability .Therehasbeenincreasinginterestonthenewphos phorsovertheworld .Thewideanddeepresearchonthisnewmaterialhasbeenmadeinrecentyears[1～ 3] .Nowadays ,thegreenandbluephosphorescencephos phorscanbesuccessfullypreparedwhichlastsmorethan 30and 12hrespectively[4 ] .Ithasalread…     

Phase Transformation Studies in U–xZr (x = 2, 5, 10 wt%) Alloys Using Dynamic Calorimetry

The thermo-kinetics aspects of phase transformations in U rich U–xZr binary alloys, with x = 2, 5 and 10 wt% Zr have been investigated using dynamic calorimetry. The on-heating and cooling transformations at controlled scan rates in the range, 1–99 K min^?1, have been monitored and the following transformation sequence is obtained at slow heating (3 K min^?1) of a U–2Zr alloy: (i) α or α′ (distorted orthorhombic martensite) + δ(UZr₂) → α + γ₂ (bcc phase enriched in Zr); (ii) α + γ₂ → β (tetragonal) + γ₂; (iii) β + γ₂ → β + γ₁ (bcc phase enriched in U); (iv) β + γ₁ → γ; (v) γ (bcc) → liquid (melting). Similar transformation sequence for other compositions with varying enthalpy effects has been witnessed for 5 and 10 Zr alloys. The observed transformation characteristics are rationalized for the effect of Zr content and heating/cooling rate variations.     

Synthesis of CaO-SiO_2-B_2O_3∶Sm_2O_3 Glasses and Luminescent Properties of Sm~(3 )

Synthesis of CaO-SiO_2-B_2O_3∶Sm_2O_3 Glasses and Luminescent Properties of Sm~(3 )