Controlled Heating Rate Research Articles

Investigation of thermal behaviour and synergistic effect in co-pyrolysis of municipal solid waste and sewage sludge through thermogravimetric analysis

Municipal solid waste (MSW) and sewage sludge (SS) co-pyrolysis have the potential to revolutionize waste management and address energy challenges. Consequently, it is crucial to explore the thermal and synergistic effect of MSW, SS and their blends using thermogravimetric analysis. Different blending ratios (MSW90%SS10 %, MSW80%SS20 % and MSW65%SS35 %) were analyzed under an inert nitrogen (N2) gas atmosphere, at various heating rates (10,20 and 30 K min−1), from 30 °C to 900 °C. This paper specifically addressed the effect of heating rate and blending ratio on separate and jointed pyrolysis of the two raw materials. The analysis revealed two significant decomposition stages observed in the individual pyrolytic processes and their blends. Results showed that a higher heating rate slowed down the decomposition rate due to less effective heat transfer. The blending ratio of 35 % SS at 20 K min−1 exhibited a positive synergistic effect while an antagonistic effect was observed in another mixing ratio. Activation energy determined using the Coats-Redfern model in the second stage of active pyrolysis for MSW90%SS10 %, MSW80%SS20 % and MSW65%SS35 % was 41.879, 43.365 and 40.271 kJ mol−1 respectively. The negative ΔS (entropy) and positive ΔH (enthalpy) values indicated a decrease in disorder and an endothermic reaction respectively. This finding was consistent with the formation of complex products from the feedstock and the endothermic nature of the pyrolysis process. Therefore, strategic co-pyrolysis optimization of MSW and SS with the precise blending ratio of 35 % sewage sludge and controlled heating rate of 20 K min−1, exhibits substantial potential for advancing eco-friendly waste management practices while enabling effective energy recuperation.

Microstructure and Recrystallization Behavior of Heating Rate-Controlled Electrolytic Capacitor Aluminum Foil under Cold Forming and Annealing.

A novel annealing process of controlled heating rate is used to produce severe cold-formed aluminum plates, which are processed into aluminum foil and mainly used for high-voltage electrolytic capacitor anodes. The experiment in this study focused on various aspects such as microstructure, recrystallization behavior, grain size, and grain boundary characteristics. The results revealed a comprehensive influence of cold-rolled reduction rate, annealing temperature, and heating rate on recrystallization behavior and grain boundary characteristics during the annealing process. The heating rate applied plays a crucial role in controlling the recrystallization process and the subsequent grain growth, which ultimately determines whether or not the grains will become larger. In addition, as the annealing temperature rises, the recrystallized fraction increases and the grains size decreases; conversely, the recrystallized fraction decreases as the heating rate increases. When the annealing temperature remains constant, the recrystallization fraction increases with a greater deformation degree. Once complete recrystallization occurs, the grain will undergo secondary growth and may even subsequently become coarser. If the deformation degree and annealing temperature remain constant, the increased heating rate will result in a lower recrystallization fraction. This is due to the inhibition of recrystallization, and most of the aluminum sheet even remains in a deformed state before recrystallization. This kind of microstructure evolution, grain characteristic revelation, and recrystallization behavior regulation can provide effective help for enterprise engineers and technicians to guide the production of capacitor aluminum foil to a certain extent, so as to improve the quality of aluminum foil and increase the electric storage performance.

Study of structural and electrical properties of Li0.35+x/2Zn0.1Mn0.1TixFe2.35−3x/2O4 ferrite synthesized by solid-state ceramic technique

The structural and electrical properties of lithium ferrite substituted by different metal ions Zn+2, Ti+4, and Mn+4 simultaneously have been reported. The samples having a representative chemical formula of Li0.35+x/2 Zn0.1Mn0.1TixFe2.35−3x/2O4 where x = 0.0, 0.15, 0.30, 0.45, 0.60, 0.75 were prepared by solid-state ceramic technique. The samples were calcined at 900 °C and sintered at 950 °C for one hour at a controlled heating rate of 10 °C/min. The study of the samples by XRD revealed the single-phase cubic spinel structure. The structural data of the compound like density, lattice constant, and crystallite size was also calculated. The microstructure of the samples was determined by the SEM and the elemental compositions of the various samples were also determined by EDAX. The frequency variation of the dielectric constant, dielectric loss, and impedance have been analyzed using an Impedance Analyzer (E4990A) at room temperature. The results obtained have been analyzed and discussed.

A 3D oxalate‐bridged [CuIIFeII] coordination polymer as molecular precursor for CuFe2O4 spinel—photocatalytic features

AbstractA 3D heterometallic oxalate‐bridged coordination polymer [CuIIFeII2(H2O)(terpy)(C2O4)3]n (terpy = 2,2′:6′,2″‐terpyridine) (1) was investigated both as photocatalyst for the organic dye removal and as a single‐source precursor for the preparation of the copper ferrite (CuFe2O4) nanocrystals by thermal processing. The dual functionality of 1 was supported by the degradation of aqueous solutions of rhodamine B (RhB) and methylene blue (MB) solutions under visible (Vis) and ultraviolet (UV) light irradiation, powder X‐ray diffraction data collection at room temperature, and the optical and scanning electron microscopy analyses. A close inspection of the X‐ray diffraction patterns unveiled qualitative and quantitative information on the phase composition obtained after the single‐source molecular precursor route to spinel oxide. By optimizing the temperature levels and setting the controlled heating rate at 6 h of holding time, the phase composition of thermal processing of 1 was evaluated—thermal treatment of 1 at 950°C for 6 h and a heating/cooling rate of 10°C min−1 resulted in the formation of solely tetragonal spinel phase of CuFe2O4, whereas the formation of both tetragonal and cubic CuFe2O4 phases was observed at 950°C by the heating rate of 30°C min−1. To obtain the high‐temperature cubic CuFe2O4 oxide, compound 1 was heated and then quenched at 925°C, which led to the formation of the cubic spinel ferrite as the main crystalline oxide phase. Moreover, the photocatalytic properties of the t‐CuFe2O4 spinel were investigated under the same conditions as for 1. The optical bandgap energies were estimated from UV–Vis absorption spectra for both metal oxide and precursor powder.

Self-template synthesis of Co3O4 nanotube for efficient Hg0 removal from flue gas

The adsorption of elemental mercury (Hg0) is a widely used technology to remove Hg0 from flue gas. The morphology and structure of sorbents, which have serious impacts on the number and availability of adsorption sites and the mass transfer of Hg0, play an important role in Hg0 removal process. Nanotube materials have through-pore structures leading to lower mass transfer resistance and more adsorption sites for Hg0. Given this, organic–inorganic hybrid nanowires were prepared by hydrothermal method as self-template. After calcination with a controlling heating rate and temperature, a series mesoporous Co3O4 nanotube sorbents were obtained. Characterization results show that the heating rate mainly affects the pore structure of the sorbents, while the calcination temperature mainly affects the surface morphology. When the calcination temperature is 400 °C and the calcination rate is 0.5 °C /min, the sorbent (Co3O4-T400-R0.5) has a clear 1D tubular structure which can effectively reduce the mass transfer resistance. And the unique internal surface of the tubular structure can provide more active sites, which can effectively avoid the competitive adsorption of Hg0 and other gas components. Furthermore, Co3O4-T400-R0.5 has the highest Co3+/Co2+ ratio leading to a better redox property, which is of benefit to Hg0 removal process. Therefore, the Hg0 removal efficiency of Co3O4-T400-R0.5 can reach more than 90% with a high gas hourly space velocity of 90,000 h− 1 and 0.02 g loading amount at 250 °C. Furthermore, Co3O4-T400-R0.5 has excellent Hg0 removal efficiencies in different flue gas condition showing a high stability.

Structural, spectroscopic and optical analysis of heterocyclic ligands (N, O) based Mg(II) complexes for advance photonic applications

In present communication, light emissive magnesium (II) metal chelates with heterocyclic moiety containing N, O donor atoms have been synthesized by conventional reflux method. Structural, spectroscopic and optical analysis of prepared materials i.e., (pyridine-1-oxide)(8-quinolinato)magnesium(II) [Mg(PNO)(q)] and (2-hydroxypyridine-1-oxide)(8-quinolato)magnesium(II) [Mg(PHNO)(q)] have also been scrutinized through various spectral techniques. Thermal studies of synthesized materials were explored via execution of thermogravimetric (TG) and differential thermal (DT) analysis using thermal analyser at controlled heating rate. Electroanalytic measurements were demonstrated through cyclic voltammetry (CV) using three-electrode system. Optical band gap (Eg) was deduced from absorption spectra of metal complexes using Tauc's method. Photoluminescence (PL) studies were conceded out in both solid and solution phase. Effect of temperature on emission profile of metal complexes was also illustrated. Three-dimensional (3D) molecular structures were geometrically optimized by means of B3LYP scheme comprising 6–31G* (d, p) cartesian-gaussian polarization with aid of theoretical computation (DFT). Moreover, emission profile was exploited to obtain required CIE constrain (CCT and color coordinates) which robustly recommendatory for their use in advance photonic applications and fabrication of light emitting devices.

Effect of Residual Deformation Energy and Critical Heating Rate on Cubic Texture and Grain Growth Behavior of Severely Deformed Aluminum Foil.

To clarify the microstructure, grain size, and recrystallization behavior during different annealing processes with controlled heating rates, the aim of this study was to investigate the effect of residual deformation energy after cold rolling and critical heating rate on cubic texture components, and grain growth behavior of aluminum plate, which was subjected to severe deformation. The experimental results revealed that the stored energy can be inferred from a calculation that fast annealing (FA) for 30 s was 2.2 times as large as slow annealing (SA) at 320 °C, which provided the driving force for grain growth during subsequent heating and resulted in a significant coarsening of grains in the FA process. In contrast, the intensity of cubic texture in SA was significantly higher than that in the FA process. A critical heating rate of 50 °C/min had been obtained to produce a homogeneous microstructure and strong cubic texture during the annealing processes with controlled heating rates and was verified by experiment. The relationship of Δηsur > 0.02ηb was as a criterion used to determine whether abnormal grain growth happened in aluminum foil, while the grain size exceeded the thickness of aluminum foil by examined calculation.

Formation of texture quality of raspberry snack under microwave puffing.

Raspberry snack, as a novel berry product, has rich favor and high crisp taste, where controllable texture quality is conducive to the palatability of the snack. Determinative factors of microwave puffing in microwave intensity and duration and key property of material in Young's modulus were introduced to investigate the formation of texture quality of berry snack under microwave puffing. The results indicate that the microwave intensity has negative correlation with Young's modulus of raspberry chips, which causes the more porosity inside under microwave puffing. Reasonable Young's modulus of raspberry chips enhances the interior porosity and exterior expansion volume of raspberry snack due to the water vapor wrapped other than escaped. The greater microwave intensity results in the higher volume expansion of raspberry chips, in which the great volume expansion from porous pores structure confers moderate hardness. In microwave puffing, the formation of hardness and crispness of raspberry snack depend on microwave puffing parameters, leading to high temperature and great dehydration rate in quick puffing duration, in addition to Young's modulus of raspberry chips, where high dehydration rate accelerates water removal inside raspberry chips to form a harder texture with decreasing springiness, whereas low dehydration rate leads to the gentle change of springiness. Raspberry snack with uniform internal pores and regular shape forming desirable texture may be achieved under the microwave intensity of 7.5 W/g and the puffing duration of 6 min. This study indicates that high-quality raspberry snack may be achieved via controlling heating rate in microwave puffing.

Temperature simulation of three-point bending geometry in a dynamic mechanical analyzer

Dynamic mechanical analysis (DMA) is a thermo-analytical technique that is widely used as a part of polymer characterization. One of the most common tests consists of measuring viscoelastic properties as a function of temperature while subjecting the sample to controlled heating rates. In that tests, due to sample and instrument geometry and sample size, it is not possible to measure the temperature in all parts of the sample. As a result, the gradient of temperatures between different parts of the sample is unknown. Thus, an accurate estimation of the sample temperature in all its parts and of the temperature gradients between different parts are crucial for setting up experimental conditions and establishing confidence temperature ranges to better interpret the test results. In the present work, a simulation study is performed through the Comsol ™ software, to estimate the temperature distribution of samples of different density and heat capacity that are located inside a typical DMA furnace, which is subjected to different heating rates. The furnace has two gas inlets and three outlets and the sample is attached through standard 3-point bending fixtures. The results show that some of the temperature gradients produced in the sample high enough to significantly affect the viscoelastic response.

Synthesis of Tri-S-Triazine Based g-C3N4 Photocatalyst for Cationic Rhodamine B Degradation under Visible Light

In this research, graphitic carbon nitride (g-C3N4) photocatalysts were synthesized through a simple calcination process at various temperatures, which were 400, 500, 550, and 600 °C, by using low-cost urea as a precursor. The obtained g-C3N4 samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) surface area and porosity analyses, and ultraviolet–visible-near-infrared (UV–VIS-NIR) spectroscopy. The correlations between the calcination temperature, properties, and photocatalytic activity of prepared products were investigated. The results demonstrated that the g-C3N4 photocatalysts can be successfully synthesized at temperatures of 500–600 °C with a controlled heating rate of 5 °C/min. In contrast, the intermediate product was observed in sample calcined at 400 °C. It was demonstrated that calcination at higher temperatures possibly increased the active sites and enhanced both of the photocatalytic activity and dye adsorption ability. Herein, the dye degradation efficiency (DE%) under visible light irradiation within 10 min were presented as 2.52, 16.01, 62.37, and 92.64% which were well developed as a function of calcination temperature from 400 °C, 500 °C, 550 °C, to 600 °C, respectively. Furthermore, the dye degradation rate could possibly induce decomposition pathway of rhodamine B. The photocatalytic efficiency was maintained after four times of reuse. It can be concluded that the thermal process plays an important role in controlling the properties and photocatalytic performance of g-C3N4.

Effect of aluminum additives on the ignition of tungsten–teflon mixtures

Thermodynamic analysis and studies of combustion and structure formation of products were carried out in the powder mixtures of tungsten and polytetrafluoroethylene (Teflon, Tf) with aluminum additives. The mixture components were selected to fabricate high-density condensed products with high ignition temperature. Aluminum was used as an energetic additive accelerating the ignition process and increasing the mixture combustion temperature. In mixtures, a tungsten/Tf ratio was fixed; the aluminum content was varied according to the formula (1 − x)(0.8W + 0.2Tf) + xAl = const. Mechanically activated mixtures were pressed into the samples and heated in special crucible with controlled heating rate. It was shown that an increase in the heating rate changes insignificantly the ignition temperature of systems, but strongly affects the structure of combustion products. The ignition and combustion of compositions with low aluminum content results a large volume of gaseous products, which fly apart or form a high-porous structure. At high Al concentration, the results of experiments and thermodynamic calculations are sufficiently different that can be explained by the lack of thermodynamic data on tungsten aluminides in the used program and by the fact that real conditions of reaction are far from equilibrium and adiabatic ones. The calculated and experimental data showed that the optimal aluminum content to form melted products with a high density (ρ(W2C) = 17.2 g/cm3) is about 10 wt %. At high Al concentration, the main combustion product (tungsten aluminide WAl4) has the lower density (ρ(WAl4) = 6.6 g/cm3) that is insufficiently for practical application.

Effect of aluminum additives on the ignition of tungsten–Teflon mixtures

Thermodynamic analysis and studies of combustion and structure formation of products were carried out in the powder mixtures of tungsten and polytetrafluoroethylene (Teflon, Tf) with aluminum additives. The mixture components were selected to fabricate high-density condensed products with high ignition temperature. Aluminum was used as an energetic additive accelerating the ignition process and increasing the mixture combustion temperature. In the mixtures, a tungsten/Tf ratio was fixed; the aluminum content was varied according to the following formula: (1– x)(0.8W + 0.2Tf) + xAl = const. Mechanically activated mixtures were pressed into the samples and heated in a special crucible with the controlled heating rate. It was shown that an increase in the heating rate changes insignificantly the ignition temperature of systems, but strongly affects the structure of combustion products. The ignition and combustion of the compositions with low aluminum content results in a large volume of gaseous products, which fly apart or form a high-porous structure. At high Al concentration, the results of the experiments and thermodynamic calculations are sufficiently different, which can be explained by the lack of thermodynamic data on tungsten aluminides in the used program and by the fact that real conditions of the reaction are far from equilibrium and adiabatic ones. The calculated and experimental data has shown that the optimal aluminum content to form the melted products with a high density (ρ(W2C) = 17.2 g/cm3) is about 10 wt %. At high Al concentration, the main combustion product (tungsten aluminide WAl4) has the lower density (ρ(WAl4) = 6.6 g/cm3), which is insufficient for a practical application.

Annealing induced modifications in physicochemical and optoelectronic properties of CdS/CuInGaSe2 thin film

The present article deals with engineering of physicochemical and optoelectronic properties of soft chemical route synthesized CdS/CuInGaSe2 heterojunction thin films upon air annealing at controlled heating rate of 3 °C/min for 100, 200 and 300 °C with the intension to optimize the post deposition treatment parameter for improvising interface between two layers, so as to obtain controlled stoichiometry (composition) and surface structure modifications. These as deposited and annealed heterojunction thin films were characterized for structural, compositional, morphological, optical and electrical characteristics. The structural pattern obtained from X-ray diffraction pattern (XRD) represents rising of new peaks of (2 1 2), (1 0 5) plane, while widening and shifting of peak position (2 0 5) can be observed on annealing at 300 °C, these planer orientation along with (1 1 2), (2 1 1), (2 1 2), (1 0 5) corresponds to chalcopyrite phase of tetragonal CuInGaSe2 materials whereas peak at 21.40° and 30.39° represents CdS and ITO substrate material respectively, the average crystallite size found to be increased from 19 nm to 48 nm on annealing treatment. Elemental composition of as deposited heterojunction thin film confirmed by studying energy dispersive X-ray absorption spectrum (EDAX) which shows presence of peaks corresponding to Cu, Cd, Ga, In, Se and S confirming expected elemental composition. Selected area electron diffraction (SAED) pattern obtained from as deposited thin film shows presence of (1 1 2) and (2 1 1) peaks while nanostructured phase confirmed by transmission electron microscopy (TEM) image. Atomic force microscopy (AFM) images of as deposited and annealed samples when compared, represents grain growth in 300 °C annealed sample, this growth may be due to external energy induced grain agglomeration by polygonization process. Optical absorbance spectra shows blue shift in optical absorbance coefficient while extrapolating for energy band gap (Eg) exhibits red shift from 1.48 eV to 1.21 eV upon annealing. The electrical properties when studied on exposing these as deposited and annealed thin films to 100 mW/cm2 light source shows an enhancement in conversion efficiency from 1.05 to 2.96% respectively.

Three-Dimensional Framework of Graphene Nanomeshes Shell/Co3O4 Synthesized as Superior Bifunctional Electrocatalyst for Zinc-Air Batteries.

The synthesis of durable and low-cost electrocatalyst is crucial but challenging. Here, we developed a one-pot pyrolysis approach toward the preparation of heteroatom-doped hierarchical porous three-dimensional (3D) graphene frameworks decorated with multilayer graphene shell-coated cobalt oxide nanocrystal. Large literal sheet size of graphene nanomeshes may stimulate rapid thermolysis with cobalt-oleate complex to form Co3O4 nanocrystals and in situ growth of multilayer graphene coating co-doped by boron and nitrogen with controlling heating rate up to 600 °C. This new material worked as superior bifunctional electrocatalyst on oxygen reduction reaction and oxygen evolution reaction to commercial Pt/C with better onset potential/half-wave potentials, larger current density, better stability, and stronger methanol tolerance. The heteroatom co-doping into porous/curved graphene confined nanocrystals in 3D porous walls provided adequate accessibility of created catalytic active sites and ideal mass transport route for the excellent catalytic activity on redox reaction of oxygen. The synthesized material-based Zn-air battery further confirmed its superior electrolytic activity with high specific capacity and smaller overpotential. This one-pot pyrolysis method shows a great potential of scalable synthesis of high-performance practical electrocatalyst for metal-air batteries and fuel cells at a low cost.

Effect of Charcoal and Kraft-Lignin Addition on Coke Compression Strength and Reactivity

The aim of this research was to investigate the effects of charcoal and Kraft-lignin additions on the structure, cold compression strength, and reactivity of bio-cokes produced at the laboratory scale. Bio-cokes were prepared by adding charcoal and Kraft-lignin (2.5, 5.0, 7.5, and 10.0 wt %) to medium-volatile coal and coking the mixture with controlled heating rate (3.5 °C/min) up to 1200 °C. In addition, four particle sizes of charcoal were added with a 5 wt % addition rate to investigate the effect of particle size on the compression strength and reactivity. Thermogravimetric analysis was used to evaluate the pyrolysis behavior of coal and biomasses. Optical microscopy was used to investigate the interaction of coal and biomass components. It was found that by controlling the amount of charcoal and Kraft-lignin in the coal blend, the compression strength of the bio-cokes remains at an acceptable level compared to the reference coke without biomass addition. The cold compression strength of the charcoal bio-cokes was higher compared to Kraft-lignin bio-cokes. The reactivity of the bio-cokes with charcoal addition was markedly higher compared to reference coke and Kraft-lignin bio-cokes, mainly due to the differences in the physical properties of the parental biomass. By increasing the bulk density of the coal/biomass charge, the cold compression strength of the bio-cokes can be improved substantially.

Steady-state and controlled heating rate methanation of CO2 on Ni/MgO in a bench-scale fixed bed tubular reactor

Chemical hydrogen storage via conversion with carbon dioxide into methane is a promising technology in an energy system that relies on renewable energy resources. Robust heterogeneous catalysts are needed for this reaction to proceed at relevant levels. Ni/MgO is a promising catalyst in terms of activity and stability. Although several microscale catalyst studies exist, there is a lack of knowledge on catalyst performance and reactor control at larger scale for carbon dioxide methanation at ambient pressure and a technically relevant stoichiometric H2:CO2 (4:1) feed. Two catalysts with a loading of 11 and 17wt.% nickel were prepared by wet impregnation, producing a Ni/MgO solid solution with a cubic lattice. Controlled increase (‘scanning experiment’) of the catalyst temperature to 500°C for the highly exothermic CO2 methanation was compared to steady-state experiments. Scanning and steady-state experiments yield comparable results in terms of carbon dioxide conversion and methane selectivity, whereas scanning experiments lead to considerable time saving. At a moderate temperature of 325°C and a feed flow consisting of H2:CO2:N2=4:1:5 at a flow rate of 250cm3STPmin−1, CO2 conversion and CH4 selectivity near thermodynamic equilibrium are achievable. The long-term stability of Ni/MgO (17wt.% Ni) at 330°C was proven during reactor operation for several days.

Thermally activated martensite formation in ferrous alloys

Magnetometry was applied to investigate the formation of α/α´ martensite in 13 ferrous alloys during immersion in boiling nitrogen and during re-heating to room temperature at controlled heating rates in the range 0.0083–0.83Ks−1. Data shows that in 3 of the alloys, those that form {5 5 7}γ martensite, no martensite develops during cooling. For all investigated alloys, irrespective of the type of martensite forming, thermally activated martensite develops during heating. The activation energy for thermally activated martensite formation is in the range 8–27kJmol−1 and increases with the fraction of interstitial solutes in the alloy.

Probing the Interior Crystal Quality in the Development of More Efficient and Smaller Upconversion Nanoparticles.

Optical biomedical imaging using luminescent nanoparticles as contrast agents prefers small size, as they can be used at high dosages and efficiently cleared from body. Reducing nanoparticle size is critical for the stability and specificity for the fluorescence nanoparticles probes for in vitro diagnostics and subcellular imaging. The development of smaller and brighter upconversion nanoparticles (UCNPs) is accordingly a goal for complex imaging in bioenvironments. At present, however, small UCNPs are reported to exhibit less emission intensity due to increased surface deactivation and decreased number of dopants. Here we show that smaller and more efficient UCNPs can be made by improving the interior crystal quality via controlling heating rate during synthesis. We further developed a unique quantitative method for optical characterizations on the single UCNPs with varied sizes and the corresponding shell passivated UCNPs, confirming that the internal crystal quality dominates the relative emission efficiency of the UCNPs.

Microstructural evolution and thixoformability of semi-solid aluminum 319s alloy during re-melting

The aim of this paper is to characterize both microstructural evolution and thixoformability during partial melting of semi-solid 319s alloy. The thixoformability criteria of 319s was initially investigated by thermodynamic analysis. In-situ observation of partial re-melting was performed by a Confocal Laser Scanning Microscope to determine the effect of heating rate on melting characteristics. Meanwhile, the microstructural evolution of 319s alloy at extremely low heating rate was also investigated in order to understand the mechanism of re-melting process. The studies demonstrated that 319s alloy is suitable for thixocasting because of the controllable liquid fraction in the operating window of 15 °C. The process window was effected by both temperature and heating time. The primary particles evolution in 319s alloy can be divided into four stages, and the coarsening rate during isothermal test is 227 μm3/s. The effective method to obtain desirable microstructure is to manage the time in the semi-solid state by controlling heating rate and soaking time.

Synthesis and properties of new infrared nonlinear optical Li2Ga2GeS6 crystal

IR Li 2 Ga 2 GeS 6 nonlinear crystals were directly obtained with the composition of 40GeS 2 - 30Ga 2 S 3 -30Li 2 S, by the conventional melt-quenching method. The high depth digital image indicated that the obtained Li 2 Ga 2 GeS 6 crystals showed a big size of 0.3 × 0.25 × 0.3 mm 3 . It was shown that the compound was very susceptive to H 2 O with second harmonic observation. Besides, the glass-forming region of GeS 2 -Ga 2 S 3 - Li 2 S system was further studied by the conventional melt-quenching method.GeS 2 -Ga 2 S 3 -Li 2 S glass-ceramics containing IR Li 2 Ga 2 GeS 6 nonlinear nanocrystals were obtained at a more carefully controlled heating rate.