Effect of sintering temperature and holding time on structure and properties of Li_(1.5)Ga_(0.5)Ti_(1.5)(PO_4)_(3)electrolyte with fast ionic conductivity

Li_(1.5)Ga_(0.5)Ti_(1.5)PO_(4))_(3)(LGTP)is recognized as a promising solid electrolyte material for lithium ions.In this work,LGTP solid electrolyte materials were prepared under different process conditions to explore the effects of sintering temperature and holding time on relative density,phase composition,microstructure,bulk conductivity,and total conductivity.In the impedance test under frequency of 1-10^(6) Hz,the bulk conductivity of the samples increased with increasing sintering temperature,and the total conductivity first increased and then decreased.SEM results showed that the average grain size in the ceramics was controlled by the sintering temperature,which increased from(0.54±0.01)μm to(1.21±0.01)μm when the temperature changed from 750 to 950°C.The relative density of the ceramics increased and then decreased with increasing temperature as the porosity increased.The holding time had little effect on the grain size growth or sample density,but an extended holding time resulted in crack generation that served to reduce the conductivity of the solid electrolyte.

Effect of Sintering Temperature on the Microstructure and Mechanical Properties of Nanocrystalline Cemented Carbide

WC-Co nanocrystalline nitrogen-containing cemented carbides were prepared by vacuum sintering and low pressure sintering.The sintering processes of Cr_(2)(C,N)doped nano WC-Co powders were studied by using thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC).The effect of sintering temperature on the microstructure and mechanical properties of nanocrystalline cemented carbide was studied by scanning electron microscope(SEM),high resolution transmission electron microscope(HRTEM)and mechanical property test.The results showed that the nano WC grains began to grow in the solid phase sintering stage.A high-performance nano-nitrogen-containing cemented carbide with uniform microstructure and good interfacial bonding can be obtained by increasing the sintering temperature to 1380℃.It has a transverse rupture strength(TRS)of 5057 MPa and a hardness of 1956 HV30.

Effect of sintering temperature on the microstructure and properties of foamed glass-ceramics prepared from high-titanium blast furnace slag and waste glass

Foamed glass-ceramics were prepared via a single-step sintering method using high-titanium blast furnace slag and waste glass as the main raw materials The influence of sintering temperature(900–1060℃) on the microstructure and properties of foamed glass-ceramics was studied. The results show that the crystal shape changed from grainy to rod-shaped and finally turned to multiple shapes as the sintering temperature was increased from 900 to 1060℃. With increasing sintering temperature, the average pore size of the foamed glass-ceramics increased and subsequently decreased. By contrast, the compressive strength and the bulk density decreased and subsequently increased. An excessively high temperature, however, induced the coalescence of pores and decreased the compressive strength. The optimal properties, including the highest compressive strength(16.64 MPa) among the investigated samples and a relatively low bulk density(0.83 g/cm^3), were attained in the case of the foamed glass-ceramics sintered at 1000℃.

Effect of sintering temperature on microstructure and properties of glass-ceramics synthesized from waste cathode ray tubes funnel glass

Waste cathode ray tube(CRT)funnel glass(FG)is an important part in the disposal of electrical and electronic waste(e-waste).A novel approach for efficient lead extraction and glass-ceramics synthesized from waste FG through collaboratively smelting FG with coal fly ash(CFA)is proposed.Glass-ceramics materials with 40 wt%-80 wt%FG additions were produced under sintering temperatures of 900-1000℃.The microstructure and phase composition of the produced glass-ceramics were studied using X-ray diffraction(XRD)and scanning electron microscopy(SEM).The density,water absorption,Vicker hardness,chemical resistance and heavy metal leaching characteristics of the glassceramics were measured.The experimental results indicate that the samples can be crystallized at sintering temperatures of 900-1000℃.An elevated sintering temperature is favorable for enhancing the degree of crystallization,while the crystallization process is inhibited at excessively high temperatures.Increasing FG addition can lead to the transformation of the main crystalline phase from diopside to gehlenite.Well-crystallized crystals were generated in the specimens with 50 wt%-70 wt%FG additions.The samples with 40 wt%,50 wt%,60 wt%,70 wt%,80 wt%FG addition exhibit the optimal chemical and physical properties at 975,925,950,925 and 900℃,respectively.Overall results demonstrate that this study provides a feasible strategy for reliably detoxifying and reusing waste FG and CFA.

Mineral-phase evolution and sintering behavior of MO–SiO_2–Al_2O_3–B_2O_3 (M = Ca,Ba) glass-ceramics by low-temperature liquid-phase sintering

In this work, network former SiO_2 and network intermediate Al_2O_3 were introduced into typical low-melting binary compositions CaO·B_2O_3, CaO·2B_2O_3, and BaO·B_2O_3 via an aqueous solid-state suspension milling route. Accordingly, multiple-phase aluminosilicate glass-ceramics were directly obtained via liquid-phase sintering at temperatures below 950°C. On the basis of liquid-phase sintering theory, mineral-phase evolutions and glass-phase formations were systematically investigated in a wide MO–SiO_2–Al_2O_3–B_2O_3(M = Ca, Ba) composition range. The results indicate that major mineral phases of the aluminosilicate glass-ceramics are Al_(20)B_4O_(36), CaAl_2Si_2O_8, and BaAl_2Si_2O_8 and that the glass-ceramic materials are characterized by dense microstructures and excellent dielectric properties.

Effects of Sintering Temperature on Crystallization Behavior and Performance of Glass-Ceramics From Coal Fly Ash

The glass-ceramics was prepared from coal fly ash, limestone and Na2CO3 by sintering processes. Effects of the crystallization temperature (850–1100 ℃) on crystallization behavior, microstructure, sintering character and chemical stability of the glass-ceramics samples were analyzed by means of DTA, XRD, SEM and other analytical methods. The results show that the main crystalline phase of as-prepared glass-ceramics after crystallization treatment is gehlenite (Ca2Al2SiO7). The species of crystalline phases keep the same, however, the main crystalline intensity, line shrinkage rate and bulk density increase first then decrease with the increasing of heat treatment temperature. Water absorption of the samples was reduced as the heat treatment temperature rising. The glass-ceramics display high performance crystallization properties and chemical stability. The optimized glass-ceramics with desired sintering character and chemical stability was obtained by crystallized at 1050 ℃.

Effect of sintering temperature on microstructure and properties of 3D printing polysilazane reinforced Al_(2)O_(3)core

Ceramic cores are the key intermediate components of hollow blades for aero-engine.Conventional processes,such as hot-press molding and gel film casting,face difficulties in fabricating complex-structured ceramic cores due to the complexity of moulds and long process cycles.Stereolithography 3D printing provides a new idea for the fabrication of complex-structured ceramic cores.The effect of sintering temperature on open porosity,bulk density,weight loss rate,shrinkage rate,flexural strength and microstructure of the Al_(2)O_(3)-based ceramic core doped with 10vol.%polysilazane(PSZ)was studied.The sintering mechanism of PSZ-reinforced ceramic cores was analyzed.Results show that the optimum sintering temperature of PSZ-reinforced ceramic cores is 1,450°C.At this temperature,the open porosity of the ceramic core is 36.60%,bulk density is 2.33 g·cm^(-3),weight loss rate is 22.11%,shrinkage rate along the X,Y,Z directions is 5.72%,5.01%,9.61%,respectively;the flexural strength is 28.794 MPa at 25°C and 13.649 MPa at 1,500°C.Properties of 3D printing PSZ-reinforced ceramic cores can meet the casting requirement of superalloy hollow blades,which is expected to promote the industrial application of 3D printing complex structure ceramic cores.

Low temperature solid-phase sintering of sintered metal fibrous media with high specific surface area

A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area（0.2 m2/g） can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C.

NUMERICAL SIMULATIONS OF TEMPERATURE FIELD IN DIRECT METAL LASER SINTERING PROCESS

A mathematical model is developed for simulating the heat transferring behavior in a direct metal laser sintering process. The model considers the thermal phenomena involved in the process, including conduction, radiation, and convection. A formula for the calculation of the heat conductivity of a sintering system containing solid phase, liquid phase, and gas phase is given. Due to the continuous movement of the laser beam, a local coordinate system centered on the laser beam is used to simplify the analytical calculation. Assuming that it is approximately a Gaussian laser beam, the heat conduction equation is resolved based on the assumption of the thermal insulating boundary conditions and the fixed thermal physical parameters. The FORTRAN language is employed to compile the program to simulate the temperature field in the direct copper powder sintering process. It shows a good agreement with the preliminary experimental results.[KH3/4D]

Effect of sintering temperature on cycling performance and rate performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2

LiNi0.8Co0.1Mn0.1O2 powder was prepared by mixing LiOH·H2O and co-precipitated Ni0.8Co0.1Mn0.1（OH）2 at a molar ratio of 1：1.05, followed by sintering at different temperatures. The effects of temperature on the morphology, structure and electrochemical performance were extensively studied. SEM and XRD results demonstrate that the sintering temperature has large influence on the morphology and structure and suitable temperature is very important to obtain spherical materials and suppresses the ionic distribution. The charge-discharge tests show that the electrochemical performance of LiNi0.8Co0.1Mn0.1O2 powders becomes better with the increase of temperature from 700 ℃ to 750 ℃ and higher temperature will deteriorate the performance. Although both of materials obtained at 750 ℃ and 780 ℃ demonstrate almost identical cyclic stability at 2C rate, which delivers 71.9%retention after 200 cycles, the rate performance of powder calcined at 780 ℃ is much poorer than that at 750 ℃. The XRD results demonstrate that the poor performance is ascribed to more severe ionic distribution caused by higher temperature.

High-temperature performance prediction of iron ore fines and the ore-blending programming problem in sintering

The high-temperature performance of iron ore fmes is an important factor in optimizing ore blending in sintering. However, the application of linear regression analysis and the linear combination method in most other studies always leads to a large deviation from the desired results. In this study, the fuzzy membership functions of the assimilation ability temperature and the liquid fluidity were proposed based on the fuzzy mathematics theory to construct a model for predicting the high-temperature performance of mixed iron ore. Comparisons of the prediction model and experimental results were presented. The results illustrate that the prediction model is more accurate and effective than previously developed models. In addition, fuzzy constraints for the high-temperature performance of iron ore in this research make the results of ore blending more comparable. A solution for the quantitative calculation as well as the programming of fuzzy constraints is also introduced.

Effect of sintering temperature on the physical properties and electrical contact properties of doped AgSnO_2 contact materials

AgSnO_ 2 electrical contact materials doped with Bi_2O_3,La_2O_3,and TiO_2 were successfully fabricated by the powder metallurgy method under different initial sintering temperatures.The electrical conductivity,density,hardness,and contact resistance of the Ag Sn O_2/Bi_2O_3,AgSnO_2/La_2O_3,and AgSnO_2/Ti O_2 contact materials were measured and analyzed.The arc-eroded surface morphologies of the doped AgSnO_2 contact materials were investigated by scanning electron microscopy(SEM).The effects of the initial sintering temperature on the physical properties and electrical contact properties of the doped AgSnO_2 contact materials were discussed.The results indicate that the physical properties can be improved and the contact resistance of the AgSnO_2 contact materials can be substantially reduced when the materials are sintered under their optimal initial sintering temperatures.

Effect of Temperature on Phase and Alumina Extraction Efficiency of the Product from Sintering Coal Fly Ash with Ammonium Sulfate

A new developed technology for extracting alumina from coal fly ash was studied in this paper. In this technology, coal fly ash is first sintered with ammonium sulfate, forming ammonium aluminum sulfate in the resultant product, where alumina can be easily leached without using any strong acid or alkali. The products obtained under different sintering conditions were characterized by X-ray diffractometry. Alumina extraction efficiency of these products was also investigated. The results show that the sintering temperature and time substantially influence the phase composition and alumina extraction efficiency of sintered products, while the heating rate has little influence. The optimal sintering condition is 400 °C for 3 h in air with a heating rate of 6 °C·min-1.Under the optimal sintering condition, the alumina extraction efficiency from as-sintered coal fly ash can reach 85% or more.

Low-field magnetoresistance of (1-x)La_(0.6)Dy_(0.1)Sr_(0.3)MnO_3/0.5x (Sb_2O_3) composite system under different sintering temperatures of matrix

A series of (1-x)La0.6Dy0.1Sr0.3MnO3/0.5x(Sb2O3)(x=0.15) samples were prepared by the solid-state reaction method, and the influence of sintering temperature of the matrix on low-field magnetoresistance of (1-x)La0.6Dy0.1Sr0.3MnO3/0.5x (Sb2O3) was studied through the measurements of X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) image, resistivity-temperature (ρ-T) curves, and magnetoresistance-temperature (MR-T) curves. The results indicate that for the samples with low sintering temperature of the matrix, lowfield magnetoresistance effect appears on the whole temperature range and can be explained by grain boundary effect; for the sample with high sintering temperature of the matrix, intrinsic magnetoresistance peak appears on the high-temperature range, low-field magnetore-sistance effect appears on low temperature range, and the magnetoresistance in the magnetic field of 0.2 T and on the comparatively large temperature range between 280 K and 225 K hardly changes with temperature and remains at 4.8%, which can be explained by the competition between the intrinsic magnetoresistance induced by double-exchange function inside grains and the tunneling magnetoresis-tance (TMR) induced by grain boundary effect. The temperature stability of magnetoresistance is beneficial to the practical applications of MR.

Studies on the Influence of Sintering Temperature on Crystalline Structures of Mg-Al Spinel Synthesized by Waste Aluminum Slag

Mg-Al spinel is synthesized by using industrial waste-residue and basic magnesium carbonate in the aluminum factory as the main raw materials. The influence of sintering temperature on crystalline structure and microstructure of Mg-Al spinel has been mainly discussed. The crystalline structure of sample is characterized by using XRD, SEM and relevant analytical software. The experimental results show that compared to the conventional synthetic method, the application of waste aluminum slag as the raw material can greatly decrease the synthetic tem-perature. The content of Mg-Al spinel first increases and then decreases with the rise of sintering temperature, and its purity can reach as high as 96wt% at 1550 ℃, which is therefore determined to be the optimum synthetic temperature. SEM observations demonstrate that as the rise of sintering temperature, the grain of Mg-Al spinel grows up obviously with typical octahedral characteristic appearance.

Optimization model coupling both chemical compositions and high-temperature characteristics of sintering materials for sintering burden

We developed a mathematical optimization model coupling chemical compositions and high-temperature characteristics of sintering materials, targeting the best quality and lowest cost. The simplex algorithm was adopted to solve this model. Four kinds of imported iron ores, two kinds of Chinese iron ore concentrates, and two kinds of fluxes were selected to verify both the model and the algorithm. The results confirmed the possibility of considering both chemical compositions and high-temperature characteristics of iron ores in the optimization model. This model provides a technical roadmap to obtain a precise mathematical correlation between the lowest cost and the grade of iron in sinters based on the condition of given raw materials, which can provide a reference to adjust the grade of iron in the sintering process for enterprise.

Effects of Rare Earth and Hot Pressing Sintering Temperature on the Transverse Rupture Strength of Fe-based Diamond Composites

Effects of sintering temperature in hot pressing, t yp es, states and amounts of rare earth as well as TiH 2 on the transverse rupture strength (TRS) of Fe-based composites are studied by means of orthogonal test and variance analysis in this paper. It is found that sintering temperature has a significant effect on the TRS of Fe-based diamond composites. The optimal sin tering temperature is 780～860 ℃. On the contrary, the effects of RE additi v es on values of TRS of the diamond composites have on distinct difference no mat ter the RE is in the state of mixture or compound or oxidization. Experimental r esults demonstrate that Fe-based diamond composites with RE additives exhibit h igher TRS, which results in an increase in diamond retention capacity. The degre e of increment of TRS is different at different sintering temperatures. The opti mal amount of rare earth was found to be about 1% in weight. The effect of RE is more significant at lower sintering temperature. The experimental results also reveal that TiH 2 additive has a negative effect on the TRS of Fe-based compos ites. Microscope observations demonstrate that specimen without TiH 2 additives , shows fewer pores and denser structures in the base metal. It can also be seen from the SEM observation of the resulting fracturing surface of bending test sp ecimens that the bonding of the diamond-matrix interface is better in the speci men without TiH 2 than in the specimen with TiH 2. Also the fracture surface o f the specimen without TiH 2 reveals ductile cup and cone behavior.

Influence of Composition on Properties of Medium Temperature Sintering (Ba,Sr)TiO_3 Series Capacitor Ceramics

The influence of the composition （Yb2O3, MgO, CeO2, Li2CO3） on the dielectric properties of medium temperature sintering （Ba, Sr）TiO3 （BST） series capacitor ceramics was investigated by means of conventional technology process and orthogonal design experiments. The major secondary influencing factors and the influencing tendency of various factor＇s levels for the dielectric properties of BST ceramics were obtained. The optimum formula for maximum dielectric constant （ε） and for minimum dielectric loss （tanδ） was obtained under the experimental conditions. The BST ceramics with optimum comprehensive properties was obtained by means of orthogonal design experiments, with the sintering temperature at 1200 ℃, the dielectric constant 5239, the dielectric loss 0.0097, withstand electric voltage over 6 MV·m^-1, capacitance temperature changing ence of various components on the providing the basis for preparation rate （△C/C） - 75.67%, and suited for Y5V character. The mechanism of the infludielectric properties of medium temperature sintering BST ceramics was studied, thus of multilayer capacitor ceramics and single-chip capacitor ceramics.

EFFECTS OF In_2O_3 DOPING AND SINTERING TEMPERATURE ON THE ELECTRICAL PROPERTIES OF ZnO VARISTORS

ZnO varistors are prepared using the 0.1-0.3mm ZnO powders. The effects of the sintering temperature, contents of In2O3 doping on the non-linear properties of ZnO varistors have been investigated. Theresults show that this kind of ZnO powder has a high sintering activity. It is suitable for making the low voltage varistors. The Vc decreases with the increase of sintered temperature, when the In2O3 content is fixed(0. 98 %, mass fraction), and increases with the increase of In2O3 contents when the temperature is steady.

Influence of sintering temperature on the thermoelectric properties of Ba_8Ga_(16)Si_(30) clathrate treated by spark plasma sintering

A series of Ba8Ga16Si30 clathrate samples were prepared by arc melting, ball milling, acid washing, and spark plasma sintering （SPS）. X-ray diffraction analysis revealed that the lattice of the Ba8Ga16Si30 samples expanded as the SPS temperature was increased from 400 to 750℃. Lattice contraction recurred when the SPS temperature was further increased in the range of 750-1000℃. This phenomenon can be explained by the variation of Ga content in the lattice. The thermoelectric figure of the merit ZT value of clathrates increased with the increase in SPS temperature and reached a maximum when the sample was subjected to SPS at 800℃. A further increase in SPS temperature did not contribute to the improvement of ZT. The variation of the lattice parameter a vs. SPS temperature T was similar to the variation ob-served in the ZT-T curve.