Effect Of Heating Temperature Research Articles

In situ generated Li2S-LPS composite for all-solid-state lithium-sulfur battery

Li3PS4(LPS) was in situ formed at the active material Li2S through the reaction of Li2S and P2S5 by mechanical ball milling, which can be used to composite cathode for Li/S battery. The fine active materials-electrolyte interface will be generated via in situ reaction. Compared with the direct mixing Li2S + LPS, the interface impedance between Li2S and LPS of Li2S-LPS had a significant decrease from 833.3 Ω to 203.7 Ω at room temperature. The effect of heat treatment temperature on the ionic conductivities of Li2S-LPS has been studied, and the Li2S-LPS-300 showed the highest ionic conductivity of 2.67 × 10−4 S cm−1 at room temperature. The all-solid-state cell (Li/LPS/Li2S-LPS) possessed a larger capacity and better rate performance than that of the cell using Li2S + LPS as cathode material, showing a discharge capacity of 624.5 mAh g−1 (g of Li2S) for the 20th cycle. We also find that high carbon content of composite cathode will reduce the utilization of Li2S. The composite cathode 90Li2S-LPS + 10C (wt%) shows the highest capacity of 763.8 mAh g−1 at the current density of 0.1 mA cm−2.

Simple synthesis of ordered platinum-gold nanoparticles with the enhanced catalytic activity for oxygen reduction reaction

Pt-Au nanoparticles supported on carbon black (PtAu/CBx) are produced by a facile chemical reduction method and subsequent heat treatment. In this paper, the effects of heat treatment temperature on structure and electrochemical properties are investigated. A series of catalysts, including PtAu/CB, PtAu/CB400 and PtAu/CB600, with different particle size are synthesized. The particle size of PtAu/CB600 is slightly larger than that of PtAu/CB400 and PtAu/CB, but the electrochemical performance of PtAu/CB600 is the best due to more active sites available in PtAu/CB600. Moreover, the durability of PtAu/CB600 and commercial Pt/C is researched in acidic media. After 5000 cycles accelerated durability test, it can be seen from CV and LSV that PtAu/CB600 shows better stability. Therefore, the better activity and stability of PtAu/CB600 can be ascribed to the ordered structure and the synergistic effect of Pt and Au.

Effect of heat treatment temperature on melamine sponge reinforced silica aerogel

A novel structure-controllable melamine sponge reinforcement silica aerogel composite (MS/aerogel) was successfully synthesized via the sol-gel and ambient pressure drying processes. MS/aerogel was heat treated under various temperature conditions to further study the basic properties. The results showed that the heat treatment temperature did have a great effect as the microstructure and inherited group changed. It turned out that MS/aerogel was converted from hydrophobic into hydrophilic. Besides, the thermal properties improved as the lowest thermal coefficient (0.0251 W · m−1 · K−1) was obtained after the sample being heated under 300 °C. As to the compressive performance, it was improved to a high level, and the heat treatment temperature had altered compressive responses significantly. A model of the aerogel particle transformation process was proposed at last to describe the strengthening mechanism briefly. This work could provide some instructional suggestions for the sustainable application of the MS/aerogel composite.

Fabrication of diamond/Cu direct bonding interface for power device applications

Direct bonding of diamond and Cu was successfully conducted by the surface activated bonding method at room temperature. The structure of the diamond/Cu bonding interface was investigated by transmission electron microscopy and electron energy-loss spectroscopy. The effect of heat treatment temperature on the interface structure was also investigated. A 4-nm-thick damaged layer was formed at the as-bonded interface, and the damaged layer’s thickness decreased with an annealing temperature rise. It was found that the atomic ratio of sp2 bonding in the bonding interface was larger than that of the diamond separated from the interface by approximately 50 nm, which indicates that the damaged layer was composed of amorphous carbon or graphite and diamond. After annealing at 700 °C, a composite layer about 2 nm thick was observed at the interface. There were no nano-voids or micro-cracks observed at the interface with annealing at a temperature as high as 700 °C. These results indicate that the diamond/Cu bonding interface has high thermal stability and can withstand the temperature rise of power devices during operation.

Effect of Heat Treatment Temperature on the Spinning Structure and Properties of a Cu-Sn Alloy.

A thin-walled copper (Cu)-tin (Sn) alloy cylinder was treated after spinning at 200-400°C for 0.5 h. The characteristics of the alloy microstructure under different temperatures were analyzed through electron back-scattered diffraction. The results were as follows. The grain size at 200-300°C decreases as the heat treatment temperature rises, but the grain size at 400°C increases. At 200-300°C, the microstructure primarily consists of deformed grains. It is found that the main reason for the formation of high-angle grain boundaries (HAGBs) is static recrystallization. For the grain boundary orientation differential, the low-angle sub-grain boundary gradually grows into the HAGB, and multiple annealing twin Σ9 boundaries appear. Grain orientation is generally random at any temperature range. The mechanical property test indicated that, at the upper critical recrystallization temperature of 300°C, the elongation of the Cu-Sn alloy gradually increases, and its yield strength and ultimate tensile strength rapidly decrease.

Effects of heat treatment on microstructure and mechanical properties of explosive welded 10CrNi3MoV steel – 304L stainless steel

This study investigated the effect of heat treatment temperature on the microstructure and mechanical properties of 10CrNi3MoV steel – 304L stainless steel bimetallic plates by explosive welding. The results show the deformed grains near the interface were recovered and grew up with increasing heat treatment temperature. Recrystallization occurred at 720 °C, which results in over heat treatment. The effect of elements (Fe, Cr and Ni) diffusion and carbides incomplete wetting distribution at the interface is to strength the wavy metallurgical bonding. The value of interfacial shear strength is greater than 400 MPa. Tensile and impact tests showed that heat treatment can regulate the incompatibilities between strength and toughness for 10CrNi3MoV steel. The temperature between 630 °C and 660 °C was effective heat treatment temperature to obtain excellent comprehensive mechanical properties.

Corrosion and wear behavior of an electroless Ni-P/nano-SiC coating on AZ31 Mg alloy obtained through environmentally-friendly conversion coating

In this paper, an environmentally-friendly pretreatment has been used for electroless NiP on AZ31 magnesium alloy. Saturated aqueous NaHCO3 solution was used to form carbonate compounds on the surface of the substrate prior to Ni-P/nano-SiC electroless plating. Various amounts of nano-SiC particles were used to enhance the hardness, corrosion and wear resistance of the coatings. The coatings were characterized by using scanning electron microscopy (SEM) equipped with energy dispersion spectroscopy (EDS), and via X-ray diffraction (XRD). Polarization tests were carried out for investigating the corrosion resistance of the coatings. Pin on disk tests were used to study wear behavior of the coatings. The effect of heat treatment temperatures on the coatings structure, hardness and corrosion behavior were studied. However, the hardness of the substrate decreased due to the growth of Mg grains at high temperatures. Moreover, heat treated NiP coatings at 300 °C exhibited better corrosion resistance compared to other heat treatment temperatures. As a result, the temperature of 300 °C was chosen as the optimum temperature. Results also indicated that 1 g L−1 nano-SiC in plating bath provided a uniform composite NiP electroless coating with high hardness (795 HV) and corrosion resistance. Adding more nano-particles to the bath resulted in agglomeration of the particles and did not have positive effect on properties. The wear behavior of coatings were investigated using steel pin (AISI 52100) as the counterpart in pin-on-disk wear test. The optimum as-plated composite coating (Ni-P/1SiC) produced the best wear resistance at a rate of 4.2 × 10−5 mm3 N−1 m−1 wear rate and the highest corrosion resistance belonged to Ni-P/1SiC after annealing at 300 °C.

Preparation and Characterization of Glass Ceramics Containing SrTiO3

The glass ceramics containing SrTiO3 crystals were successfully synthesized by high temperature melting crystallization. The optimum technological formula was determined by orthogonal experiment. The heat treatment system of the glass samples were determined by differential scanning calorimeter analysis (DSC). The effects of heat treatment temperature and time on crystal formation and grain size were discussed in detail. The ideal heat treatment condition is at 950°C for 3h. The microstructure and phase structure of glass ceramics were analyzed by scanning electron microscope and X-ray diffraction respectively, which indicate that SrTiO3 crystal were precipitated uniformly in the glass matrix.

Preparation, characterization and growth mechanism of ZrO2 nanosheets

High quality single-crystal zirconia nanosheets were successfully prepared via molten salt method, using solvothermally synthesized product as precursor. The effects of heat treatment temperature and soaking time on the phase composition and morphology of samples were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, Thermal analyzer, Raman spectrometer, Field-emission scanning electron microscope and Transmission electron microscope. The results show that zirconia nanosheets with a thickness of 60–80 nm and a width-thickness ratio up to 13 could be obtained by using NaCl and Na3PO4 as composite salts at 900 °C for 5 h. The precursors containing Zr–OH and Zr–O bonds have relatively high activity, which is beneficial to crystal growth. In addition, the as-prepared nanosheets with exposed (001) plane are monoclinic-structured and show no distinct defect. The growth behavior of particles during dissolution-recrystallization process is analogous to self-focusing mechanism. The preparation method can be extended to wet-chemical synthesis of other nanomaterials.

The effect of heat treatment temperature and Mg doping on structural and photocatalytic activity of ZnO thin films fabricated by RF magnetron co-sputtering technique

In this study, it is aimed to increase the photocatalytic activity of ZnO thin films, which have promising effect on degradation of textile dyes as photocatalysts, under the UV light by doping Mg element via magnetron co-sputtering method, and to investigate the effect of heat treatment temperature on structural and photocatalytic activity. For this purpose, 300 nm ZnO and MgZnO thin films were fabricated by RF magnetron co-sputtering method on Si (100) substrate at room temperature and heat-treated at 300 °C, 400 °C, 500 °C, and 600 °C. Microstructural, surface morphology, roughness and crystal properties of prepared thin films were characterized by Grazing Incident X-ray diffractometer (GIXRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) measurement was performed to determine chemical states on the surface. XRD patterns with (002) and (103) planes indicate that ZnO and MgZnO thin films have a hexagonal wurtzite-type structure. Also, E2High mode is the main Raman mode in the wurtzite crystal structure and confirms hexagonal wurtzite phase with good crystallinity in thin films. Photocatalytic activity of thin films was measured by UV–Vis spectroscopy with degradation of methylene blue (MB) solution under UV light irradiation. Results showed that, maximum photocatalytic efficiency was observed in heat-treated ZnO and MgZnO films at 400 °C with the kinetic rate constants 3.7 × 10−2 s−1 and 16.9 × 10−2 s−1, respectively. Also, for all samples the degradation of the MB at low concentrations are good agreement with the first-order velocity law.

Synthesis and textural evolution of mesoporous Si3N4 aerogel with high specific surface area and excellent thermal insulation property via the urea assisted sol-gel technique

Si3N4 aerogel, which is one of the most promising materials for application as high-temperature thermal insulation, is synthesized by the urea-assisted sol-gel technique, followed by the supercritical drying, carbonization, carbothermal reduction and carbon combustion processes. The effects of heat treatment temperatures on the physicochemical and textural evolution of mesoporous Si3N4 aerogel are investigated. Si3N4 aerogel is formed when the heat treatment temperature increases to 1500 °C, whereas it transforms into SiC phase with a further higher temperature of 1600 °C. The SEM analysis confirms the existence of Si3N4 nanoparticles, and the particle size of Si3N4 nanoparticles is around 20–40 nm, with pore size around 20–40 nm. The XPS measurement reveals that Si3N4 aerogel is composed of 74.4% Si3N4 phase, with lower content of 25.6% SiO2. Si3N4 aerogel possesses a large BET specific surface area of 519.6 m2/g, which results from the mesoporous pores left after carbon combustion. This value is much larger than that of the conventional Si3N4 porous ceramics and Si3N4 nano materials ever reported. The BJH adsorption average pore diameter of Si3N4 aerogel is around 11.8 nm, with a large pore volume of 3.5 cm3/g. Si3N4 oxidation with forming amorphous SiO2 layer on the surface is observed by the TG measurement. Moreover, the resulting Si3N4 aerogel shows low bulk density of 0.075 g/cm3, as well as low thermal conductivity of 0.045 W/(m·K) at room temperature. The mechanism of Si3N4 formation is based on the VS growth between C, SiO2 and N2. The structures evolution and formation mechanism of Si3N4 aerogel are also investigated in this study.

Effects of heat treatment temperatures on phase transformation, thermodynamical parameters, crystal microstructure, and electrical resistivity of NiTiV shape memory alloy

Changing physical property of NiTi shape memory alloy by adding new element and heat treatment technique has become interesting in the last decades. In this study, equiatomic NiTi alloy was doped by 1 and 5 atomic percentages of vanadium element. For each case, heat treatment was accomplished for 873, 973, 1073, and 1173 K, and its effect on phase transformation temperatures was analyzed by differential scanning calorimetry. Crystal structure and chemical compound found in XRD pattern showed the different situation for each case, e.g., TiO2 appeared in heat-treated samples, whereby the intensity of peaks varied by changing the temperature of heat treatment. In NiTi–5V alloy, each enthalpy, entropy, Gibbs free energy, and elastic energy were decreased by increasing heat treatment temperature, while grain size of the alloy extended with respect to non-heat-treated sample. Electrical resistivity of the alloys was measured as a function of temperature, which was increased by increasing vanadium composition and heat treatment temperature.

Effect of heat treatment temperature on energy storage performance of PAN co‐MMA based carbon nanofibers as freestanding lithium ion batteries anode

AbstractPolyacrylonitrile co methyl methacrylate (PAN co‐MMA) based nanofibers were synthesized by electrospinning technique and were converted into carbon nanofibers (CNFs) by heating at 1000°C (PAN‐1000), 1800°C (PAN‐1800), and 2200°C (PAN‐2200). Various characterizations such as SEM, TEM, Raman, FT‐IR have been carried out to study the effect of heat temperature on the microstructure of carbon fibers. The carbon nanofiber diameter varies in the range 600‐120 nm for different heat temperatures. Further, these CNFs were evaluated as freestanding anode in Li‐ion batteries. The PAN‐1000 and PAN‐1800 CNFs show stable capacity up to 150 cycles and specific capacity of 254 and 238 mAh g−1 at high discharge rate of 1C; however PAN‐2200 despite of better microstructure and surface area (~60m2/g) shows low specific capacity of 105 mAh g−1mAh/g, that is probably due to distribution of pore structures present in fibers as well as low electrolyte wetting through the carbon fibers electrode observed in post‐cycling SEM analysis. In addition, at higher discharge rate of 3C, PAN‐1000 shows stable cyclability and high capacity of 198 mAh g−1 over 450 cycles and 238 mAh g−1at 1C rate over 500 cycles. The microstructure and pore structure all affect the energy storage performance of PAN‐co MMA based CNFs.

Self-Toughening and Self-Enhancement Poly(arylene ether nitrile) with Low Dielectric Constant by Solid Crosslinking Reaction.

A novel poly(arylene ether nitrile) terminated with hydroxyl groups (PEN–OH) was synthesized successfully. The effects of heat-treatment temperature on the thermal properties, mechanical properties, and dielectric properties of the PEN–OH films were studied in detail. Due to the cross-linking reaction occurring, at high temperature, among the nitrile groups on the side of the PEN–OH main chain to form a structurally stable triazine ring, the structure of materials changes from a linear structure to a bulk structure. Thus, the thermal properties and mechanical properties were improved. In addition, the occurrence of cross-linking reactions can reduce the polar groups in the material, leading to the decrease of dielectric constant. As the heat-treatment temperature increased, the glass-transition temperature increased from 180.6 °C to 203.6 °C, and the dielectric constant decreased from 3.4 to 2.8 at 1 MHz. Proper temperature heat-treatment could improve the tensile strength, as well as the elongation, at the break of the PEN–OH films. Moreover, because of the excellent adhesive property of PEN–OH to copper foil, a double-layer flexible copper clad laminate (FCCL) without any adhesives based on PEN–OH was prepared by a simple hot-press method, which possessed high peel strength with 1.01 N/mm. Therefore, the PEN–OH has potential applications in the electronic field.

Effect of Heat Treatment Temperature on Martensitic Transformation and Superelasticity of the Ti49Ni51 Shape Memory Alloy

The martensitic transformation and superelasticity of Ti49Ni51 shape memory alloy heat-treatment at different temperatures were investigated. The experimental results show that the microstructures of as-cast and heat-treated (723 K) Ni-rich Ti49Ni51 samples prepared by rapidly-solidified technology are composed of B2 TiNi phase, and Ti3Ni4 and Ti2Ni phases; the microstructures of heat-treated Ti49Ni51 samples at 773 and 823 K are composed of B2 TiNi phase, and of B2 TiNi and Ti2Ni phases, respectively. The martensitic transformation of as-cast Ti49Ni51 alloy is three-stage, A→R→M1 and R→M2 transformation during cooling, and two-stage, M→R→A transformation during heating. The transformations of the heat-treated Ti49Ni51 samples at 723 and 823 K are the A↔R↔M/A↔M transformation during cooling/heating, respectively. For the heat-treated alloy at 773 K, the transformations are the A→R/M→R→A during cooling/heating, respectively. For the heat-treated alloy at 773 K, only a small thermal hysteresis is suitable for sensor devices. The stable σmax values of 723 and 773 K heat-treated samples with a large Wd value exhibit high safety in application. The 773 and 823 K heat-treated samples have large stable strain–energy densities, and are a good superelastic alloy. The experimental data obtained provide a valuable reference for the industrial application of rapidly-solidified casting and heat-treated Ti49Ni51 alloy.

Effect of heat treatment temperature to the crystal growth and optical performance of Mn3O4 doped α-Zn2SiO4 based glass-ceramics

In this work, manganese (II, III) oxide, (Mn3O4) doped zinc soda lime silica glasses have been synthesized using a conventional melt-quenching process and followed by control heat treatment process. The crystal phase composition and optical properties of α-Zn2SiO4:Mn3O4 based glass-ceramics are comprehensively studied. The physical properties and crystal growth of α-Zn2SiO4 phase were measured by density analysis, linear shrinkage, X-ray diffraction (XRD) and Fourier transform infrared reflection (FTIR) spectroscopy. From the measurement, the average density and linear shrinkage of α-Zn2SiO4:Mn3O4 based glass-ceramics increased with increasing heat treatment temperature. Besides, the presence of Zn–O–Si bands indicates the formation of α-Zn2SiO4 crystal phase and causing the decrement of energy band gap. The photoluminescence spectra of Mn2+ ions exhibit emission transitions of 4T1(G)–6A1(S) and show a prominent green emission colors of α-Zn2SiO4 phase at 524 nm.

Effect of heat treatment temperature on microstructure and electromagnetic shielding properties of graphene/SiBCN composites

Three-dimensional (3D) graphene/SiBCN composites (GF/SiBCN) were prepared by depositing SiBCN ceramics in 3D graphene foam via the chemical vapor infiltration technique. The effect of the heat treatment temperature on the microstructure, phase composition, and electromagnetic properties of the GF/SiBCN composite was investigated. The SiBCN ceramics maintained an amorphous structure in the composite below 1400 °C above which the crystallinity of the free carbon phase gradually increased. While the Si3N4 and B4C phases started to crystallize at 1500 °C and their crystallinity increased with temperature, SiC was observed at 1700 °C. The electromagnetic shielding effectiveness of GF/SiBCN increased with the heat treatment temperature.

Polymorphism and Phase Transitions in t-ZrO2/CoFe2O4 Composite Structures: Impact of Composition and Heat Treatments

A series of Zr4+, Y3+, Fe3+, and Co2+ combinations in solution form and their subsequent potential to yield the desired ZrO2/CoFe2O4 composite that possesses better structural stability at 1300 °C have been presented. The results emphasized the combined effect of heat treatment temperatures and concentration variations in Fe3+/Co2+ to retain tetragonal ZrO2 (t-ZrO2) and CoFe2O4 structures. The incidence of a gradual m- → t-ZrO2 transition alongside the enhanced phase yield of CoFe2O4 is determined. Despite the invariable presence of 8 mol % of Y2O3 in all the investigated systems, the results revealed the inability to establish t-ZrO2 stabilization at 900 and 1100 °C. XPS analysis confirms the oxidation states of iron, yttrium, cobalt, and zirconium in their respective 3+, 3+, 2+, and 4+ in the ZrO2/CoFe2O4 composite. Morphological analysis revealed the presence of distinct grains pertinent to ZrO2 and CoFe2O4 alongside pore free microstructures. The resultant microstructures demonstrated better hardness and Young’s modulus values, and moreover, the gradual increment in the phase content of CoFe2O4 in the composite revealed a corresponding surge in the ferrimagnetic features.

Formation of C-doped SiO2 coatings on carbon fibers by the sol-dipping process

The carbon-doped silicon dioxide (C-doped SiO2) coatings are prepared on the surface of carbon fibers by a facile sol-dipping method using tetraethoxysilane (TEOS) and diethoxydimethylsilane (DMDES) as precursors. The effect of heat treatment temperature and dipping times on the formation of the C-doped SiO2 coatings is studied. The structure and morphology of C-doped SiO2 coatings are analyzed by the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The oxidation resistance of the carbon fibers with and without coatings is investigated by thermogravimetric analysis (TG) and static isothermal oxidation experiments. The results show that the C-doped SiO2 products obtained by pyrolysis of the gel at 900 ℃ displays high crystallinity and low carbon content. The continuous and uniform coatings with the thickness about 200 nm are formed after three times dipping, which improves the initial oxidation temperature of carbon fibers about 110 ℃.

Effect of Heat Treatment Temperature and Lubricating Conditions on the Fretting Wear Behavior of SAF 2507 Super Duplex Stainless Steel

Super duplex stainless steel (SDSS) has excellent mechanical properties and corrosion resistance. However, currently, there are few researches conducted on its fretting wear performance. This paper studies the influence of different heat treatment temperatures and medium environment on the fretting wear performance of SAF 2507 SDSS. Results show that the combined effect of the sigma phase and seawater lubrication can significantly improve the wear resistance of SAF 2507 SDSS. After treated with different heat treatment temperatures, different contents of sigma phases are precipitated out of SAF 2507 SDSS, which improves the wear resistance of the material to different degrees. In addition, the fretting wear performance of SAF 2507 SDSS also relates to the lubrication medium. In air, the friction and wear performance of SAF 2507 SDSS is poor, while in seawater, solution and corrosion products that acted as a lubricant dramatically improve the wear resistance of the material. Under the combined action of heat treatment and seawater lubrication medium, the friction coefficient and wear reduce by 70% and 91%, respectively.