Effect Of Heating Temperature Research Articles

Effect of heat treatment on the interfacial bonding between SiC coating and alumina plate

ABSTRACTIn this paper, the SiC coating was deposited on an alumina substrate by a radio frequency magnetron sputtering method using a-SiC (99.999%) target. The produced SiC–Al2O3 structure was heat treated in air through a range of temperatures. The effects of heat treatment temperature and duration on the surface roughness, interfacial bonding and surface hardness were investigated using experimental means such as optical surface profilometer, scanning electron microscope, energy dispersive X-ray analysis and hardness analyser. The results indicated that the sputtered SiC coating is an effective approach to alter the surface properties of alumina, through significantly increasing the surface roughness and hardness. Furthermore, the heat treatment did not result in decomposition of the surface coating. Appropriate heat treatment was found to improve the interfacial bonding between the sputtering material and substrate via enhanced species diffusion.

The effects of heat treatment temperature on performance and structure of phosphorus slag-coal gangue glass-ceramics

The effects of heat treatment temperature on performance and structure of phosphorus slag-coal gangue glass-ceramics

Physical and Mechanical Properties of Thermally Cracked Andesite Under Pressure

The effects of thermal crack damage on the physical properties and rupture processes of andesite were investigated under triaxial deformation at room temperature. Thermal cracking was induced by slowly heating and cooling samples. The effects of heat treatment temperatures ranging between 500 °C and 1100 °C on the P-wave velocities and on the microstructure were investigated. Then, the mechanical properties of andesite samples treated at 930 °C were investigated under triaxial stress at room temperature using constant strain rate tests and confining pressures ranging between 0 and 30 MPa. Similar triaxial experiments were conducted on non-heat-treated samples. Our results show that: (1) for heat treatments at temperatures below 500 °C, no significant changes in the physical properties are observed; (2) for heat treatments in the temperature range of 500–1100 °C, crack density increases; and (3) thermal cracking has no influence on the onset of dilatancy but increases the strength of the heat-treated samples. This last result is counterintuitive, but seems to be linked with the presence of a small fraction of clay (3%) in the non-heat-treated andesite. Indeed, for heat treatment above 500 °C, some clay melting is observed and contributes to sealing the longest cracks.

Hierarchical carbon nanowires network modified PDCs-SiCN with improved microwave absorption performance

Abstract In order to optimize the dielectric performance of polymer derived SiCN ceramics (PDCs-SiCN), carbon nanowires (CNW) were deposited in SiCN by catalytic chemical vapor deposition (CCVD). Microstructure evolutions, dielectric property and electromagnetic (EM) wave absorption capacity of CNW/SiCN were investigated. Results show that carbon nanowires had plentiful pits/defects on their roughened surface and formed hierarchical network in SiCN which benefited the impedance match and generated strong conductivity and polarization loss, enhancing the absorption ability of CNW/SiCN. When CNW accounted for 5.61 wt%, RCmin reached −51 dB with EAB of 3.0 GHz at 2.7 mm in thick, showing excellent microwave absorbing performance. The favorable microwave absorption ability could be ascribed to three aspects including enhanced conductivity loss derived from the excellent conductivity of CNW, polarization loss generated by defects, and multiple reflection loss enhanced by hierarchical network. By comparing the variation tendency between defect concentration and electrical conductivity in CNW/SiCN, it is rational to conclude that the conductivity loss dominated the dielectric loss while the polarization loss and repeated multi-reflection simultaneously worked. This work can be further extended to study regarding the effect of heat-treatment temperature since CNW have the potential to promote the crystallization process of amorphous PDCs thereby improving their dielectric properties.

Effect of Heat Treatment on the Combustion Characteristics of a Lignite

In this study, the ignition and combustion behavior of raw and heat-treated single particles of lignite were experimentally investigated, with a focus on the effect of heat treatment temperatures. The lignite particles were heat treated to various final temperatures (473, 623 and 773 K) in nitrogen and characterized using proximate, ultimate, and Fourier transform infrared spectroscopy (FTIR) analysis. A single lignite particle of 2 or 3 mm in diameter was suspended on a silicon carbide fiber and burned in air in a horizontal tube furnace operating at 1123 K. The ignition and combustion process of the particle was record using a color CCD camera at 25 fps. The ignition mechanism, ignition delay time, volatile flame duration, and burnout time of the single particles were examined by processing the recorded images. The proximate and ultimate analysis results indicated that the volatile matter and oxygen contents decreased, while the carbon content increased with increasing temperature of heat treatment. This trend was consistent with observations in the FTIR analysis, in which the intensity of oxygen-containing functional groups decreased with increasing the heat treatment temperature. The ignition of raw and heat treated lignite particles followed a joint hetero-homogeneous mechanism under all conditions studied. The ignition delay time, volatile flame extinction time, and the total combustion time decreased with increasing heat treatment temperature up to 623 K. A further increase in the heat treatment temperature to 773 K resulted in prolonged key ignition and combustion characteristic times.

Effects of heat treatment temperature and atmosphere on the morphology and structure of calcium phosphate

Calcium phosphate can exist as several phases including hydroxyapatite (HA) and β-tricalcium phosphate (βTCP). Both HA and βTCP are chemically similar to calcified tissue, resulting in high incompatibility. In this study, we investigated the effects of heat treatment temperature (800 °C and 900 °C) and atmosphere (ambient air and argon) on the morphology, crystalline structure, and functional groups of calcium phosphate powder. Calcium phosphate without heat treatment was evaluated for comparison. The powders were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy. Under both atmospheric conditions, the effect of heat treatment at 800 °C led to the formation of both HA and βTCP, which was caused by the reduction of CO/- bond in calcium phosphate. In contrast, the heat treatment of calcium phosphate at 900 °C generated C−H and C=O groups, resulting in βTCP alone.

Effects of heat treatment temperature on the superconducting properties of Ba1−xKxFe2As2 tapes

In this study, the effects of heat treatment temperature on superconducting properties were systematically studied by sintering silver-sheathed Ba1−xKxFe2As2 tapes at different temperatures. The transport Jc increases as the sintering temperature rises from 700 °C to 850 °C. The optimized Jc values of tapes sintered at 900 °C and 850 °C reach 6.2 × 104 A cm−2 (4.2 K and 10 T) which represent a very high Jc level for flat rolled mono-core silver-sheathed iron-based superconducting wires and tapes. The properties of tapes sintered at different temperatures were investigated, including grain crystallinity, core density, c-axis texture and elemental distribution. The results demonstrate that 850 °C is a suitable temperature to fabricate silver-sheathed Ba1−xKxFe2As2 superconducting tapes.

The effect of heat treatment temperature on phase formation and luminescence properties of calcium magnesium silicate glass-ceramics doped with Sm2O3

The transparent glasses of CaO-MgO-Al2O3-SiO2-ZnO system doped with Sm2O3 was prepared by conventional melt-quenching method. The obtained glasses were heat treated at a suitable temperature (875 °C–920 °C for 2 h) identified by differential thermal analysis (DTA). Phase formation and microstructure of glass-ceramics were characterized by X-ray diffraction and scanning electron microscopy, respectively. The optical transmission spectra were recorded by UV-Vis spectrophotometer in the wavelength range between 350 and 1000 nm. It was found that the increase in heat treatment temperature reduced the transparency of the glass-ceramics. The luminescence properties were identified by fluorescence spectroscopy. The excitation spectra of Sm2O3 doped CaO-MgO-Al2O3-SiO2-ZnO glass-ceramic samples are in wavelength range of 550–750 nm and the emission spectra exhibited a strong orange-red luminescence composed of 562, 599 and 654 nm under excited at 402 nm. The results of XRD studies revealed the occurrence of diopside (CaMgSi2O6) and akermanite (Ca2MgSi2O7) phases. The increasing of heat treatment temperature has no effect on the shift of emission spectra.

Effect of heat treatment temperature on microstructure and luminescence properties of alkaline earth aluminosilicate glass- ceramic doped with Eu3+

Abstract Alkaline earth aluminosilicate single phase glass ceramics doped with rare earth (Eu3+) were successfully prepared, from the BaO-MgO-Al2O3-SiO3 glass system, by high temperature melt-quenching following by a heat treatment process to explore red phosphor materials for potential application in solid state lighting devices. It is experimentally verified that the BaAl2Si2O8 crystallites formed as a single crystalline phase after glass crystallization at temperature exceed 950°C. Participation of Eu3+ suppressed nucleation and growth rate of the BaAl2Si2O8 crystallites. Random distributions of approximately spherical shape crystallites are clearly seen in both glass ceramics with and without Eu3+ addition. PL spectra obtained from the glass ceramics with different treatment temperatures are not significantly different. Five distinguished emission peaks, located at 576, 589, 612, 649 and 701 nm, associating to transition emission between electronics states of the Eu3+ are identified. This provides strong red emission glass ceramic with the probable application as a red phosphor material.

A micro-structural corrosion mechanism on the thermal degradation of BaMgAl10O17: Eu2+ phosphor

The thermal degradation is a vital issue that restricting luminous efficiency and service life of BaMgAl10O17: Eu2+phosphor for chromogenic and illuminating fields. The effects of heat-treatment temperature on the luminescence properties and micro-structure of BAM were researched to accurately elucidate the thermal degradation mechanism. Some pieces of evidence for micro-structural corrosion were detected according to the results of PL, TL, XPS and IR. With the heat-treatment temperature increasing, a decrease of blue-emitting intensity and new red-emitting peaks revealed thermal degradation and activator oxidation. The XPS results showed the surface chemical composition changes and the micro-structure adjustment. The defects elimination detected by TL could be responsible for this micro-structural corrosion. IR results further confirmed the changes on bond forms. These were direct evidence and specific forms for the micro-structural corrosion due to the thermal degradation. Based on the relationship between micro-structural corrosion and luminescence properties, a micro-structural corrosion mechanism was given for the thermal degradation of BAM phosphor. The thermal degradation was caused in parallel by the micro-structure corrosion and the activated ion (Eu2+) oxidation.

Influence of heat treatment on microstructures and magnetic properties of Fe-based soft magnetic composites prepared by co-precipitation method

Abstract Fe/(NiZn)Fe2O4 soft magnetic composites (SMCs) were prepared by the co-precipitation method using pure atomised iron powder and chloride as raw materials. The morphology and element content of coated powders were analysed using scanning electron microscopy and energy dispersive spectroscopy. Moreover, we used electron probe micro-analyser, X-ray diffraction and Raman spectrum to systematically investigate the effect of heat treatment temperature in argon on the microstructure of SMCs, including O element distribution, phase formation and internal stress. The results show that by increasing heated temperature, the oxygen content at the boundary of the SMCs increased and the internal stress release of SMCs was more complete. Moreover, non-magnetic FeO would be generated in SMCs when the heat treatment temperature reached 550 °C. We also discussed the relationship of heat treatment temperature and atmosphere with AC magnetic properties of the samples, including permeability, core loss and coercivity. The results indicate that the SMCs annealed at 450 °C in argon had the optimum magnetic performance (µ = 55.8, P cv = 12.2 kw/m3, H c = 22.6 A/m). At the heat treatment temperature of 500 °C, the argon-annealed samples presented better magnetic properties and higher frequency stability than air-annealed samples.

The effect of heat treatment temperature and active acidity on textural properties of whey protein-pectin gels

The effect of heat treatment temperature and active acidity on textural properties of whey protein-pectin gels

EFFECT OF HEAT TREATMENT TEMPERATURE ON MICROSTRUCTURE CHARACTERISTIC AND HARDNESS PROPERTIES OF CASTED Ti-6Al-4V ELI

Ti-6Al-4V Extra Low Interstitial (ELI) alloys have been widely used for biomedical application as implant materials due to its excellent mechanical properties and good corrosion resistance. Furthermore, mechanical properties of this alloy could be improved by heat treatment process. In this research, it has been studied the effect of heat treatment temperature on microstructure and hardness properties of casted Ti-6Al-4V ELI alloy. After calculation of material balance to obtain this alloy composition, raw materials were melted using single arc melting furnace flowed with argon gas and melted alloy was casted. Then, it was heat treated by solution treatment for around 1 hour and subsequently quenched in water as medium. Solution temperature was given with temperature variables of 850 o C, 950 o C and 1050 o C . After that, it was aged at temperature of 500 o C for 4 hours. Microstructures were observed using optical microscope and hardness value were obtained by Vickers hardness method. The results of microstructure observation showed that it was changed after heat treatment process, especially on morphology of α and β phase. Thus, the hardness of alloy significantly increased compared with as-cast condition after heat treatment process. The optimum value of hardness was obtained at temperature of 850 o C that was 478 HVN.

Effect of thermal processing on the tribology of nanocrystalline Ni/TiO2 coatings

The tribological performance of a nanocrystalline coating is heavily influenced by its composition, morphology, and microstructural characteristics. This research work describes the effect of heat treatment temperature on the microstructural, morphological, and mechanical behavior of nanocrystalline Ni/TiO2 coatings produced by electrophoresis. The surface morphology and coating cross section were characterized by scanning electron microscopy (SEM). The composition of coatings and the percentage of TiO2 nanoparticles incorporated in the Ni matrix were studied and estimated by using an energy-dispersive spectroscopic (EDS) analysis, while x-ray diffractometry (XRD) was used to investigate the effect of heat treatment temperature on phase structure. The results showed agglomeration of TiO2 nanoparticles on the surface of the coating. The high hardness and wear resistance recorded for the as-deposited coating was attributed to the uniform distribution of TiO2 nanoparticle clusters throughout the cross section of the coating. Heat treatment of the Ni/TiO2 coatings to temperatures above 200 °C led to significant grain growth that changed the surface morphology of the coating and reduced the strengthening effects of the nanoparticles, thus causing a reduction in the hardness and wear resistance of the coatings.

Effects of Heat-Treatment Temperature on the Microstructure and Mechanical Properties of Steel by MgO Nanoparticle Additions.

The characteristics and formation mechanisms of intragranular acicular ferrite (IAF) in steel with MgO nanoparticle additions were systematically investigated for different isothermal heat-treatment temperatures, and its influence on mechanical properties was also clarified. The results indicate that the inclusions were finely dispersed and refined after adding MgO nanoparticles. In addition, with decreasing heat-treatment temperature, the microstructure changed from grain boundary ferrite (GBF) and polygonal ferrite (PF) to intragranular acicular ferrite. Moreover, the steel with MgO additions had excellent mechanical properties in the temperature range of 973 to 823 K and an average Charpy absorbed energies value of around 174 J at 873 K due to the significant refinement of the microstructure and nucleation of intragranular acicular ferrite.

Sintering Pmperature-Dependence on Radiopacity of Bi(2-x) ZrxO(3+x/2) Powders Prepared by Sol-Gel Process.

Bismuth oxide (Bi2O3) is an effective additive used to enhance radiography resolution for dental materials. However, there are potential concerns regarding its biocompatibility and connection to tissue discoloration. In the present study, we modified the radiopacity properties of Bi2O3 with zirconium oxide (ZrO2) using a sol-gel process and investigated the composition, as well as the effects of heat treatment temperature using Thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The harvested Bi2−xZrxO3+x/2 particles showed that the dominant phase transferred from α-Bi2O3 to β-Bi7.38Zr0.62O12.31 after a heat treatment of over 750 °C for 2 h. As the x values of Bi2−xZrxO3+x/2 increased from 0.2 to 1.0, more zirconium oxide precipitated onto the particle surface, thus enhancing the surface roughness of particles. For sol-gel Bi1.8Zr0.2O3.1 powders (x = 0.2), the radiopacity values became 4.90 ± 0.23 and 5.83 ± 0.22 mmAl after a heat treatment of 500 °C and 750 °C, respectively.

Effect of Heat Treatment Temperature on the Microstructure and Mechanical Properties of Li2O–SiO2–P2O5–Al2O3–K2O–CaO Glass-Ceramics

Effect of Heat Treatment Temperature on the Microstructure and Mechanical Properties of Li₂O–SiO₂–P₂O₅–Al₂O₃–K₂O–CaO Glass-Ceramics

ZrB2-ZrC composite nanofibers fabricated by electrospinning and carbothermal reduction: Processing, phase evolution and tensile property

ZrB2-ZrC composite nanofibers were fabricated by electrospinning and carbothermal reduction. The morphology, phase composition and interface were characterized. The fabricated ZrB2-ZrC composite nanofibers are uniform and the diameter is about 100 nm. The effects of heat-treatment temperature, n(B)/n(Zr) and n(C)/n(Zr) on the microstructure and phase composition of composite nanofibers were systematically investigated. The results shows heat-treatment temperature has influence on the phase composition and grain size of the ZrB2-ZrC composite nanofibers. The content of ZrC in the ZrB2-ZrC composite nanofibers can be adjusted by the value of n(B)/n(Zr) in the precursors. As n(B)/n(Zr) equal to 3.5, the mass ratio between ZrB2 and ZrC is about 48:52 which is very close to the eutectic composition of ZrB2-ZrC composites. The value of n(C)/n(Zr) also affects the phase composition of composite nanofibers. Reaction process and phase evolution during heat-treatment were studied based on analysis of reaction thermodynamics. The value of n(B)/n(Zr) influences the phase evolution during fabrication of ZrB2-ZrC composite nanofibers. The tensile mechanical properties were tested, indicating that the addition of ZrC has the ability to improve the plasticity of ZrB2.

Effects of heat treatment temperature on microstructure and mechanical properties of lithium disilicate-based glass-ceramics

In this study, the mechanical properties and microstructure of lithium disilicate glass-ceramics in the Li2O-SiO2-P2O5-Al2O3-K2O glass ceramics was investigated for dental applications. The glass-ceramics were prepared from the casting glass melt into warmed mold. After that the samples were heat treatment at 650–850 °C for 2 h. The heat treatment temperatures were determined from the differential thermal analysis (DTA). The microstructure of the glass–ceramics were characterized by X-ray diffraction (XRD) technique and the scanning electron microscopy (SEM). Moreover, the mechanical properties were investigated by Vickers hardness testing. Results indicated that the samples confirmed the occurrence of Li2Si2O5, LiSi2O3 Li3PO4 and LiAlSi2O6 phases in prepared glass ceramics. Moreover, the lithium disilicate glass-ceramic exhibits a high Vickers hardness values in the range of 4.92–5.90 GPa.

Crystallization kinetics and heat treatment temperature on microstructure and properties of Na2O-CaO-P2O5 bioactive glass system

This study deals with the effects of heat treatment temperature on the thermal and mechanical properties of Na2O-CaO-P2O5 glasses and glass-ceramics. The major crystalline phase was calcium phosphate along with sodium calcium phosphate as the minor crystalline phases presented in the glass-ceramics. Vickers hardness, Knoop hardness and Young's modulus values of the glass-ceramics decrease with increasing of heat treatment temperature, however, the opposite trend is found for the fracture toughness values. H550 sample confirms the dendritic-like structure, H600 and H650 samples confirms the lamellar bone-like structures and H700 sample confirms the scaffold-like structure. The microstructure, with cluster of dendritic crystal and lamellar structure, indicates a typical two-dimensional crystallization mechanism, which agrees with the above analysis of Avrami exponent (n = 2.8) for glass sample at Tp1 while scaffold structure indicates a typical three-dimensional crystallization mechanism, which is in good agreement with the above analysis of Avrami exponent (n = 4.2) for glass sample at Tp2. Moreover, all Na2O-CaO-P2O5 bioactive glass-ceramics are not toxic to the living cell and have a good bioactive property.