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Influence of Thermal Treatments on In-depth Compositional Uniformity of Culn(S,Se)2 Thin Films
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作者 谢海兵 刘伟丰 +3 位作者 江国顺 李欣益 严飞 朱长飞 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第4期481-486,I0004,共7页
CuIn(S,Se)2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-qualit... CuIn(S,Se)2 thin films were prepared by thermal crystallization of co-sputtered Cu-In alloy precursors in S/Se atmosphere. In-depth compositional uniformity is an important prereq- uisite for obtaining device-quality CuIn(S,Se)2 absorber thin films. In order to figure out the influence of heat treatments on in-depth composition uniformity of CuIn(S,Se)2 thin films, two kinds of reaction temperature profiles were investigated. One process is "one step profile", referring to formation of CuIn(S,Se)2 thin films just at elevated temperature (e.g. 500 ℃). The other is "two step profile", which allows for slow diffusion of S and Se elements into the alloy precursors at a low temperature before the formation and re-crystallization of CuIn(S,Se)2 thin films at higher temperature (e.g. first 250 ℃ then 500 ℃). X-ray diffrac- tion studies reveal that there is a discrepancy in the shape of (112) peak. Samples annealed with "one step profile" have splits on (112) peaks, while samples annealed with "two step profile" have relatively symmetrical (112) peaks. Grazing incident X-ray diffraction and en- ergy dispersive spectrum measurements of samples successively etched in bromine methanol show that CuIn(S,Se)2 thin films have better in-depth composition uniformity after "two step profile" annealing. The reaction mechanism during the two thermal processing was also investigated by X-ray diffraction and Raman spectra. 展开更多
关键词 thermal treatment In-depth compositional uniformity CuIn(S Se)2 thin film
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Impacts of freezing and thermal treatments on dimensional and mechanical properties of wood flour-HDPE composite 被引量:1
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作者 YANG Wei-jun XIE Yan-jun +2 位作者 WANG Hai-gang LIU Bao-yu WANG Qing-wen 《Journal of Forestry Research》 SCIE CAS CSCD 2013年第1期143-147,共5页
Wood plastic composite (WPC) of wood flour (WF), high density polyethylene (HDPE), maleic anhydride-grafted polyethylene (MAPE) and lubricant was prepared by extrusion, and then exposed to different temperatur... Wood plastic composite (WPC) of wood flour (WF), high density polyethylene (HDPE), maleic anhydride-grafted polyethylene (MAPE) and lubricant was prepared by extrusion, and then exposed to different temperatures to evaluate the effects of freezing and thermal treatment on its dimensional and mechanical properties. At elevated temperatures, WPC expanded rapidly initially, and then contracted slowly until reaching an equilibrium state. Treatment at 52°C and relative humidity of 50% for 16 days improved the mechanical properties of WPC: flexure, tensile strength, and izod unnotched impact strength increased by 8%, 10% and 15%, respectively. Wide-angle X-ray diffraction (XRD) tests showed that the degree of crystalization of HDPE in WPC declined with increasing treatment temperature. 展开更多
关键词 wood plastic composite freezing treatment thermal treatment DIMENSION mechanical properties X-ray diffraction
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Effects of Thermal Treatments on Helium Retention and Thermal Desorption Behaviors in a V-4Ti Aalloy
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作者 LIU Xiang T. Yamada T. Hino 《Southwestern Institute of Physics Annual Report》 2004年第1期102-105,共4页
Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium r... Vanadium alloys are considered as the promising first wall and structure materials of the future fusion reactors owing to their perfect low neutron-induced radioactivity and good high temperature performance. Helium retention and thermal desorption behaviors are key issues for the applications of vanadium alloys in fusion reactors since helium can be produced by helium discharge cleaning and neutron transmutation. A. van Veen groupt investigated helium trapping and thermal desorption mechanisms in vanadium alloys by using 1 keV helium ion irradiation to the fluence of 10^13~10^14He/cm^2, and the influenee of pre-annealing treatments on helium trapping. Two group of peaks were found at the thermal helium desorption spectrum. They thought one was due to helium-vacancyimpurity clusters and the other was corresponding to helium trapping into pre-existing traps, such as fine-size precipitates. 展开更多
关键词 Vanadium alloy TDS thermal treatment
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Comparison of microwave- and thermal-assisted rock fragmentation methods at different temperatures and loading rates
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作者 Wei Yao Shuai Wang +2 位作者 Bangbiao Wu Ying Xu Kaiwen Xia 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第6期799-819,共21页
Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,F... Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat treatment.The damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave method.The temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation energy.Thus,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably compared.The noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat treatment.Moreover,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests. 展开更多
关键词 Fangshan granite Dynamic experiments Microwave irradiation thermal treatment Loading rate FRAGMENTATION
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Recent progresses in thermal treatment of β-Ga_(2)O_(3) single crystals and devices
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作者 Yuchao Yan Zhu Jin +1 位作者 Hui Zhang Deren Yang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第7期1659-1677,共19页
In recent years,ultra-wide bandgap β-Ga_(2)O_(3) has emerged as a fascinating semiconductor material due to its great potential in power and photoelectric devices.In semiconductor industrial,thermal treatment has bee... In recent years,ultra-wide bandgap β-Ga_(2)O_(3) has emerged as a fascinating semiconductor material due to its great potential in power and photoelectric devices.In semiconductor industrial,thermal treatment has been widely utilized as a convenient and effective approach for substrate property modulation and device fabrication.Thus,a thorough summary of β-Ga_(2)O_(3) substrates and devices behaviors after high-temperature treatment should be significant.In this review,we present the recent advances in modulating properties of β-Ga_(2)O_(3) substrates by thermal treatment,which include three major applications:(ⅰ)tuning surface electrical properties,(ⅱ)modifying surface morphology,and(ⅲ)oxidating films.Meanwhile,regulating electrical contacts and handling with radiation damage and ion implantation have also been discussed in device fabrication.In each category,universal annealing conditions were speculated to figure out the corresponding problems,and some unsolved questions were proposed clearly.This review could construct a systematic thermal treatment strategy for various purposes and applications of β-Ga_(2)O_(3). 展开更多
关键词 β-gallium oxide thermal treatment SUBSTRATES DEVICES
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Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting
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作者 Yijin Qian Peng Jia +1 位作者 Songze Mao Jialiang Lu 《Deep Underground Science and Engineering》 2024年第1期103-116,共14页
In order to understand the mechanical properties and the fracture surface roughness characteristics of thermally damaged granite under dynamic splitting,dynamic Brazilian splitting tests were conducted on granite samp... In order to understand the mechanical properties and the fracture surface roughness characteristics of thermally damaged granite under dynamic splitting,dynamic Brazilian splitting tests were conducted on granite samples after thermal treatment at 25,200,400,and 600℃.Results show that the dynamic peak splitting strength of thermally damaged granite samples increases with increasing strain rate,showing obvious strain‐rate sensitivity.With increasing temperature,thermally induced cracks in granite transform from intergranular cracks to intragranular cracks,and to a transgranular crack network.Thermally induced damages reduce the dynamic peak splitting strength and the maximum absorbed energy while increasing the peak radial strain.The fracture mode of the thermally damaged granite under dynamic loads is mode Ⅱ splitting failure.By using the axial roughness index Z2 a,the distribution ranges of the wedge‐shaped failure zones and the tensile failure zones in the fracture surfaces under dynamic Brazilian splitting can be effectively identified.The radial roughness index Z_(2)^(r)is sensitive to the strain rate and temperature.It shows a linear correlation with the peak splitting strength and the maximum absorbed energy and a linear negative correlation with the peak radial strain.Z_(2)^(r)can be used to quantitatively estimate the dynamic parameters based on the models proposed. 展开更多
关键词 dynamic splitting fracture surface roughness GRANITE strain rate thermal treatment
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The effects of radio frequency atmospheric pressure plasma and thermal treatment on the hydrogenation of TiO_(2) thin film
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作者 张宇 王昊哲 +5 位作者 何涛 李妍 郭颖 石建军 徐雨 张菁 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第6期72-81,共10页
The effects of radio frequency(RF)atmospheric pressure(AP)He/H_(2)plasma and thermal treatment on the hydrogenation of TiO_(2)thin films were investigated and compared in this work.The color of the original TiO_(2)fil... The effects of radio frequency(RF)atmospheric pressure(AP)He/H_(2)plasma and thermal treatment on the hydrogenation of TiO_(2)thin films were investigated and compared in this work.The color of the original TiO_(2)film changes from white to black after being hydrogenated in He/H_(2)plasma at160 W(gas temperature~381℃)within 5 min,while the color of the thermally treated TiO_(2)film did not change significantly even in pure H_(2)or He/H_(2)atmosphere with higher temperature(470℃)and longer time(30 min).This indicated that a more effective hydrogenation reaction happened through RF AP He/H_(2)plasma treatment than through pure H_(2)or He/H_(2)thermal treatment.The color change of TiO_(2)film was measured based on the Commission Internationale d’Eclairage L*a*b*color space system.Hydrogenated TiO_(2)film displayed improved visible light absorption with increased plasma power.The morphology of the cauliflower-like nanoparticles of the TiO_(2)film surface remained unchanged after plasma processing.X-ray photoelectron spectroscopy results showed that the contents of Ti3+species and Ti-OH bonds in the plasma-hydrogenated black TiO_(2)increased compared with those in the thermally treated TiO_(2).X-ray diffraction(XRD)patterns and Raman spectra indicated that plasma would destroy the crystal structure of the TiO_(2)surface layer,while thermal annealing would increase the overall crystallinity.The different trends of XRD and Raman spectra results suggested that plasma modification on the TiO_(2)surface layer is more drastic than on its inner layer,which was also consistent with transmission electron microscopy results.Optical emission spectra results suggest that numerous active species were generated during RF AP He/H_(2)plasma processing,while there were no peaks detected from thermal processing.A possible mechanism for the TiO_(2)hydrogenation process by plasma has been proposed.Numerous active species were generated in the bulk plasma region,accelerated in the sheath region,and bumped toward the TiO_(2)film,which will react with the TiO_(2)surface to form OVs and disordered layers.This leads to the tailoring of the band gap of black TiO_(2)and causes its light absorption to extend into the visible region. 展开更多
关键词 black TiO_(2)thin film atmospheric pressure plasma thermal treatment visible light response HYDROGENATION
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Comparison of mechanical properties in high temperature and thermal treatment granite 被引量:21
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作者 尹土兵 舒荣华 +2 位作者 李夕兵 王品 刘希灵 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第7期1926-1937,共12页
Static mechanical experiments were carried out on granite after and under different temperatures using an electro-hydraulic and servo-controlled material testing machine with a heating device. Variations in obvious fo... Static mechanical experiments were carried out on granite after and under different temperatures using an electro-hydraulic and servo-controlled material testing machine with a heating device. Variations in obvious form, stress-strain curve, peak strength, peak strain and elastic modulus with temperature were analyzed and the essence of rock failure modes was explored. The results indicate that, compared with granite after the high temperature treatment, the brittle-ductile transition critical temperature is lower, the densification stage is longer, the elastic modulus is smaller and the damage is larger under high temperature. In addition, the peak stress is lower and the peak strain is greater, but both of them change more obviously with the increase of temperature compared with that of granite after the high temperature treatment. Furthermore, the failure modes of granite after the high temperature treatment and under high temperature show a remarkable difference. Below 100 ℃, the failure modes of granite under both conditions are the same, presenting splitting failure. However, after 100 ℃, the failure modes of granite after the high temperature treatment and under high temperature present splitting failure and shear failure, respectively. 展开更多
关键词 GRANITE thermal treatment high temperature effect static mechanical properties failure properties
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Preparation of Self-limiting Heating Cables with Excellent Processability, Mechanical Properties and PTC Effect via Thermal and Electrical Treatments 被引量:1
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作者 Tian-Hao Yang Tong Wu Qiang Fu 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2024年第4期511-520,共10页
Polymer/conductive filler composites have been widely used for the preparation of self-limiting heating cables with the positive temperature coefficient (PTC) effect. The control of conductive filler distribution and ... Polymer/conductive filler composites have been widely used for the preparation of self-limiting heating cables with the positive temperature coefficient (PTC) effect. The control of conductive filler distribution and network in polymer matrix is the most critical for performance of PTC materials. In order to compensate for the destruction of the filler network structure caused by strong shearing during processing, an excessive conductive filler content is usually added into the polymer matrix, which in turn sacrifices its processability and mechanical properties. In this work, a facile post-treatment of the as-extruded cable, including thermal and electrical treatment to produce high-density polyethylene (HDPE)/carbon black (CB) cable with excellent PTC effect, is developed. It is found for the as-extruded sample, the strong shearing makes the CB particles disperse uniformly in HDPE matrix, and 25 wt% CB is needed for the formation of conductive paths. For the thermal-treated sample, a gradually aggregated CB filler structure is observed, which leads to the improvement of PTC effect and the notable reduction of CB content to 20 wt%. It is very interesting to see that for the sample with combined thermal and electrical treatment, CB particles are agglomerated and oriented along the electric field direction to create substantial conductive paths, which leads to a further decrease of CB content down to 15 wt%. In this way, self-limiting heating cables with excellent processability, mechanical properties and PTC effect have simultaneously been achieved. 展开更多
关键词 Self-limiting heating cables Positive temperature coefficient thermal treatment Electrical treatment
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Mechanical properties,electrical conductivity and microstructure of CuCrZr alloys treated with thermal stretch process 被引量:2
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作者 张蓓 张治国 李卫 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第7期2285-2292,共8页
CuCrZr alloys were treated with the thermal stretch process at various temperatures from 100 to 300℃.The results reveal that the thermal stretch process is successfully developed to manufacture the precipitation hard... CuCrZr alloys were treated with the thermal stretch process at various temperatures from 100 to 300℃.The results reveal that the thermal stretch process is successfully developed to manufacture the precipitation hardening CuCrZr alloys with a good combination of microhardness and electrical conductivity.By increasing the tensile elongations at each temperature from 100 to 300℃,the microhardness increases whereas the electrical conductivity decreases slightly.Cr-containing precipitate phases with a Nishiyama-Wasserman orientation relationship to the copper matrix were observed by TEM.The achievement of high micro-hardness and acceptable electrical conductivity in the thermal stretch treated alloys is ascribed to the interactions of the heteroatom solution,dislocation increment,grain refinement and dispersive precipitation effect. 展开更多
关键词 CuCrZr alloys thermal stretch treatment MICROHARDNESS electrical conductivity
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Influence of pH, Heat and Enzymatic Treatments on the Activity of Antibacterial Substance in MRS and Milk Media Produced by Lactobacillus fermentum F6 被引量:1
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作者 ZHANG Yong LIU Yong BAO Yan ZHANG He-ping 《Agricultural Sciences in China》 CAS CSCD 2010年第6期911-920,共10页
This study aimed to investigate the influence of pH,heat and enzymatic treatments on the activity of antibacterial substance in MRS,skim soy milk and bovine milk media fermented by a potential probiotic Lactobacillus ... This study aimed to investigate the influence of pH,heat and enzymatic treatments on the activity of antibacterial substance in MRS,skim soy milk and bovine milk media fermented by a potential probiotic Lactobacillus fermentum F6.The antibacterial activity of the culture supernatant of L.fermentum F6 was tested against a wide range of Gram-positive and Gram-negative pathogenic bacteria including Staphylococcus aureus,Escherichia coli,Listeria monocytogenes,Salmonella typhimurium,and Shigella flexneri.Different antibacterial activities were detected in MRS and milk but not in soy milk.We presumed that three kinds of probable components including organic acids,heat-stable and heat-labile proteinaceous compounds were involved in antibacterial activity of fermented MRS and milk.The influence of acids on antibacterial activity was pH-dependent and this effect multiplied with thermal treatments seemed complex.Data analyses showed various significant differences of antibacterial activity among five pathogens were observed in pH and heat treatments.The untreated fermented milk showed higher inhibitory activity to Gram-positive pathogenic bacteria than Gram-negative bacteria (P 〈 0.05),indicating antibacterial substances of fermented milk are greatly different from fermented MRS.An accurate stimulated gastrointestinal transit showed antibacterial substances would have no influence on intestinal flora.Acidic range of antibacterial substances from pH 2.0 to 6.0 can be potentially used as food biopreservatives and alternative therapeutics. 展开更多
关键词 Lactobacillusfermentum F6 antibacterial activity PH thermal treatments enzymatic effect
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Temperature effects on the failure of deep circular tunnel under true-triaxial compression
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作者 HUANG Lin-qi LIU Mao-lin +4 位作者 WANG Zhao-wei GUO Yi-de SI Xue-feng LI Xi-bing LI Chao 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第9期3119-3141,共23页
The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The fa... The failure characteristics of thermal treated surrounding rocks should be studied to evaluate the stability and safety of deep ground engineering under high-ground-temperature and high-ground-stress conditions.The failure process of the inner walls of fine-grained granite specimens at different temperatures(25–600℃)was analyzed using a true-triaxial test system.The failure process,peak intensity,overall morphology(characteristics after failure),rock fragment characteristics,and acoustic emission(AE)characteristics were analyzed.The results showed that for the aforementioned type of granite specimens,the trend of the failure stress conditions changed with respect to the critical temperature(200℃).When the temperature was less than 200℃,the initial failure stress increased,final failure stress increased,and failure severity decreased.When the temperature exceeded 200℃,the initial failure stress decreased,final failure stress decreased,and failure severity increased.When the temperature was 600℃,the initial and final failure stresses of the specimens decreased by 60.93%and 19.77%compared with those at 200℃,respectively.The numerical results obtained with the software RFPA3D-Thermal were used to analyze the effect of temperature on the specimen and reveal the mechanism of the failure process in the deep tunnel surrounding rock. 展开更多
关键词 deep ground rock failure GRANITE thermal treatment true-triaxial test circular tunnel RFPA3D-thermal
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Thermal Treatment for Decreasing the Acidity of Crude Oil
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作者 申海平 王玉章 李锐 《Petroleum Science》 SCIE CAS CSCD 2004年第3期78-81,96,共5页
Highly acidic crude oil is thermally soaked to investigate how the temperature and time involved affect the removal of organic acid in feedstock. Experimental results indicate that thermal treatment is an effective a... Highly acidic crude oil is thermally soaked to investigate how the temperature and time involved affect the removal of organic acid in feedstock. Experimental results indicate that thermal treatment is an effective approach to decreasing acidity and the acid removal rate reaches 80%. Temperature is one of the main factors that determine the acid removal reaction. When the temperature ranges from 420oC to 440oC, the acid removal rate increases with the rise of the reaction temperature, but the increase slows down gradually. At the reaction temperature below 440oC, the long reaction time favors the acid removal. The cracking and polymerization of hydrocarbon molecules take place so that the properties of the crude oil change at the same time when the highly acidic crude is thermally treated. 展开更多
关键词 Highly acidic crude naphthenic acid acid removal thermal treatment VISBREAKING
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Effect of thermal treatment on energy dissipation of granite under cyclic impact loading 被引量:19
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作者 Rong-hua SHU Tu-bing YIN +2 位作者 Xi-bing LI Zhi-qiang YIN Li-zhong TANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第2期385-396,共12页
High temperature treatment causes thermal damage to rocks in deep mining.To study the thermal effect on the energy dissipation of rocks during the dynamic cyclic loading,cyclic impact loading experiments of heat-treat... High temperature treatment causes thermal damage to rocks in deep mining.To study the thermal effect on the energy dissipation of rocks during the dynamic cyclic loading,cyclic impact loading experiments of heat-treated rocks were carried out using the splitting Hopkinson pressure bar(SHPB)experimental system.The correlations among the energy dissipation,energy dissipation rate,impact times,accumulated absorbed energy per volume,failure mode and temperature were analyzed.The results show that the reflected energy under the first impact increases and finally exceeds the absorbed energy when the temperature increases;however,the total reflected energy decreases above 200℃.The absorbed energy under the first impact and the total absorbed energy all decrease as the temperature increases,the rates of which decrease accordingly.And the same phenomenon appears for the transmitted energy and the rate of the transmitted energy.On the contrary,the rate of the reflected energy increases with the rising temperature.When the temperature increases,the fewer impact times are needed to destroy the sample.In addition,the failure modes are different when the rock is treated at different temperatures;that is,when the temperature is high,even though the absorbed energy is low,the sample breaks into powder after several impacts. 展开更多
关键词 energy dissipation GRANITE cyclic impact compression thermal treatment
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Microstructures and thermal properties of municipal solid waste incineration fly ash 被引量:5
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作者 刘元元 王佳佳 +3 位作者 林祥 王里奥 钟山 杨威 《Journal of Central South University》 SCIE EI CAS 2012年第3期855-862,共8页
To analyze the feasibility of utilization of thermal technology in fly ash treatment, thermal properties and microstructures of municipal solid waste incineration (MSW1) fly ash were studied by measuring the chemica... To analyze the feasibility of utilization of thermal technology in fly ash treatment, thermal properties and microstructures of municipal solid waste incineration (MSW1) fly ash were studied by measuring the chemical element composition, specific surface area, pore sizes, functional groups, TEM image, mineralogy and DSC-TG curves of raw and sintered fly ash specimens. The results show that MSWI fly ash particles mostly have irregular shapes and non-typical pore structure, and the supersonic treatment improves the pore structure; MSWI fly ash consists of Such crystals as SiO2, CaSO4 and silica-aluminates, and some soluble salts like KCl and NaCl. During the sintering process, mineralogy changes largely and novel solid solutions are produced gradually with the rise of temperature. Therefore, the utilization of a proper thermal technology not only destructs those persistent organic toxicants but also stabilizes hazardous heavy metals in MSWI fly ash. 展开更多
关键词 municipal solid waste incineration fly ash thermal treatment SINTERING microstructure
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Utilization of Thermally Treated Flue Gas Desulfurization (FGD) Gypsum and Class-C Fly Ash (CFA) to Prepare CFA-Based Geopolymer 被引量:3
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作者 郭晓潞 施惠生 Warren A Dick 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第1期132-138,共7页
The feasibility of utilization of flue gas desulfurization (FGD) gypsum and Class-C fly ash (CFA) to prepare CFA-based geopolymer were studied. The results showed that geopolymer made from 90% CFA and 10% FGD gyps... The feasibility of utilization of flue gas desulfurization (FGD) gypsum and Class-C fly ash (CFA) to prepare CFA-based geopolymer were studied. The results showed that geopolymer made from 90% CFA and 10% FGD gypsum (FGDG) which was thermally treated at 800 ℃ for 1 h obtained the better compressive strength of 37.0 MPa. The micro characteristics and structures of the geopolymer samples of CFA and CFA-FGDG were tested by XRD, FT-IR, and SEM-EDXA after these samples cured at 75 ℃ for 8 h followed by 23 ℃ for 28 d. Both the geopolymer samples of CFA and CFA-FGDG have significant asymmetric stretching of A1-O/Si-O bonds and Si-O-Si / Si-O-A1 bending band. In geopolymer sample of CFA-FGDG, a small quantity of lathy products probably being the ettringite wrapped over the spherical fly ash particle, and the concentration of sulfur is much more than that in geopolymer sample of CFA. It is indicated that FGD gypsum may react during alkali-activated and geopolymeric process. 展开更多
关键词 flue gas desulphurization (FGD)gypsum class-C fly ash(CFA) GEOPOLYMER thermal treatment
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Damage characteristics of thermally treated granite under uniaxial compression: Insights from active and passive ultrasonic techniques 被引量:2
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作者 GUO Pei WU Shun-chuan +1 位作者 JIANG Ri-hua ZHANG Guang 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第12期4078-4093,共16页
To explore the effects of thermal treatment on cracking processes in granite, granite samples were thermally treated at 25-400 ℃ and then loaded under uniaxial compression. Active ultrasonic testing and passive acous... To explore the effects of thermal treatment on cracking processes in granite, granite samples were thermally treated at 25-400 ℃ and then loaded under uniaxial compression. Active ultrasonic testing and passive acoustic emission(AE) monitoring were combined to monitor the damage characteristics of the samples. The uniaxial compression strength(UCS) of the sample treated at 200 ℃ shows no apparent change compared with that of the nonheated sample, while the UCS increases at 300 °C and decreases at 400 ℃. As the temperature increases from 25 to 400 ℃, the initial P-wave velocity(Vp) decreases gradually from 4909 to 3823 m/s, and the initial Vpanisotropy ε increases slightly from 0.03 to 0.09. As the axial stress increases, ε increases rapidly in the crack closure stage and unstable cracking stage. The attenuation of ultrasonic amplitude spectra also shows an obvious anisotropy. Besides, the main location magnitude of AE events decreases after thermal treatment, and low-frequency AE events and high-amplitude AE events increasingly occur. However, there is insufficient evidence that the treatment temperature below 400 ℃ has a significant effect on the temporal characteristics, source locations, and b-values of AE. 展开更多
关键词 uniaxial compression thermal treatment acoustic emission ULTRASONIC B-VALUE dominant frequency
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Effect of thermal treatment and ball milling on microstructure and phase transformation of Ni-Mn-Ga-Nb alloys 被引量:2
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作者 Jun-song WANG Bing TIAN +2 位作者 Yun-xiang TONG Feng CHEN Li LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2019年第10期2117-2127,共11页
To clarify phase transformation evolution of Nb-doped Ni-Mn-Ga bulk alloys after aging and ball milling, the microstructure and phase transformation of the aged and ball-milled dual-phase Nb-doped Ni-Mn-Ga alloys were... To clarify phase transformation evolution of Nb-doped Ni-Mn-Ga bulk alloys after aging and ball milling, the microstructure and phase transformation of the aged and ball-milled dual-phase Nb-doped Ni-Mn-Ga alloys were investigated by SEM, EDS, XRD, DSC and susceptibility measurements. The as-cast alloys were mainly composed of the second phase with layer-shape and presented a reduced martensitic transformation with increasing the second phase content. The second phase transformed from layer-shape to dense bar-shape and the martensitic transformation was enhanced after being quenched at 1173 K. After aging at 673 and 873 K, the 3% Nb alloy with less second phase exhibited a single-step phase transformation, whereas the 6% Nb and 9% Nb alloys with more second phase exhibited a two-step martensitic transformation and Curie transition. The martensitic transformation and Curie transition of the as-milled dual-phase particles disappeared and were retrieved after annealing at 1073 K due to the recovery of high ordered structure of the matrix. 展开更多
关键词 Ni-Mn-Ga-Nb alloy thermal treatment ball milling MICROSTRUCTURE phase transformation
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High-temperature thermal stability of C/C−ZrC−SiC composites via region labeling method 被引量:2
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作者 Zheng PENG Chun-mao MIAO +5 位作者 Wei SUN Yong-long XU Hai-kun CHEN Yu-feng LIU Hong-bo ZHANG Xiang XIONG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第10期3349-3361,共13页
To investigate the thermal stability of ceramic-matrix composites,three kinds of C/C−ZrC−SiC composites with different Zr/Si molar ratios were synthesized by reactive melt infiltration.Employing region labeling method... To investigate the thermal stability of ceramic-matrix composites,three kinds of C/C−ZrC−SiC composites with different Zr/Si molar ratios were synthesized by reactive melt infiltration.Employing region labeling method,the high-temperature thermal stability of the composites was systematically studied by changing the temperature and holding time of thermal treatment.Results show that the mass loss rate of low Si composites has a growth trend with increasing temperature,and a crystal transformation from β-SiC toα-SiC occurs in the composites.In the calibrated area,SiC phase experiences Ostwald ripening and volume change with location migration,while ZrC phase experiences a re-sintering process with diffusion.Moreover,it is found that increasing temperature has a more obvious effect on the thermal stability than extending holding time,which is mainly attributed to the faster diffusion rate of atoms. 展开更多
关键词 thermal stability ceramic-matrix composites reactive melt infiltration high-temperature thermal treatment region labeling method
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Effects of Melt Thermal Treatment on A356 Alloy 被引量:2
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作者 Jun WANG, Shuxian HE, Baode SUN and Yaohe ZHOUSchool of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第2期152-154,共3页
To increase the casting quality of hypoeutectic Al-Si alloys, the effects of melt thermal treatment on the solidification structure of the A356 alloy were analyzed by a factorial experiment, in which the overheated me... To increase the casting quality of hypoeutectic Al-Si alloys, the effects of melt thermal treatment on the solidification structure of the A356 alloy were analyzed by a factorial experiment, in which the overheated melt was mixed with the low temperature melt. Experimental results show that the elongation ratio and strength of the treated samples increase remarkably compared with the control sample. The primary dendrite size reduces dramatically and the dendrite changes from columnar to equiaxed, with a little change of the secondary dendrite arm spacing (SDAS). Combined with the measurement of the nucleation undercooling, it is concluded that the solidification structure and refining effect are dependent primarily on the low temperature melt. The refining mechanism is believed as a result of the multiplication of the nuclei in the melt thermal treatment procedure. 展开更多
关键词 A356 Melt thermal treatment Solidification structure
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