In this study,a novel cost-effective methodology was developed to enhance the gas barrier properties and permselectivity of unfilled natural rubber(NR)/polybutadiene rubber(BR)composites through the construction of a ...In this study,a novel cost-effective methodology was developed to enhance the gas barrier properties and permselectivity of unfilled natural rubber(NR)/polybutadiene rubber(BR)composites through the construction of a heterogeneous structure using pre-vulcanized powder rubber to replace traditional fillers.The matrix material is composed of a blend of NR and BR,which is widely used in tire manufacturing.By incorporating pre-vulcanized trans-1,4-poly(isoprene-co-butadiene)(TBIR)rubber powder(pVTPR)with different cross-linking densities and contents,significant improvements in the gas barrier properties and CO_(2)permselectivity of the NR/BR/pVTPR composites were observed.The results indicated that compared to NR/BR/TBIR composites prepared through direct blending of NR,BR,and TBIR,the NR/BR/pVTPR composites exhibited markedly superior gas barrier properties.Increasing the cross-linking density of pVTPR resulted in progressive enhancement of the gas barrier properties of the NR/BR/pVTPR composite.For example,the addition of 20 phr pVTPR with a cross-linking density of 346 mol/m^(3)resulted in a 79%improvement in the oxygen barrier property of NR/BR/pVTPR compared to NR/BR,achieving a value of 5.47×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1).Similarly,the nitrogen barrier property improved by 76%compared to NR/BR,reaching 2.4×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1),which is 28%higher than the conventional inner liner material brominated butyl rubber(BIIR,PN2=3.32×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1)).Owing to its low cost,exceptional gas barrier properties,superior adhesion to various tire components,and co-vulcanization capabilities,the NR/BR/pVTPR composite has emerged as a promising alternative to butyl rubber in the inner liner of tires.Furthermore,by fine-tuning the cross-linking density of pVTPR,the high-gas-barrier NR/BR/pVTPR composites also demonstrated remarkable CO_(2)permselectivity,with a CO_(2)/N2 selectivity of 61.4 and a CO_(2)/O_(2)selectivity of 26.12.This innovation provides a novel strategy for CO_(2)capture and separation,with potential applications in future environmental and industrial processes.The multifunctional NR/BR/pVTPR composite,with its superior gas barrier properties and CO_(2)permselectivity,is expected to contribute to the development of safer,greener,and more cost-effective transportation solutions.展开更多
Improving the high-temperature performance of Inconel 718(IN718)alloys manufactured via laser powder bed fusion(LPBF)has been the most concerned issue in the industry.In this study,the effects of Ti_(2)AlC inoculants ...Improving the high-temperature performance of Inconel 718(IN718)alloys manufactured via laser powder bed fusion(LPBF)has been the most concerned issue in the industry.In this study,the effects of Ti_(2)AlC inoculants on microstructures and high-temperature mechanical properties of the as-built IN718 composites were investigated.According to statistical results of relative density and unmelted particle area in as-built alloys,the optimal energy of 112 J/mm^(3)was determined.It was observed that the precipitation of the MC carbide was significantly enhanced with the addition of Ti_(2)AlC,restricting the precipitation of the Laves phase.The MC particles were uniformly distributed along the subgrain boundaries,which contributed to the dispersion strengthening.Meanwhile,the MC particles served as nucleation sites for heterogeneous nucleation during the solidification process,facilitating the refinement of columnar and cellular grains.The simulated Scheil-Gulliver curves showed that the precipitation sequence of phases did not change with Ti_(2)AlC inoculants.The as-built 1%Ti_(2)AlC/IN718 sample demonstrated an ultimate tensile strength of 998.78 MPa and an elongation of 18.04%at 650℃,revealing a markedly improved mechanical performance compared with the LPBF-manufactured IN718 alloys.The high-temperature tensile strength of 1%Ti_(2)AlC/IN718 sample increased to 1197.99 MPa by heat treatment.It was suggested that dislocation strengthening and ordered strengthening were two most important reinforcement mechanisms.展开更多
OBJECTIVE:To identify the main active ingredients of Improved Yupingfeng Powder prescription(IYPFP,玉屏风散加味)and investigate its anti-inflammatory effects and underlying mechanisms in ovalbumins(OVA)-induced allerg...OBJECTIVE:To identify the main active ingredients of Improved Yupingfeng Powder prescription(IYPFP,玉屏风散加味)and investigate its anti-inflammatory effects and underlying mechanisms in ovalbumins(OVA)-induced allergic rhinitis(AR)in mice.METHODS:Bagg Albino/substrain mice were sensitized with OVA emulsified in aluminum hydroxide adjuvant,followed by intranasal challenge to establish AR models.Treatment groups received IYPFP(1.5 or 4.5 g/kg)via daily gavage for 14 d.The nasal mucosa tissues were collected for pathological observation.The expression of OVA-specific immunoglobulin E(Ig E),histamine,and interleukin-33(IL-33)was detected by enzyme-linked immunosorbent assay.IL-5,IL-13,IL-33,suppression of tumorigenicity 2(ST2),tumor necrosis factor-α(TNF-α)and interferon-γ(IFN-γ)in the nasal mucosa and lung were detected by quantitative polymerase chain reaction and Western blot.High performance liquid chromatography and ultra-high performance liquid chromatography quadrupole exactive orbitrap mass spectrometry were used to detect the chemical fingerprints of IYPFP,and the chemical compositions of plasma from rats treated with IYPFP at 0.5,1,1.5,2,3,4 and 6 h,respectively.Virtual screening of bioactive compounds was conducted through molecular docking targeting IL-33/ST2 pathway proteins.RESULTS:Eight chemical compounds of IYPFP were accurately identified,they are prim-O-glucosylcimifugin(peak 2),calycosin-7-O-β-D-glucoside(peak 4),cimifugin(peak 5),5-O-methylvisammioside(peak 6),sec-Oglucosylhamaudol(peak 12),calycosin(peak 15),formononetin(peak 19),and magnolin(peak 21).Compared with the OVA model group,IYPFP alleviated the nasal symptoms,improved nasal mucosal injury and downregulated the levels of OVA-specific Ig E,histamine and IL-33.Additionally,IYPFP reduced the levels of IL-5,IL-13,TNF-α,IL-33,and ST2 in the lungs,but upregulated IFN-γ.Molecular docking confirmed that eight representative compounds of IYPFP had good binding properties with IL-5,IL-13,IFN-γ,histamine,IL-33 and ST2,and were able to inhibit the activation of the IL33/ST2 inflammatory pathway.CONCLUSION:This study demonstrates that IYPFP ameliorates AR by modulating IL-33/ST2 pathway which provides a theoretical basis for the clinical treatment of patients with AR.展开更多
A unique discontinuous lamellar microstructure of titanium alloys consisting of lamellar colonies at prior β-Ti grain boundaries and internal interwoven α-laths is prepared by a TiH_(2)-based powder metallurgy metho...A unique discontinuous lamellar microstructure of titanium alloys consisting of lamellar colonies at prior β-Ti grain boundaries and internal interwoven α-laths is prepared by a TiH_(2)-based powder metallurgy method.The α-variants get various crystallographic orientations and become discontinuous during vacuum annealing at 700℃.Remarkably,nanoscale phase δ-TiH compound layers are generated between α-laths and β-strips,so that dislocations are piled up at the α/δ/βinterfaces during tensile deformation.This leads to dislocation slips being confined to individual α-laths,with differentslips and particularly pyramidal<c+a>slips being activated.The efficiency of wavy slip is promoted and the work hardening rate is enhanced.Finally,the combined effect of dispersed micro-shear bands and lath distortions is considered contributive for alleviating the stress concentration at grain boundaries,resulting in a high-promising synergy of enhanced ultimate tensile strength of 1080 MPa and good elongation to fracture of 13.6%.展开更多
The present study reports a simple,effective and energy-efficient method to prepare γ-LiAlO2 powder as a matrix in a molten carbonate fuel cell(MCFC).In our experiments,aqueous solution based sol-gel technique was us...The present study reports a simple,effective and energy-efficient method to prepare γ-LiAlO2 powder as a matrix in a molten carbonate fuel cell(MCFC).In our experiments,aqueous solution based sol-gel technique was used to synthesize γ-LiAlO2.Highly dispersed AlOOH·nH2O and LiOH·H2O aqueous solutions were mixed to form a colloid mixture,which was calcined to synthesize γ-LiAlO2.Thermogravimetric analysis(TGA),X-ray dif-fraction(XRD),and scanning electron microscopy(SEM) were used to study the composition and morphology of the intermediate and final products.The analysis results showed that an intermediate product Li2Al4CO3(OH)12 was produced after the colloid mixture was dried at 80 ℃,and highly purified γ-LiAlO2 powder with fine particle size was resulted from the subsequent calcinations.A single MCFC was assembled with a matrix of the γ-LiAlO2 pow-der.The testing results showed that the matrix performed well in preventing gas leakage.展开更多
The rapid advancement of superalloy melting technology has increased the demands on crucible materials.Y_(2)O_(3) is a promising candidate for nickel-based superalloy melting due to its outstanding high-temperature st...The rapid advancement of superalloy melting technology has increased the demands on crucible materials.Y_(2)O_(3) is a promising candidate for nickel-based superalloy melting due to its outstanding high-temperature stability and non-wetting behavior with various alloys.However,its poor sintering performance limits its development.High-density Y_(2)O_(3) ceramics were successfully prepared via pressureless sintering at 1600℃ in a carbon-embedded atmosphere with talc powder as an additive.The resulting ceramics achieved optimal properties,including a bulk density of 4.27 g cm^(−3),apparent porosity of 1.1%,and cold compressive strength of 311.27 MPa.The talc powder introduced a liquid phase during sintering,which accelerated mass transfer and promoted grain growth and densification.During cooling,this liquid phase remained at the grain boundaries and acted as an intergranular bonding agent,strengthening grain cohesion.Nevertheless,excessive liquid phase hindered grain growth,negatively affecting sintering.Additionally,the extremely low porosity and the formation of the Mg_(2)SiO_(4) phase reduced the residual strength retention ratio of the Y_(2)O_(3) ceramic after thermal shock.展开更多
Using Ti powder as reagent, TiO 2 nanoneedle/nanoribbon spheres were prepared via hydrothermal method in NaOH solution. The samples were characterized by field emission scanning electron microscopy （FESEM）, transmis...Using Ti powder as reagent, TiO 2 nanoneedle/nanoribbon spheres were prepared via hydrothermal method in NaOH solution. The samples were characterized by field emission scanning electron microscopy （FESEM）, transmission electron microscopy （TEM） with selected area electron diffraction （SAED）, X-ray diffraction （XRD）, and UV-visible light absorption spectrum. The results indicate that the growth orientations of the crystals are influenced by the hydrothermal temperature and NaOH concentration. The diameter of the nanoneedle spheres and nanoribbon spheres （40 50 μm） are almost the same as that of Ti powders. TiO 2 nanoneedle/nanoribbon sphere powders are anatase after heat treatment at 450 °C for 1 h. Furthermore, methyl orange was used as a target molecule to estimate the photocatalytic activity of the specimens. Under the same testing conditions, the photocatalytic activities of the products decrease in the following order： TiO 2 nanoneedle sphere, TiO 2 nanoribbon sphere and P25.展开更多
α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 ...α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 particles. Kinetic studies on the bismuth oxidation at low-temperatures were carried out by TGA method. The results show that bismuth beads should be reunited and oxidized to become irregular Bi2O3 powders. The bismuth oxidation follows shrinking core model, and its controlling mechanism varies at different reaction time. Within 0-10 min, the kinetics is controlled by chemical reaction, after that it is controlled by O2 diffusion in the solid α-Bi2O3 layer. The apparent activation energy is determined as 55.19 kJ/mol in liquid-phase oxidation.展开更多
基金supported by the National Key Research and Development Program of China (No. 2022YFB3704700(2022YFB3704702))the National Natural Science Foundation of China (No. 52473096)+1 种基金Major Scientific and Technological Innovation Project of Shandong Province (No. 2021CXGC010901)Taishan Scholar Program
文摘In this study,a novel cost-effective methodology was developed to enhance the gas barrier properties and permselectivity of unfilled natural rubber(NR)/polybutadiene rubber(BR)composites through the construction of a heterogeneous structure using pre-vulcanized powder rubber to replace traditional fillers.The matrix material is composed of a blend of NR and BR,which is widely used in tire manufacturing.By incorporating pre-vulcanized trans-1,4-poly(isoprene-co-butadiene)(TBIR)rubber powder(pVTPR)with different cross-linking densities and contents,significant improvements in the gas barrier properties and CO_(2)permselectivity of the NR/BR/pVTPR composites were observed.The results indicated that compared to NR/BR/TBIR composites prepared through direct blending of NR,BR,and TBIR,the NR/BR/pVTPR composites exhibited markedly superior gas barrier properties.Increasing the cross-linking density of pVTPR resulted in progressive enhancement of the gas barrier properties of the NR/BR/pVTPR composite.For example,the addition of 20 phr pVTPR with a cross-linking density of 346 mol/m^(3)resulted in a 79%improvement in the oxygen barrier property of NR/BR/pVTPR compared to NR/BR,achieving a value of 5.47×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1).Similarly,the nitrogen barrier property improved by 76%compared to NR/BR,reaching 2.4×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1),which is 28%higher than the conventional inner liner material brominated butyl rubber(BIIR,PN2=3.32×10^(-14)cm^(3)·cm·cm^(-2)·s^(-1)·Pa^(-1)).Owing to its low cost,exceptional gas barrier properties,superior adhesion to various tire components,and co-vulcanization capabilities,the NR/BR/pVTPR composite has emerged as a promising alternative to butyl rubber in the inner liner of tires.Furthermore,by fine-tuning the cross-linking density of pVTPR,the high-gas-barrier NR/BR/pVTPR composites also demonstrated remarkable CO_(2)permselectivity,with a CO_(2)/N2 selectivity of 61.4 and a CO_(2)/O_(2)selectivity of 26.12.This innovation provides a novel strategy for CO_(2)capture and separation,with potential applications in future environmental and industrial processes.The multifunctional NR/BR/pVTPR composite,with its superior gas barrier properties and CO_(2)permselectivity,is expected to contribute to the development of safer,greener,and more cost-effective transportation solutions.
基金supported by the National Natural Science Foundation of China(Nos.52374396 and 52122409).
文摘Improving the high-temperature performance of Inconel 718(IN718)alloys manufactured via laser powder bed fusion(LPBF)has been the most concerned issue in the industry.In this study,the effects of Ti_(2)AlC inoculants on microstructures and high-temperature mechanical properties of the as-built IN718 composites were investigated.According to statistical results of relative density and unmelted particle area in as-built alloys,the optimal energy of 112 J/mm^(3)was determined.It was observed that the precipitation of the MC carbide was significantly enhanced with the addition of Ti_(2)AlC,restricting the precipitation of the Laves phase.The MC particles were uniformly distributed along the subgrain boundaries,which contributed to the dispersion strengthening.Meanwhile,the MC particles served as nucleation sites for heterogeneous nucleation during the solidification process,facilitating the refinement of columnar and cellular grains.The simulated Scheil-Gulliver curves showed that the precipitation sequence of phases did not change with Ti_(2)AlC inoculants.The as-built 1%Ti_(2)AlC/IN718 sample demonstrated an ultimate tensile strength of 998.78 MPa and an elongation of 18.04%at 650℃,revealing a markedly improved mechanical performance compared with the LPBF-manufactured IN718 alloys.The high-temperature tensile strength of 1%Ti_(2)AlC/IN718 sample increased to 1197.99 MPa by heat treatment.It was suggested that dislocation strengthening and ordered strengthening were two most important reinforcement mechanisms.
基金National Natural Science Foundation of China:Exploring the Mechanism of Improved Yupingfeng Powder in Treating Allergic Rhinitis Based on the Nucleotide-Binding Oligomerization Domain,Leucine-rich Repeat and Pyrin Domain-containing Protein 3/Interleukin-33-Mediated Activation Pathway of Pulmonary Group 2 Innate Lymphoid Cells in Airway Epithelial Cells(No.82374526)Science and Technology Project of Guangzhou:Mechanism of Shikonin in Treating Acute Lung Injury Through Regulating M1 Macrophage Polarization via Adenosine 5'-monophosphate-Activated Protein Kinase/Dynamin-Related Protein 1-mediated Mitochondrial Dynamics(No.2024A04J4334)+2 种基金Exemplary Study on Process Optimization and Quality Standard Enhancement of Hospital Preparations Such as Gangmei Qingyan Mixture(No.2023A03J0299)Anti-Allergic Mechanism of Improved Yupingfeng Powder in Alleviating Nasal Mucosal Inflammation in Allergic Rhinitis via Interleukin-33/Suppression of Tumorigenicity 2-Regulated Group 2 Innate Lymphoid Cells Suppression(No.202201020457)Elite Talent Program of the First Affiliated Hospital of Guangzhou University of Chinese Medicine by 2023 Years and Guangdong Province Lingnan Characteristic Hospital Preparation Transformation Engineering Technology Research Center(No.2023A170)。
文摘OBJECTIVE:To identify the main active ingredients of Improved Yupingfeng Powder prescription(IYPFP,玉屏风散加味)and investigate its anti-inflammatory effects and underlying mechanisms in ovalbumins(OVA)-induced allergic rhinitis(AR)in mice.METHODS:Bagg Albino/substrain mice were sensitized with OVA emulsified in aluminum hydroxide adjuvant,followed by intranasal challenge to establish AR models.Treatment groups received IYPFP(1.5 or 4.5 g/kg)via daily gavage for 14 d.The nasal mucosa tissues were collected for pathological observation.The expression of OVA-specific immunoglobulin E(Ig E),histamine,and interleukin-33(IL-33)was detected by enzyme-linked immunosorbent assay.IL-5,IL-13,IL-33,suppression of tumorigenicity 2(ST2),tumor necrosis factor-α(TNF-α)and interferon-γ(IFN-γ)in the nasal mucosa and lung were detected by quantitative polymerase chain reaction and Western blot.High performance liquid chromatography and ultra-high performance liquid chromatography quadrupole exactive orbitrap mass spectrometry were used to detect the chemical fingerprints of IYPFP,and the chemical compositions of plasma from rats treated with IYPFP at 0.5,1,1.5,2,3,4 and 6 h,respectively.Virtual screening of bioactive compounds was conducted through molecular docking targeting IL-33/ST2 pathway proteins.RESULTS:Eight chemical compounds of IYPFP were accurately identified,they are prim-O-glucosylcimifugin(peak 2),calycosin-7-O-β-D-glucoside(peak 4),cimifugin(peak 5),5-O-methylvisammioside(peak 6),sec-Oglucosylhamaudol(peak 12),calycosin(peak 15),formononetin(peak 19),and magnolin(peak 21).Compared with the OVA model group,IYPFP alleviated the nasal symptoms,improved nasal mucosal injury and downregulated the levels of OVA-specific Ig E,histamine and IL-33.Additionally,IYPFP reduced the levels of IL-5,IL-13,TNF-α,IL-33,and ST2 in the lungs,but upregulated IFN-γ.Molecular docking confirmed that eight representative compounds of IYPFP had good binding properties with IL-5,IL-13,IFN-γ,histamine,IL-33 and ST2,and were able to inhibit the activation of the IL33/ST2 inflammatory pathway.CONCLUSION:This study demonstrates that IYPFP ameliorates AR by modulating IL-33/ST2 pathway which provides a theoretical basis for the clinical treatment of patients with AR.
基金financially supported by the National Natural Science Foundation of China(Nos.52301145,52275329)the Applied Basic Research Program of Liaoning Province,China(No.2023JH2/101300158)+1 种基金the Fundamental Research Fund for the Central Universities,China(No.N2202010)the Key Research Programs of High Education Institutions in Henan Province,China(No.24A430017).
文摘A unique discontinuous lamellar microstructure of titanium alloys consisting of lamellar colonies at prior β-Ti grain boundaries and internal interwoven α-laths is prepared by a TiH_(2)-based powder metallurgy method.The α-variants get various crystallographic orientations and become discontinuous during vacuum annealing at 700℃.Remarkably,nanoscale phase δ-TiH compound layers are generated between α-laths and β-strips,so that dislocations are piled up at the α/δ/βinterfaces during tensile deformation.This leads to dislocation slips being confined to individual α-laths,with differentslips and particularly pyramidal<c+a>slips being activated.The efficiency of wavy slip is promoted and the work hardening rate is enhanced.Finally,the combined effect of dispersed micro-shear bands and lath distortions is considered contributive for alleviating the stress concentration at grain boundaries,resulting in a high-promising synergy of enhanced ultimate tensile strength of 1080 MPa and good elongation to fracture of 13.6%.
基金Supported by the Green Gen plan Program of China Huaneng Group (HNKJ06-H01)
文摘The present study reports a simple,effective and energy-efficient method to prepare γ-LiAlO2 powder as a matrix in a molten carbonate fuel cell(MCFC).In our experiments,aqueous solution based sol-gel technique was used to synthesize γ-LiAlO2.Highly dispersed AlOOH·nH2O and LiOH·H2O aqueous solutions were mixed to form a colloid mixture,which was calcined to synthesize γ-LiAlO2.Thermogravimetric analysis(TGA),X-ray dif-fraction(XRD),and scanning electron microscopy(SEM) were used to study the composition and morphology of the intermediate and final products.The analysis results showed that an intermediate product Li2Al4CO3(OH)12 was produced after the colloid mixture was dried at 80 ℃,and highly purified γ-LiAlO2 powder with fine particle size was resulted from the subsequent calcinations.A single MCFC was assembled with a matrix of the γ-LiAlO2 pow-der.The testing results showed that the matrix performed well in preventing gas leakage.
基金financially supported by the National Natural Science Foundation of China(No.U21A2057).
文摘The rapid advancement of superalloy melting technology has increased the demands on crucible materials.Y_(2)O_(3) is a promising candidate for nickel-based superalloy melting due to its outstanding high-temperature stability and non-wetting behavior with various alloys.However,its poor sintering performance limits its development.High-density Y_(2)O_(3) ceramics were successfully prepared via pressureless sintering at 1600℃ in a carbon-embedded atmosphere with talc powder as an additive.The resulting ceramics achieved optimal properties,including a bulk density of 4.27 g cm^(−3),apparent porosity of 1.1%,and cold compressive strength of 311.27 MPa.The talc powder introduced a liquid phase during sintering,which accelerated mass transfer and promoted grain growth and densification.During cooling,this liquid phase remained at the grain boundaries and acted as an intergranular bonding agent,strengthening grain cohesion.Nevertheless,excessive liquid phase hindered grain growth,negatively affecting sintering.Additionally,the extremely low porosity and the formation of the Mg_(2)SiO_(4) phase reduced the residual strength retention ratio of the Y_(2)O_(3) ceramic after thermal shock.
基金Project (NS2010153) supported by Nanjing University of Aeronautics and Astronautics Research Funding, ChinaProject (BE2009130) supported by Jiangsu Key Technology R&D Program, China
文摘Using Ti powder as reagent, TiO 2 nanoneedle/nanoribbon spheres were prepared via hydrothermal method in NaOH solution. The samples were characterized by field emission scanning electron microscopy （FESEM）, transmission electron microscopy （TEM） with selected area electron diffraction （SAED）, X-ray diffraction （XRD）, and UV-visible light absorption spectrum. The results indicate that the growth orientations of the crystals are influenced by the hydrothermal temperature and NaOH concentration. The diameter of the nanoneedle spheres and nanoribbon spheres （40 50 μm） are almost the same as that of Ti powders. TiO 2 nanoneedle/nanoribbon sphere powders are anatase after heat treatment at 450 °C for 1 h. Furthermore, methyl orange was used as a target molecule to estimate the photocatalytic activity of the specimens. Under the same testing conditions, the photocatalytic activities of the products decrease in the following order： TiO 2 nanoneedle sphere, TiO 2 nanoribbon sphere and P25.
基金Project (2006BAB02B05-04- 01/02) supported by the National Key Technologies R&D Program of China
文摘α-Bi2O3 powders were prepared from nanometer Bi powders through low-temperature oxidation at less than 873.15 K. XRD, SEM, TEM and HRTEM were used to characterize the structure and morphology of Bi powders and Bi2O3 particles. Kinetic studies on the bismuth oxidation at low-temperatures were carried out by TGA method. The results show that bismuth beads should be reunited and oxidized to become irregular Bi2O3 powders. The bismuth oxidation follows shrinking core model, and its controlling mechanism varies at different reaction time. Within 0-10 min, the kinetics is controlled by chemical reaction, after that it is controlled by O2 diffusion in the solid α-Bi2O3 layer. The apparent activation energy is determined as 55.19 kJ/mol in liquid-phase oxidation.
