Magnesium slag(MS)is an industrial byproduct with high CO_(2)sequestration potential.This study investigates the carbonation behavior and microstructural changes of MS during wet carbonation at 0℃.XRD,TG,FTIR,SEM,and...Magnesium slag(MS)is an industrial byproduct with high CO_(2)sequestration potential.This study investigates the carbonation behavior and microstructural changes of MS during wet carbonation at 0℃.XRD,TG,FTIR,SEM,and BET techniques were used to characterize the phase composition,microstructure,and porosity of MS samples carbonated for different durations.The results showed that the main carbonation products were calcite,vaterite,and highly polymerized silica gel,with particle sizes around 1μm.The low-temperature environment retarded the carbonation reaction rate and affected the morphology and crystallization of calcium carbonate.After 480 min of carbonation,the specific surface area and porosity of MS increased substantially by 740%and 144.6%,respectively,indicating improved reactivity.The microstructure of carbonated MS became denser with calcite particles surrounded by silica gel.This study demonstrates that wet carbonation of MS at 0℃significantly enhances its properties,creating an ultrafine supplementary cementitious material with considerable CO_(2)sequestration capacity.展开更多
A slow scintillation component due to charge carrier capture at point defects is a serious issue in scintillator materials.Therefore,the fabrication of scintillators with a high proportion of fast components in the sc...A slow scintillation component due to charge carrier capture at point defects is a serious issue in scintillator materials.Therefore,the fabrication of scintillators with a high proportion of fast components in the scintillation response is of great interest to material scientists.By applying the defect engineering strategy in advanced optical Lu3Al5O12:Ce,Mg(LuAG:Ce,Mg)ceramics,an ultrahigh fast scintillation proportion can be achieved with a slight loss of fast scintillation light.Moreover,low-temperature thermoluminescence(TSL)investigations revealed that the intensities of all the TSL peaks decreased in the Mg^(2+)-codoped samples.The slight loss of fast scintillation light observed was explained by density functional theory(DFT)calculations.The effect of{Ce^(3+)–Mg^(2-)}pairs on emission quenching was compared with that of{Ce^(3+)–Ca^(2-)}pairs.As a consequence,the 0.3 at%Mg^(2+)-codoped ceramic sample has an LY0.5µs/LY10µs ratio of 99.8%,which is better than those reported for isostructural ceramics and single crystals.We conclude with a discussion of the role of Mg^(2+)co-doping and future research directions concerning other oxide scintillators.展开更多
For high-repetition-rate nanosecond high-power solid-state lasers,it is essential to choose gain media with moderate saturation flux.Among these materials,Nd:Lu_(3)Al_(5)O_(12)(LuAG)transparent ceramics have shown sig...For high-repetition-rate nanosecond high-power solid-state lasers,it is essential to choose gain media with moderate saturation flux.Among these materials,Nd:Lu_(3)Al_(5)O_(12)(LuAG)transparent ceramics have shown significant potential.The thermal effect limits their power density in the gain element,but increasingthe size of the gain medium can help dissipate heat.However,a large aspect ratio can lead to high spontaneous fluorescence,causing amplified spontaneous emission(ASE)and parasitic oscillations(PO_(5)).A solution is to apply cladding layers to absorb stray radiation.Sm:LuAG transparent ceramics,with high absorption at 1064 nm,good transmittance at 808 nm,and a refractive index similar to that of Nd:LuAG,are ideal for cladding Nd:LuAG laser ceramics,In this work,highly transparent Sm:LuAG ceramics were successfully fabricated first through low-temperature vacuum pre-sintering combined with high-temperature hot isostatic pressing(HiP)post-treatment using the co-precipitated Sm:LuAG nano-powders.The influences of Sm^(3+)doping concentration on the microstructure and optical transmittance of Sm:LuAG ceramics were studied.The nano-powders calcined at 1100℃for 4 h showed dendritic agglomerations but relatively small particle sizes and high uniformity.Sm:LuAG ceramics with different doping amounts were obtained by vacuum sintering at 1550℃for 3 h followed by HIP post-treatment at 1550 C in an argon atmosphere at 200 MPa for 3 h.The 3 at%Sm:LuAG transparent ceramics(1.5 mm in thickness)exhibited the highest in-line transmittance of 83.9%at 808 nm,a fine grain size of 909 nm,and an absorption coefficient of 2.44 cm^(-1)at 1064 nm,indicating that it can effectively suppress ASE and PO.展开更多
基金support from the National Key R&D Program Intergovernmental International Science and Technology Innovation Cooperation Project(2018YFE0107300)the China Building Materials Federation(20221JBGS03-11)+2 种基金the Science and Technology Project of Henan Province(211110231400,212102310559,212102310564,222300420167,22A430022)the Opening Project of the State Key Laboratory of Green Building Materials(2021GBM06)the Henan Outstanding Foreign Scientists’Workroom(GZS2021003).
文摘Magnesium slag(MS)is an industrial byproduct with high CO_(2)sequestration potential.This study investigates the carbonation behavior and microstructural changes of MS during wet carbonation at 0℃.XRD,TG,FTIR,SEM,and BET techniques were used to characterize the phase composition,microstructure,and porosity of MS samples carbonated for different durations.The results showed that the main carbonation products were calcite,vaterite,and highly polymerized silica gel,with particle sizes around 1μm.The low-temperature environment retarded the carbonation reaction rate and affected the morphology and crystallization of calcium carbonate.After 480 min of carbonation,the specific surface area and porosity of MS increased substantially by 740%and 144.6%,respectively,indicating improved reactivity.The microstructure of carbonated MS became denser with calcite particles surrounded by silica gel.This study demonstrates that wet carbonation of MS at 0℃significantly enhances its properties,creating an ultrafine supplementary cementitious material with considerable CO_(2)sequestration capacity.
基金supported by the National Natural Science Foundation of China(No.12175254)the Shanghai High-Level Talent Plan and the Opening Fund of the Key Laboratory of Rare Earths,Chinese Academy of Sciences.
文摘A slow scintillation component due to charge carrier capture at point defects is a serious issue in scintillator materials.Therefore,the fabrication of scintillators with a high proportion of fast components in the scintillation response is of great interest to material scientists.By applying the defect engineering strategy in advanced optical Lu3Al5O12:Ce,Mg(LuAG:Ce,Mg)ceramics,an ultrahigh fast scintillation proportion can be achieved with a slight loss of fast scintillation light.Moreover,low-temperature thermoluminescence(TSL)investigations revealed that the intensities of all the TSL peaks decreased in the Mg^(2+)-codoped samples.The slight loss of fast scintillation light observed was explained by density functional theory(DFT)calculations.The effect of{Ce^(3+)–Mg^(2-)}pairs on emission quenching was compared with that of{Ce^(3+)–Ca^(2-)}pairs.As a consequence,the 0.3 at%Mg^(2+)-codoped ceramic sample has an LY0.5µs/LY10µs ratio of 99.8%,which is better than those reported for isostructural ceramics and single crystals.We conclude with a discussion of the role of Mg^(2+)co-doping and future research directions concerning other oxide scintillators.
基金supported by the National Key R&D Program of China(No.2023YFB3812000).
文摘For high-repetition-rate nanosecond high-power solid-state lasers,it is essential to choose gain media with moderate saturation flux.Among these materials,Nd:Lu_(3)Al_(5)O_(12)(LuAG)transparent ceramics have shown significant potential.The thermal effect limits their power density in the gain element,but increasingthe size of the gain medium can help dissipate heat.However,a large aspect ratio can lead to high spontaneous fluorescence,causing amplified spontaneous emission(ASE)and parasitic oscillations(PO_(5)).A solution is to apply cladding layers to absorb stray radiation.Sm:LuAG transparent ceramics,with high absorption at 1064 nm,good transmittance at 808 nm,and a refractive index similar to that of Nd:LuAG,are ideal for cladding Nd:LuAG laser ceramics,In this work,highly transparent Sm:LuAG ceramics were successfully fabricated first through low-temperature vacuum pre-sintering combined with high-temperature hot isostatic pressing(HiP)post-treatment using the co-precipitated Sm:LuAG nano-powders.The influences of Sm^(3+)doping concentration on the microstructure and optical transmittance of Sm:LuAG ceramics were studied.The nano-powders calcined at 1100℃for 4 h showed dendritic agglomerations but relatively small particle sizes and high uniformity.Sm:LuAG ceramics with different doping amounts were obtained by vacuum sintering at 1550℃for 3 h followed by HIP post-treatment at 1550 C in an argon atmosphere at 200 MPa for 3 h.The 3 at%Sm:LuAG transparent ceramics(1.5 mm in thickness)exhibited the highest in-line transmittance of 83.9%at 808 nm,a fine grain size of 909 nm,and an absorption coefficient of 2.44 cm^(-1)at 1064 nm,indicating that it can effectively suppress ASE and PO.
