Conventional MgO-C bricks(graphite content>14 wt.%)produce a great deal of greenhouse gas emission,while low-carbon MgO-C bricks have serious thermal shock resistance during high-temperature service.To enhance the ...Conventional MgO-C bricks(graphite content>14 wt.%)produce a great deal of greenhouse gas emission,while low-carbon MgO-C bricks have serious thermal shock resistance during high-temperature service.To enhance the high-temperature mechanical property and thermal shock resistance of low-carbon MgO-C bricks,a novel route of introducing ZrSiO_(4) powder into low-carbon MgO-C bricks was reported in such refractories with 2 wt.% flaky graphite.The results indicate that the low-carbon MgO-C brick with 0.5 wt.%ZrSiO_(4) addition has the maximum hot modulus of rupture at 1400℃ and the corresponding specimen fired in the carbon embedded atmosphere has the maximum residual strength ratio(98.6%)after three thermal shock cycles.It is found that some needle-like AlON and plate-like Al_(2)O_(3)-ZrO_(2) composites were in situ formed in the matrices after the low-carbon MgO-C bricks were coked at 1400℃,which can enhance the high-temperature mechanical property and thermal shock resistance due to the effect of fiber toughening and particle toughening.Moreover,CO_(2) emission of the newly developed low-carbon MgO-C bricks is reduced by 58.3% per ton steel after using them as the working lining of a 90 t vacuum oxygen decarburization ladle.展开更多
Synthetic zircon(ZrSiO_(4))ceramics are typically fabricated at elevated temperatures(over 1500℃),which would lead to high manufacturing cost.Meanwhile,reports about preparing ZrSiO_(4)-based ceramic composites via c...Synthetic zircon(ZrSiO_(4))ceramics are typically fabricated at elevated temperatures(over 1500℃),which would lead to high manufacturing cost.Meanwhile,reports about preparing ZrSiO_(4)-based ceramic composites via controlling the solid-state reaction between zirconia(ZrO_(2))and silica(SiO_(2))are limited.In this work,we proposed a low-temperature strategy to flexibly design and fabricate ZrSiO_(4)-based ceramic composites via doping and tuning the solid-state reaction.Two ceramic composites and ZrSiO_(4) ceramics were in-situ prepared by reactive fast hot pressing(FHP)at approximately 1250℃ based on the proposed strategy,i.e.,a ZrSiO_(4)-SiO_(2) dual-phase composite with bicontinuous interpenetrating and hierarchical microstructures,a ZrSiO_(4)-ZrO_(2) dual-phase composite with a microstructure of ZrO_(2) submicron-and nano-particles embedded in a micron ZrSiO_(4) matrix,and ZrSiO_(4) ceramics with a small amount of residual ZrO_(2) nanoparticles.The results showed that the phase compositions,microstructure configurations,mechanical properties,and wear resistance of the materials can be flexibly regulated by the proposed strategy.Hence,ZrSiO_(4)-based ceramic composites with different properties can be easily fabricated based on different application scenarios.These findings would offer useful guidance for researchers to flexibly fabricate ZrSiO_(4)-based ceramic composites at low temperatures and tailor their microstructures and properties through doping and tuning the solid-state reaction.展开更多
ZrB2 and ZrB2-SiC powders have been produced by reducing ZrO2 and ZrSiO4 with B4C without using any furnace.Magnesium was added to the mixtures of (ZrO2+B4C) and (ZrSiO4+B4C).The reaction has been assisted by a floral...ZrB2 and ZrB2-SiC powders have been produced by reducing ZrO2 and ZrSiO4 with B4C without using any furnace.Magnesium was added to the mixtures of (ZrO2+B4C) and (ZrSiO4+B4C).The reaction has been assisted by a floral thermite packed around the compacts.By introducing elemental Si into (ZrO2+B4C) mixture,composite powders of ZrB2-SiC formed.After leaching out MgO with suitable HCl water solution,the product was analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The effect of Si,B4C,and Mg on the extent of formation of ZrB2,ZrB2-SiC,and other phases has been studied.Formation of nano-sized ZrB2 and ZrB2-SiC composite powders was identified.The adaptability of the process for bulk production was examined.展开更多
基金Enterprise Research and Development Project of Beijing Lirr High-Temperature Materials Co.,Ltd.(2020-02)Key Scientific Research Project for Universities and Colleges in Henan Province(19A430028)+1 种基金the Excellent Youth Research Project of Anhui Province(2022AH030135)the PhD Research Funding of Suzhou University(2021BSK041).
文摘Conventional MgO-C bricks(graphite content>14 wt.%)produce a great deal of greenhouse gas emission,while low-carbon MgO-C bricks have serious thermal shock resistance during high-temperature service.To enhance the high-temperature mechanical property and thermal shock resistance of low-carbon MgO-C bricks,a novel route of introducing ZrSiO_(4) powder into low-carbon MgO-C bricks was reported in such refractories with 2 wt.% flaky graphite.The results indicate that the low-carbon MgO-C brick with 0.5 wt.%ZrSiO_(4) addition has the maximum hot modulus of rupture at 1400℃ and the corresponding specimen fired in the carbon embedded atmosphere has the maximum residual strength ratio(98.6%)after three thermal shock cycles.It is found that some needle-like AlON and plate-like Al_(2)O_(3)-ZrO_(2) composites were in situ formed in the matrices after the low-carbon MgO-C bricks were coked at 1400℃,which can enhance the high-temperature mechanical property and thermal shock resistance due to the effect of fiber toughening and particle toughening.Moreover,CO_(2) emission of the newly developed low-carbon MgO-C bricks is reduced by 58.3% per ton steel after using them as the working lining of a 90 t vacuum oxygen decarburization ladle.
基金the financial support of the National Natural Science Foundation of China(52102084)Natural Science Foundation of Hunan Province(2022JJ30718)+1 种基金the financial support of the Youth Innovation Promotion Association Chinese Academy of Sciences(CAS)(2022428)the Science Fund of Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing(AMGM2021A08).
文摘Synthetic zircon(ZrSiO_(4))ceramics are typically fabricated at elevated temperatures(over 1500℃),which would lead to high manufacturing cost.Meanwhile,reports about preparing ZrSiO_(4)-based ceramic composites via controlling the solid-state reaction between zirconia(ZrO_(2))and silica(SiO_(2))are limited.In this work,we proposed a low-temperature strategy to flexibly design and fabricate ZrSiO_(4)-based ceramic composites via doping and tuning the solid-state reaction.Two ceramic composites and ZrSiO_(4) ceramics were in-situ prepared by reactive fast hot pressing(FHP)at approximately 1250℃ based on the proposed strategy,i.e.,a ZrSiO_(4)-SiO_(2) dual-phase composite with bicontinuous interpenetrating and hierarchical microstructures,a ZrSiO_(4)-ZrO_(2) dual-phase composite with a microstructure of ZrO_(2) submicron-and nano-particles embedded in a micron ZrSiO_(4) matrix,and ZrSiO_(4) ceramics with a small amount of residual ZrO_(2) nanoparticles.The results showed that the phase compositions,microstructure configurations,mechanical properties,and wear resistance of the materials can be flexibly regulated by the proposed strategy.Hence,ZrSiO_(4)-based ceramic composites with different properties can be easily fabricated based on different application scenarios.These findings would offer useful guidance for researchers to flexibly fabricate ZrSiO_(4)-based ceramic composites at low temperatures and tailor their microstructures and properties through doping and tuning the solid-state reaction.
文摘ZrB2 and ZrB2-SiC powders have been produced by reducing ZrO2 and ZrSiO4 with B4C without using any furnace.Magnesium was added to the mixtures of (ZrO2+B4C) and (ZrSiO4+B4C).The reaction has been assisted by a floral thermite packed around the compacts.By introducing elemental Si into (ZrO2+B4C) mixture,composite powders of ZrB2-SiC formed.After leaching out MgO with suitable HCl water solution,the product was analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The effect of Si,B4C,and Mg on the extent of formation of ZrB2,ZrB2-SiC,and other phases has been studied.Formation of nano-sized ZrB2 and ZrB2-SiC composite powders was identified.The adaptability of the process for bulk production was examined.
