A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary...A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.展开更多
Developing a stable insulation material stands as a crucial challenge for high-voltage direct current(HVDC)cable insulation.This work proposes an alloying strategy to significantly enhance the breakdown strength and h...Developing a stable insulation material stands as a crucial challenge for high-voltage direct current(HVDC)cable insulation.This work proposes an alloying strategy to significantly enhance the breakdown strength and high-temperature resistivity of cross-linked polyethylene(XLPE).The strategy involves blending low-density polyethylene(LDPE)with polystyrene(PS),resulting in a polymeric alloy.Confirmation of PS alloying within XLPE is supported by observed shifts in polyethylene miller indices(110)and(200)planes.The dicumyl peroxide used as a crosslinking agent demonstrates an ideal 1.41% enhancement in LDPE-PS crosslinking.The integration of aromatic ethers in the cross-linked network enhances temperature stability.Alloying PS at 220℃ in XLPE leads to improved inter-molecular interactions and increased interfacial area,creating a sea-island morphology that resolves voids and limits defect or crack propagation by form-ing additional trapping sites.The enhanced breakdown strength and reduced conductivity of XLPE-PS are attributed to increased deep trapping sites and reduced carrier mobility resulting from alloying.The reduced conductivity at 70℃ and 90℃ demonstrates stability under electric fields.Remarkable breakdown strength improvements of 27.5%and 23.6% are observed at 30℃ and 50℃.The proposed alloying strategy suggests replacing XLPE with advanced XLPE-PS,offering promising prospects for HVDC insulation.展开更多
基金Funded by the Open Project Program of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(No.KLIFMD201606)the Open Fund of National Innovation Platform(No.2017YJ163)+1 种基金the National Natural Science Foundation of China(Nos.51502220,51521001,and 51672197)the Open Foundation of Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics(Wuhan University of Technology)(No.TAM201802)。
文摘A temperature stable Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics were fabricated using a conventional solid-state route sintered at 1100℃for 4 h.The XRD results indicate that the main phase Li2ZnTi3O8 and secondary phase including SrxCa1-xTiO3(0≤x≤1)solid solution and TiO2 co-exist in composite and form a stable composite system when the(CaxSr1-x)(0≤x≤1)substitutes for Zn of Li2ZnTi3O8 ceramic.As x is increased from 0 to 1,the relative permittivity(εr)increases from 26.65 to 27.12,and the quality factor(Q×f)increases from 63300 to 66600 GHz.With the increased of x,the temperature coefficient of resonant frequency(τf)increases from 0.27 to 8.23 ppm/℃,and then decreases to 3.51 ppm/℃.On the whole,the Li2Zn0.95(SrxCa1-x)0.05Ti3O8(0≤x≤1)ceramics show excellent comprehensive properties of middleεr=25-27,higher Q×f≥60000 GHz andτf≤±8.5 ppm/℃.
基金State Grid Corporation of China,Grant/Award Number:5500-202258104A-1-1-ZN。
文摘Developing a stable insulation material stands as a crucial challenge for high-voltage direct current(HVDC)cable insulation.This work proposes an alloying strategy to significantly enhance the breakdown strength and high-temperature resistivity of cross-linked polyethylene(XLPE).The strategy involves blending low-density polyethylene(LDPE)with polystyrene(PS),resulting in a polymeric alloy.Confirmation of PS alloying within XLPE is supported by observed shifts in polyethylene miller indices(110)and(200)planes.The dicumyl peroxide used as a crosslinking agent demonstrates an ideal 1.41% enhancement in LDPE-PS crosslinking.The integration of aromatic ethers in the cross-linked network enhances temperature stability.Alloying PS at 220℃ in XLPE leads to improved inter-molecular interactions and increased interfacial area,creating a sea-island morphology that resolves voids and limits defect or crack propagation by form-ing additional trapping sites.The enhanced breakdown strength and reduced conductivity of XLPE-PS are attributed to increased deep trapping sites and reduced carrier mobility resulting from alloying.The reduced conductivity at 70℃ and 90℃ demonstrates stability under electric fields.Remarkable breakdown strength improvements of 27.5%and 23.6% are observed at 30℃ and 50℃.The proposed alloying strategy suggests replacing XLPE with advanced XLPE-PS,offering promising prospects for HVDC insulation.
