Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering （ LPS ）. The Si2 N2O phase was generated by an in-situ reaction 2 Si3 N4 （ s ） ＋ 1.5 02 （ g...Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering （ LPS ）. The Si2 N2O phase was generated by an in-situ reaction 2 Si3 N4 （ s ） ＋ 1.5 02 （ g ） = 3 Si2 N2O （ s ） ＋ N2 （ g ） . The content of Si2 N2 O phase up to 60% in the volume was obtained at a sintering temperature of 1 650℃ and reduced when the sintering temperature increased or decreased, indicating the reaction is reversible. The mass loss, relative density and average grain size increased with increasing the sintering temperature. The average grain size was less than 500 nm when the sintering temperature was below 1 700 ℃. The sintering procedure contains a complex crystallization and a phase transition ： amorphous silicon nitride→equiaxial α- Si3 N4→ equiaxial β- Si3 N4→ rod- like Si2 N2O→ needle- like β- Si3N4 . Small round-shaped β→ Si3 N4 particles were entrapped in the Si2 N2O grains and a high density of staking faults was situated in the middle of Si2 N2O grains at a sintering temperature of 1 650 ℃. The toughness inereased from 3.5 MPa·m^1/2 at 1 600 ℃ to 7.2 MPa· m^1/2 at 1 800 ℃ . The hardness was as high as 21.5 GPa （Vickers） at 1 600 ℃ .展开更多
The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties ...The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties were investigated.A distinct bipolar resistive switching behavior of the devices was observed at room temperature.The resistance ratio R_（HRS）/RLRS of high resistance state and low resistance state is as large as four orders of magnitude with a readout voltage of 2.0 V.The dominant conduction mechanism of the device is trap-controlled space charge limited current（SCLC）.The devices exhibit good durability under 1×10^3cycles and the degradation is invisible for more than 10^6 s.展开更多
采用4种不同用量的硅烷偶联剂KH-550对纳米SiO_2表面进行改性,并检测改性后纳米SiO_2粒径的大小;研究了改性后纳米SiO_2的添加量对芳纶纸性能的影响;通过扫描电镜(SEM)观察添加改性纳米SiO_2后芳纶纸的表观形貌,并将纳米SiO_2添加前后...采用4种不同用量的硅烷偶联剂KH-550对纳米SiO_2表面进行改性,并检测改性后纳米SiO_2粒径的大小;研究了改性后纳米SiO_2的添加量对芳纶纸性能的影响;通过扫描电镜(SEM)观察添加改性纳米SiO_2后芳纶纸的表观形貌,并将纳米SiO_2添加前后纸张抗张强度和介电强度进行了对比。结果表明,随着硅烷偶联剂用量的增加,改性纳米SiO_2的粒径有所减小;当纳米SiO_2与硅烷偶联剂KH-550配比为5 g∶20 m L、改性纳米SiO_2添加量为5%时,芳纶纸的抗张强度提高了66.2%,硅烷偶联剂用量的增加对纸张伸长率有一定影响,其紧度变化不明显;SEM图显示改性纳米SiO_2粒子填充在纸张空隙处利于纸张性能的增强;添加改性纳米SiO_2较未添加纳米SiO_2和添加未改性纳米SiO_2芳纶纸的抗张强度和介电强度均有所提高。展开更多
基金Funded by the National Science Foundation of China ( No.50375037)
文摘Si3N4-Si2N2O composites were fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering （ LPS ）. The Si2 N2O phase was generated by an in-situ reaction 2 Si3 N4 （ s ） ＋ 1.5 02 （ g ） = 3 Si2 N2O （ s ） ＋ N2 （ g ） . The content of Si2 N2 O phase up to 60% in the volume was obtained at a sintering temperature of 1 650℃ and reduced when the sintering temperature increased or decreased, indicating the reaction is reversible. The mass loss, relative density and average grain size increased with increasing the sintering temperature. The average grain size was less than 500 nm when the sintering temperature was below 1 700 ℃. The sintering procedure contains a complex crystallization and a phase transition ： amorphous silicon nitride→equiaxial α- Si3 N4→ equiaxial β- Si3 N4→ rod- like Si2 N2O→ needle- like β- Si3N4 . Small round-shaped β→ Si3 N4 particles were entrapped in the Si2 N2O grains and a high density of staking faults was situated in the middle of Si2 N2O grains at a sintering temperature of 1 650 ℃. The toughness inereased from 3.5 MPa·m^1/2 at 1 600 ℃ to 7.2 MPa· m^1/2 at 1 800 ℃ . The hardness was as high as 21.5 GPa （Vickers） at 1 600 ℃ .
基金Funded by the National Natural Science Foundation of China(No.51262003)the Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China(No.1110908-10-Z)
文摘The Ag/Mg0.2Zn0.8O/ZnMn2O4/p^＋-Si heterostructure devices were fabricated by sol-gel spin coating technique and the resistive switching behavior,conduction mechanism,endurance characteristic,and retention properties were investigated.A distinct bipolar resistive switching behavior of the devices was observed at room temperature.The resistance ratio R_（HRS）/RLRS of high resistance state and low resistance state is as large as four orders of magnitude with a readout voltage of 2.0 V.The dominant conduction mechanism of the device is trap-controlled space charge limited current（SCLC）.The devices exhibit good durability under 1×10^3cycles and the degradation is invisible for more than 10^6 s.
文摘采用4种不同用量的硅烷偶联剂KH-550对纳米SiO_2表面进行改性,并检测改性后纳米SiO_2粒径的大小;研究了改性后纳米SiO_2的添加量对芳纶纸性能的影响;通过扫描电镜(SEM)观察添加改性纳米SiO_2后芳纶纸的表观形貌,并将纳米SiO_2添加前后纸张抗张强度和介电强度进行了对比。结果表明,随着硅烷偶联剂用量的增加,改性纳米SiO_2的粒径有所减小;当纳米SiO_2与硅烷偶联剂KH-550配比为5 g∶20 m L、改性纳米SiO_2添加量为5%时,芳纶纸的抗张强度提高了66.2%,硅烷偶联剂用量的增加对纸张伸长率有一定影响,其紧度变化不明显;SEM图显示改性纳米SiO_2粒子填充在纸张空隙处利于纸张性能的增强;添加改性纳米SiO_2较未添加纳米SiO_2和添加未改性纳米SiO_2芳纶纸的抗张强度和介电强度均有所提高。
