The microstructure, electrical properties and density of ZnO-based varistor ceramics with different Er2O3 content prepared by high-energy ball milling (HEBM) and sintered at 800℃ were investigated. With increasing ...The microstructure, electrical properties and density of ZnO-based varistor ceramics with different Er2O3 content prepared by high-energy ball milling (HEBM) and sintered at 800℃ were investigated. With increasing Er2O3 content, the ZnO grain size decreases due to the Er-rich phases inhibiting grain growth ; and nonlinear coefficient ( α ) decreases because of the decrease of barrier height (φB) The breakdown voltage (Eb) and density increase, whereas leakage current (IL) decreases with increasing Er2O3 content. The barrier height (φB), donor concentration (Nd), density of interface states (Ns) decrease and barrier width (ω) increases with increasing Er2O3 content due to acceptor effect of Er2O3 in varistor ceramics.展开更多
The influence of Er_2 O_3 addition on the phase evolution and mechanical properties of sintered(1600 ℃,4 h) ZTA(yttria stabilized zirconia toughened alumina)-TiO_2 composites was investigated. The SEM and XRD results...The influence of Er_2 O_3 addition on the phase evolution and mechanical properties of sintered(1600 ℃,4 h) ZTA(yttria stabilized zirconia toughened alumina)-TiO_2 composites was investigated. The SEM and XRD results reveal the formation of a new erbium zirconium oxide,Zr_3 Er_4 O_(12),with a granulate morphology when Er_2 O_3 content is higher than 1 wt%. The grain sizes of both Al_2 O_3 and yttria-stabilized zirconia phases decrease with an increase in the Er_2 O_3 content. The relative density, Vickers hardness and fracture toughness of the composites are found to be strongly dependent on their grain sizes, relative densities and the formation of the Zr_3 Er_4 O_(12) secondary phases. The composite with 5 wt% Er_2 O_3 shows the highest relative density(99.93%), Vickers hardness(1752 HV) and fracture toughness(7.92 MPa·m^(1/2)).展开更多
基金Project supported by National Natural Science Foundation of China (50471045) Shanghai Nano-Technology PromotionCenter (0452nm026)
文摘The microstructure, electrical properties and density of ZnO-based varistor ceramics with different Er2O3 content prepared by high-energy ball milling (HEBM) and sintered at 800℃ were investigated. With increasing Er2O3 content, the ZnO grain size decreases due to the Er-rich phases inhibiting grain growth ; and nonlinear coefficient ( α ) decreases because of the decrease of barrier height (φB) The breakdown voltage (Eb) and density increase, whereas leakage current (IL) decreases with increasing Er2O3 content. The barrier height (φB), donor concentration (Nd), density of interface states (Ns) decrease and barrier width (ω) increases with increasing Er2O3 content due to acceptor effect of Er2O3 in varistor ceramics.
基金Project supported by National Natural Science Foundation of China(51571103,51501079)China Postdoctoral Science Foundation(2017M623319XB,2018T110999)Yunnan Provincial Department of Education Science Research Fund Project(2018JS033)
文摘The influence of Er_2 O_3 addition on the phase evolution and mechanical properties of sintered(1600 ℃,4 h) ZTA(yttria stabilized zirconia toughened alumina)-TiO_2 composites was investigated. The SEM and XRD results reveal the formation of a new erbium zirconium oxide,Zr_3 Er_4 O_(12),with a granulate morphology when Er_2 O_3 content is higher than 1 wt%. The grain sizes of both Al_2 O_3 and yttria-stabilized zirconia phases decrease with an increase in the Er_2 O_3 content. The relative density, Vickers hardness and fracture toughness of the composites are found to be strongly dependent on their grain sizes, relative densities and the formation of the Zr_3 Er_4 O_(12) secondary phases. The composite with 5 wt% Er_2 O_3 shows the highest relative density(99.93%), Vickers hardness(1752 HV) and fracture toughness(7.92 MPa·m^(1/2)).