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不同烧结环境对La0.67Sr0.33MnO3结构与电磁性能的影响
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作者 杨艺 许义开 +2 位作者 董鑫 邹福刚 陈杰 《应用物理》 CAS 2021年第5期253-258,共6页
采用固相反应方法制备了名义成分为La0.67Sr0.33MnO3的系列样品。通过X射线衍射谱、扫描电镜、电阻率–温度曲线、磁电阻–温度曲线,研究了烧结环境对样品电阻和磁电性质的影响。实验结果显示,随烧结环境氧含量的减少,铁磁性减弱,导电... 采用固相反应方法制备了名义成分为La0.67Sr0.33MnO3的系列样品。通过X射线衍射谱、扫描电镜、电阻率–温度曲线、磁电阻–温度曲线,研究了烧结环境对样品电阻和磁电性质的影响。实验结果显示,随烧结环境氧含量的减少,铁磁性减弱,导电性降低,由于烧结氛围的变化,改变了样品中的氧含量,样品中载流子的浓度以及Mn离子的局域环境随之发生变化,以及铁磁与反铁磁作用的相互竞争的结果,改变了材料的磁电性能。 展开更多
关键词 庞磁电阻效应 烧结环境 稀土锰氧化物
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高Q值铜内电极MLCC烧结工艺研究 被引量:4
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作者 胡霞 曾雨 《电子工艺技术》 2018年第6期359-362,共4页
提出了一种高Q值铜内电极多层陶瓷电容器(MLCC)的烧结工艺。研究了烧结工艺中烧结温度、保温时间以及烧结环境对高Q值铜内电极MLCC的损耗和绝缘性能的影响,结果发现,合适的烧结温度可以使陶瓷晶粒生长充分,同时可以防止铜内电极出现挥... 提出了一种高Q值铜内电极多层陶瓷电容器(MLCC)的烧结工艺。研究了烧结工艺中烧结温度、保温时间以及烧结环境对高Q值铜内电极MLCC的损耗和绝缘性能的影响,结果发现,合适的烧结温度可以使陶瓷晶粒生长充分,同时可以防止铜内电极出现挥铜现象。合适的保温时间可以在一定程度上改善瓷体颜色发白的现象。特殊的烧结环境可以使陶瓷芯片烧结更加致密,从根本上解决颜色发白的问题,从而解决铜内电极MLCC沉积后存在的损耗上升和绝缘性能下降的问题。 展开更多
关键词 铜内电极 Q值 损耗 绝缘 烧结温度 烧结环境 多层陶瓷电容器
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Calcium ferrite formation characteristic during iron ore sintering with different oxygen atmospheres 被引量:2
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作者 毛晓明 游志雄 +3 位作者 张元波 范振宇 李光辉 姜涛 《Journal of Central South University》 SCIE EI CAS 2014年第8期3043-3048,共6页
It is generally known that the large formation amount of calcium ferrite is favorable for the iron ore sintering. The effects of sintering temperature and O2 content of inlet gas on the calcium ferrite formation chara... It is generally known that the large formation amount of calcium ferrite is favorable for the iron ore sintering. The effects of sintering temperature and O2 content of inlet gas on the calcium ferrite formation characteristic of typical iron ores, including hematite, limonite, specularite and magnetite, were investigated. And the effect of O2 content on the microstructure of the roasted briquettes was also studied in detail. The results show the amount of calcium ferrite initially increases then decreases with the increase of the sintering temperature. The temperature of maximum calcium ferrite generation amount is determined as follows: for hematite and limonite it is 1275 ~C, whereas for specularite and magnetite, 1250℃. The maximum contents of calcium ferrite for hematite, limonite, specularite and magnetite under the optimal sintering temperature are 73%, 82%, 67% and 63%, respectively. Increasing O2 content of the airflow is advantageous to the formation of calcium ferrite. Relatively, the effect of O2 content on the calcium ferrite formation of magnetite is the most pronounced, while O2 content of inlet gas has little effect on the calcium ferrite formation of limonite. 展开更多
关键词 iron ore SINTERING calcium ferrite MINERALIZATION
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SYNTHESIS OF AG(NB_(0.8) TA_(0.2)) O_3 CERAMICS UNDER DIFFERENT AMBIENT CONDITIONS
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作者 郭秀盈 肖谧 +1 位作者 吴霞宛 张之圣 《Transactions of Tianjin University》 EI CAS 2006年第1期23-27,共5页
Different ambient conditions for the synthesis of Ag(Nb0.8Ta0.2)O3 ceramics were investi- gated. The Ag(Nb0.8Ta0.2)O3 powder was synthesized at 950 ℃ under different ambient conditions, and then pressed into disk... Different ambient conditions for the synthesis of Ag(Nb0.8Ta0.2)O3 ceramics were investi- gated. The Ag(Nb0.8Ta0.2)O3 powder was synthesized at 950 ℃ under different ambient conditions, and then pressed into disks and sintered between 1060 ℃ and 1100 ℃ respectively. Samples were investigated by X-ray diffraction, scanning electron microscopy and dielectric measurement. The results show that perovskite Ag(Nb0.8Ta0.2)O3 powder was easier to be synthesized in air than in vacuum at 950℃. Grain size of ceramic samples sintered in air was uniform (about 1 μm) and its dielectric loss was small for its high density. However, the samples decomposed greatly and ceramics could hardly be densified when sintered in vacuum, Thus,. higher atmospheric pressure and oxygen atmosphere would benifit the synthesis of Ag (Nb0.8Ta0.2)O3, and suppress its decomposition at high temperature. 展开更多
关键词 Ag(Nb0.8Ta0.2)O3 PEROVSKITE DECOMPOSITION
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A new sediment type of coated grain: Oolitic sinter 被引量:1
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作者 WU ChiHua YI HaiSheng +2 位作者 HUI Bo XIA GuoQing MA Xue 《Science China Earth Sciences》 SCIE EI CAS 2014年第9期2013-2024,共12页
As a special sedimentary grain type, the coated grain(with an ooid model) has been known for two centuries due to its fascinating special fabric and genesis developments. The leading factors in forming the coated grai... As a special sedimentary grain type, the coated grain(with an ooid model) has been known for two centuries due to its fascinating special fabric and genesis developments. The leading factors in forming the coated grain consist mainly of:(1) microorganism movement field;(2) chemical sedimentary effect;(3) hydrodynamic force environment and topography condition;(4) abundant core material supply;(5) embedding condition; and(6) humic acids condition in water medium. With the development of the coated grain genesis, the single factor theory cannot reasonably explain the exact formation of the surface sediment of coated grain. Here, we find a new way to study the coated grain on the basis of traditional research methods. The Wenquan area on the northeast edge of the Qiangtang Basin is one of the few areas where the coated grain is developing, and is a rare "natural laboratory" for the study of the coated grain and the thermal spring sediment. The oolitic sinter of the area has the triaxiality modality of pea polymer, and is obviously different from the karst travertine and the normal lacustrine ooid. We found that the hot spring water in the Wenquan area has higher partial pressure of CO2(PCO2) and saturation index of the calcite(SIc) than normal. Macrocosmically, the oolitic sinter is shaped like a pea, and its grains and gap fillings are light yellow. Microcosmically, the sinter grain forms six types of fundamental lamina, and those six types are developed to be four grain types with different combinations. The C-axis of the mineral grain of sinter cement(calcite) is normal to the lamina face, and grows on it with distinct generation formations. In short, the grain type of oolitic sinter is the oncoid, with the grain development caused by the factors such as the shallow water of strong hydrodynamic force, the special hydrochemistry condition, and the extensive algae activities(diatom). 展开更多
关键词 Qiangtang Basin Wenquan graben oolitic sinter coated grain oncoid
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