Reduction in sintering temperature for flash-sintering of yttria by nickel cation-doping
Reduction in sintering temperature for flash-sintering of yttria by nickel cation-doping
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DOI：
10.1016/j.actamat.2016.01.037
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发表时间：
2016-03
期刊：
影响因子：
9.4
通讯作者：
H. Yoshida;K. Morita;Byung‐Nam Kim;Y. Sakka;Takahisa Yamamoto
中科院分区：
文献类型：
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作者：
H. Yoshida;K. Morita;Byung‐Nam Kim;Y. Sakka;Takahisa Yamamoto
1mol % Ni2+掺杂的y2o3在大于300 V/cm的直流电场下表现出闪烧现象。与未掺杂的Y2O3相比，ni掺杂使闪变事件的起始温度降低了约200℃。在烧结过程中，ni掺杂y2o3的电导率在温度大于700℃时开始高于未掺杂y2o3，然后随着闪蒸事件的发生而急剧上升。电子能量损失谱（EELS）测量结果表明，在还原气氛中，镍掺杂与闪烧相结合以及常规烧结都能使y2o3高度还原。外加电场必须参与氧阴离子空位的形成和释放电子，从而增强Y2O3中的扩散质量传递和电子传导。在镍掺杂的y2o3中，闪烧的增强必须归因于镍掺杂促进了空位电子对的雪崩。
1 mol% Ni2+-doped Y2O3shows flash-sintering at DC fields greater than 300 V/cm. When compared to the undoped Y2O3, the onset temperature for the flash event is reduced by about 200 °C due to the Ni-doping. The electric conductivity during the sintering experiments for the Ni-doped Y2O3begins to increase above those of the undoped Y2O3at temperatures greater than 700 °C, then steeply rises corresponding to the flash event. Electron energy loss spectrometry (EELS) measurements indicated that Y2O3is highly reduced by the combination of the Ni-doping and flash-sintering as well as by conventional sintering in a reducing atmosphere. The applied electric field must involve the formation of oxygen anion vacancies and liberated electrons, and consequently, enhances the diffusional mass transport and electronic conduction in the Y2O3. The enhanced flash-sintering in the Ni-doped Y2O3must be attributed to an avalanche of the vacancy-electron pairs facilitated by the Ni-doping.