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Long-Term Conductivity Stability of Metastable Tetragonal Phases in 1Yb2O3–xSc2O3–(99 – x)ZrO2 (x = 7, 8 mol %)
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2020-10-19 , DOI: 10.1021/acs.jpcc.0c05298
Vandana Shukla 1 , Shashwat Singh 1 , Anandh Subramaniam 1 , Shobit Omar 1
Affiliation  

The present work studies the influence of 1 mol % Yb2O3 codoping on the long-term conductivity stability in the metastable tetragonal phases present in 8–9 mol % Sc2O3–ZrO2. Dense polycrystalline samples are synthesized via conventional solid-state reaction and pressureless sintering methods. The 8 mol % dopant containing ZrO2 compositions contain the metastable t′-phase, while the t″-phase exists in the 9 mol % doped compositions. However, the grain conductivity values in all of the compositions are comparable and insensitive to the type of tetragonal phase present in the samples. The total conductivity follows a similar trend except in the 1Yb2O3–8Sc2O3–91ZrO2 specimen, which shows a low total conductivity because of the resistive grain boundaries. Long-term thermal aging is performed on all of the tested samples at 650 °C for 2000 h in air. The in situ conductivity study suggests that the conductivity declines occur primarily in the first 650 h. The total conductivity loss at 650 °C is higher in the t′-phase (∼10–16%) compared to the t″-phase (∼3%). Even though substituting 1 mol % Yb2O3 (for Sc2O3) is beneficial in reducing the % conductivity degradation from 16 to 10% in 8Sc2O3–92ZrO2, it does not affect the long-term conductivity stability in 9Sc2O3–91ZrO2 (∼3%). Thus, the 9Sc2O3–91ZrO2 composition exhibits excellent temporal stability of oxygen-ion conductivity with the magnitude of 20.4 mS·cm–1 after 2000 h aging at 650 °C in air.

中文翻译:

1Yb 2 O 3x Sc 2 O 3 –(99 – x)ZrO 2中亚稳四方相的长期电导稳定性(x = 7,8 mol%)

目前的工作研究了1 mol%Yb 2 O 3共掺杂对8-9 mol%Sc 2 O 3 -ZrO 2中存在的亚稳四方相的长期电导率稳定性的影响。通过常规的固态反应和无压烧结方法合成致密的多晶样品。包含8 mol%掺杂剂的ZrO 2组合物包含亚稳态的t ′相,而t在9 mol%掺杂的组合物中存在``相''。但是,所有组合物中的晶粒电导率值都是可比较的,并且对样品中存在的四方相类型不敏感。除了1Yb 2 O 3 –8Sc 2 O 3 –91ZrO 2试样外,总电导率遵循相似的趋势,由于电阻晶界,其总电导率较低。在650°C下于空气中对所有测试样品进行长期热老化2000 h。该原位电导率的研究表明,主要发生在第一650小时电导率下降。650°C下的总电导率损耗在t时较高′相(〜10–16%)与t ″相(〜3%)相比。即使用1 mol%的Yb 2 O 3(用于Sc 2 O 3)有利于将8Sc 2 O 3 –92ZrO 2中的电导率降解百分比从16%降低到10%,但它不会影响硅的长期电导率稳定性。 9Sc 2 O 3 –91ZrO 2(〜3 %)。因此,9Sc 2 O 3 –91ZrO 2组合物在650°C在空气中老化2000 h后,具有优异的氧离子传导性时间稳定性,幅度为20.4 mS·cm –1
更新日期:2020-10-30
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