[论文解读] Influence of additives (CoO, CaO, B2O3) on thermal and dielectric properties of BaO-Al2O3-SiO2 glass-ceramic sealant for OTM applications

Adrian Iulian Borhan, Magdalena Gromada+2 more|arXiv (Cornell University)|Jul 13, 2015

Thermal Expansion and Ionic Conductivity参考文献 30被引用 3

一句话总结

本研究探讨了CoO、CaO和B2O3掺杂对用于氧传输膜（OTM）应用的BaO-Al2O3-SiO2（BAS）玻璃陶瓷热性能和介电性能的影响。B2O3含量较高的变体（BABS）表现出675°C的低软化温度、25%的收缩率、高的介电常数（67.8）和低损耗（10 MHz时为0.029），由于其增强的致密化能力和优异的电性能，使其成为OTM密封剂应用的理想选择。

ABSTRACT

The efficiency of glass ceramic sealants plays a crucial role in high temperature applications performance and durability, such as oxygen separation from air. In order to develop suitable sealants, operating at about 950C, several glass-ceramics with different compositional additives and ratios in BAS system have been prepared and investigated. The effects of additive oxides, CaO, CoO, B2O3, as network modifiers on the thermal and dielectric properties of BAS glass-ceramic for further oxygen transport membrane OTM applications were evaluated and discussed. The addition of additives has evident effects on the main crystalline phases and physical properties of the glass-ceramics. Among these systems, B2O3-rich BAS system, BABS, can be densified at the sintering temperature below 700C through viscous sintering. Also, BABS shows the lowest dilatometric softening temperature at 675C, which can be explained by a fast densification associated with a shrinkage of 25 percents. It has highest conductivity, a high dielectric constant of 67.8 and a loss of 0.029 at 10MHz, which provide an attractive feature for many technological applications. The electrical results obtained for BABS glass-ceramic are consistent with the typical requirements for an excellent sealant. However, considering all other properties investigated, only B2O3-rich BAS meets the requirements for use as a sealant for BSCF membrane. Low softening temperature of BABS opens more ways for adding additives to tailor its functional properties, which enable for using as sealant material for OTM applications.

研究动机与目标

• 开发一种适用于约950°C运行条件的高性能玻璃陶瓷密封剂，用于氧传输膜（OTM）应用。
• 评估CoO、CaO和B2O3掺杂对BaO-Al2O3-SiO2（BAS）玻璃陶瓷热性能和介电性能的影响。
• 确定一种具有优异烧结行为、热稳定性和电性能的成分，以实现对BSCF基OTM膜的密封。
• 实现低软化温度和高致密化，以改善高温环境下界面结合力和长期耐久性。

提出的方法

• 合成多种含CoO、CaO和B2O3的BAS基玻璃陶瓷成分。
• 采用粘性烧结工艺在700°C以下对B2O3含量高的成分进行致密化。
• 通过热机械分析测定线性收缩率，评估热加工窗口。
• 测量10 MHz下的介电性能，包括介电常数和损耗正切。
• 通过X射线衍射和热分析识别结晶相及其在热处理过程中的演变。
• 关联显微结构、热行为与电性能，以确定最优密封剂成分。

实验结果

研究问题

• RQ1 CoO、CaO和B2O3掺杂如何影响BAS玻璃陶瓷的软化温度和致密化行为？
• RQ2 这些掺杂剂对玻璃陶瓷密封剂的结晶相形成和显微结构有何影响？
• RQ3 介电性能（介电常数和损耗正切）如何随掺杂成分变化，特别是在10 MHz频率下？
• RQ4 哪种掺杂成分能实现软化温度最低、致密化程度最高且电性能最优的综合表现，适用于OTM密封应用？
• RQ5 B2O3含量高的成分是否能在保持机械和电学完整性的同时，实现更低的加工温度，适用于OTM密封剂？

主要发现

• B2O3含量高的BAS体系（BABS）的热机械分析软化温度为675°C，为所研究所有成分中的最低值。
• BABS在烧结过程中表现出25%的线性收缩率，表明其在700°C以下通过粘性烧结实现快速致密化。
• BABS在10 MHz频率下表现出67.8的高介电常数和0.029的低介电损耗，满足高性能电密封剂的关键要求。
• 添加B2O3显著降低了烧结温度并增强了致密化，从而改善了与BSCF膜的界面结合力。
• 在所测试的掺杂剂中，B2O3在热性能、显微结构和介电性能之间提供了最理想的平衡，适用于OTM密封剂应用。
• BABS成分因其低加工温度和优异的电性能，显示出作为功能密封剂的最高潜力。