Molten BaCN2 for the sintering and crystal growth of dielectric oxynitride perovskites Sr1-xBaxTaO2N (x = 0.04-0.23).
Molten BaCN2 for the sintering and crystal growth of dielectric oxynitride perovskites Sr1-xBaxTaO2N (x = 0.04-0.23).
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用于介电氮氧化物钙钛矿 Sr1-xBaxTaO2N (x = 0.04-0.23) 的烧结和晶体生长的熔融 BaCN2。
DOI：
10.1039/c7dt03765a
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发表时间：
2017
影响因子：
4
通讯作者：
S. Kikkawa
中科院分区：
文献类型：
--
作者：
A. Hosono;Y. Masubuchi;T. Endo;S. Kikkawa
高于1000 °C的介电氮氧化物钙钛矿的固相烧结伴随着它们的分解。需要后氨解以恢复它们的化学计量氮含量和介电性质。在本工作中，氧氮化物钙钛矿SrTaO 2N与BaCN 2助熔剂在约900 °C下烧结，避免其热分解。得到的相对密度为68.9%的固体产物显示出在68至90的范围内的相对介电常数，损耗值小于0.11，没有后氨解。固体内部含有矩形Sr 1-xSrTaO 2 N晶体，其中0.04 ≤ x ≤ 0.23反映了它们的自形形式。这些晶体在熔融BaCN 2中生长，比原始SrTaO 2N颗粒大20至100倍，最大晶粒尺寸为3.7 μm。Sr 1-xTaO 2N沉淀在部分溶解在BaCN 2助熔剂中的残留SrTaO 2N晶体的表面上。从外到内，在产物的单晶中观察到从富钡到富锶的组成梯度。这是有史以来第一次报告的初步液相烧结和晶体生长的介电氮氧化物钙钛矿使用熔融金属氰胺。
Solid phase sintering of dielectric oxynitride perovskites above 1000 °C is accompanied by their decomposition. Post-ammonolysis is required to recover their stoichiometric nitrogen content and dielectric properties. In the present work, the oxynitride perovskite SrTaO2N was sintered with a BaCN2 flux at approximately 900 °C avoiding its thermal decomposition. The resulting solid product with a relative density of 68.9% showed relative dielectric constants in the range from 68 to 90 with loss values less than 0.11, without the post-ammonolysis. The interior of the solids contained rectangular Sr1-xBaxTaO2N crystals for which 0.04 ≤ x ≤ 0.23 reflecting their euhedral form. These crystals were grown in molten BaCN2 from 20 to 100 times larger than the original SrTaO2N particles and had a maximum grain size of 3.7 μm. The Sr1-xBaxTaO2N precipitated on the surfaces of the residual SrTaO2N crystals that had partially dissolved in the BaCN2 flux. A compositional gradient from barium-rich to strontium-rich was observed in a single crystal of the product on going from the exterior to the interior. This is the first-ever report of the preliminary liquid phase sintering and crystal growth of a dielectric oxynitride perovskite using a molten metal cyanamide.