Liu Yuan, Shi Zongmo, Zhang Junzhan, Chen Chanli, Zhang Ying, Li Leilei, Chen Qian, Zhang Qiantao, Xing Fei
College of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, P. R. China.
School of Civil Engineering, Northwest Minzu University, Lanzhou 730000, P. R. China.
Inorg Chem. 2024 Mar 11;63(10):4628-4635. doi: 10.1021/acs.inorgchem.3c04191. Epub 2024 Feb 28.
In the field of oxide thermoelectrics, perovskite CaMnO ceramics have drawn plenty of attention due to their chemical stability, low cost, and environmental friendliness. By employing Ruddlesden-Poppe phase CaMnO as a precursor, the plate-like CaMnO microcrystals were successfully synthesized by the molten salt method combined with topochemical microcrystal conversion (TMC). The plate-like morphology of CaMnO was coordinately optimized by modulating the crystal structure of MnO and the molten salt environment. Plate-like microcrystals with an average size of ∼14.55 m and a thickness of ∼2.89 m were obtained by TMC reaction, demonstrating an obvious anisotropy. When -MnO was used as the raw material, a length-thickness ratio of 4.77 was obtained, which was attributed to the fact that CaMnO inherited the plate-like morphology of the CaMnO precursor during the TMC. The results confirm that the plate-like CaMnO microcrystals with obvious anisotropy can provide excellent template seeds for high-quality CaMnO-based textured ceramics.
在氧化物热电领域，钙钛矿型CaMnO陶瓷因其化学稳定性、低成本和环境友好性而备受关注。通过采用Ruddlesden-Poppe相CaMnO作为前驱体，结合拓扑化学微晶转化（TMC）的熔盐法成功合成了板状CaMnO微晶。通过调节MnO的晶体结构和熔盐环境，对CaMnO的板状形态进行了协同优化。通过TMC反应获得了平均尺寸约为14.55μm、厚度约为2.89μm的板状微晶，表现出明显的各向异性。当使用β-MnO作为原料时，长径比为4.77，这归因于在TMC过程中CaMnO继承了CaMnO前驱体的板状形态。结果证实，具有明显各向异性的板状CaMnO微晶可为高质量的CaMnO基织构陶瓷提供优异的模板晶种。
