Department of Mechanical and Aerospace Engineering, Department of Chemistry, Research and Education in Energy Environment and Water (RENEW) Institute, University at Buffalo, The State University of New York, Buffalo, NY 14260, United States of America.
Nanotechnology. 2020 Mar 6;31(10):105703. doi: 10.1088/1361-6528/ab59fa. Epub 2019 Nov 21.
Alumina (AlO) is one of the most widely used ceramic materials for innumerable applications, due to its unique combination of attractive physical and mechanical properties. These intrinsic properties are dictated by the numerous phases that AlO forms and its related phase transformations. Transition metal (TM) cation dopants (iron (Fe), cobalt (Co), nickel (Ni) and manganese (Mn)), even in sparse amounts, have been shown to significantly affect the phase transformation and microstructural evolution of AlO. Small concentrations of TM cation dopants have successfully been incorporated to synthesize magnetically active AlO, while reducing the θ to α phase transformation temperature by 150 °C, and maintaining the outstanding mechanical properties. In addition, first-principle calculations based on density-functional theory with hybrid functional (HSE06) and the PBE+U methods have provided a mechanistic understanding of the formation energy and magnetism of the TM-doped α and θ phases of AlO. The results reveal a potential route for phase transition regulation and external magnetic field-induced texturing of AlO ceramics.
氧化铝 (AlO) 是最广泛应用于无数领域的陶瓷材料之一，这要归因于其独特的物理和机械性能组合。AlO 形成的众多相及其相关的相变决定了这些固有特性。过渡金属 (TM) 阳离子掺杂剂（铁 (Fe)、钴 (Co)、镍 (Ni) 和锰 (Mn)），即使在少量存在的情况下，也已被证明会显著影响 AlO 的相变和微观结构演变。通过掺入少量 TM 阳离子掺杂剂，可以成功合成具有磁性的 AlO，同时将 θ 到 α 相转变温度降低 150°C，并且保持出色的机械性能。此外，基于密度泛函理论与杂化泛函 (HSE06) 和 PBE+U 方法的第一性原理计算为 TM 掺杂的 AlO 的 α 和 θ 相的形成能和磁性提供了机理理解。研究结果揭示了调控 AlO 陶瓷相变和外加磁场诱导织构的潜在途径。
