School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China.
The State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China.
Nanoscale. 2017 Mar 30;9(13):4601-4609. doi: 10.1039/c6nr08046d.
Crystallography of phase transformation combining transmission electron microscopy (TEM) with in situ heating techniques and X-ray diffraction (XRD) can provide critical information regarding solid-state phase transitions and the transition-induced interfaces in TiO nanomaterials theoretically and experimentally. Two types of reduced titanium oxides (TiO, TiO) are found during ex situ and in situ heating of TiO (B) nanofibers with a specific morphology of the {100} single form (SF) in air and vacuum. The results indicate that the phase transformation process from TiO (B) follows the TiO (B) → TiO → TiO → anatase sequence for the nanofibers with the {100} SF. The occurrence of such a phase transition is selective to the morphology of TiO (B) nanofibers. The corresponding orientation relationships (COR) between the four phases are revealed according to the TEM characterization. Four types of coherent interfaces, following the CORs are also found. They are TiO (B)/TiO, TiO (B)/TiO, TiO/anatase and TiO (B)/anatase respectively. The habit plane for the TiO (B) to TiO transition is calculated as the {100} by using the invariant line model. The detailed atomic transformation mechanism is elucidated based on the crystallographic features of the four phases.
利用透射电子显微镜（TEM）结合原位加热技术和 X 射线衍射（XRD）的晶体学相变，可以从理论和实验上为 TiO 纳米材料的固态相变和相变诱导界面提供关键信息。在空气中和真空中对具有 {100} 单形式（SF）特定形态的 TiO（B）纳米纤维进行原位和异位加热时，发现了两种还原钛氧化物（TiO、TiO）。结果表明，从 TiO（B）到 TiO 的相转变过程遵循 TiO（B）→TiO→TiO→锐钛矿的顺序，对于具有 {100} SF 的纳米纤维。这种相变的发生对 TiO（B）纳米纤维的形态具有选择性。根据 TEM 特性揭示了四个相之间的相应取向关系（COR）。还发现了四种类型的相干界面，分别是 TiO（B）/TiO、TiO（B）/TiO、TiO/锐钛矿和 TiO（B）/锐钛矿。利用不变线模型计算 TiO（B）到 TiO 转变的位错平面为 {100}。基于四个相的晶体学特征，阐明了详细的原子转变机制。
