Electron microscopy investigations on structures of ZrO₂‐rich phases in the quasibinary system ZrO₂‐Zr₃N₄

Abstract

Abstract Slowly cooled nitrided zirconia samples were investigated and characterized by means of transmission electron microscopy (TEM). Besides the well‐known different modifications of ZrO 2 some ZrO 2 ‐rich oxynitride phases could be further found, called β‐type phases. An overview regarding the formation of such different structural modifications could be gained, supported by previously performed measurements using powder X‐ray diffractometry (XRD). Similar to fast cooled nitrided zirconia samples Zr(N,O), the slowly cooled ones also contain different kinds of ZrO 2 precipitates, which can be obviously emphasized by using the methods of diffraction contrast. A super cell was successively built, derived from the unit cells of the β and β′ phase, in order to explain the structure of the observed modulated β″ phase. Agreements from the comparisons between experimental high resolution images and the simulated ones of such modulated structures confirm the suggested starting points. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)