Forming contacts and grain boundaries between MgO nanoparticles
The present article is concerned with how nanoparticles join: it considers MgO nano-cubes as a model, well-defined system. The development of grain boundaries (GBs) between cube particles has been re-examined using MgO smoke. In addition to the face-to-face contact which leads to the well-known low-∑ twist GBs, interactions are also found which initially involve point-to-face contact, edge-to-face contact, or contacts along the cube edges. It is proposed here that the point contact lead to a line contact through the requirement to balance charges, and rotation about such a line of contact leads to formation of the interface, i.e., the grain boundary. The atoms along the edges have lower coordination than the atoms in the bulk, which may contribute to the edge–edge and edge-face boundary formation. The inherently small size of nanoparticles makes transmission electron microscopy (TEM) an invaluable technique for characterizing the contacts between them without modifying them in any way. The present study uses TEM to characterize the types of boundaries formed, discusses the boundary structures, and considers how the particle morphology may determine the formation of low-∑ GBs.
KeywordsSmoke Line Contact Burger Vector Twist Boundary Smoke Particle
This research has been supported by the IGERT program of the NSF under award number DGE-0114372 and by NSF grant number CMS0322436. The authors acknowledge support from the 3M Heltzer Endowed Chair and the University of Connecticut. They would also like to thank Nicole Munoz for help with collecting the MgO smoke, Jonathan Winterstein and Dr. Ramachandran Divakar for helpful discussions, and Jessica Riesterer and Joysurya Basy for critically reading the manuscript.
- 5.Carter CB, Norton MG (2007) Ceramic materials: science & engineering. Springer, New YorkGoogle Scholar
- 12.Yoshida K, Uchiike H, Sawa M (1999) IEICE Trans Electron E82-C:1798Google Scholar
- 26.Williams DB, Carter CB (2008) Transmission electron microscopy: a textbook for materials science. Springer, New YorkGoogle Scholar
- 30.Friedel G (1926) Leçons de Cristallographie. Berger-Levrault, ParisGoogle Scholar
- 36.Winterstein JP, Carter CB (2009) Submitted Google Scholar
- 44.Hirth JP, Lothe J (1982) Theory of dislocations. Wiley, New YorkGoogle Scholar