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Grain Growth Phenomena in the Interface Region of α‐Alumina Bilayer Composites
Author(s) -
Zhao Hong,
Hu XiaoZhi,
Bush Mark B.
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb00928.x
Subject(s) - impurity , materials science , bilayer , sintering , microstructure , dopant , grain growth , ceramic , doping , composite material , chemical engineering , chemistry , biochemistry , optoelectronics , organic chemistry , membrane , engineering
Microstructural development in the interface region of α‐Al 2 O 3 bilayer composites has been systematically investigated in terms of the sintering additive CaO–SiO 2 , residual impurity level in the starting powders (particularly MgO), and sintering conditions. The interfacial microstructure is strongly related to relative CaO–SiO 2 doping levels in the two constituting layers and to residual impurities in the starting powders. The presence of high levels of impurities in the starting powder can substantially modify the features of CaO–SiO 2 ‐Al 2 O 3 liquid at the interface region, thereby strongly influencing α‐Al 2 O 3 grain growth across the interface. Three grain growth modes in the interface region thus have been identified for different combinations of impurity level and CaO–SiO 2 dopant in the α‐Al 2 O 3 bilayer. This provides an important mechanism for controlling two‐dimensional structures in coatings, films, and layered ceramic materials for various engineering applications.