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Comment on “Effect of Al 2 O 3 and Bi 2 O 3 on the Formation Mechanism of Sn‐Doped Ba 2 Ti 9 O 20 ”
Author(s) -
Wang HongWen
Publication year - 1995
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.1151-2916.1995.tb08458.x
Subject(s) - doping , materials science , activation energy , phase (matter) , mineralogy , chemical engineering , chemistry , optoelectronics , organic chemistry , engineering
in a recent article of the Journal , Yu et al . 1 reported their experimental results on the effect of Al 2 O 3 and Bi 2 O 3 on the formation mechanism of Sn‐doped Ba 2 Ti 9 O 20 . They claimed that both Al 2 O 3 and Bi 2 O 3 can dramatically assist the formation of Sn‐doped Ba 2 Ti 9 O 20 but are based on different mechanisms. They concluded that first, Bi 2 O 3 melts above 830°C and accelerates the migration of the involved reactants to form Ba 2 Ti 9 O 20 ; second, Al 2 O 3 can reduce the height of the potential energy barrier of the formation of Ba 2 Ti 9 O 20 due to the intergrowth of BaAl 2 Ti 6 O 16 phase. They explained their results from a point of view that the formation of Ba 2 Ti 9 O 20 is controlled by (1) the migration of reactants to the interfaces and (2) the height of the potential‐energy barrier of the reaction at the interfaces. However, based on their results, we feel their conclusions are incautious and may be misleading, as will be discussed later.