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Phase Composition, Oxygen Content, and Thermal Conductivity of AIN(Y 2 O 3 ) Ceramics
Author(s) -
Buhr Hendrik,
Müller Gerd,
Wiggers Hartmut,
Aldinger Fritz,
Foley Paul,
Roosen Andreas
Publication year - 1991
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.1151-2916.1991.tb06914.x
Subject(s) - oxygen , analytical chemistry (journal) , isothermal process , ceramic , thermal conductivity , phase diagram , mineralogy , conductivity , materials science , phase (matter) , chemistry , thermodynamics , metallurgy , physics , chromatography , composite material , organic chemistry
An indirect method to determine the oxygen dissolved in AIN is devised for AIN(Y 2 O 3 ) ceramics and then related to thermal conductivity. Dissolved oxygen is determined by first constructing the AIN‐rich corner of the AIN—Y 2 O 3 —Al 2 O 3 phase diagram (isothermal section). This is achieved by (1) measuring the total oxygen content and subtracting from it the oxygen in the Y 2 O 3 , resulting in a virtual alumina content; (2) placing the sample composition on the diagram; (3) determining the phases present by XRD for each sample; and (4) drawing phase boundaries which best agree with the phases present. The intersection of these tie lines through the sample location with the AIN—Al 2 O 3 axis then gives the particular Al 2 O 3 oxygen content dissolved in the AIN lattice. For the system AIN—Y 2 O 3 —Al 2 O 3 , it is shown that it is indeed this fraction of the total oxygen content that has a decisive limiting influence on thermal conductivity of dense, polyphase AIN ceramics.