Premium
Effect of Silica on the Thermal Conductivity of Aluminum Nitride
Author(s) -
Baranda Pedro Sainz,
Knudsen Arne K.,
Ruh Edwin
Publication year - 1993
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.1151-2916.1993.tb06645.x
Subject(s) - thermal conductivity , materials science , nitride , stacking , phonon scattering , sintering , scattering , phonon , aluminium , analytical chemistry (journal) , conductivity , solid solution , lattice (music) , mineralogy , composite material , condensed matter physics , metallurgy , chemistry , optics , physics , organic chemistry , layer (electronics) , chromatography , acoustics
The effect of SiO 2 on the thermal conductivity of aluminum nitride pressureless sintered with 3 wt% Y 2 O 3 as a sintering aid was investigated. SiO 2 additions greatly decreased the thermal conductivity of the sintered parts from values of around 160 W/m·K on undoped samples to about 25 W/m·K with 5 wt% SiO 2 added to the green body composition. Microstructural studies, combined with the temperature dependence of the thermal conductivity and lattice parameter measurements, indicated that defect phonon scattering was the mechanism responsible for the decrease in thermal conductivity. SiO 2 can be incorporated in limited solid solution into the AIN lattice, generating AI vacancies for charge compensation in a process not unlike the solution of oxygen in AIN. The mass difference introduced by the vacancies is the main phonon scattering defect. Beyond a concentration threshold of 2%, the SiO 2 ‐induced defects cluster to form SiAION polytypoids derived from the basic 2H AIN structure with stacking sequences that depend on the SiO 2 levels in the sample.