Effects of Y₂O₃ additions on the densification and thermal conductivity of spark plasma sintering AlN ceramics

다국어 초록 (Multilingual Abstract)

Spark plasma sintering (SPS) of AlN ceramics was carried out with Y₂O₃ as a sintering additive at sintering temperatures of
1,550 to 1,700 ℃. The effects of Y₂O₃ additions on the sintering behavior and thermal conductivity of AlN ceramics were
studied. Y₂O₃ added to AlN showed a noticeable higher densification rate than pure AlN, but the formation of yttrium
aluminate phases by the solid-state reaction of Y₂O₃ and Al2O3 occurred on the AlN surface which could retard the
densification during the sintering process. The thermal conductivity of AlN specimens was improved by the addition of Y₂O₃
up to 3 wt% in spite of the formation of a YAG secondary phase in the AlN grain boundaries because Y₂O₃ additions could
reduce the oxygen content in the AlN lattice which is primary factor controlling the thermal conductivity. However, the
thermal conductivity decreased at a 5 wt% addition because the extra formation of the YAG phase in grain boundaries could
decrease the thermal conductivity by phonon scattering thus surpassing the helpful contributions of smaller Y₂O₃ additions.

다국어 초록 (Multilingual Abstract)

Spark plasma sintering (SPS) of AlN ceramics was carried out with Y₂O₃ as a sintering additive at sintering temperatures of
1,550 to 1,700 ℃. The effects of Y₂O₃ additions on the sintering behavior and thermal conductivity of AlN ceramics were
studied. Y₂O₃ added to AlN showed a noticeable higher densification rate than pure AlN, but the formation of yttrium
aluminate phases by the solid-state reaction of Y₂O₃ and Al2O3 occurred on the AlN surface which could retard the
densification during the sintering process. The thermal conductivity of AlN specimens was improved by the addition of Y₂O₃
up to 3 wt% in spite of the formation of a YAG secondary phase in the AlN grain boundaries because Y₂O₃ additions could
reduce the oxygen content in the AlN lattice which is primary factor controlling the thermal conductivity. However, the
thermal conductivity decreased at a 5 wt% addition because the extra formation of the YAG phase in grain boundaries could
decrease the thermal conductivity by phonon scattering thus surpassing the helpful contributions of smaller Y₂O₃ additions.

참고문헌 (Reference)

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