Hf3AlN: A Novel Layered Ternary Ceramic with Excellent Damage Tolerance

Volume 93 Issue 1, Pages 228 – 234

Fangzhi Li, Bin Liu, Jingyang Wang, Yanchun Zhou
Published Online:
Oct 29 2009 6:06PM

DOI: 10.1111/j.1551-2916.2009.03387.x

ABSTRACT
In this work, bulk Hf₃AlN
ceramic was synthesized by an in situ
reaction/hot pressing method using Hf and AlN as initial materials. The
reaction path during the synthesis process was investigated. Hf₃AlN
was found to form via the reaction of Hf and AlN above 1000°C.
Furthermore, physical and mechanical properties of Hf₃AlN,
such as electrical conductivity, flexural strength, and elastic moduli
were also characterized. Similar to typical layered ternary ceramics Ti₃SiC₂
and Ti₃AlC₂, Hf₃AlN
possesses metallic conductivity and excellent damage tolerance, which
is also the first one of this type that has ever been reported to
crystallize in an orthorhombic structure. It is believed that a typical
layered crystal structure and weak interlayer bondings contribute to the
damage tolerance of Hf₃AlN. Moreover, the
stiffness of Hf₃AlN can sustain a temperature as
high as 1450°C, being 250°C higher than that of Ti₃AlC₂,
which renders it a promising high-temperature structural material.

Online Access to Journal of the American Ceramic Society