Hafnia (Hafnium Oxide, HfO2)
Hafnia is an oxide-based engineering ceramic. It has the highest density among oxide-based engineering ceramics. In addition, it has the lowest heat capacity and a very low thermal conductivity. The graph bars on the material properties cards below compare hafnia to other oxide-based engineering ceramics (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Thermal Properties
Maximum Temperature: Mechanical
2800 °C 5070 °F
Melting Onset (Solidus)
2900 °C 5250 °F
Specific Heat Capacity
120 J/kg-K 0.029 BTU/lb-°F
Thermal Conductivity
1.1 W/m-K 0.64 BTU/h-ft-°F
Thermal Expansion
6.0 µm/m-K
Other Material Properties
Density
9.7 g/cm3 610 lb/ft3
Elastic (Young's, Tensile) Modulus
57 GPa 8.3 x 106 psi
Electrical Resistivity Order of Magnitude
9.0 10x Ω-m
Common Calculations
Stiffness to Weight: Axial
3.3 points
Stiffness to Weight: Bending
13 points
Thermal Diffusivity
0.95 mm2/s
Followup Questions
Further Reading
Springer Handbook of Condensed Matter and Materials Data, W. Martienssen and H. Warlimont (editors), 2005