Hi,

Experimental measurements of Gamma is challenging for ceramic materials. I am just offering a method for a very rough estimate from the viewpoint of fracture mechanics. There is a basic relationship in Fracture mechanics telling how a material's fracture toughness K, E and surface energy Gamma are connected: K=(E*Gamma)^0.5. So if you get values of K and E, then you can derive Gamma. From literature you may find E of ca. 200 GPa for nonporous 3Y-TZP. And the biggest issue is large scattering in K values from 5~13 MPa(m)^0.5. Then you get Gamma ranging from 60 to 400 J/m^2.

Still looks too high for typical ceramics (eg. sapphire is ca. 1 J/m^2)? Then think about why K is so high for 3T-TZP (phase transfromation toughened)? You may finally find out thtat this method is thus highly microstructure dependent.

Here are two related reports:

Toughening effect of multiwall carbon nanotubes on 3Y-TZP zirconia ceramics at cryogenic temperatures

http://www.sciencedirect.com/science/article/pii/S0272884214014461

Data Sheet of Nilcra™ Zirconia 3Y-TZP Grade

http://www.morgantechnicalceramics.com/sites/default/files/datasheets/nilcra_zirconia_3y-tzp_grade_data_sheet_220114_2.pdf

Hope this helps.

Best,

Yang

Thank you Yang. I am really impressed with your analysis.