As-deposited and laboratory heat-treated (aged) electron beam physical vapor deposited (EB-PVD) thermal barrier coating (TBC) samples were characterized microstructurally using SEM and TEM, particularly focusing on the sintering accompanying aging in the ZrO 2 -based top coat. Unusual but shallow surface microcracking occurred on first heating as-deposited TBCs. The ZrO 2 top coats of the TBCs were indented at two different loading rates between room temperature and 1204°C using a commercial hot hardness tester. The aged sample is harder than the as-deposited sample under all conditions. The faster loading rate decreased the apparent hardness for both samples, and revealed a previously unrecognized dynamic effect during microindentation. In the as-deposited TBC, delocalized damage associated with microhardness indents was confined to the area directly beneath the indenter, while in the aged TBC, the damage was less delocalized, some indent-induced microcracks having propagated into the surrounding material.
[1]
J. Nicholls,et al.
Some observations on erosion mechanisms of EB PVD tbcs
,
2000
.
[2]
U. Schulz,et al.
Microstructure of ZrO2 Thermal Barrier Coatings Applied by EB-PVD
,
2000
.
[3]
A. Heuer,et al.
Mechanisms of energy dissipation during displacement-sensitive indentation in Ge single crystals at elevated temperatures
,
1998
.
[4]
A. Heuer,et al.
Energy Dissipation during High Temperature Displacement‐Sensitive Indentation in Cubic Zirconia Single Crystals
,
1998
.
[5]
R. Bruce.
Development of 1232°C (2250°F) erosion and impact tests for thermal barrier coatings
,
1998
.
[6]
J. Nicholls,et al.
Erosion and Foreign Object Damage of Thermal Barrier Coatings
,
1997
.
[7]
Gregory N. Morscher,et al.
Temperature dependence of hardness in yttria-stabilized zirconia single crystals
,
1991
.