2006 Fiscal Year Final Research Report Summary
Influence of Oxidation and Thermal Cycling on Bonding Strength of Thermal Barrier Coating at Elevated Temperature
| Project/Area Number |
17560082
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Materials/Mechanics of materials
|
|---|
| Research Institution | Tokyo University of Science |
|---|
Principal Investigator |
KANEKO Kenji Tokyo University of Science, Faculty of Eng., Prof., 工学部, 教授 (40016803)
|
|---|
| Project Period (FY) |
2005 – 2006
|
| Keywords | Strength of materials / Surface treatment / Thermal spray / Ceramic coating / Bonding engineering / Stress singularity |
|---|
| Research Abstract |
Fracture strength and adhesive strength of the thermal barrier coating were estimated experimentally and analytically. The specimen consists of two cylinders which are butted with each other and on which both of the bonding coat and the thermal barrier coating (TBC) is constructed. The coating is loaded with combined tension and torsion at room temperature to 900 degree centigrade. Also, after oxidation process at 1,100 degree centigrade, strength of the coating and the adhesive strength in the specimen were examined at room temperature.
The obtained results in the experiments are as follows,
(1) Debonded area occurred at the interface between the coating and the substrate increases quickly at the beginning of cyclic torsional loading and decreases gradually with the increase of number of cycle and the debonding rate keeps constant. Finally, the debonding were accelerated just before the coating break.
(2) The adhesive strength of the TBC under the cyclic shear loading decreases much with a increase of temperature. That is, the failure stress caused by debonding at number of loading cycle N=10^4 are 353.4[MPa] at 20℃, 168.8[MPa] at 600℃, and 21.6[MPa] at 900℃.
(3) The strength of the TBC decreases so much than the decrease in an adhesive strength of the TBC after the oxidation process.
The shear stress distributions at the tip of the debonded area in the interface were analyzed by FEM analysis. Changes of the stress intensity factor K and the singularity parameter λ in the process of debonding of the TBC were estimated. It was found that the value K decreases with the increase of debonding and that the initiation of debonding of the TBC was dominated by K and X of a shear stress distribution at the interface and the rate of debonding was predicted corresponding to the K value.
|
Research Products
(3 results)
