Fracture Behavior of Plasma-sprayed Thermal Barrier Coatings with Different Bond Coats upon Cyclic Thermal Ezposure
The effects of bond coat nature in thermal barrier coming (TBC) systems on the delamination or fracture behavior of the TBCs with different bond coats prepared using two different processes-air plasma spray (APS) and high velocity oxyfuel (HVOF)--were investigated by cyclic thermal fatigue tests. The TBCs with the HVOF bond coat were delaminated or fractured after 3-6 cycles, whereas those with the APS bond coat were delaminmed after 10 cycles or show a sound condition. These results indicate that the TBC system with the APS bond coat has better thermal durability than the system with the HVOF bond coat under long-term cyclic thermal exposure. The hardness values of the TBCs (top coats) in both systems are dependent on applied loads, irrespective of the hardness of the bond coats and the substrate. The values are not responded to the bond coat nature or the exposure time. Thermally grown oxide (TGO) layers in both cases consist of two regions with the inner TGO layer containing only Al203 and the outer TGO layer of mixed-oxide zone containing Ni, Co, Cr, Al in Al203 matrix. The outer TGO layer has a more irregular shape than the inner TGO layer, and there are many pores within the outer layer. At failure, the TGO thickness of the TBC system with the HVOF bond coat is 9-13 μm, depending on the total exposed time, and that of the TBC system with the APS bond coat is about 20 μm. The both TBC systems show the diffusion layer on the side of substrate in the interface between the bond coat and the substrate. The relationship between the delamination or fracture behavior and the bond coat nature has been discussed, based on the elemental analysis and microstructural evaluation.
Air plasma spray (APS) High velocity ozyfuel (HVOF) Bond coat Thermal barrier coating (TBC) Thermally grown ozide (TGO) Thermal durability
Young-Seok Sire Sung-Il Jung Jae-Young Kwon Jae-Hyun Lee Yeon-Gil Jung Ungyu Paik
School of Nano and Advanced Materials Engineering, Changwon National University, #9 Sarimdong, Chang Division of Advanced Materials Engineering, Hanyang University, Haengdang-dong, Sungdon-gu,Seou1133-
国际会议
10th International Symposium on Eco-Materials Processing and Design(第10届国际生态材料加工与设计研讨会)
西安
英文
343-346
2009-01-13（万方平台首次上网日期，不代表论文的发表时间）