Journal of Inorganic Materials ›› 2014, Vol. 29 ›› Issue (3): 294-300.doi: 10.3724/SP.J.1077.2014.13342

• Orginal Article • Previous Articles     Next Articles

Erosion Failure Mechanism and Model Establishment of Thermal Barrier Coatings Based on Roughness

Xiao-Feng ZHANG1,2(), Ke-Song ZHOU1,2(), Ji-Fu ZHANG2, Tao HAN2, Jin-Bing Song2, LIU-Min2   

  1. 1. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
    2. Institute of New Materials, Guangzhou Research Institute of Non-ferrous Metals, Guangzhou 510650, China
  • Received:2013-07-01 Revised:2013-08-15 Online:2014-03-20 Published:2014-02-18
  • About author:ZHANG Xiao-Feng. E-mail:zxf200808@126.com

Abstract:

Erosion failure mechanism of atmospheric plasma sprayed (APS) ZrO2-7%Y2O3 (7YSZ) thermal barrier coatings (TBCs) was studied with a san-blasting erosion tester. The failure features of TBCs with laminar and porous structure were investigated using impingement angle 90° at room temperature. Effect of porous and laminar structure on erosion rate was analyzed. Moreover, regarding the failure factors, the relation of ceramic coating roughness and erosion rate was analyzed and their mathematic model was established. The experimental results indicate that the factors of porous and laminar structures play an important role in crack propagation in TBCs. For the TBCs with ununiform, discontinuous pressure-pressure pulsating cyclic load under impact of high velocity particles, the ceramic coatings are loaded with normal stress and shear stress, in which the normal stress leads to appearance of pit in ceramic coating and the shear stress leads to grooves. Meanwhile, the crack propagation in grain boundaries and interfaces of laminar structure will appear based on the net cracks on ceramic coating surface in sprayed TBCs, which will lead to particle exfoliation and flaky debris. So the erosion failures of TBCs follows abrasive wear and low cycle fatigue mode. The relevance between ceramic coating roughness and erosion rate indicates an increased linear relation.

Key words: thermal barrier coating, erosion mechanism, roughness

CLC Number: 

  • TQ174