Journal of Inorganic Materials ›› 2017, Vol. 32 ›› Issue (9): 973-979.DOI: 10.15541/jim20160661

• Orginal Article • Previous Articles     Next Articles

Thermal Shock Analysis of Surface Al-modified 7YSZ Nano-thermal Barrier Coatin

ZHANG Xiao-Feng1, 2, ZHOU Ke-Song1, 2, LIU Min2, DENG Chun-Ming2, DENG Chang-Guang2, CHEN Huan-Tao2   

  1. (1. School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China; 2. National Engineering Laboratory for Modern Materials Surface Engineering Technology & The Key Lab of Guangdong for Modern Surface Engineering Technology, Guangdong Institute of New Materials, Guangzhou 510650, China)
  • Received:2016-11-28 Revised:2017-01-17 Online:2017-09-30 Published:2017-08-29
  • Supported by:
    Guangdong Academy of Sciences (2017GDASCX-0843);Guangdong Technical Research Program (201313050800031, 201413050502008, 2014B070706026, 2013B061800053);Guangdong Natural Science Foundation (2016A030312015)

Abstract:

In order to improve the thermal shock resistance of 7YSZ nano-thermal barrier coating (TBC), bond coating NiCoCrAlYTa was prepared on simulated turbine blade by HVOF (high velocity oxygen flame). Subsequently, 7YSZ nano-ceramic coating was produced on bond coating as top coating. Al film was deposited on the surface of TBC samples. Then the Al-deposited TBCs were carried out by heat-treatment at different pressures (200, 250, 300 Pa). After that, the thermal shock tests of as-sprayed and Al-modified 7YSZ nano-TBC were taken from 1050 ℃ to atmospheric water with holding time of 10 and 5 min, respectively. Micrograph and microstructure evolution of the TBC sample were characterized before and after thermal shock. The results show that a loose top layer with Al nano-grains is formed on the TBC surface due to evaporation and condensation of Al film at vacuum pressure. Besides, with increase of heat-treatment pressure, the density of loose layer is increased. A dense Al2O3 layer was in-situ synthesized under the loose layer due to the reaction of Al and ZrO2. The Al-modified 7YSZ nano-TBCs heat-treated at different pressures has less spallation area than the as-sprayed TBCs after withstood 73 thermal shocks, showing better thermal shock resistance.

 

Key words: thermal barrier coating, 7YSZ, thermal cycle, Al-modification

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