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Damage evolution in a self‐healing air plasma sprayed thermal barrier coating containing self‐shielding MoSi 2 particles
Author(s) -
Chen Ying,
Zhang Xun,
van der Zwaag Sybrand,
Sloof Willem G.,
Xiao Ping
Publication year - 2019
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16313
Subject(s) - materials science , thermal barrier coating , temperature cycling , composite material , coating , aluminium , yttria stabilized zirconia , electromagnetic shielding , self healing , ceramic , thermal spraying , particle (ecology) , cubic zirconia , metallurgy , thermal , medicine , oceanography , physics , alternative medicine , pathology , meteorology , geology
A self‐healing thermal barrier coating ( TBC ) system is manufactured by air plasma spraying ( APS ) and tested by thermal cycling. The ceramic topcoat in the self‐healing APS TBC system consists of an yttria stabilised zirconia ( YSZ ) matrix and contains self‐shielding aluminium containing MoSi 2 healing particles dispersed close to the topcoat/bond coat interface. After spraying the healing particles the material was annealed to promote the formation of an oxygen impermeable Al 2 O 3 shell at the MoSi 2 ‐ TBC interfaces by selective oxidation of the aluminium fraction. The samples were subsequently thermally cycled between room temperature and 1100°C. The study focussed on the spontaneous formation of the Al 2 O 3 shell as well as the subsequent damage evolution in the APS produced TBC during thermal cycling. Experimental evidence showing characteristic signs of crack healing in the topcoat is identified and analysed. The study shows that while the concept of the self‐healing APS TBC s containing self‐shielding MoSi 2 particles is promising, future study is needed to improve the protectiveness of the Al 2 O 3 shells by further tailoring the aluminium content in the MoSi 2 and the particle shape to avoid the premature oxidation of the healing particles and maximise crack healing efficiency.