Melting Refining Mechanisms in Supersonic Atmosphe

Authors: Wei Tao Zhao Jiu Hui Wu Yu Bai Zhi Hai Han

Publish Date: 2012/07/01

Volume: 32, Issue: 6, Pages: 1227-1242

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Abstract

In recent years Yttriastabilized zirconia based thermal barrier coatings TBCs are deposited by newlydeveloped highefficiency supersonic atmospheric plasma spraying SAPS technology The final microstructure of the plasmasprayed coatings is strongly dependent on the size distribution of spray particles It has been corroborated through experiments that there is a special phenomenon of particle melting refining in SAPS as compared with the conventional atmospheric plasma spraying APS This phenomenon greatly affects the final particle size and distribution which has not been explained reasonably up to now Therefore it is necessary to investigate the melting refining behavior of inflight particles to control the particle size and to analyze the coating properties In this paper the breakup of particle is presented to characterize the phenomenon of particle melting refining and the peak of size distribution becomes bigger with increasing the spray distances which is explained by collisioncoalescence Furthermore based on the maximum entropy formalism the particlesize distribution is calculated and the result is in good accordance with the plasma spraying experiment results which verifies the mechanism analysis presented in this paper This work could provide more efficient applications of the SAPS technology in highperformance TBCsThe authors are grateful for the supports provided by the National Basic Research Program 2007CB707702 the National Natural Science Foundation of China 51075325 the Program for New Century Excellent Talents in University NCET090644 and the PhD Programs Foundation of Ministry of Education of China 20090201120047 The authors would like to thank Yanyong Dai Lijun Du Xi’an Jiaotong University China and technician Y M Qiang Xi’an Jiaotong University China for their suggestions and help

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