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Study on the influence of plasma spray processes and spray parameters on the structure and crystallinity of hydroxylapatite coatings
Author(s) -
Zhao L.,
Bobzin K.,
Ernst F.,
Zwick J.,
Lugscheider E.
Publication year - 2006
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.200600029
Subject(s) - crystallinity , hydroxylapatite , materials science , microplasma , thermal spraying , coating , atmospheric pressure plasma , gas dynamic cold spray , microstructure , spray drying , amorphous solid , chemical engineering , phase (matter) , composite material , plasma , metallurgy , chemistry , crystallography , biochemistry , physics , quantum mechanics , engineering , enzyme , organic chemistry
Hydroxylapatite (HA) is one of the most important materials for human hard tissue implants. Until now, HA coatings are widely deposited on implants using atmospheric plasma spraying (APS). Due to the decomposition of HA and formation of amorphous phase during spraying, the crystallinity of APS coatings is usually below 70 %, although coarser spray powders such as one with a size distribution of –150 +45 μm are used. In this study a finer HA powder –80 +50 μm was sprayed using both a conventional APS process and the new “microplasma spraying” (MPS) process. The coatings were characterized in terms of their microstructure and crystallinity. It was found that the spray parameters influenced strongly the coating structure and phase composition. Despite the smaller particles, the HA content of APS coatings could be increased from 27 % to 72 % only by changing the spray parameters. Higher HA contents up to over 85 % could be obtained by microplasma spraying. It was found that textured coatings could form under certain conditions during both spray processes.