title: Effect of atmosphere on phase transformation in plasma-sprayed hydroxyapatite coatings during heat treatment.
abstract: The purpose of this study was to evaluate the effect of atmosphere on the phase transformation in hydroxyapatite (HA) coatings during heat treatment by varying the atmosphere in the furnace pipe. Heat treatment always increased the crystallinity of HA coatings regardless of the kind of atmosphere. Water molecules in atmosphere further promoted HA recrystallization during heat treatment. In a dry atmosphere, tricalcium phosphate (TCP) and tetracalcium phosphate (TTCP) were more stable than HA, so heat treatment could not convert them into HA. However, in a humid atmosphere, heat treatment would transform TCP and TTCP into HA by hydrolytic reactions.
authors.affiliation: Institute of Materials Science and Technology, Sichuan University, Chengdu, China.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: W
authors.initials: W
authors.lastname: Tong
authors.forename: Y
authors.initials: Y
authors.lastname: Cao
authors.forename: J
authors.initials: J
authors.lastname: Feng
authors.forename: X
authors.initials: X
authors.lastname: Zhang
mesh_terms: D001272:Atmosphere; D003460:Crystallization; D018360:Crystallography, X-Ray; D006358:Hot Temperature; D006813:Humidity; D006882:Hydroxyapatites / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D014025:Titanium
chemical_list: D006882:Hydroxyapatites; D014025:Titanium