title: Study of the interfacial reactions between a bioactive apatite-mullite glass-ceramic coating and titanium substrates using high angle annular dark field transmission electron microscopy.
abstract: Glass of generic composition SiO(2) . Al(2)O(3) . P(2)O(5) . CaO . CaF(2) will crystallise predominantly to apatite and mullite upon heat-treatment. Such ceramics are bioactive, osseoconductive, and have a high resistance to fracture. As a result, they are under investigation for use as biomedical device coatings, and in particular for orthopaedic implants. Previous work has shown that the material can be successfully enamelled to titanium with an interfacial reaction zone produced during heat treatment. The present study uses high angle annular dark field transmission electron microscopy (HAADF-TEM) to conduct a detailed examination of this region. Results show evidence of complex interfacial reactions following the diffusion of titanium into an intermediate layer and the production of titanium silicides and titanium phosphides. These results confirm previously hypothesised mechanisms for the bonding of silicate bioceramics with titanium alloys.
authors.affiliation: School of Electrical, Electronic and Mechanical Engineering, University College Dublin, Belfield, Dublin 4, Ireland. kenneth.stanton@ucd.ie
authors.forename: Kenneth T
authors.initials: KT
authors.lastname: Stanton
authors.forename: Kevin P
authors.initials: KP
authors.lastname: O'Flynn
authors.forename: Shohei
authors.initials: S
authors.lastname: Nakahara
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Vanhumbeeck
authors.forename: John M
authors.initials: JM
authors.lastname: Delucca
authors.forename: Bobby
authors.initials: B
authors.lastname: Hooghan
mesh_terms: D001031:Apatites; D002152:Calorimetry, Differential Scanning; D002516:Ceramics; D005898:Glass; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D014025:Titanium; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D014025:Titanium