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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/41662
- Oxyapatite in hydroxyapatite coatings
- Gross, Karlis A.; Berndt, C. C.; Stephens, Peter W.; Dinnebier, Robert E.
- Plasma sprayed hydroxyapatite coatings are used as bioactive surfaces for increasing the fixation of bone to the dental implants or orthopaedic prostheses. The variability in the performance of these coatings is partly attributed to the chemical phases that form at high temperatures in the plasma or fast cooling rates upon deposition. Hydroxyapatite can be accompanied by an amorphous phase constituent, tricalcium phosphate, tetracalcium phosphate, calcium oxide or the rarely mentioned oxyapatite. The high temperatures in the plasma produces a hydroxyl-depleted layer on the outside of the traversing hydroxyapatite particle. It is this dehydroxylated area which may form oxyapatite upon deposition. Higher cooling rates produce an amorphous phase, but a lower cooling rate will lead to the formation of oxyapatite. Examination of the coating at various depths with X-ray diffraction reveals a higher oxyapatite content in the underlying layers. The surface in contact with water vapour in air can be modified by the inclusion of hydroxyl ions to form oxyhydroxyapatite or hydroxyapatite. This presence and varying amounts of oxyapatite with coating thickness could influence the dissolution and mechanical performance of the coating for dental and orthopaedic prostheses.
- Publication type
- Journal article
- Journal of Materials Science, Vol. 33, no. 15 (Aug 1998), pp. 3985-3991
- Publication year
- Bioactive surfaces; Chemical phases; Cooling; Dissolution; Hydroxyapatite coatings; Ions; Mechanical properties; Oxyapatite; Performance; Phosphate coatings; Plasma spraying; Plasmas; Prosthetics; X-ray diffraction
- Publisher URL
- Copyright © 1998 Kluwer Academic Publishers.
- Peer reviewed