Abstract
A new hydrothermal method is proposed, which enables us to prepare thin hydroxyapatite (HA) ceramic coatings on Ti substrates with a curved surface at low temperatures. The method uses double layered capsules in order to produce a suitable hydrothermal condition; the inner capsule encapsulates the coating materials and a Ti substrate, and the outer capsule is subjected to isostatic pressing under the hydrothermal condition. In this study, it is demonstrated that a pure HA ceramic layer with the thickness of 50 μm could be coated to a Ti cylindrical rod at the low temperature as low as 135 °C under the confining pressure of 40 MPa. The HA coating layer had a porous microstructure with the relative density of approximately 60%. Pull-out tests were conducted to obtain an estimate for the adhesion properties of the HA coating prepared by the double capsule method. The shear strength obtained from the pull-out tests was in the range of 4.0-5.5 MPa. It was also shown that the crack propagation occurred within the HA coating layer, not along the HA/Ti interface in the pull-out tests. This observation suggests that the fracture property of the HA/Ti interface was close to or higher than that of the HA ceramics only. It is expected that the low temperature double capsule method may provide a useful method for producing bioactive HA ceramic coatings on curved prostheses surfaces.
| Original language | English |
|---|---|
| Pages (from-to) | 6801-6807 |
| Number of pages | 7 |
| Journal | Surface and Coatings Technology |
| Volume | 200 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - 2006 Aug 1 |
Keywords
- Double capsule
- Hydrothermal
- Hydroxyapatite
- Pull-out testing
- Titanium
ASJC Scopus subject areas
- Chemistry(all)
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry