Abstract
The corrosion rate of Mg alloys is currently too high for viable resorbable implant applications. One possible solution is to coat the alloy with a hydroxyapatite (HA) layer to slow the corrosion and promote bone growth. As such coatings can be under severe stresses during implant insertion, we present a nano-mechanical and nano-tribological investigation of RF-sputtered HA films on AZ31 Mg alloy substrates. EDX and XRD analysis indicate that as-deposited coatings are amorphous and Ca-deficient whereas rapid thermal annealing results in c-axis orientation and near-stoichiometric composition. Analysis of the nanoindentation data using a thin film model shows that annealing increases the coating's intrinsic hardness (H) and strain at break (H/E) values, from 2.7 GPa to 9.4 GPa and from 0.043 to 0.079, respectively. In addition, despite being rougher, the annealed samples display better wear resistance; a sign that the rapid thermal annealing does not compromise their interfacial strength and that these systems have potential for resorbable bone implant applications.
| Original language | English |
|---|---|
| Article number | 105306 |
| Journal | Journal of the Mechanical Behavior of Biomedical Materials |
| Volume | 133 |
| Early online date | 7 Jun 2022 |
| DOIs | |
| Publication status | Published (in print/issue) - 30 Sept 2022 |
Bibliographical note
Funding Information:Authors would like to acknowledge the Department for Economy (DfE), Northern Ireland for funding of the US-Ireland Centre-to-Centre partnership associated with this work (USI 111). Support of the United States NSF-ERC (Grant No. EEC-0812348) is also acknowledged.
Publisher Copyright:
© 2022 The Authors
Keywords
- hydroxyapatite
- resorbable bone implant
- magnesium alloy
- nanoindentation
- nanotribology
- Nanotribology
- Resorbable bone implant
- Magnesium alloy
- Nanoindentation
- Hydroxyapatite
