This paper presents on the direct laser melted hydroxyapatite coatings achieved by melting the pre-placed powder beds using Nd-YAG laser. The process development and optimized parameters are reported. The results show that by changing the laser power and the beam inclined plane it is possible that a desirable coating of HAP that is rich on the surface can be produced. The microstructures of the coatings showed balling and cracking at beam angles between 0-15° and at 27° a successful coating was achieved with laser power and scanning speed of 750W and 5mm/s respectively. The said coating was pore and crack free while it retained non-decomposed HAP crystallites on the surface (mixed). The microstructure of the transition layer concluded a moderate temperature process since the formed dendrites did not develop or form secondary arms. The Ca/P conducted on the coating using EDS concluded Ca/P ratio of 8.04 and the absence of titanium phosphates phase (TiP₂). TiP₂ is typically associated with the decomposition of HAP and indicate the presence of high processing temperatures. Even so, the current results indicated that the investigated process was successful in depositing HAP coating with desirable microstructures even though its bio-corrosion properties still need to be ascertained before it could be qualified as suitable for biomedical applications.

Date Published: 9 March 2015
PDF: 7 pages
Proc. SPIE 9356, High-Power Laser Materials Processing: Lasers, Beam Delivery, Diagnostics, and Applications IV, 93560X (9 March 2015); doi: 10.1117/12.2079169

Published in SPIE Proceedings Vol. 9356:
High-Power Laser Materials Processing: Lasers, Beam Delivery, Diagnostics, and Applications IV
Friedhelm Dorsch, Editor(s)