Micro-hole Array Templates On Titanium Alloy By Laser Drilling And Assembling Of Nano Hydroxyapatite

Due to the low bonding strength and thermal expansion coefficient mismatch between HA and the substrate interface, hydroxyapatite(Ca10(PO4)6(OH)2, HA) coating on the titanium alloy substrate is easy peeling and cracking, which limiting its application in medicine. Therefore, it is very important to solve the problem mentioned above.In this paper, blind micro-hole array templates were constructed by laser drilling, electrophoretic deposition and microwave sintering technology were adopted to assemble HA and HA/Al biological materials. The laser-drilled Ti6Al4 V microhole array templates were adopted to deposit nano hydroxyapatite(HA) and HA/Al powders by electrophoretic deposition. The influence of laser parameters on the morphology of the blind holes, the dynamic deposition curves with different Al content, the effect of microwave sintering temperature and holding time and Al content on grain size, and the biological activity were studied by using of 3D laser scanner, scanning electron microscope(SEM), X-ray diffraction(XRD), and SBF soaking experiments.The results show that damage threshold, i.e. the minimum laser radiation density necessary for the creation of a detectable damage on the material, is reduced with the decrease of the wavelength. the damage thresholds of the wavelength 1064 nm, 532 nm, 532 nm are 2.12 J/cm2, 1.09 J/cm2, 0.53 J/cm2. The entrance diameter and depth of the hole increase with the increase of laser average power. The entrance diameter of the micro-holes fluctuates slightly with an increase in laser irradiation time. Differently, the depth increases significantly with an increase in laser irradiation time. The addition of Al into HA increases deposition rate; The grain size of HA/Al2O3 after microwave sintering increases with the increase of sintering temperature and holding time. The suspension with the Al content of 7.5 g/L was chosen to deposit thick and crack-free AH/Al coating and the optimum sintering parameters were sintering temperature 950 °C and holding time 45 min. Finally, the deification mechanism was discussed. Laser-drilled template assembly with different contents of HA/Al coating could be able to induce the growth of bone apatite after soaking in SBF 14 days.