Pulsed laser coating of hydroxyapatite/titanium nanoparticles on Ti-6Al-4V substrates: multiphysics simulation and experiments.

Pulsed laser coating (PLC) of bioceramics/metal nanomaterials on metal substrates was investigated in this research. It is found that due to the nature of the nanosized particles and pulse laser beam, PLC processed hydroxyapatite (HAp) coatings possess strong coating/substrate interfacial bonding strength, and minimum thermal decomposition. Feasibility analysis of PLC is conducted using both simulation and experiments. In the multiphysics simulation, laser interacting with metal nanoparticles and heat conduction is simulated by coupling the electromagnetic (EM) module and heat transfer (HT) module. In experiments, HAp and titanium nanoparticle mixture are coated on Ti-6Al-4V substrate using nanosecond pulsed Nd:YAG laser with wavelength of 1064 nm. Resulting temperature is measured by calibrated infrared (IR) camera and compared with simulation results. Experimental results agree well with simulation which serves as a guidance to find appropriate processing parameters. It is found that resulting temperature increases with increasing of pulse energy linearly and decreasing of pulse duration following the power law. It is recommended that shorter pulses to be used in PLC due to its better sinterability. Microstructure and chemical characterizations confirmed that HAp was physically and chemically maintained due to pulse laser caused rapid heating and cooling processes.