We report high repetition rate picosecond laser based additive manufacturing process to coat nanoscale rough hydroxyapatite (HA) on cobalt chromium plates (CoCr). Nanoscale rough coatings of hydroxyapatite are desirable as they mimic the naturally formed hydroxyapatite and in addition provide very high surface area and surface roughness, which leads to better cell adhesion and cell-matrix interaction. Nanoscale HA powders are synthesized using sol-gel procedure and ball milling. Ball-milled powders are suspended in volatile solvents and coated on the CoCr surface using picosecond laser irradiation. The chemical composition and morphology of the coated material was characterized using electron microscopy. The laser-assisted fusion process results in HA coatings that have hierarchical surface roughness down to nanometer scale which may enhance the biocompatibility of the CoCr implants
