Sol–gel derived hydroxyapatite/calcium titanate coatings on Ti6Al4V alloy

AbstractA sol–gel dip coating method was used for coating hydroxyapatite (HA)/calcium titanate (CaTiO3/CTO) on a Ti6Al4V (TAV) substrate. A single CTO layer (∼500 nm thickness) was coated and heat treated at 750°C before five times of HA coating. The HA coating showed a thickness of 8–10 μm, after the heat treatment at 600°C. Phase formation, surface morphology and interfacial microstructure were investigated by X-ray diffraction and scanning electron microscopy. Scanning electron microscopy observations revealed no cracks on the HA/CTO surface. However surface cracks were observed when HA was directly coated on TAV. The bonding strength of HA/CTO increased almost three times compare to direct HA coatings. The higher bonding strength on CTO coated sample could be attributed to the formation of microcracks, the high surface roughness and high interfacial bonding between HA and CTO layer.