The effect of surface treatment on CaP deposition of Ti6Al4V open cell foams in SBF solution

The effects of alkali and nitric acid surface treatment and acid etching on the CaP deposition of an open cell Ti6Al4V foam (60% porous and 300–500 μm in pore size) developed for biomedical applications were investigated in a simulated body fluid (SBF) solution for 14-day. The surface roughness of the foam specimens ground flat surfaces was measured in nano-metric scale before and after SBF immersion using an atomic force microscope (AFM). A significant increase in the surface roughness of alkali treated foam specimen after SBF immersion indicated a smaller crystal size CaP deposition, which was also confirmed by the AFM micrographs. The microscopic evaluation clearly showed that alkali treatment and nitric acid treatment induced a continuous, uniform CaP deposition on the cell wall surfaces of the foam (interior of cells). While in untreated foam specimen the cells are filled with CaP precipitates and acid etching did not produce a continuous coating layer on particles interior of the cells. The coating layer thickness was ∼3 μm in alkali treated foam specimens after 14-day of SBF immersion, while nitric acid treatment induced relatively thinner coating layer, 0.6 μm.