Grit blasting of medical stainless steel: implications on its corrosion behavior, ion release and biocompatibility

This study reports on the biocompatibility of 316 LVM steel blasted with small and rounded ZrO2 particles or larger and angular shaped Al2O3 particles. The effect of blasting on the in vitro corrosion behavior and the associated ion release is also considered. Surface of Al2O3 blasted samples was rougher than that of ZrO2 blasted samples, which was also manifested by a higher surface area. Compared to the polished alloy, blasted steels exhibited a lower corrosion resistance at the earlier stages of immersion, particularly when using Al2O3 particles. With increasing immersion time, blasted samples experienced an improvement of the corrosion resistance, achieving impedance values typical of passive alloys. Blasting of the alloy led to an increase in Fe release and the leaching of Ni, Mn, Cr and Mo. On all surfaces, ion release is higher during the first 24 h exposure and tends to decrease during the subsequent exposure time. Despite the lower corrosion resistance and higher amount of ions released, blasted alloys exhibit a good biocompatibility, as demonstrated by culturing osteoblastic cells that attached and grew on the surfaces.