Effect of sandblasting on the oxidation and corrosion behaviour of an oxide-dispersed strengthened (ODS) FeCrAl alloy

Metallic biomaterials are preferred for replacements of the hard tissues si nce they are the most suitable to withstand the mechanical loads. For same components the higher surface roughness is preferred to increase the adhere nce and anchorage between the implant and the bone. In this work sandblasti ng prior to the oxidation is used to increase the surface roughness of the oxide dispersion strengthened (ODS) FeCrAl alloy. The effect of sandblastin g on its oxidation and corrosion behaviour is studied. As a comparison, pol ished samples are also studied. The alloy treated at 1 100 degreesC generat es a dense alpha -alumina layer which thickness increases with increasing e xposure time, being the values somewhat lower for the sandblasted samples. Impedance diagrams obtained for sandblasted samples preoxidised for 1 and 3 h show impedance values at the lowest frequency two orders of magnitude lo wer than those for polished samples. This decrease in the impedance value c an be attributed to the presence of paths or fine cracks in the alumina lay er that communicate the aggressive medium with the metallic substrate. Spal lation of the alumina layer in preoxidised sandblasted samples has been det ected by electrochemical impedance spectroscopy for treatment times of 10 a nd 100 h. Despite this loss of the scale integrity, the corrosion behaviour is good.