Metal release rate from AISI 316L stainless steel and pure Fe, Cr and Ni into a synthetic biological medium- a comparison
Abstract
Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using
Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result.
As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition.