Aqueous corrosion of Ni-Cr alloys in biological environments and implications for their biocompatibility

AbstractThe literature describing the corrosion of nickel based alloys with ~20 wt-%Cr and up to 10 wt-%Mo in aqueous chloride containing environments between pH 2 and 7, and at ambient or body temperatures, is critically reviewed. In many cases, uncertainty as to the extent of passivation throws doubt on the results. Corrosion rates from these publications are collated and (in cases where these are not explicit) adduced where possible. Possible weaknesses in the methodology are pointed out. The implications of the findings are considered in terms of the known concern regarding the biocompatibility of nickel and suggest that at least for those alloys which performed less well in tests, there should be a degree of concern as to whether they may be safely used in the body.