The effects of metal binder content and carbide grain size on the aqueous corrosion behaviour of TiC–316L stainless steel cermets

Abstract

The room temperature electrochemical response of TiC-based cermets, with 10 to 30vol.% 316L stainless steel binder and either fine- or coarse-grained TiC, has been investigated in an aqueous 3.5wt.% NaCl solution. The assessment methods included Tafel extrapolation, in combination with potentiodynamic and potentiostatic polarisation. Corroded samples were characterised using SEM, with post-corrosion solutions analysed using ICP-OES. The highest corrosion resistance was achieved at the lowest binder contents, while those with a more coarse-grained structure generally showed superior resistance, due to a reduced TiC–316L interfacial area. Preferential dissolution of the steel binder was observed, leaving the TiC essentially unaffected.