Influence of C content on electrochemical corrosion resistance of nanostructured hardmetals

摘要

The influence of C content on the electrochemical corrosion behavior of nanostructured WC-Co hardmetals was investigated. WC powder with an average grain size dBET 95 nm and with an addition of VC and Cr_3C_2 as a grain growth inhibitors was used as starting powders. The mixtures with 5 wt. % and 10 wt. %Co and 15 wt. %Co were consolidated by sinter-HIP process. The samples were researched by direct current and alternative current techniques in the solution of 3.5 % NaCl at room temperature. Corrosion parameters like corrosion potential (Ecorr), corrosion current density (jcorr), polarization resistance (Rp) were determined by electrochemical techniques. On the basis of conducted research it was found that C content added to the starting mixture significantly influence the electrochemical corrosion resistance; better electrochemical corrosion resistance was observed for samples with lower content of C added and lower magnetic saturation.