Corrosion of Cemented Carbide leads generally to a surface depletion of the binder phase and, thus, the surface region will remain only as a carbide skeleton. The bonds between adjacent carbide grains are rather weak and the deterioration rate will increase accordingly. At low binder phase contents, the carbide skeleton is more developed and, accordingly, such grades exhibit a somewhat higher combined wear and corrosion resistance than corresponding grades with higher binder phase contents.

However, this effect is insufficient to offer a significant life improvement. The limited corrosion resistance of straight WC-Co grades often makes them unsuitable in applications where the corrosive conditions are severe. For these applications, like carbide cutting tools, Sandvik has developed a series of highly corrosion resistant grades.

In most corrosion-wear situations, (i.e. carbide cutting tools) the better choice is specially alloyed WC-Ni grades, which are resistant down to pH 2-3. Even in certain solutions with pH values less than 2 they have proved to be resistant to corrosion. As they have WC as the hard principle, and Ni and Co are similar metals in most respects, their mechanical and thermal properties are comparable to those of the straight WC-Co grades.

The pH value is one of the most important parameters when determining the corrosivity of a medium, but other factors also have a major influence, such as the temperature and the electric conductivity of the medium. The latter is dependent on the ion concentration, i.e. the amount of dissolved salts in the solution.