Effect of binder nature and content on the cavitation erosion resistance of cemented carbides

Abstract

Cavitation erosion is a common mode of wear in flow control and fluid handling systems. To mitigate this degradation mode, CoCr superalloys or facing coatings are commonly used for flow control or pump parts. Cemented carbides, however, generally present wear resistance superior to that of those materials due to the favourable combination of their mechanical properties. In this study, the cavitation corrosion-erosion performance of cemented carbides with submicronic WC grain size was evaluated in a 3.5 wt% NaCl aerated solution at room temperature as a function of their binder volume (up to 20%) and chemistry (Co, Ni, and their combination). The effect of the addition of secondary (cubic) carbides (up to 11 vol%) on the performance of these materials was also assessed. Results showed that the cavitation erosion-corrosion resistance for these materials was controlled by the carbide contiguity and the binder chemistry. The cavitation erosion resistance increased linearly with the increase of the hardness (as well as H/E and H3/E2 ratios) for the materials having a Ni/(Ni + Co) ratio > 60% and a HV30 > 1500. Such materials presented superior performances than the CoCr superalloy reference material.