Comparison of Nickel and Cobalt Bonded Nanoscaled Hardmetals

Nanoscaled hardmetals show inferior properties regarding microstructure homogeneity, hardness, fracture toughness to hardness ratio, wear resistance and bending strength compared to conventional with coarser grain size. Besides superior mechanical properties, erosion and corrosion resistance are required in the chemical and petroleum industry due to exposure to an aggressive environment. Conventional WC-Co hardmetals are characterized by poor corrosion resistance especially in acid media due to selective dissolution of the Co binder. Thus, studying another binder metal to increase the corrosion resistance is of common interest. Within this study, two nanoscaled hardmetal grades with nickel and cobalt as binder metals were researched. The starting mixtures were prepared with the same binder content of 11 wt.% and the same size of the WC starting powder of around 150 nm. The samples were consolidated by the sinter-HIP process and their properties were investigated and compared in regard to microstructure, mechanical properties, and corrosion resistance. Nanosized WC-Co hardmetals can be used for wear resistant applications as well as for applications where a high uniformity of mechanical properties (due to low defect size and defect density) is needed. However, besides superior mechanical properties, also erosion and corrosion resistance are required in the chemical and petroleum industry where hardmetals parts are exposed to an aggressive environment. Since WC-Co hardmetals are characterized by poor corrosion resistance especially in acid media, the alternative binder could improve the electrochemical corrosion resistance of nanosized hardmetals. The combination of alternative binders and nanosized WC powder is a relatively unresearched area. The is no papers published on this topic. In order to compare more deeply and to conclude how different binder materials influence the overall properties of nanoscaled hardmetals (microstructure, mechanical properties, and corrosion resistance) the extensive research would be carried out.Nanoscaled hardmetals show inferior properties regarding microstructure homogeneity, hardness, fracture toughness to hardness ratio, wear resistance and bending strength compared to conventional with coarser grain size. Besides superior mechanical properties, erosion and corrosion resistance are required in the chemical and petroleum industry due to exposure to an aggressive environment. Conventional WC-Co hardmetals are characterized