Effect of Ni contents on mechanical properties and corrosion behavior of Ti(C,N)-WC-Mo2C-(Ni,Co) cermets

Abstract

The mechanical properties and corrosion behavior of Ti(C,N)-WC-Mo2C-(Ni,Co) cermets with different Ni/Co ratios were investigated by mechanical property tests, scanning electron microscope, abrasion resistance test, electrochemical measurements, X-ray photoelectron spectroscopy. The results showed the increasing Ni content caused the improvement of fracture toughness and the reduction of hardness and abrasion resistance. Electrochemical tests indicated that the proper Ni addition in cermet may enhance the corrosion resistance with cermet in HCl and NaOH solution. The corrosion behavior of cermet was mainly determined by the selective dissolution of the binder phase and the formation of oxides on corroded surface. Moreover, the improving corrosion resistance of cermet in NaOH solution can be attribute to a dense passive film oxidized from binder phase. Hence, cermet with an appropriate ratio may be considered as promising structural material in complicated application with acid or alkali solution.