The effect of Mo2C additions on the oxidation resistance of (Ti,W)CN cermets as base material for the production of cutting tools

Hadi, Morteza; Rafiaei, Seyed Mahdi; Fernandes, Filipe

http://hdl.handle.net/10400.22/24567

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Authors

Hadi, Morteza

Rafiaei, Seyed Mahdi

Fernandes, Filipe

Abstract(s)

The effect of Mo2C secondary carbide on the oxidation resistance of (Ti0.93W0.07)CN0.3-20%Ni cermet was investigated using DSC-TG, isothermal oxidation, XRD, and SEM/EDS characterisations. Adding Mo2C secondary carbides to (Ti, W)CN cermets is one of the methods used for improving their mechanical properties. However, Mo2C secondary carbides bring a detrimental effect to oxidation resistance. The isothermal oxidation results of the samples at 750 ◦C possessing 0% and 2% MO2C follow the parabolic law, while in the samples containing 5% and 8% Mo2C, the rate of oxidation and the spallation of the oxide scale increased significantly. The thickness of the oxide layer in the cermet containing 5% of Mo2C increased three times, whereas the mass per unit area of the detached oxides in the 8% Mo2C specimen dramatically increased up to 100 times. The investigations revealed that the increase in the amount of W and Mo on the cermet material, as well as the formation of a multi-zone oxide layer, are the main reasons for oxide phase propagation.