High temperature oxidation of tungsten carbide-cobalt composites in the presence of MDF

Recent studies have indicated that tool wear during the machining of medium density fiberboard (MDF) can be attributed mainly to oxidation and chemical attack rather than mechanical abrasion. To identify the nature and kinetics of such oxidation/corrosion reactions, WC-6% Co (C2) tool samples were exposed in oxidizing and inert gases with and without MDF chips. Thermal gravimetric experiments under continuous heating and isothermal conditions were also conducted. Post-reaction characterization using the scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) showed that C2 oxidation starts at temperatures as low as 500?C. Oxidation in the presence of MDF was found to occur in three successive stages that were dependent on MDF combustion at specific temperatures. For all temperatures tested, the oxidation rates were higher in the absence of MDF. Linear oxidation kinetics indicated that the reaction was not limited by diffusion through the product scale. Finally, an exponential increase in the oxidation rate with increasing temperature was more significant than the presence of the MDF environment.

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