Enhancement of Tungsten-Carbide Tool Life by Oxide Treatment

It is shown that the tool life of tungsten-carbide tools can be increased by at least 80 percent by treating the surface of carbide tools with various oxides. Among the oxides that increase the tool life are titanium dioxide, zirconium oxide, aluminum oxide, and chromium sesquioxide. The oxide treatment was done by diffusing the oxide layer, which had been coated on the tool surface, into the subsurface layer in a vacuum of 10⁻⁵ torr at various temperatures. The increase in tool life is greater at higher temperatures of the oxide treatment, the maximum temperature being the sintering temperature of the carbide tools. It is believed that the decrease in the tool wear rate is caused by the retardation of mass diffusion between the tool and work, lowering of the chip-tool interfacial friction, and by decrease in the temperature at the chip-tool interface. Other possible causes are also discussed.