Cutting tools coated with TiBON films of different boron concentrations and thicknesses are made, and then the effects of boron concentrations and coating film thicknesses on tool wear are investigated in turning and milling of Inconel 718 under dry cutting conditions. Results show that the tool coated with the film that has a boron concentration of 15%has the longest tool life, about four times longer than that of a tool coated with a single TiAlN layer. The wear progress rate of the tool decreases as the TiBON film thickness increases. Specifically, the life of tools with a TiBON film is twice as long or longer that of tools with a TiAlN film when Inconel 718 is being cut. The mechanism behind the extended tool life is a combination of the effect of preventing adhesion by the formation of oxide material along with the lubrication afforded by the deposition of BN in the high temperature range.