PVD coated cutting tool and method of its production

A method of making a cutting tool comprising a body with at least on the functional parts of the surface thereof, a 0.5 to 20 μm thick hard and wear resistant coating, said process comprising depositing at least one refractory layer consisting of a nanocyrstalline Al-spinel compound of the type (Me)xAl2O3+x (0<x≦1), where Me is selected from the group consisting of Mg, Zn, Mn, Fe, Co, Ni, Cd, Cu, Cr and Sn and mixtures thereof, by reactive pulsed magnetron sputtering in a mixture of a rare and a reactive gas under the following conditions:

• the pulse frequency is set for 10 to 100 kHz,
• the deposition occurs with a rate of at least 1 nm/s with reference to a stationarily arranged substrate,
• the flux of the impinging particles onto each individual substrate is cyclically interrupted,
• the magnetron power density in time average is set for at least 10 W/cm2,
• the flow of the reactive gas is set for such a value that the impedance of the magnetron discharge lies between 150% and 250% of the impedance of a discharge burning between totally oxide-covered target electrodes, and
• the substrate temperature is set in the range 400° C. to 700° C. depending on the material of the tool body being coated.