Characteristics of Cr-Al-N films prepared by pulsed laser deposition

Summary form only given, as follows. The synthesis of (Cr/sub 1-x/Al/sub x/)N films is of great interest from a viewpoint of wear-protective coatings with high oxidation. The (Cr/sub 1-x/Al/sub x/)N coatings will provide a promising alternative rather than CrN coatings used conventionally. From such an idea, the preparation of (Cr/sub 1-x/Al/sub x/)N films have been tried by pulsed laser deposition (PLD). YAG laser (3/spl omega/, 355 nm, 7 ns) was used in the experiment. The laser beam was focused by a tens, yielding the energy density of 2 J/cm/sup 2/ on the target. The deposition was carried out for 1 hour at a pulse repetition rate of 10 Hz. Plates of Cr/sub 2/N and AlN were used as the target. The experiment was carried out by changing the surface area ratio of the target (AlN/(Cr/sub 2/N+AlN)) from 0 to 100%. The film composition was measured by energy-dispersive X-ray spectroscopy (EDS) and Rutherford backscattering spectroscopy (RBS). The surface morphology was evaluated by scanning electron microscopy (SEM). The crystal structure of the films was studied by X-ray diffraction (XRD). The hardness of the (Cr/sub 1-x/Al/sub x/) N films showed the maximum value (HV/spl sim/4000) at x = 0.5. Phase transition from the B1 structure to the B4 (wurtzite) structure occurred above x = 0.75, being in reasonable agreement with the theoretical prediction. The result of the oxidation test revealed that the CrN film was oxidized at approximately 600/spl deg/C. Furthermore, in the (Cr/sub 0.5/Al/sub 0.5/) N film, the existence of oxide has not been observed in the annealing temperature between RT to 900/spl deg/C.