THE ION CURRENT-DENSITY AND SPECTROSCOPIC STUDY IN A STRAIGHT MAGNETIC FILTERING ARC DEPOSITION SYSTEM

The changes of plasma states during cathodic arc discharges of Ti and TiAl under various magnetic fields of straight magnetic solenoid were analyzed by Langmuir probe method and optical emission spectroscopy (O ES). The ion emission intensity of Ti II for Ti arc discharge was enha nced by a factor of 2, with increasing magnetic field up to 150 Gauss compared to that under no magnetic fields. For discharging TiAl with a mbient N-2 under 150 Gauss, however, the emission of Al exhibited domi nant neutral emission of Al I only with slight increase of ionized Al II emission while Ti II emissions were increased at a similar ratio as measured in Ti discharge. The enhancement of electron density induced by a straight solenoid magnetic field promoted the effective ionizati on of metal vapors, therefore producing a high fraction of ionized vap or flux including macroparticles, which contributed to the increase of deposition rate and sputtering of macroparticles seated on the film s urface by energetic metal ion flux. The changes of surface morphology and film formation behaviors of TiN and (TiAl)N arc was evaluated with a variation of external magnetic field in conjunction with plasma con ditions obtained from Langmuir probe, OES and XRD analyses. The corres ponding hardness and friction coefficient variations are also illustra ted. (C) 1997 Elsevier Science S.A.