Large-scale plasma source ion implantation and deposition experiments´

Plasma source ion implantation [1] (PSII) is a technique which enables implanting a high dose of ions in a simple, fast, efficient, and cost-effective manner. In PSII a negative high-voltage pulse is applied to a workpiece which is immersed in a plasma. Plasma ions are accelerated by the electrical potential and are implanted into the surface of the workpiece. PSII offers several improvements over conventional beamline techniques in that it is a non-line-of-sight process enabling conformal implantation simultaneously into all exposed surfaces of the workpiece. System efficiencies are improved since the perpendicular ion trajectories into the workpiece eliminate the need for masking. Implant times are short when compared to beam-line techniques since high-current, pulsed-power supplies compatible with this process can provide up to two orders of magnitude higher average currents than conventional accelerators. In this paper we report recent results obtained on the large-scale PSII facility (1.5-m diam, 5-m long) at Los Alamos [2]. Pulsed power is supplied by a hard-tube modulator capable of providing 125-kV, 60-A, 0.02 ms-long pulses at 2 kHz [3]. Most of our research has been focused on metallurgic wear and corrosion applications. Improved tribological properties (increased hardness, lower friction, and significantly reduced wear) are observed with nitrogen and carbon implantation into several steel alloys and chromium. Metallic ion generation and implantation have been accomplished with a cathodic arc ion source. By combining PSII with plasma enhanced chemical vapor deposition, adherent diamond-like carbon films have been deposited onto relatively large batches of aluminum automotive components. Films are hard (> 20 GPa) with a low coefficient of friction. The PSII process is found to create a graded interface between coatings and substrates, significantly improving film adhesive properties.