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ABSTRACT Ion beam processing, including ion implantation and ion beam assisted deposition (IBAD), are established surface modification techniques which have been used successfully to synthesize materials for a wide variety of tribological applications. In spite of the flexibility and promise of the technique, ion beam processing has been considered too expensive for mass production applications. However, an emerging technology, Plasma Source Ion Implantation (PSII), has the potential of overcoming these limitations to become an economically viable tool for mass industrial applications. In PSII, targets are placed directly in a plasma and then pulsed-biased to produce a nonline-of-sight process for intricate target geometries without complicated fixturing. If the bias is a relatively high negative potential (20-100kV) ion implantation will result. At lower voltages (50-1200V), deposition occurs. Potential applications for PSII are in lowvalue-added products such as tools used in manufacturing, orthopedic devices, and the production of wear coatings for hard disk media. This paper will focus on the technology and materials science associated with PSII. INTRODUCTION There currently exists a broad range of applications for which the ability to produce an adherent, hard, wear and corrosion-resistant coating plays a vital role. These applications include engine components, orthopedic devices, textile manufacturing components, hard disk media, optical coatings, and cutting and machining tools (e.g., punches, taps, scoring dies, and extrusion dies). Plasma-based ion processing can play an important role in all of the applications listed above. The ability to provide flux, energy, and temporal control of a variety of ions, allows one to tailor surface structure and chemistry necessary to solve current and future problems involving corrosion, surface hardness and other tribological properties. Ion implantation and energetic deposition processes, e.g., ion-beam-assisted deposition and ion plating, are well established techniques that have been successfully used in scientific studies to tailor surface properties such as corrosion, hardness, friction and wear, and fracture toughness. Many examples can be found in the literature [1,2]. The principal reasons for the success of these ion beam process are listed in Table 1.

455 Mat. Res. Soc. Symp. Proc. Vol. 396 © 1996 Materials Research Society

Table 1 Advantages and Features of Ion Beam Surface Modification Techniques Ion Implantation Energetic Ion Deposition

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Solid solubility limit can be exceeded Unique metastable phases are possible Alloy preparation independent of diffusion No sacrifice of bulk properties Low temperature process No significant dimensional changes No adhesion problems since there is no sharp interface Controllable depth concentrations Clean vacuum process

Good adhesion with substrate Unique metastable phases are possible Control of nucleation or nucleation density Control of morphology Control of density Control of composition Low temperature process C