ECM: Development of Plasma-Based Techniques to Reduce the Environmental Hazards Associated with Wet-Bath Electroplating Processes

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9528746 Conrad The objective of this research is to investigate Plasma Source Ion Implantation (PSII), a dry, non-polluting surface modification technique, to mitigate the problems associated with wet chemical bath plating procedures. PSII is a non-line-of-sight, dry surface modification technique that has been shown tos improve wear and corrosion of materials. In PSII, the parts to be treated are placed in a plasma (ionized gas) and pulse-biased to a high negative potential. As a result, ions in the plasma are accelerated into the parts' surfaces at high velocities, resulting in the enhancement of its surface properties. In addition to implantation, the PSII process can be used to deposit overlay coatings with a degree of mixing at the coating-substrate interface that assures good adhesion. This research will involve the application of the PSII process in both the ion implantation and deposition modes. Process variables in PSII such as energy, dose, and pulse shape will be utilized to control the phases and microstructure of the coatings. The PSII-treated coatings will be characterized using Auger spectroscopy and electron microscopy for microstructural aspects such as grain size, cracks, and porosity. Wear, corrosion, and adhesion characteristics of the coatings will be of primary interest and will be studied in detail, modeled computationally, and compared to existing electroplated coatings. The research will be performed in a multi-disciplinary environment involving plasma physics, materials science, ion-materials interactions, computer modeling, and tribology. Consequently, it will develop new knowledge at the interfaces between these areas and apply the fundamental knowledge in these fields to environmentally conscious manufacturing, where it has the potential to make a significant impact on ecology and workers' environment. The research will have a strong educational component as well as industrial participation. Currently, wet chemical bath platings (e.g., chromium and cadmium) are widely used for improving wear, corrosion, and erosion resistances and lowering friction in a variety of machine tooling, process equipment, and manufactured goods. However, the chemical baths and the rinse water generated from the plating plants are environmentally toxic and present significant problems in both handling and disposal. PSII provides an appealing substitute to these wet chemical processes, because of its ability to produce high performance material surfaces in a chemical-free, environmentally-clean manner.