Effective, safe, and non-damaging cleaning technologies are critical for maintaining aircraft and other defense systems in operational readiness. This project will demonstrate the feasibility of applying gliding arc discharge-generated plasma-activated water (PAW) for the removal of oils and greases from metal surfaces. PAW is a novel technology currently under study for microbial decontamination of surfaces. PAW can be applied in the form of bulk water, as well as water droplets, known as plasma-activated mist (PAM). 

This project aims to achieve the following objectives:

Objective 1: Evaluate the efficiency of PAW in removing grease from aluminum, magnesium, and steel surface.

Objective 2: Assess the effectiveness of PAM in removing grease from aluminum, magnesium, and steel surfaces.

Objective 3: Investigate the potential effects of temperature on the vaporization and condensation processes of PAW during the cleaning process.

Plasma technology has been proven effective in removing lubricant oil from metal surfaces without damaging the material. The research team has previously focused on utilizing plasma for the removal of organic pollutants from granular activated carbon, soil and resin. PAW is a novel technology currently under study for microbial decontamination of surface. PAW can be applied in the form of bulk water, as well as water droplets, PAM. Recent observations of PAW have indicated surfactant behavior, suggesting that the activation of water with non-equilibrium plasma can decrease its surface tension. However, the efficacy of PAW in removing oils and greases from impacted substrates, such as polymers, elastomers, and metals, remains unexplored. 
 
The approach taken in this project has the potential to produce results that demonstrate the proof-of-concept of using PAW to remove grease from different substrates such as aluminum, magnesium, and steel surfaces. To evaluate the effectiveness of PAW and PAM for grease removal, the project team intends to adhere to the ADS-61A-PRF (Aeronautical Design Standard, Performance. Specification, Cleaners, Aqueous and Solvent, for Army Aircraft). In brief, a standard contaminant will be applied to aluminum, magnesium and steel coupons, followed by two-hours baking at 130°F. Subsequently, all coupons will be photographed and weighed before and after contamination, with comparisons to after treating with PAW and PAM. Additionally, infrared ray analysis will be utilized to detect residual grease content on the metal surface post-treatment. Trichloroethylene will be employed as a baseline degreasing solvent.

PAW offers a gentle effective cleaning solution, capable of removing oils and residues without damaging material surfaces. By eliminating the need for harsh chemicals, PAW supports safer maintenance operations and lowers waste generation from during vapor degreasing operations. The adoption of plasma-based cleaning technology could also provide long-term cost savings through reduced chemical use, streamlined logistics, and improved operational efficiency in maintaining critical defense systems. (Anticipated Project Completion - 2026)