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Atmospheric Plasma Coating Removal (APCR)- A New Coating Removal Technology 
Peter J. Yancey, Atmospheric Plasma Solutions, Inc. (APS) 

Introduction: Atmospheric Plasma Coating Removal (APCR) is the next generation of coating removal and surface preparation technology that represents a giant step forward in developing environmentally responsible methods for coating removal. Tested in U.S. government trials, APCR is found be a safe and effective alternative to media blasting and wet abrasive blasting. Requiring only compressed air and electricity to operate, a concentrated, low temperature, air plasma beam is created which enables rapid coating removal without the use of any media, eliminating the need for containment. Plasma beams may be configured for handheld or machine-mounted use to prepare a variety of substrates. The coating removal and cleaning process converts most paint, sealants, and organic coatings into carbon dioxide and water vapor. 

Problem Statement: The US Navy and other DoD Components have a critical need for media-free, high performance, environmentally friendly coating removal processes for ship hulls in dry-dock, and numerous other weapons platforms. Current technologies including wet or dry media blasting, mechanical sanding, laser ablation, induction heating, and chemical stripping and have limited flexibility as a complete coating removal solution to address multiple substrates, coating types, and applied coating thicknesses. Aircraft inspection and maintenance represents another area for effective coating removal. During maintenance and inspection scenarios coatings such as Advanced Performance Coating (APC) and other oxidation resistant aircraft coatings need to be removed from rivets and other fasteners as well as from welds and lap joint seams to facilitate inspection for cracks and breaks. In addition, polysulfide sealants used on aluminum lap joint fasteners found in fuel tanks and other wing structures need to be removed for inspection on a regular basis for cracks and corrosion. Almost every building and permanent installation necessary for the support of military forces, whether they are stationed in bases, being deployed or engaged in operations, such as barracks, headquarters, airfields, communications facilities, stores of military equipment, port installations, and maintenance stations, require regular maintenance of steel and concrete structure coatings. Maintenance personnel are seeking solutions that eliminate the costs and hazards of using aggressive solvents or abrasives in the removal of paint and other coatings from these structures. 

Outline of Key Points and Case Studies: The presentation and technical paper will explain the science behind the technology and also provide case studies and examples of how the technology has been effective in several Naval and DoD applications. APS has successfully completed several SBIR projects and related contracts with the US Navy, US Air Force, and the Strategic Environmental Research and Development (SERDP) program. Media Free Coating Removal Technology for Navy Platforms Using Atmospheric Plasma - Sponsored by the Office of Naval Research SBIR Phase I and II contracts, as well as SERDP, this work demonstrated coating removal for ship-board applications including haze-grey silicone alkyd topside coatings as well as copper-loaded epoxy anti-fouling coating on DH36 steel. Aircraft Sealant Removal - Sealant removal trials were conducted at the request of NAVAIR Cherry Point. In the course of this work, APCR was used to remove aircraft sealants up to several millimeters thick from a variety of fasteners on aluminum and magnesium substrates. Media-Free Aircraft Coating Removal - Atmospheric Plasma Solutions, Inc. (APS) completed an Air Force SBIR Phase I and II program that demonstrated that a low temperature plasma beam could be generated, using just compressed air and electricity to remove organic components in paints and other coating materials. The technology was successfully applied to both radar absorbing material (RAM) coatings and fluorinated urethane aerospace coatings or Advanced Performance Coatings (APC) in the course of the SBIR projects. APC Coating Removal for NDI - This work was requested by Air Force Research Laboratory (AFRL) to investigate the use of different coating removal methods for Non-Destructive Inspection (NDI), particularly for detection of cracks. The program demonstrated complete removal of APC coatings from aluminum aircraft parts to the alodine-treated substrate surface. The original substrate surface topology of the painted surface was preserved through the atmospheric plasma paint removal process, including any surface roughness or scratches. Furthermore the APCR process enhanced the fluorescent dye penetration and increased the brightness in the engineered cracks in the test samples. Selective APC Removal from Composites - This work sponsored by the US Air Force demonstrated removal of coatings from contoured, temperature-sensitive carbon fiber substrates. Much of the work for the Air Force contract was focused on exploring the effects of varying several process parameters on the coating removal rate for a number of coatings and substrates. Additional work has been performed to characterize the removal rate and removal pattern from, and the surface characteristics of, the treated samples. 

Conclusions: Within both the federal government and the private sector, there is a growing need for environmentally safe and cost effective solutions capable of removing paint and coatings from a wide range of surfaces including steel, aluminum, concrete and composites. The Atmospheric Plasma Coating Removal system presents a novel technology to remove coatings from virtually any substrate material. APCR has been demonstrated to be an effective alternative to media and wet abrasive blasting on a wide range of surfaces and coatings found in the US Navy and other DoD service branches.