Accession Number : ADA309972

Title :   Novel NDE Corrosion Detection: Nuclear Magnetic Resonance.

Descriptive Note : Final rept. 30 Sep 93-30 Nov 95,

Corporate Author : MCDONNELL DOUGLAS ASTRONAUTICS CO ST LOUIS MO

Personal Author(s) : Palmer, Donald D. ; Snyderman, David M. ; Conradi, Mark S.

PDF Url : ADA309972

Report Date : JAN 1996

Pagination or Media Count : 98

Abstract : Nuclear magnetic resonance (NMR), a technique utilized extensively in the medical, chemical and petroleum industries, has shown to be very sensitive to corrosion and moisture entrapped in aircraft structures in cursory studies performed prior to this program. Both aluminum and hydrogen NMR techniques were evaluated relative to sensitivity to thin layers of corrosion on several aluminum alloys and a high strength steel. Other hydrogen-bearing aerospace materials were characterized to determine if discrimination between these materials and corrosion could be made relative to hydrogen NMR. RF magnetic field modelling was performed using two- and three-dimensional electromagnetic modelling codes to determine if RF magnetic fields could penetrate through gaps in joints and around fasteners. Actual RF magnetic field penetration was determined experimentally using simplified butt-joint, lap joint and fastener hole structures. The potential for detecting actual corrosion in these structures was also evaluated experimentally. In addition, the ability to detect corrosion under paint, primer and sealant was determined. Recommendations for future work relative to NMR as an inspection tool for detection and characterization of corrosion are included.

Descriptors :   *NUCLEAR MAGNETIC RESONANCE, *DETECTION, *CORROSION, *NONDESTRUCTIVE TESTING, TEST AND EVALUATION, MAGNETIC FIELDS, AIRCRAFT, ALUMINUM ALLOYS, TOOLS, LAYERS, MATERIALS, STRUCTURES, HIGH STRENGTH ALLOYS, SENSITIVITY, STEEL, HYDROGEN, AEROSPACE SYSTEMS, PENETRATION, HOLES(OPENINGS), AIRFRAMES, THINNESS, MOISTURE, FASTENINGS, RADIOFREQUENCY, SEALING COMPOUNDS, PETROLEUM PRODUCTS.

Subject Categories : Atomic and Molecular Physics and Spectroscopy
      Inorganic Chemistry
      Organic Chemistry
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE