Applications of nuclear magnetic resonance to nondestructive evaluation of advanced materials

Miscellaneous · Tue Jan 01 00:00:00 EST 1991

OSTI ID:7038628

Lizak, M J

Two applications of nuclear magnetic resonance to nondestructive evaluation are presented. The first application is NMR imaging of gases and liquids imbibed into porous ceramic matrix composites. This inspection technique takes advantages of the porosity of the ceramic composite material. A fluorocarbon liquid or gas is infiltrated into the pores of the material, and NMR imaging is performed on the fluorine nuclei. The gases and liquids have more amenable relaxation times for imaging than the ceramic itself, enabling imaging to be performed on commercially available equipment. The ceramic composite restricts the diffusion rate of the gas and dramatically alters the spin relaxation times. These differences provide good contrast mechanisms for the NMR imaging techniques. The second application is to monitoring curing of epoxies. Relaxation times were measured for several curing-epoxy systems. It was found that the transverse relaxation time, T{sub 2}, and the relaxation time of dipolar order, T{sub 1D}, were good indicators of the epoxy cure state. The relaxation times are easy to measure and are relatively insensitive to instrumental settings.

• Research Organization: Washington Univ., Seattle, WA (United States)
• OSTI ID: 7038628
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
36 MATERIALS SCIENCE
COMPOSITE MATERIALS
MICROSTRUCTURE
NONDESTRUCTIVE TESTING
EPOXIDES
CURING
NMR IMAGING
PERFORMANCE
CERAMICS
DIFFUSION
IMPURITIES
RELAXATION TIME
CRYSTAL STRUCTURE
DIAGNOSTIC TECHNIQUES
MATERIALS
MATERIALS TESTING
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
TESTING
420500* - Engineering- Materials Testing
360600 - Other Materials