Three-dimensional nuclear magnetic resonance and x-ray microtomographic imaging of composite materials.

摘要

This paper presents a new-three-dimensional nuclear magnetic resonance (NMR) imaging technique for nondestructive evaluation of green-state ceramic composite materials. The technique is based on a 3-D backprojection protocol for data acquisition combined with a Radon reconstruction technique. Particularly for NMR of solid materials, this imaging protocol can provide higher three dimensional spatial resolution than is possible with commonly applied slice-selection protocols. The applicability of this 3-D NMR imaging technique was demonstrated using whisker-reinforced Si(sub 3)N(sub 4)/Si(sub 3)N(sub 4) ceramic composites. While NMR is a sensitive and unique method for spatial discrimination of chemical properties (e.g., organic distributions), x-ray CT is a sensitive and proven technique for determining variations in density (i.e., voids and inclusions) within an object. The complementary nature of these two techniques was shown by imaging a piece of green ceramic composite material by both NMR and x-ray microtomography techniques.