Ps. Wang et al., NMR CHARACTERIZATION OF INJECTION-MOLDED ALUMINA GREEN COMPACTS .2. T-2-WEIGHTED PROTON IMAGING, Journal of Materials Science, 30(4), 1995, pp. 1069-1074
Injection-moulded alumina green compacts containing polypropylene, wax
, and stearic acid were studied for binder distribution by proton nucl
ear magnetic resonance (H-1 NMR) imaging. The solid imaging technique
of nuclear spin-spin relaxation time, T-2, weighted imaging at 400 MHz
was used. This imaging technique utilizes a multiple pulse sequence o
f 0-(pi/2)(+/-)-tau-D-10-D-7-(pi)(x)-D-7-D-10-AQ-D-0 for echo detectio
n and phase encoding. Two-and three-dimensional images were constructe
d from the intensities of these nuclear echo signals. Spatially resolv
ed two-dimensional images obtained by the application of this techniqu
e indicated that the green compacts fabricated from the same nominal b
inder composition did not contain the same amounts of binder. This obs
ervation agrees well with our previous conclusion drawn from nuclear s
pin echo studies by Hahn's pulse sequence. A 64 x 64 x 64 three-dimens
ional imaging revealed that the inhomogeneity of binder distribution a
nd internal imperfection do exist at certain locations of the samples.
A binder-rich folding line was also detected in one of these green co
mpacts.