Polymeric binder distribution maps in green ceramics by 1H NMR imaging

Nuclear magnetic resonance-compatible furnace for high temperature MR imaging and spectroscopy in situ

“…In both cases, the isotopic selectivity of NMR imaging permits the spatial mapping of the concentrations, flows, diffusion coefficients, and ionic mobilities of specific elements, and in many cases specific compounds or sites in crystal lattices [37]. Many of the ions important in superionic conductivity, such as 1 H þ , 7 Li þ , 19 F À , 17 O 2À , and 23 Na þ are good NMR targets [38,39], as are many nuclei of lattice-formers (for example, 11 B, 17 O, 27 Al, 29 Si, and 31 P) [40].…”

“…Nondestructive evaluation (NDE) of parts and processes has proven to be of enormous value in optimizing the production of ceramics. We and others have reported the use of MRI for nondestructive measurement of porosity and binder distribution in green and partially sintered ceramics and other engineering materials at ambient temperature [2][3][4][5][6][7][8][9][10][11][12][13][14]; little high temperature work has been published [15]. The hostile conditions (high temperature, noxious chemistry, etc.)…”

Modern applications of NMR tomography in physical chemistry. The characteristic features of the technique and its applications to studies of liquid-containing objects

“…Different strategies of magnetic resonance imaging and recording spatially resolved NMR spectra of a polymeric binder were compared taking the compacts prepared by compacting alumina powder mixed with polymeric binder (2.5 mass % or 15 mass %) as examples. 108,151 No effect of the average particle size on the binder distribution was found; however, a decrease in the length-to-diameter ratio of the compact down to 0.17 led to increased concentration of the polymer around the periphery of the sample, which was associated with features of the pressing mechanics. The signal intensity histograms constructed based on the two-dimensional images of the compacts can be used for controlling the binder distribution homogeneity.…”

“…27 The relaxation times can also depend on the mechanical prehistory of the sample. 108 Magnetic resonance imaging studies should be carried out taking into account specific features of systems of different nature. For instance, in most of biological objects the spin systems do not exhibit a single-exponential relaxation due to structural inhomogeneity at the cell and tissue level.…”

“…The signal intensity histograms constructed based on the two-dimensional images of the compacts can be used for controlling the binder distribution homogeneity. 108 An NMR imaging study of a Si 3 N 4 sample pressed in the form of a disk with openings of different diameters containing organic binder (15 mass %) has been reported. 151 The relaxation times of lowmolecular-mass poly(ethylene oxide), polyvinyl alcohol and poly(ethylene terephthalate) used as binders in fabrication of ceramics are *1 ms (T 2 ) and *300 ms (T Ã 2 ).…”