T. Ohsuna et al., ELECTRON-MICROSCOPIC STUDY OF INTERGROWTH OF MFL AND MEL - CRYSTAL FAULTS B-MEL, JOURNAL OF PHYSICAL CHEMISTRY B, 101(48), 1997, pp. 9881-9885
Recently, a pure MEL type silica zeolite was successfully synthesized
by one of the authors. Boron atoms were incorporated into its framewor
k structure by using similar synthesis conditions with gels containing
boron in an effort to confer catalytic activity. The nature of crysta
l faults in the borosilicate-MEL zeolite (B-MEL) was studied using tra
nsmission and scanning electron microscopy (TEM and SEM). Electron dif
fraction (ED) patterns show characteristic diffuse streaks along the [
100] and [010] directions. From the analyses of both the diffuse strea
ks in ED patterns and high-resolution electron microscopy (HREM) image
s, it was determined that the framework structure of the B-MEL crystal
has many planar faults that are parallel to the (100) and (010) plane
s. The local structure of the planar faults can be interpreted by the
intergrowth of the MFI type structure, and a model of the growth proce
ss for the B-MEL is speculated from the results.