Vitrification of Y zeolite and its effects on HREM images

Technical Report · Thu May 01 04:00:00 EDT 1986

OSTI ID:5698689

Csencsits, R

Electron diffraction has been used to study the vitrification of Y zeolite in the transmission electron microscope (TEM). Calculations and experimental evidence have confirmed that in the range 80 to 200kV, the damage of Y zeolites in radiolytic in the TEM. Incident beam electrons interact with specimen electrons which leads to a rearrangement of the structure. The proposed mechanism for this transformation involves enhancement of structural relaxation at A+ sites due to the presence of a charge compensating cation. Computer image simulation was used to assess the effects of damage on high resolution electron microscope (HREM) images of Y zeolites. Simulated images of perfect Y zeolite revealed that only for a specimen 10 to 20nm thick would the HREM image be a structure image at Scherzer defocus (-60nm); at thickness greater than 20nm the images contain non-structural detail due to second order interferences. Al larger defocus values (-100nm), thicker crystals (60nm) ''with 30 to 50% of their thickness amorphous'' produce images which can be related to the structure because the presence of the amorphous material decreases the visibility of the non-structural detail.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5698689
• Report Number(s): LBL-21640; ON: DE86013005
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360605* -- Materials-- Radiation Effects
BEAMS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
COMPUTERIZED SIMULATION
DAMAGE
DECOMPOSITION
ELECTRON BEAMS
ELECTRON MICROSCOPY
ENERGY RANGE
IMAGES
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
KEV RANGE
LEPTON BEAMS
MATERIALS
MICROSCOPY
MINERALS
PARTICLE BEAMS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIOLYSIS
SIMULATION
TRANSMISSION ELECTRON MICROSCOPY
VITRIFICATION
ZEOLITES