The mechanical properties of siliceous ZSM-5 (MFI) crystals

The micromechanical compressive response of siliceous ZSM-5 single-crystals (silicalite) has been measured using an in-house-built micromechanical tester. Single-crystals (similar to300 mum) were prepared using the method of Shimizu and Hamada [Angew. Chemie Int. Ed. 38 (1999) 2725]. High-quality crystals with no evident microcracks and which were optically transparent were subjected to measurements using single, cyclic and two-directional compression tests. ZSM-5 crystals are highly brittle and prone to microcracking. An average Young's modulus of similar to4 GPa was measured. No difference in Young's modulus between as-synthesized and calcined crystals is detected and little mechanical anisotropy is observed. The cyclic tests reveal gradual stiffness deterioration through a microcracking process. (C) 2002 Elsevier Science Inc. All rights reserved.