Micromechanical compressive response of a zeolite single crystal

Abstract

In this work the mechanical properties of a widely used zeolite catalyst, ZSM-5, are measured. Single crystals of the ZSM-5, of average size 500 microns, are prepared using an organic template molecule. Testing is performed on the single crystal size scale. An in-house microdeformation tester is designed and manufactured. Loading on the crystal is provided by a high precision stepper motor. Both crystal displacement and applied load are continually monitored through a computer. The entire testing assembly is placed under an optical microscope and a CCD camera is used to obtain real time optical images of the deformation. In this way monotonic and cyclic loading compression stress strain curves are generated. The material is seen to have an average elastic modulus of 4 GPa. It is also seen to be brittle and undergo a gradual stiffness deterioration through a microcracking process. Crystal anisotropy is also investigated by performing two directional tests. However, for the [100] and [010] directions little mechanical anisotropy is observed.