On the Elastic Behaviour of Zeolite Mordenite: a Synchrotron Powder Diffraction Study
The high-pressure elastic behavior of a synthetic zeolite mordenite, Na{sub 6}Al{sub 6.02}Si{sub 42.02}O{sub 96}{center_dot}19H{sub 2}O [a=18.131(2), b=20.507(2), c=7.5221(5) Angstroms, space group Cmc2{sub 1}], has been investigated by means of in situ synchrotron X-ray powder diffraction up to 5.68 GPa. No phase transition has been observed within the pressure range investigated. Axial and volume bulk moduli have been calculated using a truncated second-order Birch-Murnaghan equation-of-state (II-BM-EoS). The refined elastic parameters are: V{sub 0}=2801(11) Angstroms{sup 3}, K{sub T0}= 41(2) GPa for the unit-cell volume; a 0=18.138(32) Angstroms, K {sub T0}(a)=70(8) GPa for the a-axis; b 0=20.517(35) Angstroms, K{sub T0}(b)=29(2) GPa for the b-axis and c 0=7.531(5) Angstroms, K {sub T0}(c)=38(1) GPa for the c-axis [K {sub T0}(a): K {sub T0}(b): K {sub T0} (c)=2.41:1.00:1.31]. Axial and volume Eulerian finite strain versus 'normalized stress' plots (fe-Fe plot) show an almost linear trend and the weighted linear regression through the data points yields the following intercept values: Fe(0)=39(4) GPa for V; Fe {sub a} (0)=65(18) GPa for a; Fe {sub b} (0)=28(3) GPa for b; Fe {sub c} (0)=38(2) GPa for c. The magnitudes of the principal Lagrangian unit-strain coefficients, between 0.47 GPa (the lowest HP-data point) and each measured P>0.47 GPa, were calculated. The unit-strain ellipsoid is oriented with {var_epsilon}{sub 1} || b, {var_epsilon}{sub 2} || c, {var_epsilon}{sub 3} || a and |{var_epsilon}{sub 1}|> |{var_epsilon}{sub 2}|> |{var_epsilon}{sub 3}|. Between 0.47 and 5.68 GPa the relationship between the unit-strain coefficient is {var_epsilon}{sub 1}: {var_epsilon}{sub 2}: {var_epsilon}{sub 3}=2.16:1.81:1.00. The reasons of the elastic anisotropy are discussed.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 914042
- Report Number(s):
- BNL-78610-2007-JA; PCMIDU; TRN: US0801496
- Journal Information:
- Phys. Chem. Miner., Vol. 32; ISSN 0342-1791
- Country of Publication:
- United States
- Language:
- English
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