|
|||||
|
|
P-V equation of state of portlandite, Ca(OH)2, from powder neutron diffraction data |
|
| Authors: | A Pavese M Catti G Ferraris S Hull |
| Institution: | Dipartimento Scienze della Terra – Sez. Mineralogia – Università degli Studi di Milano, Via Botticelli 23, Milano 20133, Italy E-mail pavese @iummi4.terra.unimi.it, IT Dipartimento di Chimica Fisica ed Elettrochimica – Università degli Studi di Milano, Via Golgi 19, Milano 20133, Italy, IT Dipartimento di Scienze Mineralogiche e Petrologiche – Università degli Studi di Torino, Via Valperga Caluso 35, Torino 10125, Italy, IT Rutherford Appleton Laboratory, ISIS Facility, Chilton-Didcot, Oxfordshire, OX11 0QX, United Kingdom, GB |
| Abstract: | A high pressure neutron powder diffraction study of portlandite Ca(OH)2] has been performed at ISIS facility (U.K.); nine spectra have been collected increasing the pressure by steps, up to 10.9 GPa, by means of a Paris-Edinburgh cell installed on the POLARIS diffractometer. The tensorial formalism of the lagrangian finite strain theory and the Birch-Murnaghan equation of state have been used to determine, independently, two values of the bulk modulus of portlandite, obtaining K 0=38.3(±1.1) GPa linear incompressibilities: K 0a=188.4(±9.9), K 0c=64.5(±2.5) GPa] and K 0=34.2(±1.4) GPa, respectively. The present results comply with values from previous measurements by X-ray diffraction K 0=37.8(±1.8) GPa] and Brillouin spectroscopy K 0=31.7(±2.5) GPa]. Reasonably, Ca(OH)2 has revealed to be bulkly softer than Mg(OH)2 K 0=41(±2), K 0a=313, K 0c=57 GPa]. The Ca(OH)2 linear incompressibility values reflect the nature of forces acting to stabilize the (001) layer structure and, further, prove that the replacement Ca/Mg mainly affects the elastic properties in the (001) plane, rather than along the 001] direction. Data from a full refinement of the structure at room pressure are reported. Received January 12, 1996/Revised, accepted June 15, 1996 |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ | |