|AVS 58th Annual International Symposium and Exhibition|
|Neutron Scattering Focus Topic||Tuesday Sessions|
|Session:||Neutron Scattering Poster Session|
|Presenter:||P. Wang, Los Alamos National Laboratory|
|Authors:||P. Wang, Los Alamos National Laboratory
D. Hickmott, Los Alamos National Laboratory
A. Lerner, Los Alamos National Laboratory
J. Majewski, Los Alamos National Laboratory
|Correspondent:||Click to Email|
To understand the interfacial behaviors of materials under high pressure (P) and temperature (T) are of great importance and interest since lots of natural phenomena and practical applications involve those conditions. For instance, mineral surface/fluid interactions control success or failure of many attempts to engineer Earth’s subsurface for energy and/or environmental applications. The corrosion of metals and alloys in high subcritical aqueous systems, and especially in supercritical environments is an important safety issue in nuclear power plants.
However, due to the fact that most interface characterization techniques are difficult to implement at elevated P-T, little experimental attention has focused on solid/fluid interfaces at high P-T.
Neutron reflectometry (NR) is increasingly being used as a characterization tool to study the surface/interface of planar substrates. SPEAR at Lujan center is a Time-of-Flight (ToF) NR facility which is specifically designed to study solid-liquid interface and is able to in-situ monitor the surface/interface behavior with a space resolution of a few angstroms. The obtained real space model from reflectivity curve fitting can provide a lot of physical and chemical information about the interface.
One key gap to study the interfacial behaviors of materials under high P-T conditions is the lack of well designed pressure cell capable of handling P-T conditions close to or above supercritical conditions. To build up the capability of studying high P-T surface/interface, Lujan Center developed a special designed pressure cell which allows us to reach 200 MPa and 250 °C (in the future such cell will be equipped with with in-situ spectroscopic Raman and IR capabilities). Neutron is highly penetrating, which is able to “see through” high P-T aluminum cell walls and examining the surface/interface properties. Besides the pressure cell itself, the high P-T cell system includes three other subsystems: temperature, pressure and sample chamber environment control systems.