In-situ x-ray diffraction under hydrothermal condition using synchrotron radiation and its application to tobermorite formation reaction

A method of in-situ transmission X-ray diffraction (XRD) under a hydrothermal condition has been developed using a newly designed autoclave cell in combination with high-energy X-rays from a synchrotron-radiation source. The autoclave cell has X-ray windows made of thin beryllium foil, which enables one to obtain XRD patterns without any interference signals from the window materials. This method was applied to an in-situ investigation of a tobermorite formation reaction. It has been revealed that there are at least two pathways for tobermorite formation with different intermediate materials, which occur sequentially rather than simultaneously. (author)