Autoclave for high-temperature, high-pressure XRD studies.

The properties of oxide film layers define many local corrosion phenomena. However, online oxide film characterization is challenging due to the high-temperature, high-pressure environment and the presence of water in the pressure vessel, which limits the application of surface analysis testing methods. While one can prepare an oxide film in an high-tempreature high-pressure environment, cool it down, depressurize the testing cell, and study the film in an ambient environment, this approach is not always representative, as the oxide film structure often changes during the cooling period.

To address this challenge, Cormet has designed and built an autoclave for high-temperature, high-pressure XRD studies. The autoclave features a vertical shaft in its middle, allowing rotation of the specimen holder attached to it. Two sapphire windows are attached to the testing cell walls: one for the incoming X-ray beam and another for the beam scattered from the specimen.

The University of Wisconsin has utilized this instrument to characterize oxide films on nuclear power plant construction materials in situ.