Measurements of the interface between 5083 aluminium and liquid mercury using impedance spectroscopy

In natural gas processing plants, the aluminium oxide passive layer has been postulated to protect the underlying aluminium from mercury embrittlement. Under certain circumstances the oxide film may break down, leading to catastrophic failure. In this study, impedance techniques are used to investigate the interface between Al-5083 and liquid mercury at room temperature. The effects of aging time, aging atmosphere and mercury exposure time on the interface were studied and are discussed in terms of the nature of the film. The implications of this work on the integrity of aluminium gas processing equipment exposed to mercury are examined.

Research highlights
► The stability of the interface between mercury and 5083 aluminium is studied.
► 100% humid air leads to accelerated film formation compared with desiccated air.
► Films become more complex as the aging process continues.
► The electrical impedance of thin films decay with the time of exposure to mercury.