Understanding high-temperature corrosion behavior of an AlN/Mo functionally graded material exposed to Li/LiF-LiCl-LiBr vapor

The high-temperature corrosion behavior of an AlN/Mo functionally graded material (FGM) under the Li/LiF-LiCl-LiBr vapor has been investigated. It is suggested that the Li vapor diffuses along the AlN and AlN/Mo grain boundaries and enters the interior of adjacent AlN grains, leading to the disintegration of AlN grains and subsequent failures. The 3D Mo networks are barely corroded, thus preventing cracking that may occur due to the inconsistent deformation inside the FGM. This work unravels the high-temperature corrosion mechanisms for the AlN/Mo FGM. Meanwhile, the operating temperature threshold for the liquid metal batteries employing Mo/AlN/Mo seals is determined to be ∼ 600 °C.