High-temperature corrosion of a Si3N4/W composite exposed to molten MgCl2-NaCl-KCl salts

Abstract

The high-temperature corrosion behavior of a Si3N4/W composite under the molten MgCl2-NaCl-KCl salts has been investigated. It is suggested that the molten salts diffuse along the physical surface defects and enter the interior of adjacent Si3N4/W grains, leading to the 9.1% bending strength loss after 400 hours for corrosion. In air atmosphere, oxidation products WO2, WO3, and corrosion product MgWO4 caused a 34.3% bending strength decrease after 400 hours for corrosion. This study elucidates the high-temperature molten chloride salt corrosion mechanisms of the Si3N4/W composite material under two different atmospheres. The composite demonstrates relatively excellent corrosion resistance in service environments.