Local corrosion of solid oxides at the slag-metal interface has been investigated for the systems of Al2O3, SiO2-(PbO-SiO2) slag-Pb. Results obtained are as follows : (1) The major part of the local corrosion zone appears below the horizontal slag-metal interface, and slag film below 350 μm in thickness exists between the solidified metal and the oxide specimen in the local corrosion zone. (2) Direct observation of the local corrosion occurring in a transparent fused silica tube has revealed the modes of the slag film formation and its active motion in the local corrosion zone. Changes in SiO2 content in the solidified slag film are detected along and perpendicular to the inner surface of the tube in the local corrosion zone. (3) Shape and linear loss, Δds-m, of both the oxide specimens in the local corrosion zone show characteristic changes with dipping time and slag composition. For SiO2 specimen, they show marked changes with the initial diameter of the specimen and the thickness of the bulk slag phase. (4) These experimental evidences support that the local corrosion for the present system is mainly caused by the interfacial turbulence of the thin slag film between the metal and the oxide specimen in the local corrosion zone.
