1984 Volume 70 Issue 8 Pages 823-830
Laboratory corrosion test of clay-bonded SiC specimen at the slag surface has been carried out in argon, argon-oxygen and air, in order to elucidate the mechanism of local attack of blast-furnace-trough material at the slag surface.
The local corrosion arises only in the oxidizing atmosphere in the narrow zone just above the slag surface. The corrosion zone of solidified specimen during the progress of the corrosion is covered with thin liquid slag film. Supplying rate of oxygen from the atmosphere gives remarkable influences on the relations between the corrosion rate and dipping times, slag compositions, etc. It is estimated that the slag film, crept up from the bulk slag, plays important roles in the occurence of the local corrosion by accelerating mass transfer and causing the abrasion of the specimen due to its active movements in diffusion layer caused by Marangoni effect. SiC granules on the surface of the specimen are oxidized by iron oxide in the film into carbon granules, which causes Marangoni effect and also facilitates the dissolution and abrasion of the specimen. Some countermeasures against the local corrosion have been offered from the corrosion mechanism.
