Post mortem study of Al2O3/SiC/C/MgAl2O4 ceramic lining used in torpedo cars

A post mortem study of Al2O3/SiC/C/MgAl2O4 (ASCMg) refractory lining used in Companhia Siderurgica Nacional (CSN) torpedo car was conducted in order to determine the corrosion equation developed during industrial application. Different samples were collected and characterized using the following techniques: Chemical Analysis by X-Ray Fluorescence, Thermal-Gravimeter and Differential Thermal Analysis (TG-DTA), Mercury Porosimetry, Helium Picnometry, Dilatometry, X-Ray Diffractometry, Scanning Electronic Microscopy (SEM) and Energy Dispersive Scanning (EDS). It was found that slag containing a high amount of calcium aluminum silicate interacts with refractory microstructure causing corrosion. From this effect it is noted the introduction of an alkaline incorporating concurrent mechanism, in addition to corundum being turned into β-alumina and the oxidation of SiC through Na2O resulting in better protective conditions to graphite, thereby improving refractory lining shelf life.