ИСТИНА

The key process in fabrication of Nitride bonded Silicon Carbide side lining of reduction pots is the reaction between Nitrogen and Silicon. Silicon may react with Nitrogen in solid, liquid and gaseous phase. The reaction is strongly exothermal. Almost all N-SiC refractory materials of more or less big shapes have the gradients of porosity from middle to the edges. The reason for these gradients may be the overheating of the middle part of shapes, comparing to edges, due to the exothermal effect and consequent increased part of volatile Silicon. Volatile Silicon tends to move in the places with lower temperature and the gradients of porosity are 1-2 %, but sometimes it may reach 5-7%. The problems with side lining may be due to the design of the pots with technology, yet the structure of N-SiC materials might be also critical.