ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 53, (4) 242 - 249 (2009)


OPTIMIZATION OF THE CORROSION BEHAVIOR OF MULLITE REFRACTORIES AGAINST ALKALI VAPOR VIA ZrSiO4 ADDITION TO THE BINDER PHASE
 
Baspinar M. Serhat 1, Kara Ferhat 2
 
1 Afyon Kocatepe University, Technical Education Faculty, ANS Campus 03200, Afyonkarahisar, Turkey
2 Anadolu University, Engineering Faculty, Material Science Engineering Department, 2 Eylul Campus, Eskişehir, Turkey

Keywords: Refractories, Mullite, ZrSiO₄, Corrosion, Alkali
 

Effect of ZrSiO₄ addition to the binder matrix of the reaction sintered mullite refractories on the alkali corrosion (Na₂CO₃, at 1370°C) behaviour was investigated. Important improvements on the corrosion behaviour were observed when zircon was introduced to the binder matrix of the mullite refractories. Zircon addition to the mullite forming mixtures improved the densification. Densification effect reduced the tendency of infiltration of the alkali vapours. The investigation of the corrosion product at the reaction interface revealed that after alkali vapour (Na₂O) attack, mullite phase decomposed into sodium-aluminate-silicate type phase (carnegieite) and alumina. These expansive phase formation is the main reason for the damage after alkali vapour attack. It was concluded that, apart from densification effect with zircon addition, mullitization and densification behaviour of the binder matrix and type of the stage grains (sinter or fused) are important factors for the alkali corrosion behaviour of the mullite refractories.


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