ABSTRACT

This chapter discusses the predicted gelation reactions of mullite gels synthesized by various methods. In this connection, during gelation, it is recalled that kaolinite/metakaolinite contained tetrahedral sheets proceed in the direction. The cause of the early mullitization was explained after measuring the polymerization state of the Si ion in the gelation state by the absorption method and trimethylsilylation. The different conditions and procedures attributed to the kinetics of hydrolysis and subsequent polymerization processes are outlined below. Different mechanisms for employing catalysts in sol-gel processing were proposed by Pope and Mackenzie. A comprehensive literature on this subject on controlling the hydrolysis, condensation, size of the polymeric particles is presented. The gelation reactions in two major categories of mullite precursors, hydrolysis-gelation and hydrolysis-coprecipitation processes, have been enumerated to bring focus to the role of the gelation process versus the phase transformation processes.