The Microstructure Of Fused Cast Azs Materials Before, During And After The Use For Glass Melting

A part of a soldier bock, placed in a float glass furnace near the hot spot area, was investigated to learn about the changes in the microstructure during the production of the block, during the use for glass melting and after the shutdown of the furnace and the cooling of the block. Besides the three phases after the production (baddeleyite, corundum, vitreous phase) during use as a soldier block mullite and secondary corundum as well as a secondary zirconia may occur. Cooling down the used block after the furnace campaign the beginning of the crystallisation of feldspars may be seen.