Influence of Agglomeration and Contamination in the Course of Amorphous Powder Grinding on Structure and Microstructure of Sintered Mullite

Sa？etak The process of grinding of amorphous pre-mullite powder has been investigated. The powder has been obtained by sol-gel process followed by drying, calcination and wet milling in planetary ball mill for various periods. While particle size distributions shifts to finer size distributions as the grinding time increase, the specific surface area dependence on the grinding time shows complex behavior. This was attributed to the agglomeration in the course of calcinations partially promoted by slight re-esterification of the sample surface in the course of grinding. Mill wear debris has been observed in samples grinded for longer periods. The influence of particle size, re-esterification, agglomeration and contamination of samples on the mullite formation process, structure, sintering process and microstructure development, has been further investigated. Slight changes in samples phase composition, as well as mullite structure, and the great decrease of sintered body porosity with the duration of grinding have been observed. (doi: 10.5562/cca1662