| Fast firing has been used to produce dense ceramics usually in less than 10 min using conventional furnaces. Most of densification occurs under non-isothermal conditions. The very fast densification rates observed are related to high heat inputs, originated from changes in the internal structure of the sample during fast firing. The amount of energy available for sintering increases by the formation of a dense outer layer which controls the flux of heat to the interior of the compact. High thermal stresses were expected to be generated from high heating rates in fast firing, but no serious manufacturing defect was observed. This fact could be related to the formation of a densification front moving from the outer surface towards the centre of the sample. In this paper, the production of dense, fine-grained ceramics through fast firing is reviewed. The variables that control the microstructure and densification are discussed. |
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