Forming of alumina by extrusion

Extrusion is very old forming process which has a background on classical ceramicand refractory scopes and proved itself as an essential and economic technique atproduction of long dimensioned ceramic products. Furnace tubes, bricks, insulators,catalytic and electronic mounts, thermocouple protective tubes, and recently heatexchangers and honeycomb formed mounts are manufactured with extrusiontechnique.Classical ceramics contains clay minerals like coalinit and they would have highlyplastic property with mixing with water. For modern ceramic compositions whichdon?t contain clay like Al2O3 , ZrO2, SiO2, extrusion process needs organic additivesat proper conditions to prepare plastic characterized mixtures.This study, the optimum conditions was determined for extrusion of Alcoa CT 3000SG, original Seydişehir alumina powder and washed-calsined Seydişehir aluminapowder with various binders. After binder removing and sintering (at 1450, 1500,1550, 1600 and 1650 ºC) process, various characterization tests were applied to tubeand rod type extrusion parts. The absorption and compressive strength values for thespecimens were measured and determined.For all specimens strengths increased parallel to the sintering temperature. Thehighest strengths were taken from the products produced from Alcoa alumina. Theproducts which produced from Seydişehir alumina powder which was washed andsodium oxide removed and then calsined at 1200ºC showed higher strength thanoriginal Seydişehir alumina.2006, 80 pagesKey Words: Alumina, Extrusion, Organic additive, Seydişehir alumina, Cr2O3additive, Na-CMC