Al2O3 Ceramics with Graded Porosity Produced from Natural and Artificial Pore Formers

Özet

Al2O3 ceramics with graded porosity were produced by using corn starch and PMMA sphere as pore former additives (PFA). Graded porosity was obtained by uniaxially pressing the stacks of Al2O3 mixtures with and without PFA together. Pressed samples were heat-treated to remove PFAs at 600oC and sintered at 1540oC. Final porosity of graded ceramics produced from starch and PMMA were measured as 12 and 16%, obtained median pore size were 3 and 11 µm, respectively. The elastic moduli of the samples were measured by pulse-echo method and results showed that moduli values of the samples varied significantly depending on the PFA type. PMMA added samples had lower elastic moduli values than starch added ceramics as a result of higher pore size and interconnected pore structure. By using the pulse-echo method, the elastic properties of the graded samples couldn’t be measured effectively.