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Pressure slip casting and cold isostatic pressing of aluminum titanate green ceramics: A comparative evaluation

Papitha Ramanathan (International Advanced Research Centre for Powder Metallurgy and New Materials, Centre for Ceramic Processing, Hyderabad, India)
Suresh Madireddy Buchi (International Advanced Research Centre for Powder Metallurgy and New Materials, Centre for Ceramic Processing, Hyderabad, India)
Rao Yebaluri Srinivas (International Advanced Research Centre for Powder Metallurgy and New Materials, Centre for Ceramic Processing, Hyderabad, India)
Saha Bhaskar Prasad (International Advanced Research Centre for Powder Metallurgy and New Materials, Centre for Ceramic Processing, Hyderabad, India)
Das Dibakar (University of Hyderabad, School of Engineering Sciences & Technology (SEST), Hyderabad, India)
Johnson Roy (International Advanced Research Centre for Powder Metallurgy and New Materials, Centre for Ceramic Processing, Hyderabad, India)

Aluminum titanate (Al2TiO5) green bodies were prepared from mixture of titania and alumina powders with different particle sizes by conventional slip casting (CSC), pressure slip casting (PSC) and cold isostatic pressing (CIP). Precursor-powder mixtures were evaluated with respect to the powder properties, flow behaviours and shaping parameters. Green densities were measured and correlated with the fractographs. A substantial increase in green densities up to 60 %TD (theoretical density of 4.02 g/cm3, calculated based on rule of mixtures) is observed with the application of 2-3 MPa pressure with PSC. While particle size distribution and solid loading are the most influential parameters in the case of CSC, with PSC pressure also plays a key role in achieving the higher green densities. Being a dry process, high pressure of > 100 MPa for CIP is essential to achieve densities in the range of 60-65 %TD. Slip pressurization under PSC conditions facilitate the rearrangement of particles through rolling, twisting and interlocking unlike CIP processing where pressure is needed to overcome the inter-particle friction.

Keywords: aluminium titanate ceramics, shaping, slip casting, pressing, thermal applications