A novel gel tape casting process based on gelation of sodium alginate

A novel gel tape casting process by sodium alginate is described. Sequestrant and calcium salts are added into ceramic suspension simultaneously, thus the gelation between calcium salts and sodium alginate is avoided because a stable complex was formed from sequestrant and calcium salts. By adding adipic acid, calcium ions are released from the complex and react with sodium alginate to form a three-dimensional (3D) network. Therefore, ceramic particles are held in this network thus resulting in a green tape. The effect of dispersant and binders on the rheological behavior of suspensions was investigated. The optimal amount of dispersant was found to be ∼0.3 wt.%. The addition of styrene-acrylic latex changed the rheological behavior of the suspensions and improved the flexibility of green tapes. Gelation rate suitable for tape casting could be easily controlled by the amounts of adipic acid and sequestrant. Green tapes with homogeneous microstructure have been fabricated by this process.