Effect of surrounding polydimethylsiloxane frame and substrate on drying behavior of aqueous alumina suspensions

The drying behavior of aqueous alumina suspensions surrounded with and without polydimethylsiloxane (PDMS) frames was studied. The capillary stress generated in the bodies was measured in situ using a cantilever deflection method. The relationship between the capillary stress and the formation of cracks was discussed. Compared with the suspensions dried without surrounding PDMS frames, the drying rates of the suspensions were significantly decreased by the surrounding PDMS frames. By drying a suspension on a strong hydrophilic substrate, the PDMS frame hardly reduced the capillary stress. When drying the suspension on a hydrophobic or weak hydrophilic substrate, the elastic deformation of thick PDMS frames could effectively release the capillary stress and therefore crack‐free ceramic green bodies could be obtained.