Abstract:
In this paper, the effects of three rheological additives including fumed silica, polyamide powder and modified polyurea on the rheologocial properties of silver paste were studied by means of stress sweeping, frequency sweeping, and printing simulation oscillation shear dynamic sweeping. The correlation between paste rheology and printability was established. The results showed that with the increase of modufied polyurea, the internal hydrogen bonding of silver paste was increased, the interactions among particles to form three-dimensional crosslinking network was enhanced, resulting in the increase of viscosity and the yield stress as well as the decrease of the loss angle and the enhancement of recovery speed. Silver paste with 1.5% dosage(mass fraction) of modified polyurea showed a fine line with small diffusion, sharp edge, uniform distribution, and good line type.