Ultrafast joining of zirconia ceramics using electric field at low temperatures

This work describes an electric-field assisted joining technique that is capable of joining 3 mol.% yttria stabilized zirconia (3YSZ) ceramics within 1 min at furnace temperature of 400 °C. The joint with 94–99% of the parent material's three-point bending strength (638 ± 21 MPa) was achieved at furnace temperature of 600–900 °C by optimizing the key joining parameters, including the applied electric current, joining time and furnace temperature. Increase in current and joining time promoted the formation of dense joint, but they also led to degradation of the strength of parent material via defect accumulation. The furnace temperature enhanced the defect annihilation, which lowered the extent of strength degradation of the parent material. Therefore, the joint formed at high furnace temperature with threshold current and appropriate joining time displayed high strength. It was experimentally demonstrated that the electric field enabled the ultrafast joining, rather than the Joule heating.