Exploring the role of Ag foam interlayer in alleviating the brittleness of G018 glass sealant for joining YSZ to Mn–Co spinel coated Crofer 22 H

Glass/Glass-ceramic sealing is always accompanied by issues of high porosity and brittle joints. To migrate these problems, an Ag foam was innovatively induced as an interlayer in the process of glass sealing the yttria-stabilized zirconia (YSZ) ceramic to Mn–Co spinel-coated Crofer 22 H stainless steel. Interlayer-added joints showed a significant reduction in porosity, and the shear strength was improved to 52.3 MPa, with an enhancement of 37.8 %. The influence of interlayer on the microstructure of the joint has been investigated and the formation process of the joint is illustrated. The Ag interlayer expels gases from the sealant material through expansion at high temperatures and promotes finer nucleation grains of crystallites integrating with the interlayer, reducing the porosity and alleviating the brittleness as well.