DOE awards Development of Cost-Effective YSZ Coating Methods for SOFC Interconnects
Solid oxide fuel cells (SOFCs) require robust seals that can prevent intermixing of air and fuel, remain inert in reducing and oxidizing environments while in contact with SOFC materials, and maintain their effectiveness through repeated thermal cycles. Recent research has focused on “compliant (or viscous)” glasses that remain vitreous over time in the SOFC stack operating environment, and are able to tolerate relative motion between the surfaces being sealed without the development of permanent leaks. Certain glasses (under investigation by MO-SCI and others) considered for this sealing application have broadly desirable thermo-mechanical properties and thermo-chemical characteristics, but have been found to chemically react with both bare and aluminized stainless steel SOFC interconnects, consequently forming phases that may adversely affect the integrity of the seal. On the other hand, these glasses do not react with the yttria-stabilized zirconia (YSZ) electrolyte used in most SOFC designs. Thus, YSZ could be an attractive barrier layer between the metallic SOFC interconnect and the sealing glass. The main goal of this project is to develop a dense and well-bonded YSZ coating on an SOFC interconnect alloy. This project will assist the nation’s SOFCs program in meeting its cost and performance targets by ensuring a stable barrier layer between SOFC interconnects and seals, and consequently achieving reliable seal operation over an extended operating life.