Patent ID: 8343686

Claim:
A method of joining concentric tubular structures to form a composite tubular structure comprising: forming a free-standing inner tubular structure and a free-standing porous outer tubular structure, the outer tubular structure having a higher radial shrinkage upon free sintering than the inner tubular structure, wherein one of the tubular structures comprises ceramic and the other tubular structure comprises metal; concentrically disposing the outer tubular structure over the inner tubular structure; sintering the concentrically disposed tubular structures such that the outer tubular structure radially shrinks and mechanically joins to the inner structure to form the composite tubular structure; wherein the composite structure is a solid oxide fuel cell structure, the outer tubular structure comprises metal, and the inner tubular structure comprises, an inner tubular current collector layer comprised of a porous metal, an inner electrode layer adjacent the inner current collector layer, the inner electrode layer comprised of porous ceramic electrolyte, an electrolyte layer adjacent the inner electrode layer, the electrolyte layer comprised of a dense ceramic, and an outer electrode layer adjacent the electrolyte layer, the outer electrode layer comprised of porous ceramic electrolyte.