Tubular ceramic structures, e.g., anode components of tubular fuel cells, are manufactured by applying ceramic-forming composition to the external surface of the heat shrinkable polymeric tubular mandrel component of a rotating mandrel-spindle assembly, removing the spindle from the assembly after a predetermined thickness of tubular ceramic structure has been built up on the mandrel and thereafter heat shrinking the mandrel to cause the mandrel to separate from the tubular ceramic structure.

A mandrel for a molding process. The mandrel includes a first portion that has a first draft surface and a second draft surface. A second portion and a third portion are included. The second portion has a third draft surface and the third portion has a fourth draft surface wherein the first draft surface engages the third draft surface and the second draft surface engages the fourth draft surface. A channel extends along a length of the mandrel at an interface between the first, second, and third portions such that the second portion does not contact the third portion.

A mandrel for a molding process. The mandrel includes a first portion that has a first draft surface and a second draft surface. A second portion and a third portion are included. The second portion has a third draft surface and the third portion has a fourth draft surface wherein the first draft surface engages the third draft surface and the second draft surface engages the fourth draft surface. A channel extends along a length of the mandrel at an interface between the first, second, and third portions such that the second portion does not contact the third portion.

A method of fabricating a ceramic matrix composite component includes fabricating a ceramic preform, the preform comprising a hollow portion with an internal cavity extending along a first axis from a first end to a second end of the hollow portion, supporting the hollow portion with an auxetic mandrel disposed within and the internal cavity and coaxial with the hollow portion, the auxetic mandrel comprising a first mandrel end and a second mandrel end, at least partially densifying the preform with a matrix, and removing the auxetic mandrel from the internal cavity by simultaneously applying a compressive force to each of the first mandrel end and the second mandrel end creating a deformed auxetic mandrel to reduce a cross-sectional profile of the auxetic mandrel along a second axis orthogonal to the first axis, and extracting the deformed auxetic mandrel from the first end of the hollow portion.

A method of fabricating a ceramic matrix composite component includes fabricating a ceramic preform, the preform comprising a hollow portion with an internal cavity extending along a first axis from a first end to a second end of the hollow portion, supporting the hollow portion with an auxetic mandrel disposed within and the internal cavity and coaxial with the hollow portion, the auxetic mandrel comprising a first mandrel end and a second mandrel end, at least partially densifying the preform with a matrix, and removing the auxetic mandrel from the internal cavity by simultaneously applying a compressive force to each of the first mandrel end and the second mandrel end creating a deformed auxetic mandrel to reduce a cross-sectional profile of the auxetic mandrel along a second axis orthogonal to the first axis, and extracting the deformed auxetic mandrel from the first end of the hollow portion.