Method of forming a thermally insulated composite article

Claim 1

The process as described in claim 1 wherein said core member is machined from a block of rigid ceramic foam material.

Claim 10

A method of forming a thermally insulated composite fluid conducting article comprising the steps of: mixing raw ceramic material and foaming agents; pouring the mixture into a mold of predetermined shape and core wall thickness; removing said core from the mold after the foaming agents have reacted; firing the core component to a rigid structure; applying a dense layer of powdered ceramic material to the inner surfaces of said core, said dense layer being impervious to penetration and being resistant to erosion by fluids passing through said passage; coating the outer surfaces of said core with a cushioning layer of resilient fibrous aluminum silicate material; positioning the coated ceramic core in a mold cavity; pouring a molten cast iron into said cavity forming a metal covered thermally insulated composite fluid conducting article whereby said ceramic core is protected from shrinkage of the cast metal and operational shocks to said metal cover by said cushioning layer.

Claim 11

A method of forming a thermally insulated fluid conducting composite article comprising the steps of forming a block of fused silica ceramic foam, machining the block in the form of a component of a ceramic core having inner surfaces defining a portion of one fluid passage, applying a dense layer of powdered fused silica material to the inner surfaces of at least two of said core portions defining the fluid passage, said dense layer being impervious to penetration and being resistant to erosion by fluids passing through said passage when said portions are assembled, joining the rigid ceramic core portions with a refractory cement such as aluminum silicate forming an intricate core structure, coating the outer surfaces of said assembled core with a cushioning layer of resilient fibrous aluminum silicate material, positioning the coated ceramic core assembly in a mold cavity, and pouring a molten aluminum alloy into said cavity forming a metal covered ceramic fluid conducting article whereby said ceramic core is protected from cast metal shrinkage and operational shocks by said cushioning layer.

Claim 13

A method of fabricating a thermally insulated composite fluid conducting article comprising the steps of forming a block of fused silica ceramic foam, machining the block in the form of a ceramic core half having an inner surface defining at least one-half of one fluid passage and at least one-half of one inlet and one outlet port, applying a dense layer of fused silica material to the inner surfaces of said liner half, said dense layer being impervious to penetration and resistant to erosion of fluids passing through said passage, positioning said core halves upon a preformed sand core, cementing the core halves together about said sand core with a refractory cement forming an intricate core structure, coating the outer surfaces of said core with a cushioning layer of resilient fibrous aluminum silicate material, positioning the coated ceramic core with the sand core therein in a mold cavity, pouring a molten aluminum alloy into said cavity forming a metal covered thermally insulated composite fluid conducting article whereby said ceramic core is protected from metal shrinkage and operational shocks by said cushioning layer, removing said thermally insulated composite article from the mold, and heating the composite article to 600* F. for five hours to decompose the sand core within said core.