Double transition joint for the joining of ceramics to metals

摘要

The invention is directed to effective means for joining materials having dissimilar coefficients of thermal expansion, such as advanced ceramics with metallic compounds. Moreover, the present invention relates to furnace tubes and methods of fabricating a joint between two different materials, which is compositionally graded to provide a substantially graded coefficient of thermal expansion between the joint materials.

主权项

1. A method of fabricating a joint between two materials in an apparatus comprising transitioning from a first material A to a first metal material B wherein first material A and first metal material B are chemically and thermomechanically incompatible at a temperature of operation of said apparatus, said method comprising:
i) a first transitioning of said first material A to a second material C, wherein second material C is compatible at the temperature of operation of said apparatus with both first material A and first metal material B, said first transitioning between first material A and second material C is graded to provide a gradation starting with 100 percent first material A and having a continuous compositional change in the amount of first material A and second material C until there is 100 percent of second material C having a coefficient of thermal expansion which substantially grades between the first material A and second material C; and ii) a second transitioning of said second material C to the first metal material B, said second transitioning between the second material C and first metal material B is graded to provide a gradation starting with 100 percent second material C and having a continuous compositional change in the amount of second material C and first metal material B until there is 100 percent of first metal material B having a coefficient of thermal expansion which substantially grades between the second material C and the first metal material B, wherein first material A is silicon carbide based, first metal material B is iron chromium nickel based, and second material C is alumina and the proviso that said joint contains at least two gradations.