Connection assembly for joining two parts

In an assembly of two parts having confronting ends defining therebetween a joint and a connection joining said two parts, said assembly intended for operation at an operating temperature from approximately 200.degree. C. to approximately 800.degree. C., the improvement wherein said connection comprises:

• a dimensionally stable coupling member surrounding said joint and at least one of said ends, said coupling member and said at least one said end defining therebetween a space;
• and
• ceramic fiber mat material positioned within said space and containing approximately 40-60 weight % of a swelling agent capable of volume expansion when subjected to said operating temperature, thereby forming means for, upon said assembly being subjected to said operating temperature, swelling said mat material and compressing said mat material between said coupling member and said at least one end, thereby connecting said two parts.