Joining and sealing pressurized ceramic structures

A method of joining and sealing a ceramic structure and an end plug, comprising:

• forming a joint of the ceramic structure including a tubular structure and the end plug located inside the tubular structure using a first sealing material;
• applying the first sealing material between the ceramic structure and the end plug, wherein the first sealing material includes a preceramic polymer and a plurality of inclusions;
• locally heating the first sealing material applied between the ceramic structure and the end plug to form a solid ceramic from the first sealing material;
• and
• crystallizing the solid ceramic to form a crystalline matrix comprising a ceramic polymorph that is the same as the ceramic structure and the end plug, the plurality of inclusions being disposed within the crystalline matrix,
• wherein the end plug is structured to include a hole that goes through a top surface and a bottom surface of the end plug,
• wherein a pin is positioned in the hole;
• and wherein the method comprises:
• placing a second sealing material in the hole of the end plug;
• applying heat to a section of the ceramic structure near the end plug to heat the second sealing material;
• and
• applying pressure to the pin so that the pin presses the heated second sealing material in the hole to seal the end plug.