A spiral gasket is very much a sealing solution for high-pressure high-temperature applications. It is made by winding alternating layers of metal and soft material; it provides excellent resistance to corrosive chemical agents, extreme pressures, and thermal cycling. As for the metal, it provides structural strength, and the filler includes seal-tightness against leaks. Spiral gasket... https://goodrichgasket.com/Spiral-Wound-Gaskets