The investment casting process is widely used for the production of small- and medium-sized parts of precision metal castings having complicated geometries. The process starts by dipping a foam or wax pattern in a slurry of ceramic powders (e.g., fused silica, zircon, alumina, etc.). Refractory powders (stucco) are next applied to the slurry coated pattern. The pattern is then removed from the ceramic shell by melting the wax or thermally decomposing the foam. Finally, the ceramic shell is cleaned of the pattern residue and fired to provide enough strength to hold the pressure of the liquid metal during the casting process.
Understanding the creep behavior of the ceramic shell is important because shell distortion at high temperatures must be minimized during the metal casting process. The high-temperature stability of the ceramic shell must be maintained in order to provide metal castings with precise dimensions.