Theoretical Approach on Outflow Phase of the Evaporative Pattern Process by Permeability Tests Made on Refractory Coatings

The aim of the research was to understand the roll of the layer of pigment applied on the surface of the expanded polystyrene patterns. Among the different parameters characteristic of the layer, of particular importance is density of the refractory coating and thickness of the stratum after painting and drying of the patterns. The values of the two variables affect the permeability of the layer of refractory coating. Permeability is a critical parameter for control of the outflow of gases during casting. A good agreement between experimental and theoretical results was found.