Enhancement of the Surface Hydrophilicity of Casting Models on Application of the Primer Layer of Ceramic with a Developed Surface

Abstract

The most promising method for the manufacture of metal parts with complex forms is casting according to lost-wax or burnt-out models. The melted material used is a complex composition of wax with other organic compounds, characterized by high constancy of physicochemical and mechanical properties, since the accuracy of repeated reproduction of critical parts, for example, turbojet engine blades, depends on this. A wax model is necessary to grow a ceramic shell around it, whose manufacturing accuracy is decisive for obtaining a high-quality casting. Since the surface of the wax model is hydrophobic and the ceramic slurry applied to the model is water-based, a critical factor in shell technology is the ideal wettability of the model surface by the slurry applied to it. Improving wettability can be achieved not only by introducing special surfactant wetting agents into the aqueous phase, but also by changing the properties of the wax surface itself, i.e., giving it hydrophilic properties. A method of physically modifying the surface of a wax model is presented — application to it of a thin layer of ceramic powder, which is well wetted by aqueous ceramic suspensions.