Evaluation of Primary Slurry Used in Ceramic Shell Investment Casting Process

Abstract — Ceramic shell investment casting process is used to produce high quality metal products with relatively close dimensional tolerances. The refractory primary slurry that is applied to the surface of the pattern assembly, to pick up its surface details plays a very important role in ceramic shell investment casting process (CSICP). It produces a smooth, acceptable surface finish of the ceramic shell mould, which in turn is transmitted to the casting. Zircon flour, though costly, is being used as a primary slurry material in the ceramic shell investment casting process. To reduce the cost of primary slurry material, some refractory filler materials were added with the zircon flour. The Scanning Electronic Microscopy (SEM) technique has been used to study the surface morphology of ceramic shell prepared from primary slurry. Parameters like viscosity and plate weights of the slurries have been measured. The results reveal that the fused silica with colloidal silica binder when used as a filler material in zircon flour primary slurry gives the best results with respect to above properties.