Effect of mixing proportion and mixing time on primary slurry retention and surface roughness of investment casting shells

Abstract

Surface quality of investment cast parts are mainly depends upon primary slurry condition which is used to make face coat. Zircon flour (ZrSiO4) is widely used to make primary slurry. In this work different composition (75% - 25%, 70% - 30% and 65% - 35%) of zircon flour and colloidal silica is analyzed at different mixing time (at 24hrs, 48hrs and 72hrs). Viscosity, wettability, slurry retention, and surface roughness are measured and analysed. From the experimental work conclusion derived that composition with 75% zircon and 25% colloidal silica at mixing time of 72 hour gives best result in surface finish.