Characterization of Zircon-Based Slurries for Investment Casting

Zircon is used in either the prime slurry and/or stucco in a majority of investment casting foundries. The current shortage in the supply of zircon, together with its rising price, means that many investment casting foundries will be forced to use alternate materials, or cut back on production. It would be of great benefit to the industry if functional alternatives to zircon could be identified and produced at comparable cost. This paper contains a baseline evaluation of a zircon prime slurry, including tests and quality metrics to quantify its behavior. Specifically, the following measurements were conducted on a set of six identical zircon prime slurries: viscosity, bulk density, pH, temperature, wet film thickness, prime coat bubble count, and plate retention. These quality metrics and other tests could be used to assess/benchmark potential zircon alternatives, and evaluate their performance compared to zircon.