Effects of Heavy Calcium Carbonate Additive on the Properties of Slurry and Ceramic Shell Mold

摘要

The heavy calcium carbonate additive has been added in the backup slurry of the ceramic shell mold. The effect of this additive on the basic properties and rheology of the slurry, the mechanical properties and permeability of the ceramic shell mold were studied. The materials for primary slurry were zircon flour and colloidal silica; for backup slurry, the materials were mullite and colloidal silica. The results showed that the calcium carbonate additive had little effects on pH value, specific gravity, moisture content and temperature of the slurry. According to the additive amount, the time for steady state were influenced by the viscosity of the slurry. While the additive addition amount in the backup slurry increased, the green strength and hot strength of ceramic shell mold were decreased; on the other hand, the fired strength was increased. The permeability was improved obviously while sintering at 800～1000℃.