With different additives mixed into investment gypsum casting powder

the effects of different additives on the fluidity

solidified time and baked strength of investment gypsum casting powder were investigated. The results show that the polycarboxylic acid water reducing agent has severely retarded the gypsum casting powder slurry

although enhancing the fluidity of the gypsum casting powder slurry

and the 0.1% content is more suitable for gypsum casting powder. When less silica sol is added to the water and the ratio of water to silica sol is less than 1∶1

the silica sol can promote the fluidity of the gypsum casting powder slurry

appropriately increasing the solidified time

and increasing the strength of the gypsum casting mold. When the ratio of water to silica sol is 4∶1

the fluidity of the gypsum casting powder slurry is satisfied. When the water: silica sol is 1∶1

the strength of the gypsum mold is desirable.