Lower shelling performance of sol silicate mold shell could directly affect the product efficiency and surface quality of complicated investment castings.Shelling performance can be improved by employing mixed coating in transition layers of mold shell

greatly improving shelling efficiency.High temperature strength of shell mold is slightly affected due to grain precipitation at high temperature and phase transformation at low temperature of molten quartz in the mixed coating

and residual strength can be greatly decreased as a result of volumetric contraction of phase transformation in molten quartz during solidification

which obviously improves shelling performance.The process and other assistant measures improving shelling performance were described.