Silica sol shell and preparation method thereof

The invention relates to the technical field of investment casting, in particular to a silica sol shell and a preparation method thereof. The preparation method of the silica sol mold shell comprises the steps that a mold shell is obtained after a module is sequentially subjected to surface layer coating dip-coating, surface layer sand scattering, transition layer coating dip-coating, transition layer sand scattering, reinforcing layer coating dip-coating, reinforcing layer sand scattering and slurry sealing layer coating dip-coating; the shell is dewaxed and roasted to obtain the silica sol shell; wherein the transition layer coating is prepared from the following components in parts by weight: 800 to 1000 parts of mullite powder, 0.8 to 1.2 parts of carbon fiber and 480 to 520 parts of silica sol; the reinforcing layer coating is prepared from the following components in parts by weight: 1400 to 1800 parts of mullite powder, 0.8 to 1.2 parts of carbon fiber and 480 to 520 parts of silica sol. According to t