METHOD OF PRODUCING CERAMIC SHELL MOULDS FOR INVESTMENT CASTING Russian patent published in 2011 - IPC B22C9/04 

FIELD: process engineering.

SUBSTANCE: proposed method comprises producing mould, layer-by-layer application of fire-proof suspension based on pulverised alundum and coating every layer by granular alundum. First two layers are applied using organoaluminium binder in ceramic suspension of general formula RO{[-Al(OR)-O-]_x[-Al(OR*)-O-]_y}_zH, where z=3-100; x+y=1; R*/Al=0.05÷0.95; R=C_nH_2n+1; n=1÷4; R*=C(CH₃)=CHC(O)C_nH_2n+1; C(CH₃)-CHC(O)OC_nH_2n+1, while the following layers are produced using hydrolysed solution of ethyl-silicate. Ceramic mould layers are dried in chamber with moisture content of, at least 95% of first layer for 1 h, second layer for 3 h, the other layer for 4-6 hours with subsequent convective drying of each layer. Ceramic mould is incinerated at 1250-1350°C for 4-6 hours.

EFFECT: higher heat resistance and strength.

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