METHOD OF PREPARING ETHYL SILICATE BINDER Russian patent published in 1998 - IPC

FIELD: foundry practice, more particularly manufacture of ethyl silicate molds and rods in precision casting. SUBSTANCE: ethyl silicate is hydrolyzed by stirring with aqueous solution of aluminium salt when continuously affected by nanosecond electromagnetic pulses. Ratio of resistivity of ethyl silicate to be hydrolyzed and original ethyl silicate is continuously measured. As soon as ratio of resistivities of (0.08-0.5)•10^-4 and (0,04-0,1)10^-4 is achieved, diluent is added for ethyl silicate-40 and ethyl silicate-32, respectively, 20-25-% aqueous solution of aluminium chloride or 25-30-% solution of aluminium nitrate is used for hydrolysis. Improved quality of ethyl silicate binder and castings is attained due to accelerated hydrolysis process of ethyl silicate, higher wetting power and viability of the binder. EFFECT: greater strength of ceramic molds. 3 cl, 4 ed, 2 tbl