Process for preparing foundry cores and ceramic composition which can be used for the implementation of the said process

摘要

The process intended for preparing foundry cores consists in bringing to a temperature lying between 50 DEG C and 150 DEG C a mixture comprising a ceramic charge of molten silica and of zircon in respective mass proportions of 60 to 80 and 40 to 20, 100 parts of charge, by weight, 2 to 8 parts of silicone resin and 10 to 20 parts of plasticiser, the said resin thus being maintained in the uncrosslinked plastic state, then in injecting the mixture into a cold mould where the resin solidifies at less than 50 DEG C and finally, after stripping, in carrying out a firing operation on the object in the shape of a core with a plateau around 1000/1200 DEG C in order to transform the resin into a siliceous product. The mixtures used can also comprise a silicone oil and a stripping agent.