Sized molds obtainable from a molding material mixture containing an inorganic bonding agent and phosphatic compounds and oxidic boron compounds and method for production and use thereof

A mould or core having a coating obtained by moulding and hardening a moulding material mixture to obtain a mould or core and the mould or core, wherein the moulding material mixture at least comprises:

• a refractory mould base material;
• water glass;
• particulate amorphous silicon dioxide, in the range of 0.1 to 2% by weight, relative to the weight of the refractory mould base material;
• at least one oxidic boron compound, in the range of greater than 0.002 and less than 1% by weight, relative to the weight of the refractory mould base material;
• and
• at least one phosphate-containing compound, in the range of 0.05 to 1.0% by weight, relative to the weight of the refractory mould base material;
• and
• the coating is a water-containing coating.