An aggregate mixture for a mold, the aggregate mixture including an aggregate, a water-soluble binder, a water-soluble foaming agent, an aqueous mold release agent, and water.

Supports for supporting mould parts and/or cores in investment casting, comprise support material comprising: a mechanically supportive continuous matrix phase comprising alumina; at least one second phase interpenetrating the matrix phase and providing a pathway for leachants to penetrate into the material; wherein the support material comprises: in the range of 1 wt % and 12 wt % of the second phase; and less than 15 vol % voids.

Supports for supporting mould parts and/or cores in investment casting, comprise support material comprising: a mechanically supportive continuous matrix phase comprising alumina; at least one second phase interpenetrating the matrix phase and providing a pathway for leachants to penetrate into the material; wherein the support material comprises: in the range of 1 wt % and 12 wt % of the second phase; and less than 15 vol % voids.

The invention relates to core-shell particles for use as a filler for feeder compositions for producing feeders, comprising (a) a core which possesses one or more cavities and a wall surrounding these cavities, where the core (a) has an average diameter in the range from 0.15 to 0.45 mm, (b) a shell enclosing the core and consisting of or comprising (b1) particles comprising or consisting of a material from the group consisting of calcined kaolin or cordierite, where the particles (b1) have a d10 of at least 0.05 m and a d90 of at most 45 m, and also (b2) a binder which binds the particles (b1) to one another and to the core (a).

The invention relates to core-shell particles for use as a filler for feeder compositions for producing feeders, comprising (a) a core which possesses one or more cavities and a wall surrounding these cavities, where the core (a) has an average diameter in the range from 0.15 to 0.45 mm, (b) a shell enclosing the core and consisting of or comprising (b1) particles comprising or consisting of a material from the group consisting of calcined kaolin or cordierite, where the particles (b1) have a d10 of at least 0.05 m and a d90 of at most 45 m, and also (b2) a binder which binds the particles (b1) to one another and to the core (a).

A structure for manufacturing castings, containing an inorganic fiber, a layered clay mineral, and an inorganic particle other than the layered clay mineral and having an organic content of 5 mass % or lower or having a mass loss of 5 mass % or lower when heated at 1000 C. for 30 minutes. The inorganic particle preferably contains one or more selected from obsidian, graphite, and mullite. The inorganic fiber preferably contains carbon fiber. The inorganic fiber preferably has an average length of 0.5 to 15 mm. The layered clay mineral preferably contains one or more selected from bentonite and montmorillonite.

Provided are: a coated sand having improved fluidity and being capable of improving a filling rate of a casting mold to be obtained; and a coated sand for advantageously manufacturing a casting mold having excellent strength, which coated sand provides a casting mold with good mold-releasability and collapsibility, gives cast products a favorable casting surface, and effectively improves sand adhesion on cast products. The coated sand is formed as a dry granular material having fluidity at room temperature, in which the surface of a refractory aggregate is coated with a solid layer of a water-soluble inorganic binder, and spherical particles of silicone resin having binder-repellency exist on the surface of the binder layer, or form a layer on the surface of the binder layer, a part of the spherical particles being not covered with the water-soluble inorganic binder and being exposed.

A moulding material mixture with at least one refractory material and water glass as an inorganic binding agent is used for producing casting moulds. The binding agent is cured with the aid of a carbonyl compound that has a molecular weight greater than 88 g/mol and less than 200 g/mol and a boiling point at 1013 hPa greater than 20 C. and less than 200 C. The at least one carbonyl compound is introduced into the gas phase, or carried with the gas phase. The at least one carbonyl compound has the formula R.sup.1R.sup.2CO, where R.sup.1 is H or a C1 or C2 alkyl and R.sup.2 is a carboxyl group RC(O)O bonded via the oxygen atom, where R is a C1 to C3 hydrocarbon.

A moulding material mixture with at least one refractory material and water glass as an inorganic binding agent is used for producing casting moulds. The binding agent is cured with the aid of a carbonyl compound that has a molecular weight greater than 88 g/mol and less than 200 g/mol and a boiling point at 1013 hPa greater than 20 C. and less than 200 C. The at least one carbonyl compound is introduced into the gas phase, or carried with the gas phase. The at least one carbonyl compound has the formula R.sup.1R.sup.2CO, where R.sup.1 is H or a C1 or C2 alkyl and R.sup.2 is a carboxyl group RC(O)O bonded via the oxygen atom, where R is a C1 to C3 hydrocarbon.

A method of forming a component by investment casting includes disposing at least a portion of an investment casting pin within a core. The investment casting pin includes a ceramic base pin having a perimeter and a length extending perpendicular to the perimeter and a sacrificial coating disposed about the perimeter of the ceramic base pin along at least a portion of the length of the ceramic base pin. A metal casting is formed around the core. The core and the sacrificial coating are leached with a leaching solution and the investment casting pin is removed from the metal casting.