A curing agent for water glass molding comprises: ester; amorphous silica; and water. The amorphous silica is formed by means of a pyrolysis method and/or by means of a precipitation method. Also disclosed is a use of the curing agent for water glass molding in preparation of a casting mold and a mold core. Respective components of the curing agent comprising ester, amorphous silica and water are mixed at a high speed to form a suspension. Next, the suspension is applied to prepare a water glass self-hardening sand. The curing agent does not cause powder contamination, and can be measured and added conveniently. Also disclosed are a manufacturing method of the curing agent for water glass molding and a water glass self-hardening sand.

The invention relates to a method and to a device for generating three-dimensional objects by means of a generative method. According to the invention, powdered material and binding agents are applied sequentially and electromagnetic waves are used to cure the binding agent so that the powdered material bonded with the binding agent forms the three-dimensional object. The electromagnetic waves used are RF radiation. As a result, a fast and uniform curing of the three-dimensional object is achieved.

Provided are a binder in the producing of a casting sand mold according to an ink jet type lamination shaping method in which a binder is printed with respect to sand, a method for producing the binder, and a method for producing a casting sand mold using the binder. Specifically, provided are a binder useful for a casting sand mold of an ink jet type, containing: a resol-type phenolic resin that is obtained by reacting aldehydes (A1), phenols (P1), and a compound (N) having two or more phenolic hydroxyl groups in one molecule or by reacting the aldehydes (A1) and a novolac-type phenolic resin (N1), in the presence of an alkali catalyst, and has a dispersion degree (Mw/Mn) of 1.0 to 3.5 and a phenolic monomer residue of 5% or less, a method for producing the binder, and a method for producing a casting sand mold.

Methods for forming ceramic cores are disclosed. A ceramic core formed using the method of the present application includes a silica depletion zone encapsulating an inner zone. The inner zone includes mullite and the silica depletion zone includes alumina. The method includes heat-treating a ceramic body in a non-oxidizing atmospheric condition for an effective temperature and time combination at a pressure less than 10.sup.2 atmosphere to form the silica depletion zone at a surface of the ceramic core.

Compositions useful for foundry processes such as green sand casting are discussed. The compositions may comprise an aggregate, at least one inorganic binding agent, and at least one high aspect ratio silicate. For example, the composition may comprise sand, one or more clay materials serving as a binding agent, and a high aspect ratio silicate chosen from mica, talc, or a combination thereof. The composition may be formed into a green sand mold for use in casting molded articles. Incorporation of the high aspect ratio silicate may help to improve the quality of the casted article.

A translucent material according to this invention includes a base made of a glass-based material, and an oxide layer layered in an upper direction (or on an upper surface) of the base. Examples of the base may include tempered glass using soda lime glass or aluminosilicate glass, heat-resistant glass mostly using borosilicate glass, and quartz glass. The oxide layer includes yttrium oxide (Y.sub.2O.sub.3) as a base material thereof and further includes nitrogen and a Group 4A element. The translucent material having such a composition is qualified to constitute a low-adhesion material and a molding member. When quartz glass is selected and used as the base material, an intermediate layer may be interposed between the base and the oxide layer.

A hydraulic composition for an additive manufacturing device, the hydraulic composition containing at least sand, an inorganic binder, and polyvinyl alcohol, wherein the hydraulic composition for an additive manufacturing device satisfies conditions (1) and (2). (1) The mass ratio of sand/(inorganic binder+polyvinyl alcohol) is 4 to 12. (2) The mass ratio of polyvinyl alcohol/inorganic binder is 0.1 to 0.4. The hydraulic composition for an additive manufacturing device also preferably satisfies condition (3). (3) The mass ratio of water/(inorganic binder+polyvinyl alcohol) is 0.30 to 1.30.

Methods for forming ceramic cores are disclosed. A ceramic core formed using the method of the present application includes a silica depletion zone encapsulating an inner zone. The inner zone includes mullite and the silica depletion zone includes alumina. The method includes heat-treating a ceramic body in a non-oxidizing atmospheric condition for an effective temperature and time combination at a pressure less than 10 atmosphere to form the silica depletion zone at a surface of the ceramic core.

Described is a two-component system, particularly for forming an adhesive, which is suitable, for example, for applications in the foundry industry and in the construction industry.

The invention relates to a mineral composition for the preparation of foundry molds, comprising: (a) from 20% to 90% by weight of plaster, (b) from 10% to 80% by weight of a mineral component based on silica and/or alumina, and (c) from 0.5% to 4.8%, preferably from 1.5% to 4.5% and in particular between 2% and 4.5% by weight, of a mineral powder having a thermal conductivity (), at 20 C., of greater than 15 W/(m.Math.K) and a specific surface area of greater than 10 m.sup.2/g, these percentages being relative to the total weight of the sum of the components (a), (b) and (c).