A process for coating a refractory alloy part is provided and includes coating an area of a refractory alloy part by means of a treatment composition including a type of preceramic polymer and a solvent, and heat treating the part coated with the treatment composition. The heat treating partially converts the preceramic polymer and forms a ceramic coating obtained by conversion, the ceramic coating protecting the refractory alloy from oxidation. The treatment composition also includes active fillers to form an alloy coating on a surface of the part by solid diffusion in addition to the ceramic coating obtained by conversion, and the alloy coating generates a protective oxide layer when subjected to oxidizing conditions.

A process for coating a refractory alloy part is provided and includes coating an area of a refractory alloy part by means of a treatment composition including a type of preceramic polymer and a solvent, and heat treating the part coated with the treatment composition. The heat treating partially converts the preceramic polymer and forms a ceramic coating obtained by conversion, the ceramic coating protecting the refractory alloy from oxidation. The treatment composition also includes active fillers to form an alloy coating on a surface of the part by solid diffusion in addition to the ceramic coating obtained by conversion, and the alloy coating generates a protective oxide layer when subjected to oxidizing conditions.

A coating composition is described, for use in the foundry, in particular comprising particulate, amorphous silicon dioxide (SiO.sub.2) and an aqueous phase having a pH of at most 5, and also coated, waterglass-bound foundry molding elements, especially coated, waterglass-bound foundry molds and foundry cores, which each comprise a coating composition of the invention. Further described is the use of a coating composition of the invention for producing a coating on a waterglass-bound foundry molding element and a method for producing a waterglass-bound foundry molding element (mold or core) coated with a water-containing refractory coating. Likewise specified is a kit whose contents include a coating composition of the invention.

This technology relates to refractory coatings used in metal casting by the foundry industry. Refractory coatings are often used to coat foundry cores and molds for the purpose of improving the quality of castings formed in connection with the cores or molds, particularly at the surface of the casting. Whereas traditional coatings comprise water based solvents that require excessive drying times or HAPs that emit hazardous VOCs, preferred embodiments of the present invention comprise refractory coatings having VOC-exempt ester based solvents, such as a dimethyl carbonate (DMC). Other preferred embodiments of the present invention comprise methods for reduction of VOC content in a foundry article.

This technology relates to refractory coatings used in metal casting by the foundry industry. Refractory coatings are often used to coat foundry cores and molds for the purpose of improving the quality of castings formed in connection with the cores or molds, particularly at the surface of the casting. Whereas traditional coatings comprise water based solvents that require excessive drying times or HAPs that emit hazardous VOCs, preferred embodiments of the present invention comprise refractory coatings having VOC-exempt ester based solvents, such as a dimethyl carbonate (DMC). Other preferred embodiments of the present invention comprise methods for reduction of VOC content in a foundry article.

A riser tube coating for a cast aluminum alloy includes a coating-riser tube contact layer material and a coating-aluminum liquid contact layer material. The present invention has a coating protection effect to the maximum mainly by designing ratios of ZrO, Al.sub.2O.sub.3, ZnO, binders and other materials and a coat drying heat treatment process, and finally realizes effects of protecting a riser tube, being free of aluminum sticking and prolonging a service life.

A riser tube coating for a cast aluminum alloy includes a coating-riser tube contact layer material and a coating-aluminum liquid contact layer material. The present invention has a coating protection effect to the maximum mainly by designing ratios of ZrO, Al.sub.2O.sub.3, ZnO, binders and other materials and a coat drying heat treatment process, and finally realizes effects of protecting a riser tube, being free of aluminum sticking and prolonging a service life.

Disclosed is a preparation method of a foamed aluminum special-shaped part. The preparation method comprises the following steps: S1, pressing wax molds; S2, making a shell; S3, carrying out smelting; S4, carrying out casting; and S5, vibrating the shell. Finally, the foamed aluminum special-shaped part is obtained for a preparation process of a foamed aluminum compound casting.

Disclosed is a preparation method of a foamed aluminum special-shaped part. The preparation method comprises the following steps: S1, pressing wax molds; S2, making a shell; S3, carrying out smelting; S4, carrying out casting; and S5, vibrating the shell. Finally, the foamed aluminum special-shaped part is obtained for a preparation process of a foamed aluminum compound casting.

An inorganic mold release agent for a core that is applied to a surface of a core containing an aggregate and an inorganic binder, and the mold release agent for a core is a powder containing silica powder, which is applied in a powder form to the surface of the core.