Bulk paint and ceramic powder systems, methods of forming same, and methods of forming a flexible ceramic coating on a metal substrate are disclosed. The systems may include a ceramic composition having between 2 to 30 weight percent of an alkali metal oxide, such as K.sub.2O, Na.sub.2O, and Li.sub.2O or mixtures thereof, between 10 to 74 weight percent SiO.sub.2, and between 23 to 79 weight percent B.sub.2O.sub.3. Additives that are nonwetting with molten metals, such as boron nitride, provide durable coatings for metal processing operations. The ceramic composition may include less than 5 weight percent additional metal oxides. The bulk paint system further may include water and a cellulosic suspension agent to form a bulk paint. The ceramic powder system may be processed to form a uniform powder. The bulk paint or uniform powder may be applied to a metal substrate, such as a ferrous metal substrate, dried, and heated to form a flexible coating on the metal substrate.

Bulk paint and ceramic powder systems, methods of forming same, and methods of forming a flexible ceramic coating on a metal substrate are disclosed. The systems may include a ceramic composition having between 2 to 30 weight percent of an alkali metal oxide, such as K.sub.2O, Na.sub.2O, and Li.sub.2O or mixtures thereof, between 10 to 74 weight percent SiO.sub.2, and between 23 to 79 weight percent B.sub.2O.sub.3. Additives that are nonwetting with molten metals, such as boron nitride, provide durable coatings for metal processing operations. The ceramic composition may include less than 5 weight percent additional metal oxides. The bulk paint system further may include water and a cellulosic suspension agent to form a bulk paint. The ceramic powder system may be processed to form a uniform powder. The bulk paint or uniform powder may be applied to a metal substrate, such as a ferrous metal substrate, dried, and heated to form a flexible coating on the metal substrate.

The present invention provides methods for preparing or repairing a chemically-resistant coating such as a porcelain enamel on a metal substrate. One such method involves forming a ground coat on the substrate, cooling the substrate to substantially near ambient temperature, optionally by applying a heat source to cool the substrate slowly, followed by flame-spray depositing a coating material onto the softened ground coat. Then, the substrate is allowed to cool slowly so the chemically-resistant coating can form with less stress. Optionally, an induction coil is used to heat the substrate, both to form the ground coat and to slow the cooling of the substrate. Such methods allow for easier and faster repairs, and even in situ repairs of articles such as chemical reactor vessels, covers, baffles, thermowells, agitators, agitator shafts, pipes, heat exchangers, and storage tanks, as well as white goods such as ovens, stoves, washing machines, driers, in addition to bathtubs, sinks, and shower stalls, in addition to steel girders and steel reinforcing bars. Articles having a chemically-resistant coating also form a part of the invention.

The present invention provides methods for preparing or repairing a chemically-resistant coating such as a porcelain enamel on a metal substrate. One such method involves forming a ground coat on the substrate, cooling the substrate to substantially near ambient temperature, optionally by applying a heat source to cool the substrate slowly, followed by flame-spray depositing a coating material onto the softened ground coat. Then, the substrate is allowed to cool slowly so the chemically-resistant coating can form with less stress. Optionally, an induction coil is used to heat the substrate, both to form the ground coat and to slow the cooling of the substrate. Such methods allow for easier and faster repairs, and even in situ repairs of articles such as chemical reactor vessels, covers, baffles, thermowells, agitators, agitator shafts, pipes, heat exchangers, and storage tanks, as well as white goods such as ovens, stoves, washing machines, driers, in addition to bathtubs, sinks, and shower stalls, in addition to steel girders and steel reinforcing bars. Articles having a chemically-resistant coating also form a part of the invention.

A metal substrate (71) is coated with an enamel or other coating material (72) by irradiating the coating material (72) and substrate (71) with electromagnetic radiation to melt an underlying surface of the metal substrate (71) before melting the coating material (72) to create, after cooling, a fusion bond between the solidified substrate and coating material, whereby the fusion bonded interface (73) has an intermeshing irregular tongue and groove like microstructure profile shown in FIG. 7. The electromagnetic radiation may be unfocussed, circulinear or focussed at a point located within the metal substrate (71) to first melt the substrate (71).

Bulk paint and ceramic powder systems, methods of forming same, and methods of forming a flexible ceramic coating on a metal substrate are disclosed. The systems may include a ceramic composition having between 2 to 30 weight percent of an alkali metal oxide, such as K.sub.2O, Na.sub.2O, and Li.sub.2O or mixtures thereof, between 10 to 74 weight percent SiO.sub.2, and between 23 to 79 weight percent B.sub.2O.sub.3. Additives that are nonwetting with molten metals, such as boron nitride, provide durable coatings for metal processing operations. The ceramic composition may include less than 5 weight percent additional metal oxides. The bulk paint system further may include water and a cellulosic suspension agent to form a bulk paint. The ceramic powder system may be processed to form a uniform powder. The bulk paint or uniform powder may be applied to a metal substrate, such as a ferrous metal substrate, dried, and heated to form a flexible coating on the metal substrate.

Bulk paint and ceramic powder systems, methods of forming same, and methods of forming a flexible ceramic coating on a metal substrate are disclosed. The systems may include a ceramic composition having between 2 to 30 weight percent of an alkali metal oxide, such as K.sub.2O, Na.sub.2O, and Li.sub.2O or mixtures thereof, between 10 to 74 weight percent SiO.sub.2, and between 23 to 79 weight percent B.sub.2O.sub.3. Additives that are nonwetting with molten metals, such as boron nitride, provide durable coatings for metal processing operations. The ceramic composition may include less than 5 weight percent additional metal oxides. The bulk paint system further may include water and a cellulosic suspension agent to form a bulk paint. The ceramic powder system may be processed to form a uniform powder. The bulk paint or uniform powder may be applied to a metal substrate, such as a ferrous metal substrate, dried, and heated to form a flexible coating on the metal substrate.

A method and resulting gas turbine engine component (40) having a protective layer of metallic glass (14) deposited over a superalloy substrate (12). A further layer of ceramic insulating material (42) may be deposited over the metallic glass. The metallic glass functions as a bond coat to provide thermal insulation and mechanical compliance. The metallic glass may be deposited onto the substrate by a flux mediated laser deposition process wherein powdered alloy material (18) is melted together with powdered flux material (20). The flux material can facilitate the glass forming process by adding to the solidification confusion effect and/or by providing an active cooling effect.

A method and resulting gas turbine engine component (40) having a protective layer of metallic glass (14) deposited over a superalloy substrate (12). A further layer of ceramic insulating material (42) may be deposited over the metallic glass. The metallic glass functions as a bond coat to provide thermal insulation and mechanical compliance. The metallic glass may be deposited onto the substrate by a flux mediated laser deposition process wherein powdered alloy material (18) is melted together with powdered flux material (20). The flux material can facilitate the glass forming process by adding to the solidification confusion effect and/or by providing an active cooling effect.

The present invention relates to a baking tray (20) or baking grid, in particular a baking tray (20) for a cooking appliance (1), having a non-stick and/or non-wetting coating (12) obtainable by a process characterised by the following steps, a) providing a baking tray (20) or baking grid having a surface, in particular having an upper surface (7a) and a bottom surface (7b), b) preferably, pretreating of the surface (7a, 7b) of the baking tray (20) or baking grid at least partially, in particular completely, for providing a surface having a roughness being suitable for applying a non-stick and/or non-wetting coating (12) by mechanical treatment, physical treatment or chemical treatment, in particular by sandblasting and/or laser treatment and/or a surface activation treatment, particularly a plasma treatment, and/or an enameling process to form a ground layer (13), c) applying the non-stick and/or non-wetting coating (12) to the pretreated surface (7a, 7b) of the baking tray (20) or baking grid or a surface (14a) of the ground layer (13), wherein the non-stick and/or non-wetting coating (12) comprises at least one layer (17) that is obtained by a sol-gel process from a first composition comprising a silica sol and a silane. The invention further relates to a cooking appliance (1), in particular a domestic oven comprising such a baking tray (20) or baking grid and a method for manufacturing such a baking tray (20) or baking grid.