The invention relates to a method for treating magnesia-carbon products.

A honeycomb structure according to at least one embodiment of the present invention includes: partition walls defining cells each extending from a first end surface of the honeycomb structure to a second end surface thereof to form a fluid flow path; and an outer peripheral wall. The partition walls and the outer peripheral wall are each formed of ceramics containing silicon carbide and silicon. A surface of the silicon has formed thereon an oxide film having a thickness of from 0.1 μm to 5.0 μm.

A honeycomb structure according to at least one embodiment of the present invention includes: partition walls defining cells each extending from a first end surface of the honeycomb structure to a second end surface thereof to form a fluid flow path; and an outer peripheral wall. The partition walls and the outer peripheral wall are each formed of ceramics containing silicon carbide and silicon. A surface of the silicon has formed thereon an oxide film having a thickness of from 0.1 μm to 5.0 μm.

The present invention concerns a method for obtaining a finished or semi-finished zirconia-based article (1), the article having a metallic external appearance and non-zero surface electrical conductivity, characterized in that the method includes the steps consisting in: taking at least one zirconia article, pre-shaped in its finished or semi-finished form; placing said article inside a chamber (10) in which a gaseous mixture is arranged, this gaseous mixture including at least a first hydrogen and carbon based gas compound in a first concentration (C1) and a second hydrogen and nitrogen based gas compound in a second concentration (C2); heating the gaseous mixture until the molecules of the first and second compounds dissociate and keeping said article in the reactive atmosphere thereby created to obtain diffusion of the carbon and nitrogen atoms in the external surface (2) of said article and to form stoichiometric carbonitride (ZrC.sub.x—N.sub.y) at the surface, and prior to the step of heating the process gases contained in the chamber, a reduction step consisting in placing said article inside a chamber into which dihydrogen is injected and in heating the dihydrogen allowing diffusion towards the surface and release of the oxygen contained in said zirconia article.

The present invention concerns a method for obtaining a finished or semi-finished zirconia-based article (1), the article having a metallic external appearance and non-zero surface electrical conductivity, characterized in that the method includes the steps consisting in: taking at least one zirconia article, pre-shaped in its finished or semi-finished form; placing said article inside a chamber (10) in which a gaseous mixture is arranged, this gaseous mixture including at least a first hydrogen and carbon based gas compound in a first concentration (C1) and a second hydrogen and nitrogen based gas compound in a second concentration (C2); heating the gaseous mixture until the molecules of the first and second compounds dissociate and keeping said article in the reactive atmosphere thereby created to obtain diffusion of the carbon and nitrogen atoms in the external surface (2) of said article and to form stoichiometric carbonitride (ZrC.sub.x—N.sub.y) at the surface, and prior to the step of heating the process gases contained in the chamber, a reduction step consisting in placing said article inside a chamber into which dihydrogen is injected and in heating the dihydrogen allowing diffusion towards the surface and release of the oxygen contained in said zirconia article.

The present invention relates to a metalized ceramic substrate and a method for manufacturing the same. The method for manufacturing a metalized ceramic substrate of the present invention comprises the steps of: mixing copper powder and metal oxide to manufacture a copper paste; applying the copper paste to an upper surface of a ceramic substrate; and sintering the copper paste to form a copper metallization layer on the upper surface of the ceramic substrate. According to the present invention, it is possible to form, on the ceramic substrate, a thin copper metallization layer with high density, high bonding strength and low impurities.

The present invention relates to a metalized ceramic substrate and a method for manufacturing the same. The method for manufacturing a metalized ceramic substrate of the present invention comprises the steps of: mixing copper powder and metal oxide to manufacture a copper paste; applying the copper paste to an upper surface of a ceramic substrate; and sintering the copper paste to form a copper metallization layer on the upper surface of the ceramic substrate. According to the present invention, it is possible to form, on the ceramic substrate, a thin copper metallization layer with high density, high bonding strength and low impurities.

A method includes depositing a porous silicon coat on a substrate to form a bulk phase of a bond coat and introducing a reactive gas into pores of the porous silicon coat. The reactive gas reacts with silicon adjacent the pores of the porous silicon coat to form a ceramic phase of the bond coat comprising a silicon-based ceramic and reduce porosity of the porous silicon coat. A temperature of the reactive gas is greater than about 1000° C.

A method includes depositing a porous silicon coat on a substrate to form a bulk phase of a bond coat and introducing a reactive gas into pores of the porous silicon coat. The reactive gas reacts with silicon adjacent the pores of the porous silicon coat to form a ceramic phase of the bond coat comprising a silicon-based ceramic and reduce porosity of the porous silicon coat. A temperature of the reactive gas is greater than about 1000° C.

A method of forming a barrier layer on a ceramic matrix composite (CMC) is described. The method includes forming a particulate surface layer comprising silicon particles on an outer surface of a fiber preform. The particulate surface layer is nitrided to convert the silicon particles to silicon nitride particles. After the nitriding, the fiber preform and the particulate surface layer are infiltrated with a molten material comprising silicon. Following infiltration, the molten material is cooled, thereby forming a ceramic matrix composite with a barrier layer thereon, where the barrier layer comprises silicon nitride and less than 5 vol. % free silicon. The barrier layer may also include silicon carbide and/or one or more refractory metal silicides.