The present invention relates to a method for producing a metal nitride, which is a method for synthesizing a metal nitride by igniting a raw material powder containing a metal powder housed in a reaction vessel (2) under a nitrogen atmosphere and propagating nitriding combustion heat of the metal powder to the whole of the housed raw material powder, characterized in that the raw material powder is housed in the reaction vessel (2) as a molded body (1B) having a void ratio of 40 to 70%. According to the present invention, it is possible to provide a method for producing a metal nitride capable of suppressing the occurrence of powder scattering and improving the recovery rate of the metal nitride.

Novel N-alkyl substituted perhydridocyclic silazanes, oligomeric N-alkyl perhydridosilazane compounds, and N-alkylaminodihydridohalosilanes, and a method for their synthesis are provided. The novel compounds may be used to form high silicon nitride content films by thermal or plasma induced decomposition.

Novel N-alkyl substituted perhydridocyclic silazanes, oligomeric N-alkyl perhydridosilazane compounds, and N-alkylaminodihydridohalosilanes, and a method for their synthesis are provided. The novel compounds may be used to form high silicon nitride content films by thermal or plasma induced decomposition.

A 1,1,1-tris(organoamino)disilane compound and a method of preparing the 1,1,1-tris(organoamino)disilane compound are disclosed. The method comprises aminating a 1,1,1-trihalodisilane with an aminating agent comprising an organoamine compound to give a reaction product comprising the 1,1,1-tris(organoamino)disilane compound, thereby preparing the 1,1,1-tris(organoamino)disilane compound. A film-forming composition is also disclosed. The film-forming composition comprises the 1,1,1-tris(organoamino)disilane compound. A film formed with the film-forming composition, and a method of forming the film, are also disclosed. The method of forming the film comprises subjecting the film-forming composition comprising the 1,1,1-tris(organoamino)disilane compound to a deposition condition in the presence of a substrate, thereby forming the film on the substrate.

A 1,1,1-tris(organoamino)disilane compound and a method of preparing the 1,1,1-tris(organoamino)disilane compound are disclosed. The method comprises aminating a 1,1,1-trihalodisilane with an aminating agent comprising an organoamine compound to give a reaction product comprising the 1,1,1-tris(organoamino)disilane compound, thereby preparing the 1,1,1-tris(organoamino)disilane compound. A film-forming composition is also disclosed. The film-forming composition comprises the 1,1,1-tris(organoamino)disilane compound. A film formed with the film-forming composition, and a method of forming the film, are also disclosed. The method of forming the film comprises subjecting the film-forming composition comprising the 1,1,1-tris(organoamino)disilane compound to a deposition condition in the presence of a substrate, thereby forming the film on the substrate.

The present invention relates to a method for producing a metal nitride by igniting a raw material powder containing a metal powder filled in a reaction vessel under a nitrogen atmosphere and propagating nitriding combustion heat generated by a nitriding reaction of the metal to the whole raw material powder, the method including forming a heat insulating layer made of a material having nitrogen permeability and inert to the nitriding reaction on an upper surface of a layer made of the raw material powder. According to the present invention, it is possible to provide a method for reducing the amount of unreacted metal powder when producing a metal nitride by a combustion synthesis method.

A method for forming an isolating layer of a crucible includes placing a round crucible sideways with a bottom surface of an inside thereof perpendicular to a horizontal plane, and then performing a plurality of spraying processes to form the isolating layer on the bottom surface and a wall surface of the round crucible. Each spraying process includes spraying a slurry on the bottom surface; using an optical positioner to set a spraying range the same as one of a plurality of partial areas divided from the wall surface; aligning one of the plurality of partial areas with the spraying range; fixing the round crucible and spraying the slurry in the spraying range; stopping the spraying; and rotating the round crucible to move another partial area to the spraying range. Then, the steps are repeated until the spraying of all the partial areas is completed.

A method for forming an isolating layer of a crucible includes placing a round crucible sideways with a bottom surface of an inside thereof perpendicular to a horizontal plane, and then performing a plurality of spraying processes to form the isolating layer on the bottom surface and a wall surface of the round crucible. Each spraying process includes spraying a slurry on the bottom surface; using an optical positioner to set a spraying range the same as one of a plurality of partial areas divided from the wall surface; aligning one of the plurality of partial areas with the spraying range; fixing the round crucible and spraying the slurry in the spraying range; stopping the spraying; and rotating the round crucible to move another partial area to the spraying range. Then, the steps are repeated until the spraying of all the partial areas is completed.

The present invention is directed to a method for producing a silicon nitride sintered material, the method including heating a molded article, which contains a silicon nitride powder having a β phase ratio of 80% or more, a dissolved oxygen content of 0.2% by mass or less, and a specific surface area of 5 to 20 m.sup.2/g, and a sintering auxiliary containing a compound having no oxygen bond, and which has an overall oxygen content controlled to be 1 to 15% by mass and an aluminum element overall content controlled to be 800 ppm or less, to a temperature of 1,200 to 1,800° C. in an inert gas atmosphere under a pressure of 0 MPa.Math.G or more and less than 0.1 MPa.Math.G to sinter the silicon nitride.

In the present invention, there can be provided a method for producing a silicon nitride sintered material, which method is advantageous in that a silicon nitride sintered material having high thermal conductivity can be obtained even when using a silicon nitride powder having a high β phase ratio and conducting calcination under normal pressure or substantially normal pressure.

There is provided a multi-layered membrane comprising a top layer, a bottom layer, and a spacer layer; wherein said spacer layer is interposed between said top layer and said bottom layer; wherein said top layer, said bottom layer and said spacer layer are each independently composed of one or more selective layers, each selective layer comprising a 2D material; wherein said spacer layer comprises at least one channel for receiving a fluid; wherein said bottom layer comprises a hole with an area in the range of 1 μm.sup.2 to 1 mm.sup.2; and wherein said hole is capable of being in fluid communication with said at least one channels of said spacer layer.

There is also provided a method to synthesize the top layer of a multi-layered membrane as disclosed herein, methods for separating a plurality of ions or molecules in a fluid stream, a device comprising a multi-layered membrane as disclosed herein, and use of the method or the device as disclosed herein in osmotic power generation.