A process for producing a highly oriented graphene oxide (GO) film, comprising: (a) preparing either a GO dispersion having GO sheets dispersed in a fluid medium or a GO gel having GO molecules dissolved in a fluid medium; (b) dispensing the GO dispersion or gel onto a surface of an application roller rotating in a first direction to form an applicator layer of GO and transferring the applicator layer to a surface of a supporting film driven in a second direction opposite to the first direction to form a wet layer of GO on the supporting film; and (c) removing said fluid medium from the wet layer of GO to form a dried layer of GO having an inter-planar spacing d.sub.002 of 0.4 nm to 1.2 nm and an oxygen content no less than 5% by weight. This dried GO layer may be heat-treated to produce a graphitic film.

A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m.Math.K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

A cathode diffusion layer for organic hydride production of the present disclosure includes a carbon foam. the carbon foam being a porous body with continuous voids, and having lincar portions and node portions joining the linear portions.

MXene compound having a novel crystalline morphology, and process for fabricating a compound of MAX phase type for synthesis of said MXene compound. The invention firstly relates to a MXene compound advantageously having a crystalline morphology that is mostly in tablet form which may be obtained from a MAX phase precursor obtained by spark plasma sintering process whereby the powders of the mixture are insulated, and to a process for fabricating the MXene compound. The invention also relates to compound of MAX phase type obtained by spark plasma sintering process whereby the powders of the mixture are insulated. The invention also relates to a synthesis process of an MXene compound from said precursor, and to the MXene compound thus obtained advantageously having a crystalline morphology that is mostly in tablet form.

A polycrystalline composite comprising diamond particles and non-diamond carbon, wherein: the sum of the content Vd of the diamond particles and the content Vg of the non-diamond carbon is more than 99% by volume based on the total volume of the polycrystalline composite; the median diameter d50 of the diamond particles is 10 nm or more and 200 nm or less; the dislocation density of the diamond particles is 1.010.sup.13 m.sup.2 or more and 1.010.sup.16 m.sup.2 or less; and the content Vd of the diamond particles and the content Vg of the non-diamond carbon satisfy the relationship represented by the formula 1:0.01<Vg/(Vd+Vg)0.5 Formula 1.

A polycrystalline super hard construction comprises a body of polycrystalline diamond (PCD) material and a plurality of interstitial regions between inter-bonded diamond grains forming the polycrystalline diamond material. The body of PCD material comprises a working surface positioned along an outside portion of the body, and a first region adjacent the working surface, the first region being a thermally stable region. The first region and/or a further region and/or the body of PCD material has/have an average oxygen content of less than around 300 ppm. A method of forming such a construction is also disclosed.

A method for producing ceramic fibers of a composition in the SiC range, starts from a spinning material that contains a polysilane-polycarbosilane copolymer solution. The spinning material is extruded through spinnerets in a dry spinning method and spun through a spinning duct into green fibers, and the green fibers are subsequently pyrolyzed. Accordingly, the polysilane-polycarbosilane solution contains between 75 wt. % and 95 wt. %, in particular between 80 and 90 wt. %, of an indifferent solvent, and the spinnerets have a capillary diameter between 20 and 70 m, in particular between 30 and 60 m, in particular between 40 and 50 m.

A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m.Math.K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/rum or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

To provide a power-module substrate and a manufacturing method thereof in which small voids are reduced at a bonded part and separation can be prevented. Bonding a metal plate of aluminum or aluminum alloy to at least one surface of a ceramic substrate by brazing, when a cross section of the metal plate is observed by a scanning electron microscope in a field of 3000 magnifications in a depth extent of 5 m from a bonded interface between the metal plate and the ceramic substrate in a width area of 200 m from a side edge of the metal plate, residual-continuous oxide existing continuously by 2 m or more along the bonded interface has total length of 70% or less with respect to a length of the field.

A method for synthesizing a TiB.sub.2 powder includes the reduction of titanium oxide by carbon in the presence of a source of boron, the method includes heating a mixture of a carbon source, a boron carbide powder whose median particle diameter is between 5 and 100 microns and a powder of titanium oxide whose median particle diameter is between 5 and 80 microns, the mixture being placed in an enclosure under an inert gas sweep flow rate between 0.5 and 10 L/min/m/m.sup.3 of enclosure at a temperature of between 1500 C. and 2000 C., as well as the TiB.sub.2 powder obtained by such a method.