Abstract: The present disclosure relates to a novel sp2-sp3 hybrid crystalline boron nitride and its preparation process. A novel sp2-sp3 hybrid crystalline boron nitride allotrope, named Gradia BN, is synthesized using sp2 or sp3 hybridized boron nitride as raw materials under high-temperature and high-pressure. The basic structural units of Gradia BN are composed of sp2 hybridized graphite-like structural units and sp3 hybridized diamond-like structural units. Gradia BN disclosed in the present disclosure is a class of new sp2-sp3 hybrid boron nitride allotrope, whose crystal structure can vary with the widths and/or crystallographic orientation relationships of internal sp2 and/or sp3 structural units, and may have variable physical properties.

Abstract: The present application discloses a conductive high-strength diamond/amorphous carbon composite material and a preparation process thereof. The diamond/amorphous carbon composite material is composed of an amorphous carbon continuous phase and multiple separate diamond phases embedded in the amorphous carbon continuous phase, wherein the diamond phases exhibit an ordered sp3 hybrid state, and the amorphous carbon continuous phase exhibits a disordered sp2 hybrid state. The present application further discloses a process for preparing the above diamond/amorphous carbon composite material. The process comprises using sp3 carbon powder or glassy carbon as a raw material to obtain the above-mentioned material by sintering. The diamond/amorphous carbon composite material shows good electrical conductivity, good electrical discharge machining ability, good chemical stability and light weight, and has broad application prospects in aerospace, automobile industry and biomedical equipment.

Abstract: The present disclosure belongs to the technical filed of new carbon materials and relates to a novel sp2-sp3 hybrid crystalline carbon named Gradia and its preparation process. A novel sp2-sp3 hybrid carbon named Gradia is synthesized using sp2 hybrid carbon as raw materials under high temperature and high pressure. The basic structural units of Gradia are composed of sp2 hybrid graphite-like structural units and sp3 hybrid diamond-like structural units. Gradia disclosed in the present disclosure is a class of new sp2-sp3 hybrid carbon allotrope, whose crystal structure can vary with the widths and/or crystallographic orientation relationships of internal sp2 and/or sp3 structural units.

Abstract: The application provides a porous carbon block material having high elasticity and high sealing, and provides a method for preparing the same. Particularly, the present application provides a porous carbon block material, wherein the porous carbon block material has a pore size in the range of from 3 nm to 100 nm, a porosity of from 50% to 87%, and the pores in the material are closed pores. In addition, the application provides a method for preparing the porous carbon block material according to the present application. The porous carbon block material according to the present application has small pore size, high porosity, and closed pores, and thus has high strength combined with high elasticity, high sealing property, and low density. Hence, the porous carbon block material according to the present application may be used as a sealing material.

Abstract: The present disclosure relates to a dense boron nitride ceramic with high plasticity and high elasticity and the preparation process thereof. The preparation process includes the following steps: A) weighing a predetermined amount of spherical boron nitride nano-powders with onion-like structure, pre-pressing them into a pre-pressed body and putting the pre-pressed body into a sintering mold; B) putting the pre-pressed body obtained in step A) together with the sintering mold into a spark plasma sintering apparatus or a hot-pressing sintering apparatus for sintering; and C) taking out the mold after cooling, and removing the mold to obtain the boron nitride dense ceramic block with high plasticity and high elasticity. According to the present invention, a boron nitride ceramic with high strength and high plasticity is obtained via sintering spherical boron nitride nano-powders with onion-like structure.

Abstract: The present disclosure relates to a novel sp2-sp3 hybrid crystalline boron nitride and its preparation process. A novel sp2-sp3 hybrid crystalline boron nitride allotrope, named Gradia BN, is synthesized using sp2 or sp3 hybridized boron nitride as raw materials under high-temperature and high-pressure. The basic structural units of Gradia BN are composed of sp2 hybridized graphite-like structural units and sp3 hybridized diamond-like structural units. Gradia BN disclosed in the present disclosure is a class of new sp2-sp3 hybrid boron nitride allotrope, whose crystal structure can vary with the widths and/or crystallographic orientation relationships of internal sp2 and/or sp3 structural units, and may have variable physical properties.

Abstract: The present disclosure relates to a dense boron nitride ceramic with high plasticity and high elasticity and the preparation process thereof. The preparation process includes the following steps: A) weighing a predetermined amount of spherical boron nitride nano-powders with onion-like structure, pre-pressing them into a pre-pressed body and putting the pre-pressed body into a sintering mold; B) putting the pre-pressed body obtained in step A) together with the sintering mold into a spark plasma sintering apparatus or a hot-pressing sintering apparatus for sintering; and C) taking out the mold after cooling, and removing the mold to obtain the boron nitride dense ceramic block with high plasticity and high elasticity. According to the present invention, a boron nitride ceramic with high strength and high plasticity is obtained via sintering spherical boron nitride nano-powders with onion-like structure.

Abstract: The present disclosure belongs to the technical filed of new carbon materials and relates to a novel sp2-sp3 hybrid crystalline carbon named Gradia and its preparation process. A novel sp2-sp3 hybrid carbon named Gradia is synthesized using sp2 hybrid carbon as raw materials under high temperature and high pressure. The basic structural units of Gradia are composed of sp2 hybrid graphite-like structural units and sp3 hybrid diamond-like structural units. Gradia disclosed in the present disclosure is a class of new sp2-sp3 hybrid carbon allotrope, whose crystal structure can vary with the widths and/or crystallographic orientation relationships of internal sp2 and/or sp3 structural units.

Abstract: The present invention relates to ultrahard nanotwinned diamond bulk materials and synthetic method thereof. In particular, the present invention discloses a diamond bulk material containing high density of nanocrystalline twins and synthetic method thereof, in which a nanotwinned diamond bulk is synthesized from particles of nanospherical onion-like carbon without diamond core (preferably with a size of 5-70 nm) as raw materials by using high temperature and high pressure synthesis. As compared with the prior art, the nanotwinned diamond bulk obtained according to the present invention has a much higher hardness than that of single crystal diamond and that of ultrahard polycrystalline diamond. The nanotwinned diamond bulk has wide prospects in various applications, including geological drilling, machining fields such as high speed cutting and precision and ultra-precision machining, abrasives, drawing dies, and special optics as well as other fields.

Abstract: The invention relates to an ultrahard nanotwinned boron nitride bulk material and synthetic method thereof. Particularly, the invention discloses a nanocrystalline cubic boron nitride bulk material containing high density of twins and synthetic method thereof, in which a nanotwinned boron nitride bulk are synthesized from nanospherical boron nitride particles (preferably with a size of 5-70 nm) with onion-like structure as raw materials by using high temperature and high pressure synthesis. As compared with the prior arts, the nanotwinned boron nitride bulk obtained according to the invention has a much higher hardness than that of a normal cubic boron nitride single crystal. The nanotwinned boron nitride bulk has great prospects in applications, such as precision and ultra-precision machining, abrasives, drawing dies, and special optics as well as other fields.

Abstract: The present invention relates to ultrahard nanotwinned diamond bulk materials and synthetic method thereof. In particular, the present invention discloses a diamond bulk material containing high density of nanocrystalline twins and synthetic method thereof, in which a nanotwinned diamond bulk is synthesized from particles of nanospherical onion-like carbon without diamond core (preferably with a size of 5-70 nm) as raw materials by using high temperature and high pressure synthesis. As compared with the prior art, the nanotwinned diamond bulk obtained according to the present invention has a much higher hardness than that of single crystal diamond and that of ultrahard polycrystalline diamond. The nanotwinned diamond bulk has wide prospects in various applications, including geological drilling, machining fields such as high speed cutting and precision and ultra-precision machining, abrasives, drawing dies, and special optics as well as other fields.

Abstract: The invention relates to an ultrahard nanotwinned boron nitride bulk material and synthetic method thereof. Particularly, the invention discloses a nanocrystalline cubic boron nitride bulk material containing high density of twins and synthetic method thereof, in which a nanotwinned boron nitride bulk are synthesized from nanospherical boron nitride particles (preferably with a size of 5-70 nm) with onion-like structure as raw materials by using high temperature and high pressure synthesis. As compared with the prior arts, the nanotwinned boron nitride bulk obtained according to the invention has a much higher hardness than that of a normal cubic boron nitride single crystal. The nanotwinned boron nitride bulk has great prospects in applications, such as precision and ultra-precision machining, abrasives, drawing dies, and special optics as well as other fields.

Abstract: The present invention provides a method for the fabrication of high performance densified nanocrystalline bulk thermoelectric material, comprising: (1) preparing a thermoelectric alloy nanopowders by a ball milling process to achieve an average crystal size of 5-30 nm, and (2) preparing the nanocrystalline bulk thermoelectric material by high pressure sintering at a temperature of 0.25-0.8 Tm under a pressure of 0.8-6.0 GPa for 10-120 minutes, to achieve a relative density of 90-100% and an average grain size of 10-50 nm. The method is easy to operate and allows the production of a thermoelectric material with a ZT value higher than 2. In addition, the method can ensure both good thermoelectric properties and high density, and therefore have important applications for energy industry.