A method and apparatus for producing boron nitride nanotubes and continuous boron nitride nanotube yarn or tapes is provided. The apparatus includes rotating reaction tubes that allow for continuous chemical vapor deposition of boron nitride nanotubes. The rotation of the reaction tubes allows the boron nitride nanotubes to be spun into yarns or made into tapes, without post process or external rotation or spinning of the gathered nanotubes. Boron nitride nanotube yarns or tapes of great length can be produced as a result, thereby providing industry with a readily useable format for this type of material. Dopants such as carbon can be added to engineer the band gap of the nanotubes. Catalysts may be formed outside or inside the reactor.

Provided is a method of manufacturing a hexagonal boron nitride multilayer according to an embodiment of the inventive concept, which includes providing a catalyst substrate including iron into a tube, using a heater to raise an internal temperature of the tube to 1400? C. or higher, and providing a boron nitride precursor into the tube to form a hexagonal boron nitride multilayer on the catalyst substrate.

BN nanosheets are prepared by a method comprising heating to a temperature of at least 500 C., a mixture comprising: (1) an alkali borohydride, and (2) an ammonium salt. NaN.sub.3 may be included to increase the yield. No catalyst is required, and the product produced contains less than 0.1 atomic percent metal impurities.

A boron nitride powder that is an aggregate of boron nitride particles, wherein the boron nitride powder has a BET specific surface area of 4.6 m.sup.2/g or more, and an average pore diameter of 0.65 ?m or less. A resin composition containing: the boron nitride powder, and a resin.

Provided is a hexagonal boron nitride powder including: secondary particles formed through agglomeration of primary particles of hexagonal boron nitride, in which in a cumulative distribution of volume-based particle sizes measured through a laser diffraction/light scattering method, the particle sizes at which cumulative values from small particle sizes reach 10%, 50%, and 90% of the total are respectively D10, D50, and D90, with D50 being 3 to 30 ?m, and a D90/D10 ratio is 4.0 or more.

The present disclosure discloses a boron nitride nanomaterial, and preparation method and use thereof. The preparation method comprises: heating a precursor in a nitrogen atmosphere to a high temperature, to prepare the boron nitride nanomaterial. The precursor comprises boron, and at least one metal element, and/or at least one non-metallic element rather than boron, the metal element is at least one selected from the group consisting of lithium, beryllium, magnesium, calcium, strontium, barium, aluminum, gallium, indium, zinc, and titanium, and the non-metallic element comprises silicon. The preparation method of the boron nitride nanomaterial provided by the disclosure is simple, controllable, and economical with readily available and inexpensive starting materials, and high conversion rates of the starting materials, and facilitates mass production. Furthermore, the obtained boron nitride nanomaterials further have advantages, such as excellent quality, and controllable appearance, and have very good application prospects in many fields, such as electronic devices, deep ultraviolet light emitting, composite materials, heat dissipating materials, friction materials, drug loading, and catalyst loading.

BN nanosheets are prepared by a method comprising heating to a temperature of at least 500 C., a mixture comprising: (1) an alkali borohydride, and (2) an ammonium salt. NaN.sub.3 may be included to increase the yield. No catalyst is required, and the product produced contains less than 0.1 atomic percent metal impurities.

A flexible boron nitride nanoribbon aerogel has an interconnected three-dimensional porous network structure which is formed by mutually twining and contacting boron nitride nanoribbons and consists of macropores having a pore diameter of more than 50 nm, mesopores having a pore diameter of 2-50 nm and micropores having a pore diameter of less than 2 nm. The preparation method of the flexible boron nitride nanoribbon aerogel includes the following steps: performing high-temperature dissolution on boric acid and a nitrogen-containing precursor to form a transparent precursor solution, preparing the transparent precursor solution into precursor hydrogel, subsequently drying and performing high-temperature pyrolysis to obtain the flexible boron nitride nanoribbon aerogel. The boron nitride nanoribbon aerogel has excellent flexibility and resilience and can withstand different forms of loads from the outside within a wide temperature range.

A floating catalyst chemical vapor deposition system produces nanotubes. The system includes a reaction chamber, a heater for heating a nanotube-material precursor and a catalyst precursor, and an injector for injecting the precursors into the chamber. In the chamber, the catalyst precursor is pyrolysed to produce catalyst particles, and the nanotube-material precursor is pyrolysed in the presence of the catalyst particles in order to produce nanotubes. A controller controls at least one operational parameter, e.g., injection temperatures of the precursors, flow rates of carrier gases of the precursors, and a reaction temperature of the chamber and of the precursors. An injection pipe extends into the chamber to an adjustable extent in order to control the injection temperature of the catalyst precursor and/or the nanotube-material precursor.

A hexagonal boron nitride powder, in which an attenuation rate of a positive charge is higher than an attenuation rate of a negative charge when the attenuation rates of the positive and negative charges determined through charge attenuation measurement are compared with each other. A method for producing a hexagonal boron nitride powder includes: a calcination step of firing a raw material powder containing a boron-containing compound powder and a nitrogen-containing compound powder at 600? C. to 1300? C. in an atmosphere of an inert gas, ammonia gas, or a mixed gas thereof to obtain a calcined product containing hexagonal boron nitride; and a firing step of heating and firing a mixed powder containing the calcined product and an aid at 1900? C. to 2100? C. for 10 to 50 hours in an atmosphere of an inert gas, ammonia gas, or a mixed gas thereof.