A kind of preparation method of high crystallinity boron nitride

Abstract

The invention relates to a preparation method of high-crystallinity boron nitride, which comprises the following steps: (1) mixing 20 parts of dioxane solution containing 0.002 mol of sodium borohydride per milliliter and 20 parts of dioxane solution containing 0.002 mol of ammonium salt per milliliter, reacting, and performing vacuum filtration to obtain an ammonia borane clear solution; (2) preparing 20 parts of PVB solution containing 0.001-0.01 gram of PVB per milliliter of dioxane; (3) sequentially pouring the clear solutions prepared in the step (1) and the step (2) into a high-pressure autoclave to obtain an ammonia borane-PVB mixed solution, performing solvothermal reaction at 160 DEG C for 4-8 hours, standing, cooling, and distilling off the solvent to obtain white hybrid powder; and (4) putting the white powder obtained in the step (3) in a pipe furnace, calcining in an ammonia gas atmosphere at 900-1000 DEG C, keeping the temperature for 5 hours, and calcining in an air atmosphere at 700 DEG C in a muffle furnace for 2 hours to obtain the high-crystallinity boron nitride product. The PVB assisted synthesis method adopted by the invention obviously improves the crystallinity of the boron nitride, and lowers the crystallization temperature of the boron nitride, thereby being beneficial to lower the cost and save the energy.

Description

technical field [0001] The technical solution of the invention belongs to boron nitride materials, and relates to a preparation method of boron nitride with high crystallinity. Background technique [0002] Boron nitride has various structures, such as hexagonal boron nitride (h-BN), cubic boron nitride (c-BN), and trigonal boron nitride (r-BN). Among them, hexagonal boron nitride is widely used in various industries such as electronics and foundry because of its excellent physical and chemical properties, especially excellent dielectric properties, dielectric frequency stability and high thermal conductivity. Important raw materials for composite ceramics, electrical insulation, daily cosmetics, etc., have high application value and have become a hot research topic for scholars at home and abroad. In recent years, researchers at home and abroad have studied the preparation methods of h-BN in depth, but the traditional methods for preparing boron nitride are mainly concentr...

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Problems solved by technology

(P.Dibandjo, L.Bois.Thermalstabilityofmesoporousboronnitridetemplatedwithacationicsurfactant.JournaloftheEuropeanCeramicSociety.2007,27:313-317) However, this method has the disadvantages that MAB needs multi-step reactions to synthesize, long production cycle, high calcination temperature, and high cost of templating agent

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