Boron nitride coating evaporation boat and preparation method thereof

The invention provides a boron nitride coating evaporation boat and a preparation method thereof, and the preparation method comprises the following steps: placing a boron source at the bottom of a reaction chamber made of a boron nitride material, placing a graphite evaporation boat substrate in the reaction chamber and keeping a distance of 20-50mm between the graphite evaporation boat substrate and the boron source, wherein the boron source is selected from any one of diboron trioxide and boric acid; placing the reaction chamber in a chemical vapor deposition furnace, vacuumizing the chemical vapor deposition furnace, heating to 500-700 DEG C, introducing nitrogen, keeping positive pressure in the furnace, and continuously introducing nitrogen in the reaction; and heating the chemical vapor deposition furnace to the reaction temperature of 1750-1950 DEG C, keeping the temperature for 1-8 hours, and depositing and growing the boron nitride coating on the graphite evaporation boat substrate. The raw material