Preparation method of silicon nitride rich in fiber morphology

The invention discloses a preparation method of silicon nitride rich in fiber morphology. The preparation method includes weighing 5 wt% of Fe powder and 3 wt% of NH4Cl powder and adding them to Si powder to obtain a powder mixture, subjecting the power mixture to ball milling and mixing uniformly, placing the mixture in a high-temperature tube furnace, vacuumizing and introducing nitrogen gas, powering on to heat the mixture to 1300 DEG C and holding the temperature for 4 hours, after finishing reaction, reducing temperature of the furnace to the room temperature, and finally collecting a silicon nitride product. The added Fe powder and NH4Cl powder react to produce a reducing atmosphere containing hydrogen gas, which facilitates gasification of Si powder and catalysis of fibrous siliconnitride; the prepared silicon nitride powder has rich fiber and long length. The preparation method is easy, needs low cost, low energy consumption, short reaction time and simple source of raw materials, and is suitable for