Method for preparing silicon nitride powder with low energy consumption and cost

Abstract

The invention relates to a method for preparing silicon nitride powder with low energy consumption and cost. In the method, a nitridation synthetic reaction is performed on the basis of the principle of a silicon powder direct nitridation method, a nitridation reaction is performed in a nitriding furnace, and the temperature of the nitriding furnace is regulated by a heating element in the furnace wall and a temperature-control system. The method comprises the main steps of: 1, performing a nitridation synthetic reaction directly, namely calcining 99.99 percent of monocrystalline silicon powder serving as raw materials in the nitriding furnace at the temperature of 1,250 DEG C, and keeping the temperature for 30 to 38 hours under the nitriding condition of introducing N2 at a flow rate of 4L / minute; and 2, performing aftertreatment such as ball-milling, scouring and the like on silicon nitride powder obtained by calcining to obtain Si3N4 powder of which the purity is up to 99.99 percent. The method has the advantages that (1) a reaction is quick, namely the synthetic reaction is finished within 38 to 40 hours; (2) the energy consumption is low, and the temperature of direct nitriding is lower than that of the conventional method; (3) equipment is simple, investment is small, and the generality is high; and (4) the nitriding activity is high, and the preparation time is short.

Description

technical field [0001] The invention relates to a method for preparing silicon nitride powder with low energy consumption and low cost, and belongs to the technical field of preparation technology. Background technique [0002] Nano-Si3N4-based ceramics have the characteristics of high density, small thermal expansion coefficient, high hardness, high elastic modulus, thermal stability, chemical stability and electrical insulation, and have been widely used in automobiles, machinery, metallurgy and chemical engineering. And gradually penetrate into many cutting-edge scientific fields such as space technology, ocean development, electronic technology, medical and health care, non-destructive testing, automatic control, radio and television; in order to obtain silicon nitride ceramic materials with excellent performance, high-purity and ultra-fine nitrogen Silicon powder. [0003] There are many methods for preparing Si3N4 powder, and the most widely used ones are as follows: ...

AI Technical Summary

Problems solved by technology

However, the existing silicon powder direct nitriding method requires a long holding time, usually 48-50 hours, and the preparation temperature is also relatively high, usually around 1380°C, which leads to a long preparation time and relatively energy consumption. The cost is also greatly increased