Preparation method of sub-micron powder of high-entropy nitride via nitride thermal reduction with soft mechano-chemical assistance

A preparation method of sub-micron powder of (Hf0.2Ti0.2Zr0.2Nb0.2Ta0.2)N high-entropy powder via nitride thermal reduction with soft mechano-chemical assistance, wherein the method comprises:

• (1) material preparation:
• mixing ingredients at a molar ratio of HfO2:ZrO2:TiO2:Nb2O5:Ta2O5:Si3N4=2:2:2:1:1:(6-14) and obtaining a mixed material;
• (2) grinding:
• weighing the mixed material, placing the mixed material in a mixing mill, adding deionized water, until a solid content is 45%˜75%, adding zirconia balls with a particle size of 1˜3 mm, grinding until the mixed material is dispersed evenly;
• (3) activation:
• placing the mixed material after grinding into a mixing dispenser, conducting soft mechano-chemical activation at a rate of 800˜1600 r/min, activation time is 5˜20 h, separating the zirconia balls and drying the mixed material;
• (4) prefabrication:
• compacting powder of the mixed material after drying to be loose pieces of 5˜20 g with circular cast steel molds, wherein prefabrication pressure is 10˜50 MPa, and pressure is maintained for 10˜50 s;
• and
• (5) reaction:
• putting the prefabricated loose pieces into a vacuum synthesis furnace, vacuuming the vacuum synthesis furnace, filling N2 shielding air, heating the vacuum synthesis furnace until 1500˜2000° C. for synthesis reaction, maintaining reaction temperature for 30˜90 min, furnace cooling and obtaining the (Hf0.2Ti0.2Zr0.2Nb0.2Ta0.2)N high-entropy powder.