Method for preparing high-performance composite ferrite for self-biased circulator

A method for preparing high-performance composite ferrite for a self-biased circulator, comprising:

• (1) preparing BaM ferrite initial powder:
• taking BaCO3, La2O3 and Fe2O3 as raw materials, and weighing and mixing the materials according to the proportion of 5-15 mol % of BaCO3, 2-12 mol % of La2O3 and 73-93 mol % of Fe2O3 to obtain the BaM ferrite initial powder;
• (2) preparing NiCuZnSn ferrite initial powder:
• taking NiO, ZnO, CuO, SnO2, Co2O3 and Fe2O3 as raw materials, and weighing and mixing the materials according to the proportion of 20-40 mol % of NiO, 5-30 mol % of ZnO, 2-10 mol % of CuO, 1-5 mol % of SnO2, 4-10 mol % of Co2O3 and 40-68 mol % of Fe2O3 to obtain the NiCuZnSn ferrite initial powder;
• (3) uniformly mixing the BaM ferrite initial powder obtained in step (1), the NiCuZnSn ferrite initial powder obtained in step (2) and deionized water according to a mass ratio of 1:
• (0.1-1):
• (3-5) to obtain mixed powder slurry, and then uniformly mixing the mixed powder slurry in a high-energy ball mill, wherein the high-energy ball-milling time is 1-3 hours;
• (4) drying ball-milled powder obtained in step (3), sieving, and then performing primary pre-sintering and secondary pre-sintering on the powder to obtain mixed powder, wherein in the primary pre-sintering, the sintering temperature is 1050-1350° C., the heating rate is 1-3° C./min and the heat preservation time is 2-7 hours, and in the secondary pre-sintering, the sintering temperature is 800-1000° C., the heating rate is 1-3° C./min and the heat preservation time is 1-4 hours;
• (5) uniformly mixing the mixed powder obtained in step (4) and deionized water according to a mass ratio of 1:
• (3-5), and performing secondary high-energy ball milling to obtain powder slurry, wherein the high-energy ball-milling time is 0.5-1.5 hours;
• (6) preparing a green compact from the powder slurry obtained in step (5) by a low-temperature magnetic field orientation forming technology, wherein in the low-temperature magnetic field orientation forming technology, the temperature is 50-150°° C., the pressure is 40- 150 MPa, and the magnetic field intensity is 2-4 T;
• and
• (7) performing magnetic field heat treatment on the green compact obtained in step (6) to finally obtain the high-performance composite ferrite for the self-biased circulator.