METHOD OF PRODUCING PARAMETRIC SERIES FERRITE MATERIAL OF LITHIUM FERROSPINEL FOR MICROWAVE ELECTRONICS Russian patent published in 2024 - IPC B22F3/12 H01F1/34 

FIELD: powder metallurgy.

SUBSTANCE: invention relates to production of parametric ferrite materials of lithium ferrospinel for microwave electronic equipment. Charge is prepared in two stages: at the first one prepares part of charge containing Fe₂O₃, Li₂CO₃, MnCO₃ and ZnO with subsequent calcination of this part of mixture at 930–970 °C for (36.0–39.6)·10³ s. At the second stage, Bi₂O₃ is added to said part of the mixture in amount of 2–4 wt.% of the total composition of the mixture of ferrite material and binder and mixed in a ball mill using balls from high-carbon, wear-resistant steel with diameter of 8–14 mm at ratio of mixture of oxides of ferrite material, binder and balls 46:29:25 wt.%, respectively, for (79.2–86.4)·10³ s. Prior to forming the workpiece, the charge is fore-evacuated for (0.9–1.2)·10³ s to viscosity of 4.5–8.0 Pa·s. At least one tape of given thickness is formed by slip casting on a carrier from polyethylene terephthalate moving along the thermal zone at rate of (6.3–7.0)·10⁻³ m/s with simultaneous, uniform temperature rise to 70–75 °C. Obtained tape is sintered by heating in an oxidizing medium at a rate of temperature rise of not more than 15.0·10⁻³ °C/s to temperature of 440–460 °C, holding at this temperature for not more than 10.0·10³ s with subsequent temperature rise at rate of (42.0–55.0)·10⁻³ °C/s to a temperature equal to 0.8 of temperature in range of 1,000–1,100 °C, holding at this temperature for (7.2–7.5)·10³ s and cooling at a rate of not more than 27.0·10⁻³ °C/s, at pressure (1.0–1.2)·10⁵ Pa.

EFFECT: lower sintering temperature, higher efficiency, expanded performances, expanded functionality, ensuring specified values of electromagnetic parameters.

3 cl, 2 dwg, 1 tbl, 5 ex