Method for Improving Bs of MnZn Power Ferrite Material by Moving Valley Point

Abstract

A method for improving the Bs of an MnZn power ferrite material by moving the valley point includes the following steps: 1) mixing Fe.sub.2O.sub.3, MnO and ZnO, and performing primary sanding; 2) adding glue, performing spraying and granulating, and then performing pre-sintering to obtain a pre-sintered material; 3) adding additives to the pre-sintered material, and performing secondary sanding; and 4) adding glue to the secondary sanded material, performing spraying and granulating, pressing into a standard ring, and then performing sintering. The method controls and moves the valley point, reduces loss and improves the Bs of a material by controlling the Fe.sub.2O.sub.3 content and the Co.sub.2O.sub.3 content, and the method is relatively simple and suitable for industrialization.

Claims

1. A method for improving Bs of an MnZn power ferrite material by moving a valley point, comprising the following steps: 1) mixing Fe.sub.2O.sub.3, MnO and ZnO, and performing primary sanding to obtain a first sanded material; 2) adding a glue to the first sanded material, performing spraying and granulating to obtain a material to be pre-sintered, and then performing pre-sintering to obtain a pre-sintered material; 3) adding additives to the pre-sintered material, and performing secondary sanding to obtain a secondary sanded material; and 4) adding the glue to the secondary sanded material, performing spraying and granulating, pressing into a standard ring, and then performing sintering.

2. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 1, wherein proportions of the components in step 1) are as follows: 52.9-53.3 mol % of Fe.sub.2O.sub.3, 38.3-39.08 mol % of MnO, and 7.62-8.8 mol % of ZnO.

3. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 1, wherein the additives in step 3) comprise the following components in mass percentages accounting for the pre-sintered material: 0.03-0.08 wt % of CaCO.sub.3, 0.015-0.04 wt % of ZrO.sub.2, 0.43-0.52 wt % of Co.sub.2O.sub.3, and 0.05-0.2 wt % of SnO.sub.2.

4. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 1, wherein in step 1 and step 3, a material-to-ball-to-water ratio in the primary sanding and the secondary sanding is 1:5-7:0.4-0.6, and a sanding time is 0.5-1.5 h.

5. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 1, wherein the glue added in step 2) accounts for 10% of a total mass of the material to be pre-sintered and the glue has a mass fraction of 7.5%.

6. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 1, wherein the pre-sintering in step 2) is performed in a rotary kiln at 900-1000° C.

7. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 1, wherein the glue added in step 3) accounts for 10% of a total mass of the secondary sanded material and the glue has a mass fraction of 7.5%.

8. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 1, wherein a pressing pressure in step 4) is 6-8 Mpa.

9. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 2, wherein the additives in step 3) comprise the following components in mass percentages accounting for the pre-sintered material: 0.03-0.08 wt % of CaCO.sub.3, 0.015-0.04 wt % of ZrO.sub.2, 0.43-0.52 wt % of Co.sub.2O.sub.3, and 0.05-0.2 wt % of SnO.sub.2.

10. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 2, wherein in step 1 and step 3, a material-to-ball-to-water ratio in the primary sanding and the secondary sanding is 1:5-7:0.4-0.6, and a sanding time is 0.5-1.5 h.

11. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 2, wherein the glue added in step 2) accounts for 10% of a total mass of the material to be pre-sintered and has a mass fraction of 7.5%.

12. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 2, wherein the pre-sintering in step 2) is performed in a rotary kiln at 900-1000° C.

13. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 2, wherein the glue added in step 3) accounts for 10% of a total mass of the secondary sanded material and has a mass fraction of 7.5%.

14. The method for improving the Bs of the MnZn power ferrite material by moving the valley point according to claim 2, wherein a pressing pressure in step 4) is 6-8 Mpa.

Description

DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with specific embodiments.

[0023] Embodiment 1: A method for improving the Bs of an MnZn power ferrite material by moving the valley point, includes the following steps: [0024] 1) 52.9 mol % of Fe.sub.2O.sub.3, 38.3 mol % of MnO and 8.8 mol % of ZnO were mixed, and sanded for the first time for 1.5 h in a material-to-ball-to-water ratio of 1:5:0.4; [0025] 2) glue accounting for 10% of the total mass of the material to be pre-sintered and having a mass fraction of 7.5% was added, and the material to be pre-sintered was sprayed and granulated, and then pre-sintered at 900° C. in a rotary kiln to obtain the pre-sintered material; [0026] 3) additives including the following components in mass percentages accounting for the pre-sintered material, namely 0.03% of CaCO.sub.3, 0.04% of ZrO.sub.2, 0.44% of Co.sub.2O.sub.3, and 0.05% of SnO.sub.2, were added to the pre-sintered material, and then, the pre-sintered material was sanded for the second time for 1.5 h at a material-to-ball-to-water ratio of 1:5:0.4; and [0027] 4) glue accounting for 10% of the total mass of the secondary sanded material and having a mass fraction of 7.5% was added to the secondary sanded material, and the secondary sanded material was sprayed, granulated, pressed into a standard ring at 6 Mpa and then sintered.

[0028] Embodiment 2: A method for improving the Bs of an MnZn power ferrite material by moving the valley point, includes the following steps: [0029] 1) 53.3 mol % of Fe.sub.2O.sub.3, 39.08 mol % of MnO and 7.62 mol % of ZnO were mixed, and sanded for the first time for 0.5 h in a material-to-ball-to-water ratio of 1:7:0.6; [0030] 2) glue accounting for 10% of the total mass of the material to be pre-sintered and having a mass fraction of 7.5% was added, and the material to be pre-sintered was sprayed and granulated, and then pre-sintered at 1000° C. in a rotary kiln to obtain the pre-sintered material; [0031] 3) additives including the following components in mass percentages accounting for the pre-sintered material, namely 0.03% of CaCO.sub.3, 0.04% of ZrO.sub.2, 0.48% of Co.sub.2O.sub.3, and 0.05% of SnO.sub.2, were added to the pre-sintered material, and then, the pre-sintered material was sanded for the second time for 0.5 h at a material-to-ball-to-water ratio of 1:7:0.6; and [0032] 4) glue accounting for 10% of the total mass of the secondary sanded material and having a mass fraction of 7.5% was added to the secondary sanded material, and the secondary sanded material was sprayed, granulated, pressed into a standard ring at 8 Mpa and then sintered.

[0033] Embodiment 3: A method for improving the Bs of an MnZn power ferrite material by moving the valley point, includes the following steps: [0034] 1) 53.1 mol % of Fe.sub.2O.sub.3, 38.5 mol % of MnO and 8.4 mol % of ZnO were mixed, and sanded for the first time for 1 h in a material-to-ball-to-water ratio of 1:6:0.5; [0035] 2) glue accounting for 10% of the total mass of the material to be pre-sintered and having a mass fraction of 7.5% was added, and the material to be pre-sintered was sprayed and granulated, and then pre-sintered at 950° C. in a rotary kiln to obtain the pre-sintered material; [0036] 3) additives including the following components in mass percentages accounting for the pre-sintered material, namely 0.03% of CaCO.sub.3, 0.04% of ZrO.sub.2, 0.52% of Co.sub.2O.sub.3, and 0.05% of SnO.sub.2, were added to the pre-sintered material, and then, the pre-sintered material was sanded for the second time for 1 h at a material-to-ball-to-water ratio of 1:6:0.5; and [0037] 4) glue accounting for 10% of the total mass of the secondary sanded material and having a mass fraction of 7.5% was added to the secondary sanded material, and the secondary sanded material was sprayed, granulated, pressed into a standard ring at 7 Mpa and then sintered.

[0038] Comparative example 1: A method for improving the Bs of an MnZn power ferrite material by moving the valley point, includes the following steps: [0039] 1) 52.6 mol % of Fe.sub.2O.sub.3, 38.6 mol % of MnO and 8.8 mol % of ZnO were mixed, and sanded for the first time for 1.5 h in a material-to-ball-to-water ratio of 1:5:0.4; [0040] 2) glue accounting for 10% of the total mass of the material to be pre-sintered and having a mass fraction of 7.5% was added, and the material to be pre-sintered was sprayed and granulated, and then pre-sintered at 900° C. in a rotary kiln to obtain the pre-sintered material; [0041] 3) additives including the following components in mass percentages accounting for the pre-sintered material, namely 0.03% of CaCO.sub.3, 0.04% of ZrO.sub.2, 0.44% of Co.sub.2O.sub.3, and 0.05% of SnO.sub.2, were added to the pre-sintered material, and then, the pre-sintered material was sanded for the second time for 1.5 h at a material-to-ball-to-water ratio of 1:5:0.4; and [0042] 4) glue accounting for 10% of the total mass of the secondary sanded material and having a mass fraction of 7.5% was added to the secondary sanded material, and the secondary sanded material was sprayed, granulated, pressed into a standard ring at 6 Mpa and then sintered.

[0043] Comparative example 2: A method for improving the Bs of an MnZn power ferrite material by moving the valley point, includes the following steps: [0044] 1) 53.3 mol % of Fe.sub.2O.sub.3, 39.08 mol % of MnO and 7.62 mol % of ZnO were mixed, and sanded for the first time for 0.5 h in a material-to-ball-to-water ratio of 1:7:0.6; [0045] 2) glue accounting for 10% of the total mass of the material to be pre-sintered and having a mass fraction of 7.5% was added, and the material to be pre-sintered was sprayed and granulated, and then pre-sintered at 1000° C. in a rotary kiln to obtain the pre-sintered material; [0046] 3) additives including the following components in mass percentages accounting for the pre-sintered material, namely 0.03% of CaCO.sub.3, 0.04% of ZrO.sub.2, 0.35% of Co.sub.2O.sub.3, and 0.05% of SnO.sub.2, were added to the pre-sintered material, and then, the pre-sintered material was sanded for the second time for 0.5 h at a material-to-ball-to-water ratio of 1:7:0.6; and [0047] 4) glue accounting for 10% of the total mass of the secondary sanded material and having a mass fraction of 7.5% was added to the secondary sanded material, and the secondary sanded material was sprayed, granulated, pressed into a standard ring at 8 Mpa and then sintered.

[0048] Comparative example 3: A method for improving the Bs of an MnZn power ferrite material by moving the valley point, includes the following steps: [0049] 1) 53.5 mol % of Fe.sub.2O.sub.3, 38.9 mol % of MnO and 7.6 mol % of ZnO were mixed, and sanded for the first time for 1 h in a material-to-ball-to-water ratio of 1:6:0.5; [0050] 2) glue accounting for 10% of the total mass of the material to be pre-sintered and having a mass fraction of 7.5% was added, and the material to be pre-sintered was sprayed and granulated, and then pre-sintered at 950° C. in a rotary kiln to obtain the pre-sintered material; [0051] 3) additives including the following components in mass percentages accounting for the pre-sintered material, namely 0.03% of CaCO.sub.3, 0.04% of ZrO.sub.2, 0.52% of Co.sub.2O.sub.3, and 0.05% of SnO.sub.2, were added to the pre-sintered material, and then, the pre-sintered material was sanded for the second time for 1 h at a material-to-ball-to-water ratio of 1:6:0.5; and [0052] 4) glue accounting for 10% of the total mass of the secondary sanded material and having a mass fraction of 7.5% was added to the secondary sanded material, and the secondary sanded material was sprayed, granulated, pressed into a standard ring at 7 Mpa and then sintered.

[0053] The valley point and Bs of the MnZn power ferrite materials prepared in the Embodiments and Comparative examples are tested, and the data obtained are shown in the table below.

TABLE-US-00001 TABLE 1 Test data of Embodiments and Comparative examples Pcv (kW/m3) 100 kHz Bs (mT) 200 mT 8218 test 1194 A/m 50 Hz 25° C. 80° C. 100° C. 120° C. 25° C. 100° C. Embodiment 1 290 280 275 320 545 430 Comparative 260 275 310 360 535 421 example 1 Embodiment 2 325 280 285 310 550 438 Comparative 290 310 330 390 550 436 example 2 Embodiment 3 335 285 295 305 545 439 Comparative 380 370 360 380 550 435 example 3

[0054] From the above table, Embodiment 1 and Comparative example 1 are different in the Fe.sub.2O.sub.3 content and same in the Co.sub.2O.sub.3 content. In Embodiment 1, the Fe.sub.2O.sub.3 content is high, but the valley point moves to high temperature, and in Comparative example 1, the Fe.sub.2O.sub.3 content is low, but the valley point moves to low temperature, which are caused by addition of certain amounts of Co.sub.2O.sub.3. Also, when the Fe.sub.2O.sub.3 content is high, the Bs is high.

[0055] Embodiment 2 and Comparative example 2 are only different in the Co.sub.2O.sub.3 content. The Co.sub.2O.sub.3 content in Comparative example 2 is not within the range of the present invention. Therefore, when the Fe.sub.2O.sub.3 content is high, the valley point moves to low temperature.

[0056] Comparing Embodiment 3 with Comparative example 3, Comparative example 3 exceeds the range of the present invention in the Fe.sub.2O.sub.3 content and ZnO content, and has higher loss.