Power ferrite material, its preparation method and use

Abstract

The present disclosure discloses a power ferrite material, its preparation method and use. [Solution] The power ferrite material is composed of a main component and an auxiliary component, and in mole percentages, the main component includes 52.7-53 mol% Fe2O3, 10-12 mol% ZnO, and 35-37.3 mol% MnO, and the auxiliary components include 0.08-0.1 wt% CaCO3, 0.02-0.04 wt% Nb2O5, and 0.4-0.42 wt% Co2O3. By adjusting the content ratio of the main component and the auxiliary component rationally, the prepared power ferrite material has wide temperature and low loss properties and can meet the requirements for power ferrite in automotive electronic products.

Description

[Technical Field]

[0001] The embodiments of the present application relate to the technical field of soft magnetic materials, such as power ferrite materials, their preparation methods and uses. [Background technology]

[0002] Soft magnetic ferrites have low coercive force and high magnetic permeability, and are therefore often used in the fields of communications and electronics. For high current and power applications, power ferrites are required to have wide temperature characteristics and low loss at high temperatures. As MnZn power ferrites are widely used, further improvements in their wide temperature and high temperature low loss characteristics are expected.

[0003] CN107573051A discloses a method for improving the core strength of MnZn power ferrite without increasing loss, which involves adding 200-400 ppm of CaCO3, 240-410 ppm of V2O5, and 100-200 ppm of ZrO2 when preparing the MnZn power ferrite. This application can effectively improve the core strength of ferrite without increasing loss. However, this application does not increase loss within the range of 25-100°C, and the loss at 100°C is 400 kW / m 3 and losses remain high at high temperatures.

[0004] CN104078185A discloses a cobalt oxide-based ferrite core material, comprising a main raw material and additives, the main raw material comprising, in molar ratios, 56.1-64 mol of iron oxide, 15.3-22.1 mol of manganese oxide, 11-16.6 mol of zinc oxide, 1-1.3 mol of zirconium oxide, 0.03-0.1 mol of strontium oxide, 1.2-1.6 mol of lithium oxide, and 0.01-0.02 mol of rare earth composite magnetic powder. The rare earth composite magnetic powder added to the ferrite core material of this application has a high magnetic energy product, and the finished product is characterized by high grain boundary resistivity, low porosity, and large, uniform crystal grains. However, the ferrite core material has a loss of 421 kW / m at 100°C. 3and cannot meet the high temperature and low loss performance requirements.

[0005] CN105565790A relates to a manganese zinc ferrite material with a wide temperature range of YR950, high DC current superposition, and low power consumption, and its preparation method. The preparation method in this application sequentially includes raw material selection, component design and weighing, raw material mixing, calcination, impurity addition, secondary ball milling, and molding and sintering. The manganese zinc ferrite material in this application has stable performance, high magnetic permeability, and a power consumption of 350 kW / m between 25 and 120°C. 3 However, the application has some limitations as it fails to take into account losses at higher temperatures.

[0006] In response to the deficiencies in the related art, there is a need to provide a power ferrite material that has wide temperature properties and low losses at high temperatures. Summary of the Invention [Problem to be solved by the invention]

[0007] The following is a summary of the subject matter described in detail in the present text. This summary does not limit the scope of the claims.

[0008] The examples of the present application provide a power ferrite material, its preparation method and use. By adjusting the reasonable compounding ratio of the main components and auxiliary components and adopting an oxidation process in the sintering temperature-reducing stage, the prepared power ferrite material has the characteristics of wide temperature range and low loss, and can be applied to automotive electronic products. [Means for solving the problem]

[0009] In aspect 1, the present embodiment comprises: A power ferrite material composed of a main component and an auxiliary component, In terms of molar percentage, the main components include 52.7 to 53 mol% of Fe2O3, 10 to 12 mol% of ZnO, and 35 to 37.3 mol% of MnO, In terms of the total mass percentage of the main components, the auxiliary components include 0.08-0.1 wt% CaCO3, 0.02-0.04 wt% Nb2O5, and 0.4-0.42 wt% Co2O3. A power ferrite material is provided.

[0010] In the present invention, the blending ratio of the main component and the auxiliary component is rationally controlled, and in particular, the content range of Fe2O3 and Co2O3 is strictly adjusted, so that the power ferrite material can meet the low loss requirement in a wide temperature range of 25 to 150°C, and can be widely applied to automotive electronic products.

[0011] In terms of molar percentage, the molar percentage of Fe2O3 in the main component is 52.7 to 53 mol%, and may be, for example, 52.7 mol%, 52.8 mol%, 52.9 mol%, or 53 mol%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0012] In this application, the molar percentage of Fe2O3 is controlled within a reasonable range to meet the requirements for wide temperature range and low loss. Too much Fe2O3 increases eddy current loss, which is unfavorable for reducing high temperature loss. Too little Fe2O3 cannot form enough iron ferrite to cooperate with cobalt ferrite to reduce hysteresis loss, making it difficult to achieve wide temperature range and low hysteresis loss.

[0013] In terms of molar percentage, the molar percentage of ZnO in the main component is 10 to 12 mol%, and may be, for example, 10 mol%, 10.5 mol%, 11 mol%, 11.5 mol%, or 12 mol%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0014] In terms of mole percentage, the mole percentage of MnO in the main component is 35 to 37.3 mol%, and may be, for example, 35 mol%, 35.5 mol%, 36 mol%, 36.5 mol%, or 37.3 mol%, but is not limited to the recited numerical values, and other unrecited numerical values ​​within the numerical range also apply.

[0015] As a percentage of the total mass of the main component, the mass percentage of CaCO3 in the auxiliary component is 0.08-0.1 wt%, and may be, for example, 0.08 wt%, 0.085 wt%, 0.09 wt%, 0.095 wt%, or 0.1 wt%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0016] As a percentage of the total mass of the main component, the mass percentage of Nb2O5 in the auxiliary component is 0.02-0.04 wt%, and may be, for example, 0.02 wt%, 0.025 wt%, 0.03 wt%, 0.035 wt%, or 0.04 wt%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0017] As a percentage of the total mass of the main component, the mass percentage of Co2O3 in the auxiliary component is 0.4 to 0.42 wt%, and may be, for example, 0.4 wt%, 0.405 wt%, 0.41 wt%, 0.415 wt%, or 0.42 wt%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0018] The mass percentage of Co2O3 in the auxiliary components must be strictly controlled. If the Co2O3 content is too high, the negative magnetocrystalline anisotropy constant K2 value will increase, and the hysteresis loss will increase. If the Co2O3 content is too low, a sufficient amount of cobalt ferrite cannot be formed, making it difficult to achieve wide temperature range and reduced hysteresis loss.

[0019] In aspect 2, the present embodiment comprises: Step (1) of subjecting the raw materials of the main components to first sand mill mixing according to the blending amounts, and then sequentially performing first spray granulation and pre-calcination to obtain a pre-calcined material; and step (2) of subjecting the raw materials of the auxiliary components and the calcined material obtained in step (1) to a second sand mill mixing in accordance with the blending amounts, and then sequentially subjecting the raw materials to a second spray granulation, press molding, and sintering to obtain the power ferrite material. According to a first aspect, there is provided a method for preparing a power ferrite material.

[0020] The method for preparing the power ferrite material according to the present invention uses two sand milling processes to fully fuse the main component and the auxiliary component, and employs an oxidation process in the cooling stage of the sintering process, which can effectively reduce the high temperature loss. The preparation process is simple and low cost, and is suitable for industrial production.

[0021] Preferably, the mass ratio of powder to sand mill balls to grinding aid in the first sand mill mixing described in step (1) is 1:(5-7):(1.5-1.6), and may be, for example, 1:5:1.5, 1:5.5:1.52, 1:6:1.55, 1:6.5:1.58 or 1:7:1.6, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0022] Preferably, the Sand mill The ball includes a steel ball.

[0023] Preferably, the grinding aid comprises deionized water.

[0024] Preferably, the time for the first sand mill mixing described in step (1) is 55 to 65 minutes, and may be, for example, 55 minutes, 58 minutes, 60 minutes, 62 minutes, or 65 minutes, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0025] Preferably, the average particle size after the first sand mill mixing described in step (1) is 1.3 to 1.5 μm, and may be, for example, 1.3 μm, 1.35 μm, 1.4 μm, 1.45 μm, or 1.5 μm, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0026] Preferably, the mass of the binder used in the first spray granulation described in step (1) is 8 to 12 wt% of the pellet material after sand milling, and may be, for example, 8 wt%, 9 wt%, 10 wt%, 11 wt%, or 12 wt%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0027] Preferably, the binder comprises polyvinyl alcohol.

[0028] Preferably, the mass concentration of the polyvinyl alcohol is 7 to 8 wt%, and may be, for example, 7 wt%, 7.2 wt%, 7.5 wt%, 7.8 wt%, or 8 wt%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0029] Preferably, the temperature of the calcination described in step (1) is 900 to 950°C, and may be, for example, 900°C, 910°C, 920°C, 930°C, 940°C, or 950°C, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0030] Preferably, the calcination time described in step (1) is 5 to 9 hours, and may be, for example, 5 hours, 6 hours, 7 hours, 8 hours, or 9 hours, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0031] Preferably, the mass ratio of powder to sand mill balls to grinding aid in the second sand mill mixing described in step (2) is 1:(5-7):(0.4-0.5), and may be, for example, 1:5:0.4, 1:5.5:0.42, 1:6:0.45, 1:6.5:0.48, or 1:7:0.5, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0032] Preferably, the Sand mill The ball includes a steel ball.

[0033] Preferably, the grinding aid comprises deionized water.

[0034] Preferably, the time for the second sand mill mixing described in step (2) is 150 to 180 min, for example, 150 min, 155 min, 160 min, 170 min, or 180 min, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0035] Preferably, the average particle size after sand mill mixing in step (2) is 1 to 1.2 μm, and may be, for example, 1 μm, 1.05 μm, 1.1 μm, 1.15 μm, or 1.2 μm, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0036] The mass of the binder used in the second spray granulation described in step (2) is 8 to 12 wt% of the pellet material after sand milling, and may be, for example, 8 wt%, 9 wt%, 10 wt%, 11 wt%, or 12 wt%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0037] Preferably, the binder comprises polyvinyl alcohol.

[0038] Preferably, the mass concentration of the polyvinyl alcohol is 7 to 8 wt%, and may be, for example, 7 wt%, 7.2 wt%, 7.5 wt%, 7.8 wt%, or 8 wt%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0039] Preferably, the pressure of the press molding described in step (2) is 6 to 8 MPa, and may be, for example, 6 MPa, 6.5 MPa, 7 MPa, 7.5 MPa, or 8 MPa, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0040] Preferably, the sintering described in step (2) comprises a first heat treatment and a second heat treatment.

[0041] Preferably, the first heat treatment is performed in a nitrogen gas atmosphere by raising the temperature to 1280 to 1300° C. and maintaining the temperature for 6 to 8 hours.

[0042] In the first heat treatment, the temperature is raised to 1280 to 1300°C, which may be, for example, 1280°C, 1285°C, 1290°C, 1295°C, or 1300°C, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0043] The first heat treatment is maintained at the temperature for 6 to 8 hours, and may be, for example, 6 hours, 6.5 hours, 7 hours, 7.5 hours, or 8 hours, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0044] Preferably, the second heat treatment is performed in a nitrogen gas atmosphere, decreasing the temperature to 1148 to 1152°C, for example, 1148°C, 1149°C, 1150°C, 1151°C, or 1152°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range also apply.

[0045] Preferably, in the temperature increasing process, oxygen is not contained in the temperature increasing process from 998 to 1002°C to the end point of the temperature, and the oxygen content in the temperature maintaining process is 4 to 6%.

[0046] During the temperature increase process, the temperature is increased from 998 to 1002°C to the end point, which may be, for example, 998°C, 999°C, 1000°C, 1001°C, or 1002°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range also apply.

[0047] The oxygen content during the incubation process is 4 to 6%, and may be, for example, 4%, 4.5%, 5%, 5.5%, or 6%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0048] Preferably, in the temperature decreasing process, the oxygen content during the temperature decrease from 1248-1252°C to 1198-1202°C is 2.8-3.3%, and the oxygen content during the temperature decrease from 1198-1202°C to the end point is 0.6-1.2%.

[0049] In the second heat treatment of sintering according to the present invention, the temperature is lowered by an oxidation process, which can effectively increase the resistivity of the material and reduce high-temperature loss compared with the conventional temperature lowering by equilibrium oxygen partial pressure.

[0050] During the temperature drop process, the oxygen content in the temperature drop from 1248-1252°C to 1198-1202°C is 2.8-3.3%, and may be, for example, 2.8%, 2.9%, 3%, 3.1%, 3.2%, or 3.3%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0051] The temperature reduction from 1248 to 1252°C may be, for example, 1248°C, 1249°C, 1250°C, 1251°C, or 1252°C, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0052] The temperature reduction to 1198 to 1202°C may be, for example, 1198°C, 1199°C, 1200°C, 1201°C, or 1202°C, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0053] During the temperature drop process, the oxygen content in the temperature drop from 1198 to 1202°C to the end point is 0.6 to 1.2%, and may be, for example, 0.6%, 0.7%, 0.8%, 1%, 1.1%, or 1.2%, but is not limited to the recited values, and other unrecited values ​​within the numerical range also apply.

[0054] As a preferred technical solution of the preparation method according to aspect 2 of the present application, the preparation method includes the following steps:

[0055] Step (1): The main component raw materials are subjected to a first sand mill mixing for 55 to 65 minutes according to the blending amount, and then subjected to a first spray granulation and a pre-baking at 900 to 950°C for 5 to 9 hours, to obtain a pre-baked material.

[0056] The mass ratio of powder to sand mill balls to grinding aid in the first sand mill mixing is 1:(5-7):(1.5-1.6), the average particle size after the first sand mill mixing is 1.3-1.5 μm, the mass of the binder used in the first spray granulation is 8-12 wt% of the pellet material after sand milling, the binder contains polyvinyl alcohol, and the mass concentration of the polyvinyl alcohol is 7-8 wt%.

[0057] Step (2): The raw materials of the auxiliary components and the calcined material obtained in step (1) are subjected to a second sand mill mixing for 150 to 180 minutes according to the compounding amounts, and then a second spray granulation, press molding at 6 to 8 MPa, and sintering are sequentially performed to obtain the power ferrite material.

[0058] The mass ratio of the powder to the sand mill balls to the grinding aid in the second sand mill mixing is 1:(5-7):(0.4-0.5), the average particle size after the second sand mill mixing is 1-1.2 μm, the mass of the binder used in the second spray granulation is 8-12 wt % of the pellet material after sand milling, the sintering includes a first heat treatment and a second heat treatment, and the first heat treatment is performed by heating to 1280-1300°C in a nitrogen gas atmosphere and maintaining the temperature for 6-8 hours. The second heat treatment is performed in a nitrogen gas atmosphere, and the temperature is lowered to 1148-1152°C. During the temperature increase process, no oxygen is contained in the temperature increase from 998-1002°C to the end point, and the oxygen content during the temperature retention process is 4-6%. During the temperature decrease process, the oxygen content during the temperature decrease from 1248-1252°C to 1198-1202°C is 2.8-3.3%, and the oxygen content during the temperature decrease from 1198-1202°C to the end point is 0.6-1.2%.

[0059] In aspect 3, the present embodiment comprises: The power ferrite material is used in the field of automotive electronic products; The present invention provides a use of a power ferrite material according to the first aspect. [Effects of the Invention]

[0060] Compared to the related art, the embodiments of the present application have the following beneficial effects:

[0061] (1) The power ferrite material according to the embodiment of the present application is manufactured by adjusting the content ratio of the main component and the auxiliary component in a reasonable manner, and by strictly controlling the content of Fe2O3 and Co2O3 in particular, the power ferrite material has the characteristics of wide temperature range and low loss, and the power consumption at 25°C is 306 kW / m 3 The power consumption at 100°C is as low as 280kW / m 3 The power consumption at 120°C is 297kW / m 3 The power consumption at 140°C is 329kW / m 3 The power consumption at 150°C is 371kW / m 3and can meet the requirements for power ferrite in automotive electronic products.

[0062] (2) In the present embodiment, an oxidation process is adopted in the second heat treatment of the sintering process, and the oxygen content at the corresponding temperature is strictly controlled, thereby effectively increasing the resistivity of the material and reducing the high-temperature loss. The preparation method is simple and low-cost, and is suitable for industrial production.

[0063] Other aspects may be understood upon reading and understanding the detailed description. DETAILED DESCRIPTION OF THE INVENTION

[0064] The technical solution of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the above examples are only for understanding the present application and should not be considered as specific limitations of the present application. [Example]

[0065] This example provides a power ferrite material, which is composed of a main component and an auxiliary component. In terms of mole percentage, the main component includes 52.8 mol% FeO, 11 mol% ZnO, and 36.2 mol% MnO. In terms of percentage of the total mass of the main component, the auxiliary components include 0.09 wt% CaCO, 50.03 wt% NbO, and 0.41 wt% CoO.

[0066] The method for preparing the power ferrite material includes the following steps:

[0067] (1) According to the blending amounts, the main component raw materials were subjected to the first sand mill mixing for 60 minutes, followed by the first spray granulation and pre-baking at 930°C for 7 hours to obtain pre-baked materials.

[0068] The mass ratio of powder to steel balls to deionized water in the first sand mill mixing was 1:6:1.55, the average particle size after the first sand mill mixing was 1.4 μm, the mass of polyvinyl alcohol used in the first spray granulation was 10 wt% of the pellet material after sand milling, and the mass concentration of the polyvinyl alcohol was 7.5 wt%.

[0069] (2) According to the compounding amounts, the raw materials of the auxiliary components and the pre-sintered material obtained in step (1) were subjected to a second sand mill mixing for 160 minutes, and then a second spray granulation, press molding at 7 MPa, and sintering were carried out sequentially to obtain the power ferrite material.

[0070] The mass ratio of powder to steel balls to deionized water in the second sand mill mixing was 1:6:0.45, the average particle size after the second sand mill mixing was 1.1 μm, the mass of polyvinyl alcohol used in the second spray granulation was 10 wt% of the pellet material after sand milling, the sintering included a first heat treatment and a second heat treatment, the first heat treatment was heating to 1290°C in a nitrogen gas atmosphere and holding the temperature for 7 hours, and the second heat treatment was cooling to 1150°C in a nitrogen gas atmosphere, during the heating process, no oxygen was contained in the temperature rise from 1000°C to the end point, and the oxygen content during the holding process was 5%. During the cooling process, the oxygen content during the temperature drop from 1250°C to 1200°C was 3%, and the oxygen content during the temperature drop from 1200°C to the end point was 0.8%. [Example]

[0071] This example provides a power ferrite material, which is composed of a main component and an auxiliary component, and the main component includes, in mole percentage, 52.8 mol% FeO, 10.5 mol% ZnO, and 36.7 mol% MnO. The auxiliary components include, in percentage of the total mass of the main component, 0.0085 wt% CaCO, 50.025 wt% NbO, and 0.405 wt% CoO.

[0072] The method for preparing the power ferrite material includes the following steps:

[0073] (1) According to the blending amounts, the main component raw materials were subjected to the first sand mill mixing for 58 minutes, followed by the first spray granulation and pre-baking at 940°C for 6 hours to obtain the pre-baked material.

[0074] The mass ratio of powder to steel balls to deionized water in the first sand mill mixing was 1:5.5:1.58, the average particle size after the first sand mill mixing was 1.35 μm, the mass of polyvinyl alcohol used in the first spray granulation was 9 wt% of the pellet material after sand milling, and the mass concentration of the polyvinyl alcohol was 7.2 wt%.

[0075] (2) The raw materials of the auxiliary components and the calcined material obtained in step (1) were subjected to a second sand mill mixing for 155 minutes according to the compounding amounts, and then a second spray granulation, press molding at 7.5 MPa, and sintering were carried out sequentially to obtain the power ferrite material.

[0076] The mass ratio of powder to steel balls to deionized water in the second sand mill mixing was 1:5.5:0.42, the average particle size after the second sand mill mixing was 1.05 μm, the mass of polyvinyl alcohol used in the second spray granulation was 9 wt% of the pellet material after sand milling, the sintering included a first heat treatment and a second heat treatment, the first heat treatment was to heat the mixture to 1295°C in a nitrogen gas atmosphere and hold the temperature for 6.5 hours, and the second heat treatment was to cool the mixture to 1151°C in a nitrogen gas atmosphere, during the heating process, no oxygen was contained in the temperature rise from 1001°C to the end point, and the oxygen content during the heat hold process was 4.5%. During the cooling process, the oxygen content during the temperature drop from 1251°C to 1201°C was 2.9%, and the oxygen content during the temperature drop from 1201°C to the end point was 0.7%. [Example]

[0077] This example provides a power ferrite material, which is composed of a main component and an auxiliary component, and the main component includes, in mole percentage, 52.9 mol% Fe2O3, 11.5 mol% ZnO, and 35.6 mol% MnO, and the auxiliary components include, in percentage of the total mass of the main component, 0.095 wt% CaCO3, 0.035 wt% Nb2O, and 0.415 wt% Co2O3.

[0078] The method for preparing the power ferrite material includes the following steps:

[0079] (1) According to the blending amounts, the main component raw materials were subjected to the first sand mill mixing for 62 minutes, followed by the first spray granulation and pre-baking at 915°C for 8 hours to obtain the pre-baked material.

[0080] The mass ratio of powder to steel balls to deionized water in the first sand mill mixing was 1:6.5:1.6, the average particle size after the first sand mill mixing was 1.45 μm, the mass of polyvinyl alcohol used in the first spray granulation was 11 wt% of the pellet material after sand milling, and the mass concentration of the polyvinyl alcohol was 7.8 wt%.

[0081] (2) The raw materials of the auxiliary components and the calcined material obtained in step (1) were subjected to a second sand mill mixing for 170 minutes according to the compounding amounts, and then a second spray granulation, press molding at 6.5 MPa, and sintering were carried out sequentially to obtain the power ferrite material.

[0082] The mass ratio of powder to steel balls to deionized water in the second sand mill mixing was 1:6.5:0.48, the average particle size after the second sand mill mixing was 1.15 μm, the mass of polyvinyl alcohol used in the second spray granulation was 11 wt% of the pellet material after sand milling, the sintering included a first heat treatment and a second heat treatment, the first heat treatment was to heat the mixture to 1285°C in a nitrogen gas atmosphere and hold the temperature for 7.5 hours, and the second heat treatment was to cool the mixture to 1149°C in a nitrogen gas atmosphere, during the heating process, no oxygen was contained in the temperature rise from 999°C to the end point, and the oxygen content during the heat hold process was 5.5%. During the cooling process, the oxygen content during the temperature drop from 1249°C to 1199°C was 3.2%, and the oxygen content during the temperature drop from 1199°C to the end point was 1%. [Example]

[0083] This example provides a power ferrite material, which is composed of a main component and an auxiliary component, and the main component includes, in mole percentage, 52.7 mol% FeO, 10 mol% ZnO, and 37.3 mol% MnO. The auxiliary components include, in mole percentage based on the total mass of the main component, 0.08 wt% CaCO, 50.02 wt% NbO, and 0.4 wt% CoO.

[0084] The method for preparing the power ferrite material includes the following steps:

[0085] (1) According to the blending amounts, the main component raw materials were subjected to the first sand mill mixing for 55 minutes, followed by the first spray granulation and pre-baking at 950°C for 5 hours to obtain the pre-baked material.

[0086] The mass ratio of powder to steel balls to deionized water in the first sand mill mixing was 1:5:1.5, the average particle size after the first sand mill mixing was 1.3 μm, the mass of polyvinyl alcohol used in the first spray granulation was 8 wt% of the pellet material after sand milling, and the mass concentration of the polyvinyl alcohol was 7 wt%.

[0087] (2) The raw materials of the auxiliary components and the calcined material obtained in step (1) were subjected to a second sand mill mixing for 150 minutes according to the compounding amounts, and then a second spray granulation, press molding at 8 MPa, and sintering were carried out sequentially to obtain the power ferrite material.

[0088] The mass ratio of powder to steel balls to deionized water in the second sand mill mixing was 1:5:0.4, the average particle size after the second sand mill mixing was 1 μm, the mass of polyvinyl alcohol used in the second spray granulation was 8 wt% of the pellet material after sand milling, the sintering included a first heat treatment and a second heat treatment, the first heat treatment was to heat the mixture to 1300°C in a nitrogen gas atmosphere and hold the temperature for 6 hours, and the second heat treatment was to cool the mixture to 1152°C in a nitrogen gas atmosphere, during the heating process, no oxygen was contained in the temperature rise from 1002°C to the end point, and the oxygen content during the heat hold process was 4%. During the cooling process, the oxygen content during the temperature drop from 1252°C to 1202°C was 2.8%, and the oxygen content during the temperature drop from 1202°C to the end point was 0.6%. [Example]

[0089] This example provides a power ferrite material, which is composed of a main component and an auxiliary component, and the main component includes, in mole percentage, Fe2O3 53 mol%, ZnO 12 mol%, and MnO 35 mol%, and the auxiliary components include, in percentage of the total mass of the main component, CaCO3 0.1 wt%, Nb2O 50.04 wt%, and Co2O3 0.42 wt%.

[0090] The method for preparing the power ferrite material includes the following steps:

[0091] (1) According to the blending amounts, the main component raw materials were subjected to the first sand mill mixing for 65 minutes, followed by the first spray granulation and pre-baking at 900°C for 9 hours to obtain pre-baked materials.

[0092] The mass ratio of powder to steel balls to deionized water in the first sand mill mixing was 1:7:1.6, the average particle size after the first sand mill mixing was 1.5 μm, the mass of polyvinyl alcohol used in the first spray granulation was 12 wt% of the pellet material after sand milling, and the mass concentration of the polyvinyl alcohol was 8 wt%.

[0093] (2) The raw materials of the auxiliary components and the calcined material obtained in step (1) were subjected to a second sand mill mixing for 180 minutes according to the compounding amounts, and then a second spray granulation, press molding at 6 MPa, and sintering were carried out sequentially to obtain the power ferrite material.

[0094] The mass ratio of powder to steel balls to deionized water in the second sand mill mixing was 1:7:0.5, the average particle size after the second sand mill mixing was 1.2 μm, the mass of polyvinyl alcohol used in the second spray granulation was 12 wt% of the pellet material after sand milling, the sintering included a first heat treatment and a second heat treatment, the first heat treatment was heating to 1280°C in a nitrogen gas atmosphere and holding the temperature for 8 hours, and the second heat treatment was cooling to 1148°C in a nitrogen gas atmosphere, during the heating process, no oxygen was contained in the temperature rise from 998°C to the end point, and the oxygen content during the holding process was 6%. During the temperature decrease process, the oxygen content during the temperature decrease from 1248°C to 1198°C was 3.3%, and the oxygen content during the temperature decrease from 1198°C to the end point was 1.2%. [Example]

[0095] This example provides a power ferrite material, which is different from Example 1 in that in step (2) of the preparation method of the power ferrite material, the oxygen content during the temperature drop from 1250°C to 1200°C is 2.5%, and the oxygen content during the temperature drop from 1200°C to the end point is 0.5%, but otherwise is the same as Example 1. [Example]

[0096] This example provides a power ferrite material, which is different from Example 1 in that in step (2) of the preparation method of the power ferrite material, the oxygen content during the temperature drop from 1250°C to 1200°C is 3.5%, and the oxygen content during the temperature drop from 1200°C to the end point is 1.5%, but otherwise is the same as Example 1. [Example]

[0097] This example provides a power ferrite material, which is the same as Example 1 except that in step (2) of the preparation method for the power ferrite material, an equilibrium oxygen partial pressure is used during the temperature drop process, and the oxygen partial pressure is 0.5%.

[0098] [Comparative Example 1] This comparative example provided a power ferrite material, which was different from Example 1 in that the molar percentage of Fe2O3 in the main components of the power ferrite material was adjusted to 52.5 mol% and the molar percentage of MnO was adaptively adjusted to 36.5 mol%, but otherwise was the same as Example 1.

[0099] Comparative Example 2 This comparative example provided a power ferrite material, which was different from Example 1 in that the molar percentage of Fe2O3 in the main components of the power ferrite material was adjusted to 53.5 mol% and the molar percentage of MnO was adaptively adjusted to 35.5 mol%, but otherwise was the same as Example 1.

[0100] Comparative Example 3 This comparative example provided a power ferrite material, which was the same as Example 1 except that the molar percentage of ZnO in the main components of the power ferrite material was adjusted to 9 mol% and the molar percentage of MnO was adaptively adjusted to 38.2 mol%.

[0101] Comparative Example 4 This comparative example provided a power ferrite material, which was the same as Example 1 except that the molar percentage of ZnO in the main components of the power ferrite material was adjusted to 13 mol% and the molar percentage of MnO was adaptively adjusted to 34.2 mol%.

[0102] Comparative Example 5 This comparative example provided a power ferrite material, which was the same as Example 1 except that the mass percentage of Co2O3 in the auxiliary components of the power ferrite material was adjusted to 0.38 wt%.

[0103] Comparative Example 6 This comparative example provided a power ferrite material, which was the same as Example 1 except that the mass percentage of Co2O3 in the auxiliary components of the power ferrite material was adjusted to 0.45 wt%.

[0104] Comparative Example 7 This comparative example provided a power ferrite material, which was the same as Example 1 except that it used an equimolar amount of Mn3O4 instead of MnO as the main component of the power ferrite material.

[0105] [Comparative Example 8] This comparative example provided a power ferrite material, which was the same as Example 1 except that it used an equal mass of SiO2 instead of Nb2O5 as an auxiliary component of the power ferrite material.

[0106] A power consumption test was conducted on the power ferrite materials according to Examples 1 to 8 and Comparative Examples 1 to 8, using an IWATSU 8218 AC BH analyzer under the conditions of 100 kHz and 200 mT. The results are shown in Table 1.

[0107] [Table 1]

[0108] From the comparison of Example 1 with Examples 2 to 5 in Table 1, it can be seen that the present invention adjusts the content ratio of the main components and auxiliary components reasonably, and particularly strictly controls the content of Fe2O3 and Co2O3, so that the prepared power ferrite material has the characteristics of wide temperature low loss. In combination with the oxidation process used in the second heat treatment, the oxygen content at the corresponding temperature is strictly controlled, which effectively reduces the high temperature loss and meets the requirements for a high performance power ferrite material.

[0109] A comparison between Examples 1, 6, and 7 revealed that if the oxygen content during the temperature drop in the second heat treatment was too low or too high, the overall loss increased. A comparison between Examples 1 and 8 revealed that if the temperature drop in the second heat treatment was at the equilibrium oxygen partial pressure, it was not favorable for improving the resistivity and the loss increased.

[0110] A comparison of Example 1 with Comparative Examples 1 and 2 revealed that a low Fe2O3 content in the main component was detrimental to achieving wide-temperature and reduced hysteresis loss, while a high Fe2O3 content increased eddy-current loss and was detrimental to reducing high-temperature loss. A comparison of Example 1 with Comparative Examples 3 and 4 revealed that when the ZnO and MnO contents in the main component exceeded the reasonable ranges described herein, the loss of the power ferrite material was significantly reduced. A comparison of Example 1 with Comparative Examples 5 and 6 revealed that a low Co2O3 content increased the power loss of the material, while a high Co2O3 content increased the negative magnetocrystalline anisotropy constant K2 and increased hysteresis loss. A comparison of Example 1 with Comparative Examples 7 and 8 revealed that using Mn3O4 instead of MnO as the main component increased the loss of the ferrite material, while using SiO2 instead of Nb2O5 as the auxiliary component changed the composition of the ferrite material, but the loss still increased.

[0111] In summary, the power ferrite material according to the present invention is prepared by adjusting the content ratio of the main components and auxiliary components in a reasonable manner, and by strictly controlling the content of Fe2O3 and Co2O3 in particular, the prepared power ferrite material has the characteristics of wide temperature range and low loss, and the power consumption at 25°C is 306 kW / m 3 The power consumption at 100°C is as low as 280kW / m 3 The power consumption at 120°C is 297kW / m 3 The power consumption at 140°C is 329kW / m 3 The power consumption at 150°C is 371kW / m 3 and can meet the requirements for power ferrite in automotive electronic products.

[0112] This application employs an oxidation process in the second heat treatment of the sintering process, and strictly controls the oxygen content at the corresponding temperature, thereby effectively increasing the resistivity of the material and reducing high-temperature loss.The preparation method is simple and inexpensive, making it suitable for industrial production.

[0113] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and it should be understood that any modifications or replacements that a person skilled in the art can easily conceive within the technical scope disclosed in the present application are all included in the scope of protection and disclosure of the present application.

Claims

1. A power ferrite material composed of a main component and an auxiliary component, In mole percentage, the major components are: Fe ２ O ３ 52.7~53mol%、 ZnO 10-12 mol%, MnO 35-37.3 mol%, Including, As a percentage of the total mass of the primary component, the secondary component comprises: Cocoa ３ 0.08~0.1wt%、 Nb ２ O ５ 0.02~0.04wt%、 Co ２ O ３ 0.4~0.42wt%、 Including, Power ferrite material.

2. 2. A method for preparing the power ferrite material according to claim 1, comprising: Step (1) of subjecting the raw materials of the main components to first sand mill mixing according to the blending amounts, and then sequentially performing first spray granulation and pre-calcination to obtain a pre-calcined material; and step (2) of subjecting the raw materials of the auxiliary components and the calcined material obtained in step (1) to a second sand mill mixing in accordance with the blending amounts, and then sequentially subjecting the raw materials to a second spray granulation, press molding, and sintering to obtain the power ferrite material. Preparation method.

3. The mass ratio of the powder to the sand mill balls to the grinding aid in the first sand mill mixing described in step (1) is 1: (5-7): (1.5-1.6); The preparation method according to claim 2.

4. The grinding balls include steel balls. The preparation method according to claim 3.

5. The grinding aid comprises deionized water.

5. The preparation method according to claim 3 or 4.

6. The time of the first sand mill mixing described in step (1) is 55 to 65 minutes. The preparation method according to any one of claims 2 to 5.

7. The average particle size after the first sand mill mixing described in step (1) is 1.3 to 1.5 μm; The preparation method according to any one of claims 2 to 6.

8. The mass of the binder used in the first spray granulation described in step (1) is 8 to 12 wt % of the pellet material after sand milling; Preferably, the binder comprises polyvinyl alcohol; Preferably, the mass concentration of the polyvinyl alcohol is 7 to 8 wt %. The preparation method according to any one of claims 2 to 7.

9. The temperature of the calcination described in step (1) is 900 to 950°C, Preferably, the calcination time described in step (1) is 5 to 9 hours. The preparation method according to any one of claims 2 to 8.

10. The mass ratio of the powder to the sand mill balls to the grinding aid in the second sand mill mixing described in step (2) is 1: (5-7): (0.4-0.5); Preferably, the grinding balls comprise steel balls; Preferably, the grinding aid comprises deionized water; Preferably, the time for the second sand mill mixing described in step (2) is 150 to 180 min; Preferably, the average particle size after the second sand mill mixing described in step (2) is 1 to 1.2 μm. The preparation method according to any one of claims 2 to 9.

11. The mass of the binder used in the second spray granulation described in step (2) is 8 to 12 wt % of the pellet material after sand milling, Preferably, the binder comprises polyvinyl alcohol; Preferably, the mass concentration of the polyvinyl alcohol is 7 to 8 wt %, Preferably, the pressure of the press molding described in step (2) is 6 to 8 MPa. The preparation method according to any one of claims 2 to 10.

12. The sintering according to step (2) includes a first heat treatment and a second heat treatment; Preferably, the first heat treatment is performed in a nitrogen gas atmosphere by increasing the temperature to 1280 to 1300°C and maintaining the temperature for 6 to 8 hours; Preferably, the second heat treatment is performed in a nitrogen gas atmosphere, and the temperature is reduced to 1148 to 1152°C. Preferably, in the temperature rising process, oxygen is not contained in the temperature rising from 998 to 1002 ° C to the temperature end point, and the oxygen content in the temperature keeping process is 4 to 6%; Preferably, in the temperature-lowering process, the oxygen content during the temperature-lowering process from 1248-1252°C to 1198-1202°C is 2.8-3.3%, and the oxygen content during the temperature-lowering process from 1198-1202°C to the end point is 0.6-1.2%. The preparation method according to any one of claims 2 to 11.

13. It includes the following steps: Step (1): According to the blending amount, the raw material of the main component is subjected to first sand mill mixing for 55 to 65 minutes, and then subjected to first spray granulation and pre-baking at 900 to 950 ° C. for 5 to 9 hours to obtain a pre-baked material; the mass ratio of the powder to the sand mill balls to the grinding aid in the first sand mill mixing is 1:(5 to 7):(1.5 to 1.6), the average particle size after the first sand mill mixing is 1.3 to 1.5 μm, the mass of the binder used in the first spray granulation is 8 to 12 wt % of the pellet material after sand milling, the binder contains polyvinyl alcohol, and the mass concentration of the polyvinyl alcohol is 7 to 8 wt %, Step (2): The raw materials of the auxiliary components and the calcined material obtained in step (1) are subjected to a second sand mill mixing for 150 to 180 minutes according to the blending amounts, and then a second spray granulation, press molding at 6 to 8 MPa, and sintering are sequentially performed to obtain the power ferrite material; The mass ratio of the powder to the sand mill balls to the grinding aid in the second sand mill mixing is 1: (5 to 7): (0.4 to 0.5), the average particle size after the second sand mill mixing is 1 to 1.2 μm, the mass of the binder used in the second spray granulation is 8 to 12 wt % of the pellet material after sand milling, the sintering includes a first heat treatment and a second heat treatment, and the first heat treatment is performed by heating to 1280 to 1300° C. in a nitrogen gas atmosphere and maintaining the temperature for 6 to 8 hours. the second heat treatment is performed in a nitrogen gas atmosphere, and the temperature is lowered to 1148-1152°C; in the temperature-raising process, oxygen is not contained in the temperature rise from 998-1002°C to the temperature end point, and the oxygen content in the temperature-retaining process is 4-6%; in the temperature-lowering process, the oxygen content in the temperature decrease from 1248-1252°C to 1198-1202°C is 2.8-3.3%, and the oxygen content in the temperature decrease from 1198-1202°C to the temperature end point is 0.6-1.2%; The preparation method according to any one of claims 2 to 12.

14. The power ferrite material is used in the field of automotive electronic products; Use of the power ferrite material according to claim 1.

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