Soft magnetic composite with glass xerogel serving as coating layer and method for preparing soft magnetic composite

Abstract

The invention relates to a soft magnetic material and a method for preparing the same, in particular to a soft magnetic composite with glass xerogel serving as a coating layer and a method for preparing the soft magnetic composite. The soft magnetic composite with glass xerogel serving as the coating layer and the method for preparing the soft magnetic composite solve the problems that coefficients of thermal expansion of an inorganic insulating layer and magnetic powder are large in difference and the intrinsic coefficient of thermal expansion of the inorganic insulating layer is unchangeable. The soft magnetic composite with glass xerogel serving as the coating layer is composed of the magnetic powder, a silicon dioxide layer coating the magnetic powder and a glass xerogel layer coating the silicon dioxide layer. The preparation method includes: firstly, preprocessing the magnetic powder; secondly, coating the silicon dioxide layer on the surface of the magnetic powder; thirdly, preparing the glass xerogel; fourthly, coating the glass xerogel layer outside the silicon dioxide layer; fifthly, preparing blanks of the soft magnetic material; and sixthly, preparing the soft magnetic material. The soft magnetic composite with glass xerogel serving as the coating layer and the method for preparing the soft magnetic composite are applicable to the field of switch magnetic resistors, resonance inductors, anti-lock brake sensors, electromagnetic driving devices, brushless direct-current motors, rotary machinery and low-frequency filters.

Description

technical field [0001] The invention relates to a preparation method of a soft magnetic material. Background technique [0002] Soft magnetic composite material refers to a type of soft magnetic material in which magnetic powders are independent of each other and connected by insulating layer materials. The outstanding advantages of this soft magnetic composite material are low iron loss and three-dimensional isotropic properties under AC magnetic field. Therefore, many components that are difficult to realize with conventional soft magnetic materials can be prepared, and have been used in switched reluctance, resonant inductors, anti-lock brake sensors, electromagnetic drives, brushless DC motors, rotating machinery, low-frequency filters and other fields. The preparation process of soft magnetic composite materials is usually to coat the surface of metal or alloy magnetic powder with an insulating layer of inorganic and organic matter, or to form a composite soft magnetic...

AI Technical Summary

Problems solved by technology

For the existing organic-coated soft magnetic composite materials, a pressure greater than 800 MPa needs to be applied during its preparation to achieve the required compaction density, but at the same time it must satisfy good saturation magnetic induction and magnetic permeability. rate, it is necessary to anneal the soft magnetic composite material containing the organic coating layer to remove the residual stress of the material, because the organic coating layer is usually not resistant to high temperature, so it is difficult to effectively remove the residual stress

For the soft magnetic composite material of the existing inorganic cladding layer, the insulation of the cladding layer cannot meet the requirements, and the existing cladding layer containing P or S is serious to the environmental pollution, so the use of SiO 2 , MgO, SiO 2 Mixture with water, Al 2 o 3 mixed with water, ZrO 2 The inorganic insulating layer prepared by mixing with water, mica powder and water is used as the inorganic coating layer, and the inorganic insulating layer is generally stable at high temperature, which overcomes the disadvantage that the organic coating layer is usually not resistant to high temperature

However, the existing inorganic insulating layer also has disadvantages. The thermal expansion coefficient of the inorganic insulating layer and the magnetic powder differ greatly, and the thermal expansion coefficient of the inorganic insulating layer itself cannot be changed. In an environment with a large temperature difference or during long-term use, the magnetic powder will Thermal stress is generated inside, which leads to the failure of the soft magnetic composite material coated with inorganic materials to have excellent magnetic properties.

These problems restrict the development and application of soft magnetic composite materials.

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