A Fe-based SiC magnetic abrasive and its preparation method

Abstract

The present invention belongs to the technical field of magnetic abrasive machining, and specifically discloses an Fe-based SiC magnetic abrasive and a preparation method thereof; in the present invention, SiC superhard abrasive phases are prepared by in-situ reaction of Si powder and C powder, and the binding ability between the prepared abrasive phases and ferromagnetic phases is enhanced. The Fe-Si alloy layer formed by the reaction between Fe-based and SiC endows the prepared Fe-based SiC magnetic abrasive with both high magnetic permeability and high hardness; the spherical abrasive particles ensure that each part of the workpiece can be evenly stressed during the grinding process, and no deep scratches will appear; the prepared magnetic abrasive has good self-sharpening property and strong grinding force, can solve the problems of low service life and complex processing technology of traditional magnetic abrasives, and can perform precision grinding and polishing on workpieces.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic abrasive machining, and particularly relates to an Fe-based SiC magnetic abrasive and a preparation method thereof. Background Art

[0002] As a flexible machining method, the machining principle of magnetic abrasive machining is that under the action of a magnetic field, magnetic abrasives are linked together along the direction of magnetic force lines to form a "magnetic brush". The machining area of the magnetic brush can cover the entire surface of the workpiece. During the movement of the magnetic abrasives, they collide, scrape, and roll with the machining area of the workpiece. Through this disordered impact, the surface quality of the workpiece is improved. It can be seen from this that an excellent magnetic abrasive is important in the whole magnetic abrasive machining process. Magnetic abrasives can basically be divided into two parts, a magnetic conduction phase and a hard abrasive phase. For the magnetic conduction phase, ferromagnetic materials with low cost and excellent magnetic conduction performance are usually selected, while the hard abrasive phase needs to meet the requirements of high hardness, good self-sharpening ability, high thermal stability, and chemical stability.

[0003] At present, the traditional preparation methods of magnetic abrasives can be divided into mechanical mixing method, composite material method (sintering method, bonding method, composite plating method), casting method (external particle composite method, in-situ reaction composite method), etc. The mechanical mixing method has simple preparation process and low cost. However, during grinding, the abrasive particles are easy to separate and scatter from the magnetic powder, and the grinding efficiency is not high, which limits its application. The sintering method has complex process and high cost, and the abrasive particles are irregular and the bonding strength is low. The abrasive prepared by the bonding method has loose structure, poor thermal stability, and the abrasive phase is easy to fall off. The composite plating method has high cost, cannot realize mass production, and improper treatment of the plating solution is easy to cause environmental pollution. Although the casting method has high requirements for raw material selection, it is a relatively good preparation method for magnetic abrasives after process improvement and is expected to realize mass production. Therefore, the existing magnetic abrasive machining technologies have problems such as low grinding efficiency, high abrasive cost, complex machining process, and low grinding service life. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide an Fe-based SiC magnetic abrasive and a preparation method thereof, so as to solve the problems of low grinding service life and complex machining process of traditional magnetic abrasives.

[0005] In order to achieve the above purpose, the present invention is implemented by adopting the following technical solutions:

[0006] In the first aspect, the present invention provides a preparation method of an Fe-based SiC magnetic abrasive, including:

[0007] After uniformly mixing C powder, Si powder and spherical Fe-based powder, perform mechanical ball milling to in-situ synthesize the abrasive phase SiC, and SiC is uniformly distributed on the surface of the Fe-based to obtain the abrasive;

[0008] After mechanical ball milling, the abrasive is heat-treated, and the surface of the spherical Fe-based powder is slightly melted. The Fe-based powder reacts with SiC to form an Fe-Si alloy layer, obtaining Fe-based SiC magnetic abrasive; the spherical Fe-based powder serves as the ferromagnetic phase.

[0009] Furthermore, the volume ratio of the C powder, Si powder, and spherical Fe-based powder is 1:1:3.

[0010] Furthermore, ball milling is carried out using a ball milling tank, and the ball milling tank is evacuated, with the vacuum degree less than 10 -3 ; the ball milling speed is 300 r / min, and the ball milling time is 4 h - 8 h.

[0011] Furthermore, the ball-to-material ratio of the ball milling is 12:1.

[0012] Furthermore, the particle size of the C powder is 10 μm - 20 μm.

[0013] Furthermore, the particle size of the Si powder is 10 μm - 20 μm.

[0014] Furthermore, the particle size of the spherical Fe-based powder is 100 μm - 300 μm.

[0015] Furthermore, the uniform mixing time of the C powder, Si powder, and spherical Fe-based powder is 60 min.

[0016] Furthermore, during the heat treatment, the heating rate is 2 °C / min - 5 °C / min, the heat treatment temperature is 1000 °C - 1400 °C, the heat treatment time is 2 h - 6 h, and the cooling rate is 3 °C / min.

[0017] In a second aspect, the present invention provides an Fe-based SiC magnetic abrasive, which is prepared according to the preparation method of an Fe-based SiC magnetic abrasive described in any one of the above.

[0018] The present invention has at least the following beneficial effects:

[0019] 1. In the present invention, the SiC superhard grinding phase is prepared by the in-situ reaction of Si powder and C powder. The binding ability between the prepared grinding phase and the ferromagnetic phase is enhanced. The Fe-Si alloy layer formed by the reaction between Fe-based and SiC endows the prepared Fe-based SiC magnetic abrasive with both high magnetic permeability and high hardness; the spherical abrasive particles ensure that each part of the workpiece can be uniformly stressed during the grinding process, and no deep scratches will appear; the prepared magnetic abrasive has good self-sharpening property and strong grinding force, which can solve the problems of low service life and complex processing technology of traditional magnetic abrasives, and can perform precision grinding and polishing on workpieces.

[0020] 2. In the present invention, the Fe-based surface hard grinding phase is evenly distributed radially, which can ensure the original high magnetic permeability of the ferromagnetic phase matrix and increase the grinding pressure; the height of the SiC abrasive grains on the Fe-based surface is also basically the same, which can ensure excellent processing effects during grinding and maximize the sphericity and uniformity of the morphological characteristics of the abrasive grains. Therefore, the method for preparing a magnetic abrasive with in-situ generated SiC superhard grinding phase on the surface of Fe-based powder has certain advantages in meeting the requirements for preparing high-performance magnetic abrasives. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0022] Figure 1 is a schematic flow chart of the method for preparing in-situ synthesized Fe-based SiC magnetic abrasive;

[0023] Figure 2 is an SEM image of Fe-based SiC magnetic abrasive prepared by the traditional sintering method;

[0024] Figure 3 is an SEM image of in-situ synthesized Fe-based SiC magnetic abrasive;

[0025] Figure 4 is a three-dimensional morphology diagram of a titanium tube after grinding with Fe-based SiC magnetic abrasive prepared by the traditional sintering method;

[0026] Figure 5 is a three-dimensional morphology diagram of a titanium tube after grinding with in-situ synthesized Fe-based SiC magnetic abrasive. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments. It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0028] The following detailed descriptions are all exemplary descriptions, aiming to provide further detailed descriptions of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments of the present invention.

[0029] A method for preparing an Fe-based SiC magnetic abrasive includes:

[0030] On the surface of Fe-based spherical powder particles, SiC hard nano-particles are in-situ generated from C powder and Si powder under certain conditions as the grinding phase of magnetic abrasive. An Fe-Si alloy layer will be formed between Fe-based and SiC due to the reaction between Fe and Si, realizing the effective combination of ferromagnetic phase and grinding phase. The alloy layer has good magnetic conductivity, and SiC has high hardness. The prepared abrasive has good soft magnetic effect, good self-sharpening property, and strong grinding force, and can perform precision grinding and polishing on workpieces.

[0031] SiC super-hard grinding phase is prepared by in-situ reaction of Si powder and C powder under certain conditions. The SiC grinding phase has strong bonding ability with the ferromagnetic phase. The Fe-Si alloy layer formed between Fe-based and SiC endows the prepared magnetic abrasive with both high magnetic conductivity and high hardness. The spherical abrasive particles ensure that each part of the workpiece can be evenly stressed during grinding, and no deep scratches will appear.

[0032] Such as Figure 1 As shown, it is the preparation process of Fe-based - SiC magnetic abrasive. First, on the surface of Fe-based, by using the method of mechanical ball milling - in-situ synthesis, after adding C powder and Si powder, the hard grinding phase SiC is generated. SiC is evenly distributed on the surface of Fe-based. At the same time, there is an Fe-Si alloy layer between Fe-based and SiC. The ferromagnetic phase, the grinding phase and their edge connection parts are effectively combined together to form a composite abrasive with high magnetic conductivity and high hardness. The particle sizes of the ferromagnetic phase and the grinding phase are relatively small, and the grinding processing effect is good, which is suitable for precision machining of the surface of complex workpieces.

[0033] The specific steps are as follows:

[0034] S1: After C powder, Si powder and spherical Fe-based powder are uniformly mechanically mixed at a volume ratio of 1:1:3, they are added into a ball milling tank for mechanical ball milling to in-situ synthesize the hard grinding phase SiC. SiC is evenly distributed on the surface of Fe-based to obtain the abrasive;

[0035] The ball milling balls are 316 stainless steel balls with a diameter of 2mm, and the ball-to-powder ratio is 12:1. After evacuating the ball milling tank to a vacuum state (vacuum degree less than 10 -3 ), the ball milling speed is 300r / min, and the ball milling time is 4h - 8h.

[0036] The particle size of C powder is 10μm - 20μm, the particle size of Si powder is 10μm - 20μm, the particle size of spherical Fe-based powder is 100μm - 300μm, and the mechanical mixing time is 60min.

[0037] S2: After mechanical ball milling, the abrasive is heat-treated. The surface of the spherical Fe-based powder is slightly melted, and Fe-based reacts with SiC to form an Fe-Si alloy layer to obtain Fe-based SiC magnetic abrasive; the spherical Fe-based powder serves as the ferromagnetic phase, improving the bonding ability between the grinding phase and the ferromagnetic phase surface.

[0038] The heating rate during heat treatment is 2°C / min - 5°C / min, the heat treatment temperature is 1000°C - 1400°C, the heat treatment time is 2h - 6h, and the cooling rate is 3°C / min.

[0039] Example 1

[0040] S1: After uniformly mixing C powder, Si powder and spherical Fe-based powder in a volume ratio of 1:1:3 by mechanical means, add them to a ball mill tank for mechanical ball milling to in-situ synthesize the hard grinding phase SiC. SiC is uniformly distributed on the surface of the Fe-based powder to obtain abrasives;

[0041] The ball milling balls are 316 stainless steel balls with a diameter of 2 mm, and the ball-to-material ratio is 12:1. After evacuating the ball mill tank to a vacuum state (vacuum degree less than 10 -3 ), the ball milling speed is 300 r / min, and the ball milling time is 4 h.

[0042] The particle size of C powder is 10 μm, the particle size of Si powder is 10 μm, the particle size of spherical Fe-based powder is 100 μm, and the mechanical mixing time is 60 min.

[0043] S2: After mechanical ball milling, heat treat the abrasives. The surface of the spherical Fe-based powder is slightly melted, and Fe-based reacts with SiC to form an Fe-Si alloy layer to obtain Fe-based SiC magnetic abrasives; the spherical Fe-based powder serves as the ferromagnetic phase, improving the bonding ability between the grinding phase and the surface of the ferromagnetic phase.

[0044] The heating rate during heat treatment is 2°C / min, the heat treatment temperature is 1000°C, the heat treatment time is 2 h, and the cooling rate is 3°C / min.

[0045] Example 2

[0046] S1: After uniformly mixing C powder, Si powder and spherical Fe-based powder in a volume ratio of 1:1:3 by mechanical means, add them to a ball mill tank for mechanical ball milling to in-situ synthesize the hard grinding phase SiC. SiC is uniformly distributed on the surface of the Fe-based powder to obtain abrasives;

[0047] The ball milling balls are 316 stainless steel balls with a diameter of 2 mm, and the ball-to-material ratio is 12:1. After evacuating the ball mill tank to a vacuum state (vacuum degree less than 10 -3 ), the ball milling speed is 300 r / min, and the ball milling time is 5 h.

[0048] The particle size of C powder is 15 μm, the particle size of Si powder is 15 μm, the particle size of spherical Fe-based powder is 150 μm, and the mechanical mixing time is 60 min.

[0049] S2: After mechanical ball milling, heat treatment is performed on the abrasive. The surface of the spherical Fe-based powder is slightly melted, and the Fe-based powder reacts with SiC to form an Fe-Si alloy layer, obtaining Fe-based SiC magnetic abrasive; the spherical Fe-based powder serves as the ferromagnetic phase, improving the bonding ability between the grinding phase and the surface of the ferromagnetic phase.

[0050] The heating rate during heat treatment is 3 °C / min, the heat treatment temperature is 1100 °C, the heat treatment time is 3 h, and the cooling rate is 3 °C / min.

[0051] Example 3

[0052] S1: After C powder, Si powder and spherical Fe-based powder are uniformly mechanically mixed at a volume ratio of 1:1:3, they are added to a ball milling tank for mechanical ball milling to in-situ synthesize the hard grinding phase SiC. SiC is uniformly distributed on the surface of the Fe-based powder, obtaining the abrasive.

[0053] The ball milling balls are 316 stainless steel balls with a diameter of 2 mm, and the ball-to-material ratio is 12:1. After evacuating the ball milling tank to a vacuum state (vacuum degree less than 10 -3 ), the ball milling speed is 300 r / min, and the ball milling time is 6 h.

[0054] The particle size of the C powder is 20 μm, the particle size of the Si powder is 20 μm, the particle size of the spherical Fe-based powder is 200 μm, and the mechanical mixing time is 60 min.

[0055] S2: After mechanical ball milling, heat treatment is performed on the abrasive. The surface of the spherical Fe-based powder is slightly melted, and the Fe-based powder reacts with SiC to form an Fe-Si alloy layer, obtaining Fe-based SiC magnetic abrasive; the spherical Fe-based powder serves as the ferromagnetic phase, improving the bonding ability between the grinding phase and the surface of the ferromagnetic phase.

[0056] The heating rate during heat treatment is 4 °C / min, the heat treatment temperature is 1200 °C, the heat treatment time is 4 h, and the cooling rate is 3 °C / min.

[0057] Example 4

[0058] S1: After C powder, Si powder and spherical Fe-based powder are uniformly mechanically mixed at a volume ratio of 1:1:3, they are added to a ball milling tank for mechanical ball milling to in-situ synthesize the hard grinding phase SiC. SiC is uniformly distributed on the surface of the Fe-based powder, obtaining the abrasive.

[0059] The ball milling balls are 316 stainless steel balls with a diameter of 2 mm, and the ball-to-material ratio is 12:1. After evacuating the ball milling tank to a vacuum state (vacuum degree less than 10 -3 ), the ball milling speed is 300 r / min, and the ball milling time is 7 h.

[0060] The particle size of the C powder is 17 μm, the particle size of the Si powder is 13 μm, the particle size of the spherical Fe-based powder is 250 μm, and the mechanical mixing time is 60 min.

[0061] S2: After mechanical ball milling, the abrasive is heat-treated. The surface of the spherical Fe-based powder is slightly melted, and the Fe-based powder reacts with SiC to form an Fe-Si alloy layer, obtaining an Fe-based SiC magnetic abrasive; the spherical Fe-based powder serves as the ferromagnetic phase, improving the bonding ability between the grinding phase and the surface of the ferromagnetic phase.

[0062] The heating rate during heat treatment is 3 °C / min, the heat treatment temperature is 1300 °C, the heat treatment time is 5 h, and the cooling rate is 3 °C / min.

[0063] Example 5

[0064] S1: After the C powder, Si powder, and spherical Fe-based powder are uniformly mechanically mixed at a volume ratio of 1:1:3, they are added to a ball milling tank for mechanical ball milling to in-situ synthesize the hard grinding phase SiC. The SiC is uniformly distributed on the surface of the Fe-based powder, obtaining the abrasive.

[0065] The ball milling balls are 316 stainless steel balls with a diameter of 2 mm, and the ball-to-material ratio is 12:1. After the ball milling tank is evacuated to a vacuum state (vacuum degree less than 10 -3 ), the ball milling speed is 300 r / min, and the ball milling time is -8 h.

[0066] The particle size of the C powder is 13 μm, the particle size of the Si powder is 17 μm, the particle size of the spherical Fe-based powder is 300 μm, and the mechanical mixing time is 60 min.

[0067] S2: After mechanical ball milling, the abrasive is heat-treated. The surface of the spherical Fe-based powder is slightly melted, and the Fe-based powder reacts with SiC to form an Fe-Si alloy layer, obtaining an Fe-based SiC magnetic abrasive; the spherical Fe-based powder serves as the ferromagnetic phase, improving the bonding ability between the grinding phase and the surface of the ferromagnetic phase.

[0068] The heating rate during heat treatment is 5 °C / min, the heat treatment temperature is 1310 °C, the heat treatment time is 6 h, and the cooling rate is 3 °C / min.

[0069] Application Example

[0070] The Fe-based SiC magnetic abrasive prepared by the sintering method and the Fe-based SiC magnetic abrasive in-situ synthesized in the present invention are respectively used to process titanium tubes; after processing with the Fe-based SiC magnetic abrasive prepared by the sintering method, the surface roughness Ra of the titanium tube is 0.653 μm, as Figure 4 shown; after processing with the in-situ synthesized Fe-based SiC magnetic abrasive prepared in the present invention, the surface roughness Ra of the titanium tube is 0.324 μm, as Figure 5 shown.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that modifications or equivalent replacements can still be made to the specific embodiments of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A preparation method of Fe-based SiC magnetic abrasive, characterized in that, it includes: After uniformly mixing C powder, Si powder and spherical Fe-based powder, mechanical ball milling is carried out to in-situ synthesize the grinding phase SiC. SiC is uniformly distributed on the surface of the Fe-based to obtain the abrasive; the spherical Fe-based powder serves as the ferromagnetic phase; After mechanical ball milling, the abrasive is heat-treated. The surface of the spherical Fe-based powder is slightly melted, and the Fe-based reacts with SiC to form an Fe-Si alloy layer, obtaining the Fe-based SiC magnetic abrasive; The particle size of the C powder is 10μm - 20μm; The particle size of the Si powder is 10μm - 20μm; The particle size of the spherical Fe-based powder is 100μm - 300μm; The heat treatment temperature is 1000℃ - 1310℃.

2. The preparation method of an Fe-based SiC magnetic abrasive according to claim 1, characterized in that, The volume ratio of the C powder, Si powder and spherical Fe-based powder is 1:1:

3.

3. The preparation method of an Fe-based SiC magnetic abrasive according to claim 1, characterized in that, During ball milling, a ball milling jar is used for ball milling. The ball milling jar is evacuated, and the vacuum degree is less than 10 -3 ; the ball milling speed is 300 r / min, and the ball milling time is 4 h - 8 h.

4. The preparation method of an Fe-based SiC magnetic abrasive according to claim 3, characterized in that, The ball-to-material ratio of the ball milling is 12:

1.

5. The preparation method of an Fe-based SiC magnetic abrasive according to claim 1, characterized in that, The uniform mixing time of the C powder, Si powder and spherical Fe-based powder is 60min.

6. The preparation method of an Fe-based SiC magnetic abrasive according to claim 1, characterized in that, The heating rate during the heat treatment is 2℃ / min - 5℃ / min, the heat treatment time is 2h - 6h, and the cooling rate is 3℃ / min.

7. An Fe-based SiC magnetic abrasive, characterized in that, The Fe-based SiC magnetic abrasive is prepared according to the preparation method of an Fe-based SiC magnetic abrasive described in any one of claims 1 - 6.

Images