JP3088124B2 - Manufacturing method of composite abrasive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

METHOD for FIELD THE INVENTION The present invention production of a composite abrasive grain, in particular using an acid, a composite abrasive manufacturing how for magnetic abrasive.

[0002]

2. Description of the Related Art Recently, a new polishing method called a magnetic polishing method has been developed and attracts attention. This method is used for deburring parts, polishing cylindrical parts, flat parts, inner surfaces of parts, complicated shapes such as spherical surfaces, grinding of free-form surfaces of molds, edge finishing of various shapes, and hard and brittle parts such as ceramics and silicon wafers. It can be widely applied to precision finishing of materials. The magnetic abrasive grains in this case are so-called composite abrasive grains having both a magnetism and a polishing effect, and are required to have both ferromagnetism and high grindability.

[0003] Conventionally, such composite abrasive grains are produced by a method in which iron and fine powder of a high-grinding abrasive are press-formed and then sintered in an atmosphere furnace or hot-pressed and sintered. Using a method of internally nitriding, a method of generating a carbon material from a molten metal alloy and carbon, and an exothermic reaction of carbon and titanium,
How to make a composite compound of titanium carbide and iron (ABLyashe
henko et al., Poroshkovaya Metallurgiya, 9, 44-48
(1983)), a method of mixing iron and alumina and heating them under an inert gas atmosphere (Japanese Patent Application Laid-Open No. 61-250084).
), A method of forming a composite abrasive by melting a mixture of iron and an abrasive by plasma heating (Masahiro Anzai et al., Journal of the Japan Society for Abrasive Processing, 33 (4), 34 (1989)), and iron by electroless plating. And a method of attaching a diamond have been proposed.

However, expensive atmosphere furnaces, crushers,
Despite the need for a plasma generator and expensive chemicals, it has low productivity, low grinding power and low processing efficiency, and has disadvantages that are not economical.

[0005]

The performance required of magnetic abrasive grains is that they can be mass-produced at low cost in terms of grinding power, surface finish, durability of abrasive grains, and wide applicability. . None of the abrasives obtained by the conventional method sufficiently satisfies all of these points. An object of the present invention is to obtain excellent magnetic polishing abrasive particles satisfying all the above points.

[0006]

Means for Solving the Problems As a result of diligent research to achieve the above object, powder particles of a magnetic metal such as iron and abrasive particles are allowed to act with various acids in an aqueous solution so that the surface of the magnetic metal can be treated. The present inventors have found that abrasive particles are firmly fixed, and have reached the present invention.

[0007] Thus, the present invention is to stir and mix magnetic metal particles and abrasive particles in an aqueous solution of a mineral acid or an organic carboxylic acid, and then dry or calcine them to fix the abrasive particles on the surfaces of the magnetic metal particles. This is a method for producing composite abrasive grains.

[0008] In the present invention, the magnetic metal used is, for example, iron, cobalt, nickel or an alloy containing them, and the particle diameter is 0.5 to 5000.
μm, preferably about 20 to 600 μm.

When the particle diameter is smaller than 0.5 μm, the magnetism is weakened and the grinding force is reduced.
If it is larger, the magnetism becomes stronger and the surface finish becomes worse. It is also used in needles, in which case the size is 5 to 2000 μm in diameter,
The thickness is suitably 30 to 200 μm, the length is 1 to 20 mm, and preferably about 3 to 6 mm.

When the diameter is smaller than 5 μm, the needle-like body is difficult to entangle and grind. On the other hand, when the diameter is larger than 2000 μm, the whole surface area becomes extremely small and the grinding force is reduced, which is not preferable.

Examples of the abrasive include oxides of metals such as chromium oxide, cerium oxide and zirconium oxide; nitrides of metals such as silicon nitride, niobium nitride and tungsten nitride;
Metal carbides such as silicon carbide, niobium carbide, titanium carbide and chromium carbide, diamond and the like can be used as appropriate.

The size of such abrasive particles is 0.01 to
200 μm, preferably about 0.1 to 20 μm is appropriate. When the size is smaller than 0.01 μm, the grinding force is reduced. On the other hand, when the size is larger than 200 μm, the surface finish is deteriorated due to the roughness of the particle size.

The amount of the abrasive particles fixed to the magnetic metal particles is suitably 0.01 to 50% by weight, preferably about 0.1 to 30% by weight, based on the total amount of the composite abrasive grains. . If the amount of the abrasive particles is less than 0.01% by weight, the grinding power will be extremely reduced, and conversely 50% by weight.
If the amount is larger, the abrasive particles have poor adhesion and tend to be detached.

Means for fixing the abrasive particles to the magnetic metal particles include, for example, magnetic metal particles, abrasive particles, mineral acid,
And an aqueous solution of an organic carboxylic acid in a ball mill internally coated with stainless steel or polyamide resin or the like for 5 to 5 minutes.
Means for fixing by rotating at a rotational speed of about 100 rpm for about 0.5 to 25 hours, or at a rotational speed of about 5 to 100 rpm in a stainless steel, FRP, or glass lined tank with a stirrer. Means such as fixing by rotating about 5 to 25 hours may be appropriately employed.

As the mineral acid used in the present invention, for example, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid and the like are suitable.
As the acid, For example acetic acid, formic acid, citric acid, oxalic acid,
Such as tartaric acid is suitable. Of these, the use of a mineral acid is preferred because it has a particularly strong fixing power and is persistent. The concentration of the aqueous solution of the mineral acid or the organic carboxylic acid used is 0.
001 to 2N, preferably 0.1 to 0.3N is suitable.

When the concentration of the aqueous solution of a mineral acid or an organic carboxylic acid is less than 0.001N, the abrasive particles are not completely fixed to the surface of the magnetic metal particles. Since the reaction is too vigorous and the abrasive particles are not sufficiently fixed, none of them is preferable. The above aqueous solution used when fixing abrasive particles to magnetic metal particles
The temperature of the solution is suitably from 0 to 100 ° C, preferably from 20 to 40 ° C.

[0017] If the temperature is lower than 0 ℃ it is sticking abrasive particles reactive the acid is reduced is incomplete, 1 conversely
If 00 higher than ℃, for example, water solution containing the acid or bumping, because the fixation of the abrasive particles be incomplete, both undesirable. Thus the abrasive particles secured to the magnetic metal is separated from the acid, is dried or calcined to further firmly fixed.

The temperature required for drying or firing is 80 to 10
It is appropriate to employ 00C, preferably 110-500C. When the temperature is lower than 80 ° C., the adhered abrasive particles are easily released. When the temperature is higher than 1000 ° C., the oxidation of the magnetic metal surface is promoted and the abrasive particles are easily released. Not preferred.

In the present invention, the fixing mechanism of the abrasive particles in the composite abrasive particles or the composite abrasive needles produced by the above-mentioned acid treatment is not always clear, but it is inferred from the result of the powder X-ray diffraction data that The surface of the magnetic metal is ionized, and for example, when the γ-FeOOH phase is generated on the surface, the abrasive particles are fixed by this, and by drying or firing, it is thought that the two are united and strongly adhered. .

The composite abrasive obtained in the present invention has high grinding power, surface finish, and durability. Thus among conventional hot press molding method, an alloy nitriding method, melting carbide method, iron - alumina heating method, a plasma heating method, compared to an electroless plating method, or the like, the composite abrasive particles obtained by the production how the present invention Is extremely excellent for magnetic polishing.

[0021]

EXAMPLES Example 1 90 g of iron powder (particle size: 70 to 80 μm; hereinafter, the values in parentheses represent the particle size unless otherwise specified) and 10 g of chromium oxide (1 to 2 μm). Disperse in 40 cc of 3N nitric acid, and mix the mixture with a ball mill (with gas plate holes, internal volume 2).
(00 cc, made of polyamide resin). After the abrasive particles were fixed, the mixture was filtered under reduced pressure and washed with water. The obtained cake was dried at 110 ° C.
100 g of composite abrasive particles containing 0% by weight were obtained. The grinding power of the obtained abrasive grains was about twice as high as that of a commonly used abrasive, and the durability was about twice as high as that of a normal product.

Example 2 70 g of iron powder (10 to 20 μm) and chromium oxide (1 to 2 μm)
m) Disperse 30 g in 70 cc of 0.2 N nitric acid, and prepare 30% chromium oxide containing 30% by weight in the same manner as in Example 1 below.
0 g of composite abrasive particles were obtained. The grinding power of the obtained abrasive grains was about twice as high as that of a commonly used abrasive, and the durability was about twice as high as that of a normal product.

Example 3 90 g of iron powder (70 to 80 μm) and diamond (2 to 4)
μm) is dispersed in 40 cc of 0.3 N nitric acid, and the same as in Example 1 except that
00 g of composite abrasive particles were obtained. The grinding power of the obtained abrasive grains was about three times that of a commonly used abrasive grain, and the durability was about twice that of a normal product.

Example 4 97 g of iron powder (800 to 2000 μm) and 3 g of diamond (2 to 4 μm) were dispersed in 30 cc of 0.3 N nitric acid, and 100 g containing 3% by weight of diamond was prepared in the same manner as in Example 1. Was obtained. The grinding power of the obtained abrasive grains is about 3 times that of the usual one.
As for the durability and the durability, the performance was about twice that of the normal product.

Example 5 95 g of iron powder (200 to 300 μm) and diamond (8
１６16 μm) 5 g was dispersed in 40 cc of 0.3 N nitric acid,
Thereafter, in the same manner as in Example 1, 100 g of composite abrasive grains containing 5% by weight of diamond were obtained. The grinding power of the obtained abrasive grains was about three times that of a commonly used abrasive grain, and the durability was about twice that of a normal product.

Example 6 80 g of iron powder (70 to 80 μm) and alumina (WA # 40)
00 (manufactured by Fujimi Incorporated), 3μ
m) 20 g were dispersed in 40 cc of 0.3N nitric acid, and 100 g of composite abrasive particles containing 20% by weight of alumina were obtained in the same manner as in Example 1 below. The grinding power of the obtained abrasive grains was about twice as high as that of a commonly used abrasive, and the durability was about twice as high as that of a normal product.

Example 7 94 g of iron powder (200 to 300 μm) and alumina (WA #)
1200 (manufactured by Fujimi Incorporated), 1
6 g of 2 μm) was dispersed in 40 cc of 0.3N hydrochloric acid, and 100 g of composite abrasive particles containing 6% by weight of alumina were obtained in the same manner as in Example 1 below. The grinding power of the obtained abrasive grains was about twice as high as that of a commonly used abrasive, and the durability was about twice as high as that of a normal product.

Example 8 85 g of iron powder (70-80 μm) and cerium oxide (Luminox EH (manufactured by Seimi Chemical Co., Ltd.), 1-2 μm)
15 g was dispersed in 40 cc of 0.3 N nitric acid, and 100 g of composite abrasive particles containing 15% by weight of cerium oxide were obtained in the same manner as in Example 1 below. The grinding power of the obtained abrasive grains was about twice as high as that of a commonly used abrasive, and the durability was about twice as high as that of a normal product.

Example 9 90 g of iron powder (70 to 80 μm) and silicon nitride (2 to 3 μm)
m) 10 g was dispersed in 40 cc of 0.3 N sulfuric acid, and 100 g of composite abrasive particles containing 10% by weight of silicon nitride were obtained in the same manner as in Example 1 below. The grinding power of the obtained abrasive grains was about twice as high as that of a commonly used abrasive, and the durability was about twice as high as that of a normal product.

Example 10 90 g of iron powder (70 to 80 μm) and 10 g of zirconium oxide (0.5 to 1 μm) were dispersed in 40 cc of 0.3 N acetic acid. Thus, 100 g of composite abrasive particles containing zirconium oxide were obtained.
The grinding power of the obtained abrasive grains is about twice as large as that of ordinary products, and the durability is about 2 times that of ordinary products.
Showed twice the capacity.

Example 11 96 g of an iron needle (90 μm in diameter, 3 mm in length) and 4 g of diamond (1-2 μm) were dispersed in 40 cc of 0.3 N nitric acid. 100 g of composite abrasive grains containing diamond were obtained. The grinding power of the obtained abrasive grains is about 2 times that of ordinary ones.
As for the durability and the durability, the performance was about twice that of the normal product.

Example 12 95 g of an iron needle (50 μm in diameter, 3 mm in length) and 5 g of alumina (WA # 4000 (same as above), 3 μm) were dispersed in 40 cc of 0.3 N nitric acid. As a result, 100 g of composite abrasive particles containing 5% by weight of alumina were obtained. The grinding power of the obtained abrasive grains was about twice as high as that of a commonly used abrasive, and the durability was about twice as high as that of a normal product.

Comparative Example 1 70 g of iron powder (70 to 80 μm) and alumina (WA # 40)
00 (same as above), 3 μm) were mixed well, and the mixed powder was hot-pressed at 900 ° C. under 4000 kg / cm ² pressure to obtain a total of 90 g of 5 pellets having a diameter of 20 mm and a thickness of 10 mm. The pellets were pulverized with a jaw crusher and a roller mill to obtain 75 g of composite abrasive particles having a particle size of 80 to 150 μm.

Comparative Example 2 70 g of iron powder (70 to 80 μm) and niobium carbide (3 μm)
30 g were mixed well, and the mixed powder was used in the same manner as in Comparative Example 1 to obtain 75 g of composite abrasive particles having a particle size of 80 to 150 μm.

The composite abrasive particles obtained in Examples 1 to 12 and Comparative Examples 1 and 2 were examined for grinding power, surface finish, and durability. Table 1 shows the measurement results. For comparison, tests were also conducted on commercially available electrodeposited diamond composite abrasive grains (Comparative Example 3), which are said to have high strength, and simple iron needles (diameter 90 μm, length 3 mm) (Comparative Example 4).

[0036]

[Table 1]

The grinding power and surface finish of the composite abrasive of the present invention,
The test conditions for examining durability are as follows:
A cylindrical silicon nitride ceramic rod having a length of 6 mm and a length of 10 mm (surface roughness Rmax 1.5 μm), a magnetic polishing machine using a TMX101 type machine manufactured by Toyo Abrasives Co., Ltd., a rotation peripheral speed of 60 m / s, and excitation. Current 2A (flux density 1.2
Polishing was performed with Tesla for 10 minutes. The grinding force is the amount of polishing (mg) of the work material, and the surface finish is the surface roughness Rmax (μ
m) was measured. Regarding the durability, under the above conditions, 6
The test was performed at intervals of 0 minutes for a total of 9 hours, and the amount of abrasive particles such as diamond and alumina remaining on the surface was quantified by X-ray diffraction, and expressed as a residual adhesion rate (%) of the abrasive particles after the test. .

[0038]

The abrasive grains according to the present invention have approximately twice the grinding power and durability as compared with conventional ones, and are efficient and excellent in durability.

Claims (4)

(57) [Claims] 1. The method of claim 1, wherein the magnetic metal particles and the abrasive particles are mixed with a mineral acid or
A method for producing composite abrasive grains , comprising stirring and mixing in an aqueous solution of an organic carboxylic acid , followed by drying or baking to fix abrasive particles to the surfaces of magnetic metal particles. 2. The method for producing composite abrasive grains according to claim 1, wherein the amount of the abrasive particles fixed is 0.01 to 50% by weight based on the total amount of the composite abrasive grains. 3. The method for producing composite abrasive grains according to claim 1, wherein the concentration of the aqueous solution of the mineral acid or the organic carboxylic acid is 0.001 to 2N. 4. The method according to claim 1, wherein the mineral acid or organic carboxylic acid is nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, formic acid, citric acid, oxalic acid,
4. The method for producing composite abrasive grains according to claim 1, 2 or 3, which is tartaric acid.