JPH10113877A - Super abrasive grain grindstone and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve grinding performance and mechanical strength by constituting a grindstone of a sintered body with super abrasive grains consisting of diamond or cBN an average grain diameter of which is within a specific range and binding material particles and making these binding material particles of metal particles on surfaces of which oxide films are formed and of more than a specific melting point. SOLUTION: An average grain diameter of a super abrasive grain grindstone 10 is within a range of 0.5μm-60μm. It is constituted of a sintered body of super abrasive grains 1 of diamond or cBN and binding material particles 2. These binding material particles are made of particles 4 of metal of of a melting point of more than 2000 deg.C on surfaces of which oxide films 3 are formed, for example, of W. The average grain diameter of these super abrasive grains 1 is made within the range of 0.5μm-60μm. Consequently, sharpness of the super abrasive grains 1 is not spoiled by high temperature sintering, a dressing property is favourable, blinding is hardly caused, natural tooth cutting work is provided, grinding resistance is small, and grinding performance is favourable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superabrasive grindstone used in the field of precision machining, and more particularly to a superabrasive grindstone having high grinding performance and excellent physical strength, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, structural ceramics such as Si ₃ N ₄ , alumina, zirconia, and Al ₂ O ₃ .TiC ceramics, which are difficult to grind, have been frequently used. Reduction of the processing cost occupying the weight has become a major issue.

Conventionally, for the precision processing of these difficult-to-grind materials, a grindstone using so-called “super-abrasive grains” having high hardness such as diamond or cubic boron nitride (hereinafter referred to as “cBN”) as abrasive grains. Used, the material of the workpiece,
Based on various requirements such as dimensions, shapes, margins, machining efficiency, machining accuracy, and machining quality, the machining method and grinding machine are determined, and at the same time the shape, dimensions, and specifications of the most effective grinding stone are determined.

[0004] A grindstone containing superabrasive grains is called a "superabrasive grindstone" and is generally constructed by holding superabrasive grains with a binder, and depending on the type of the binder, for example, a synthetic resin is used as the binder. It is classified into several types, such as resin-bonded grinding wheels, vitrified bonded grinding wheels using glass, and metal-bonded grinding wheels using metal. Conventionally, the above-mentioned metal-bonded grindstone has been used as a thin blade grindstone used for precision cutting of ceramics or the like, which are difficult to grind materials, from the viewpoint of mechanical strength of the grindstone.

[0005] This metal-bonded grindstone is made of a soft metal such as bronze or nickel or a cast iron (Japanese Patent Laid-Open No. 3-2).
64263) and a sintering method or an electroforming method. The resulting metal bond grindstone has a high mechanical strength of the grindstone itself because the structure of the binder is dense, and also has a high holding force of the abrasive grains by the binder particularly required for grinding difficult-to-grind materials, Less deformation of the grinding wheel during grinding,
It has advantages such as good finishing accuracy.

[0006]

However, in the above-mentioned metal bond whetstone, the phenomenon that a new cutting edge of abrasive grains constantly appears on the grinding surface of the whetstone because the bonding material structure is dense and hard to be worn out,
The so-called "self-generated blade action" is small, clogging is liable to occur, and grinding efficiency is high, so that high-efficiency machining becomes difficult, and the dressing (sharpening) property is poor.

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and an object of the present invention is to provide a material which is excellent in both grinding efficiency and mechanical strength and can be suitably used for precision machining of difficult-to-grind materials. It is an object of the present invention to provide a super-abrasive grindstone and a method of manufacturing the same.

[0008]

As a means for solving the above-mentioned problems, the present invention provides a method for firing super-abrasive grains of diamond or cBN having an average particle diameter in the range of 0.5 μm to 60 μm and binder particles. Consisting of binders, the binder particles
Provided is a superabrasive grindstone made of metal particles having a melting point of 2000 ° C. or more and having an oxide film formed on the surface. The metals are W, Os, Ta, Ir, Mo, and Ru.
It is preferable that at least one selected from the group consisting of

[0009] The present invention also relates to the present invention.
A super-abrasive made of diamond or cBN within a range of 0 μm, and a melting point of 200 having an oxide film formed on the surface.
Mixing with binder particles composed of metal particles at 0 ° C. or higher,
Provided is a method for producing a superabrasive grindstone including a step of sintering the obtained powder mixture. The sintering is preferably performed using a spark plasma sintering method or a hot isostatic press sintering method. The sintering is preferably performed in an atmosphere having an inert gas or oxygen partial pressure of 0.01 MPa or less. In addition, the sintering is performed at 0.5 Tm (Tm is the melting point or liquid phase generation temperature of the binder expressed by absolute temperature ゜ K).
It is preferable to perform the sintering at the following sintering temperature for 30 minutes or less.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to an embodiment. As schematically shown in FIG. 1, a superabrasive grindstone 10 of this embodiment is made of a sintered body of superabrasive grains 1 of diamond or cBN and binder particles 2. The binder particles 2 are made of a metal having a melting point of 2000 ° C. or higher, for example, W particles 4 having an oxide film 3 formed on the surface. The average particle size of the superabrasive particles 1 is 0.5 μm to 60 μm.
It is in the range of μm.

The superabrasive grindstone 10 can be manufactured, for example, by the following method. That is, a binder composed of superabrasive grains 1 made of diamond or cBN having an average particle size in the range of 0.5 μm to 60 μm, and metal particles 4 having a melting point of 2000 ° C. or more and having an oxide film 3 formed on the surface. The particles 2 are mixed with each other, and the obtained powder mixture is subjected to, for example, spark plasma sintering (hereinafter, referred to as “SPS”) or hot isostatic pressing (hereinafter, referred to as “HI”).
P method).

Since the obtained superabrasive grindstone 10 uses fine diamond particles or cBN particles having an average particle diameter of 0.5 μm to 60 μm as abrasive grains, it grinds difficult-to-grind materials such as ceramics precisely. be able to.

As the binder, hard and brittle metal particles having a high melting point of 2000 ° C. or more, such as W, are used.
Since the refractory metal particles have a strong bonding force with the superabrasive grains 1 when sintered, and the sintered structure formed by fusion of the binder particles has a moderate collapse property. When this super-abrasive grindstone is used for grinding, the physical strength of the grindstone itself is high, the abrasive grains are strongly retained, and the dressing (sharpening) property is good. In addition, the grinding resistance is small and efficient grinding can be performed.

However, at the time of manufacturing a superabrasive grindstone, at least 0.6 T is required in order to strongly fuse the superabrasive grain 1 with the high melting point metal particles or between the high melting point metal particles.
m or more. This temperature is
For example, when W (melting point 3655 ° K) is used as the binder, the temperature is about 1900 ° C or more. However, it was found that at this sintering temperature, the superabrasive grains 1 themselves deteriorated due to the high temperature, and the grinding force was reduced, so that the target grinding performance could not be sufficiently exhibited.

Therefore, the present inventors have conducted intensive research and have found that
When the oxide film 3 is formed on the surface of the refractory metal particles 4,
The melting point of the oxide film 3 is much lower than the melting point of the metal itself, such as tungsten trioxide WO ₃ , which is an oxide of W, at 1400 ° C., for example. 0.5 Tm or less, for example, 150
It has been found that by heating at about 0 ° C., the superabrasive grains 1 and the binder particles 2, and the binder particles 2 are fused to each other on their surfaces to form a strong sintered structure, and have reached the present invention. .

In the sintered structure, the oxide film 3
Are formed only on the surface of the binder particles 2, the particles fuse with each other only in the coating layer on this surface, and the hard and brittle properties of the binder metal particles 4 themselves are not lost. Therefore, the superabrasive grindstone 10 of the present invention has good dressing properties, is hardly clogged, has a spontaneous blade action, has a small grinding resistance, and does not impair the sharpness of the superabrasive grains 1 due to high-temperature sintering. It becomes an efficient precision grinding wheel.

Next, various elements constituting the superabrasive grinding wheel of the present invention will be described in detail. The superabrasive used in the superabrasive grindstone of the present invention is diamond or cBN. For example, in the case of finely processing a hard object to be ground such as a ceramic material, it is preferable to use diamond having the highest hardness. This diamond may be a single crystal or a polycrystal, and any of natural diamond and artificial diamond can be used.

However, when processing an iron-based workpiece, there is a problem in using diamond. In this case, it is preferable to use cBN. This cBN may be either single-crystal or polycrystalline. The superabrasive grains used in the present invention may be a mixture of any two or more of the above.

The average grain size of the superabrasive grains is 0.5 μm to 60 μm.
m. If the average particle size is less than 0.5 μm, the particles are too fine and the grinding ability is not sufficiently exhibited,
If the whetstone is exceeded, for example, when this grindstone is used for fine grinding or lapping, the finish of the surface to be ground becomes rough, which is inappropriate. From this viewpoint, the average particle size of the superabrasive particles is 0.5
It is preferable to set it in the range of μm to 10 μm.

The metal used as the binder has a melting point of 2
000 ° C. or higher, an oxide film can be formed on the particle surface, and any oxide film can be used as long as it can be melted at a temperature that does not deteriorate superabrasive grains.
Preferred metals are those selected from the group consisting of W, Os, Ta, Ir, Mo, and Ru. Table 1 shows the hardness (Hv), melting point (° C.), oxide composition, and oxide melting point (° C.) of the above preferable metals. Among them, a particularly preferable metal is W having the highest melting point.

[0021]

[Table 1]

The particle size of the binder particles is not particularly limited, but is preferably in the range of 5% to 50% of the average particle size of the superabrasive particles. If the particle size of the binder particles with respect to the superabrasive particles exceeds 50%, the contact area between the superabrasive particles and the binder particles in the state where the mixture is filled in the mold during sintering becomes small, Insufficient bonding force reduces the strength of the grindstone itself. If it is less than 5%, the contact area is sufficiently large so that there is no problem in the bonding force at the time of sintering.

The superabrasive grindstone of the present invention is formed by surface sintering of powder, and as shown in FIG. 1, its structure contains many pores 5 and is porous. . The porosity is preferably in the range of 5% to 60%. When the porosity is less than 5%, the structure of the binder becomes dense and hard to wear, so that the spontaneous cutting action does not easily occur, and also a pocket (6 in FIG. 1) for accommodating chips generated during grinding. 2) capacity is insufficient, and the circulation of the cooling liquid is also insufficient, so that clogging and melting due to frictional heat are likely to occur. If the porosity exceeds 60%, the physical properties of the grindstone itself are reduced, and dropout or crushing is likely to occur. From these viewpoints, the porosity is more preferably in the range of 5% to 45%. The porosity is determined by the particle size of the superabrasive grains and the binder particles, the mixing ratio, the pressure applied during sintering,
It can be adjusted by selecting various conditions such as the presence or absence of volatile inclusions during mixing.

In producing the superabrasive grindstone of the present invention, high melting point metal particles having an oxide film 3 formed on the surface are prepared in advance. In order to form an oxide film on the surface of the refractory metal particles, the refractory metal particles are left in the air to be naturally oxidized, forcibly oxidized by heating in an oxygen atmosphere, or formed into a refractory metal particle. There are methods such as applying the oxide, and any of these methods may be used.

Next, the superabrasive grains and the binder particles are uniformly mixed. The mixing ratio of the superabrasives and the binder is preferably in the range of 1: 0.5 to 1: 3 in terms of the volume ratio of the superabrasives: the binder. If the ratio of the binder is less than 1: 0.5, the density of the superabrasive grains is too high, the strength of the sintered body is reduced, and the grindstone becomes brittle. When the ratio of the binder is larger than 1: 3, the grinding ability is reduced.

When mixing the superabrasive with the binder, a volatile liquid such as ethanol is added, and the mixture is dispersed in a liquid using a ball mill or the like. It is preferred to obtain a powder mixture of the particles and the binder particles. According to this method, agglomeration of the superabrasive grains is prevented, and not only a powder mixture in which the superabrasive grains are uniformly dispersed in the binder is obtained, but also the dulling of the cutting blade due to powder friction during mixing and heat generation. Deterioration is prevented.

The sintering is preferably performed by using the SPS method or the HIP method. These are all powder sintering methods, and according to these sintering methods, diffusion, reaction, solid solution, etc., at the interface between the superabrasive grains and the binder particles are promoted, and the superabrasive grains and the binder particles are formed. Is strengthened.

The SPS method can be performed using, for example, a discharge plasma sintering apparatus (SPS apparatus) schematically shown in FIG. In FIG. 2, this SPS device is a cylindrical die 2.
1, a core 22 inserted coaxially with the die 21,
An upper punch 23 and a lower punch 24 fitted to the die 21 and the core 22, and upper and lower punches 2
And a thermocouple 26 for measuring the temperature of the powder mixture 25 sandwiched between 3 and 24. The upper punch 23 and the lower punch 24 are connected to a press (not shown) for pressing the powder mixture 25 filled in the gap between the die 21 and the core 22 from above and below. 25
Each electrode for applying a pulse current to the electrodes is constituted. In this SPS device, at least a portion sandwiched between upper and lower punches 23 and 24 is a chamber (not shown).
And the inside of this chamber is evacuated to a vacuum or
Alternatively, an inert gas is introduced.

A predetermined amount of the powder mixture 25 of the superabrasive grains and the binder is filled in the gap between the die 21 and the core 22 formed in a predetermined grinding stone shape, and the inside of the chamber is evacuated, or After the replacement with the inert gas, the upper and lower punches 23 and 24 compress the pressure from above and below at a predetermined pressure, and then apply a pulse current.

According to this SPS method, the powder mixture 25 can be uniformly and quickly heated to a predetermined sintering temperature by adjusting the current, and the temperature control and the sintering time control are strictly controlled. It can be carried out. Examples of the SPS device that can be used in the above-described SPS method include a model SPS-2050 type discharge plasma sintering device manufactured by Sumitomo Coal Mining Co., Ltd.

On the other hand, in the HIP method, for example, a wax or the like is added as a molding aid to a mixture of superabrasive grains and binder particles,
Using a uniaxial press or the like, pressurize to a pressure of about 10 MPa to produce a powder compression molded product, and heat the powder compression molded product to about 800 ° C. in a vacuum to remove wax and perform preliminary sintering. After shaping, the main body is sintered by applying heat and pressure in a vacuum or an inert gas atmosphere to obtain a sintered body.

In any sintering method, sintering is preferably performed in an atmosphere having an inert gas or an oxygen partial pressure of 0.01 MPa or less. When sintering is performed by applying heat pressure in an atmosphere in which the oxygen partial pressure exceeds 0.01 MPa, the superabrasive grains are altered or the oxide film on the surface of the binder is increased, so that the binder is a high melting point metal. May lose the benefits of As the inert gas, N ₂ or Ar is preferably used.

At the time of sintering, the sintering temperature is preferably 0.5 Tm or less. Here, Tm is the absolute temperature ゜ K
Is the melting point of the binder metal or the liquid phase formation temperature. By setting the sintering temperature to 0.5 Tm or less, as described above, the binder particles are fused together only by the oxide film, and while maintaining the strength of the grindstone itself, it has a moderate collapse property and is spontaneously generated. A blade effect is exhibited, and good grinding properties are maintained.

The lower limit of the sintering temperature depends on the properties of the binder used and the sintering pressure, but is set at a temperature at which at least the particles can be surface-fused with each other to form a fusion phase. This lower limit temperature is usually 600 ° C. or higher. From this viewpoint, a practically preferable sintering temperature range is 600 ° C. to 1500 ° C.
It is in the range of ° C.

In sintering, the time for maintaining the above sintering temperature is preferably within 30 minutes. If the temperature at which a liquid phase is generated is maintained for more than 30 minutes, the amount of superabrasive grains is significantly reduced. From this viewpoint, the SPS method in which the sintering temperature and the sintering time can be strictly controlled is a method suitable for producing the superabrasive of the present invention.

(Example 1) Super abrasive grains having an average grain size of 25 µm
m of diamond, W having a particle size of 1 μm to 2 μm having an oxide film formed on the surface was used as a binder, and mixing was performed with a volume ratio of superabrasive: binder of 25:32. The oxide film on the surface of the W particles is obtained by heating the W particles at 800 ° C. in air.
After heating for an hour, it was formed by natural cooling. At this time, the thickness of the oxide film was 0.05 μm to 0.5 μm.

Ethanol is added to the above mixture to form a slurry, which is then charged in a ball mill, and dispersed by a liquid dispersion method. After completion, the ethanol is removed under reduced pressure, so that the superabrasive grains are uniform in the binder. To obtain a powder mixture dispersed.

The obtained powder mixture was subjected to SPS shown in FIG.
Sintered using the equipment. The die 21 is made of graphite, has an inner diameter of 92 mm, and the core 22 has an outer diameter of 40 mm.
Met. The gap between the die 21 and the core 22 was filled with 14.7 g of the powder mixture, and the atmosphere of the die was changed to O _2.
Replace with a gas having a partial pressure of 0.01 MPa or less,
3 and the lower punch 24 to drive the powder mixture 25
A pressure was applied to 0 MPa and a pulse current was applied between both punches, and the punch was heated to 1260 ° C. for 5 minutes.

The obtained superabrasive grindstone of the embodiment has an outer diameter of 92.
mm, an inner diameter of 40 mm, and a thickness of 0.429 mm were used as a thin blade grindstone. The weight was 14.6444 g, and the porosity was 42.2% by volume.

Comparative Example 1 The same super abrasive grains as in Example 1 were used, Co having a particle size of 5 μm was used as the binder, and the volume ratio of super abrasive grains to the binder was 25:32. And dried under reduced pressure to obtain a powder mixture.

The obtained powder mixture was sintered in the same manner as in Example 1 except that the sintering temperature was set to 780 ° C. using the same die and SPS apparatus as in Example 1, and the grindstone of Comparative Example 1 was used. Obtained. It has a thickness of 0.327 mm and a weight of 7.76.
18 g, porosity was 23.6% by volume.

A grinding test was performed using the superabrasive grindstones of Example 1 and Comparative Example 1. As a grinding test, a wet constant-pressure grinding method that was not affected by the Young's modulus of the grinding wheel, the rigidity of the grinding machine, and the horsepower was adopted. As the object to be ground, Al ₂ O ₃ .T
iC ceramics (a bending strength of 588 MPa and a micro Vickers hardness of 19 GPa) was used.

For further comparison, as Comparative Example 2, a commercially available electroformed metal-bonded superabrasive having a similar shape was used. FIG. 3 shows the relationship between the grinding pressure (MPa) measured for the superabrasive grindstones of Example 1, Comparative Examples 1 and 2, and the amount of grinding (mm ³ ) when grinding for 30 seconds at each grinding pressure. .

As a result of the test, the electroformed metal bond of Comparative Example 2
The super-abrasive grindstone has a grinding pressure of about 0.9MPa
As a result, grinding became impossible. The grinding amount at this pressure limit is about 2
mm ^ThreeMet. Super abrasive whetstone of Co binder of Comparative Example 1
Was destroyed at a grinding pressure of about 1.25 MPa. This pressure limit
Approximately 4.5mm grinding time^ThreeMet.

On the other hand, the superabrasive grindstone of Example 1
The grinding performance was still normal at a grinding pressure of about 2 MPa, and the grinding amount was about 6 mm ^{3 at} a grinding pressure of about 2 MPa. From these results, the superabrasive grindstone of Example 1 was excellent in physical properties despite being higher in porosity than that of Comparative Example 1, and was not destroyed even when the grinding pressure was increased, and was substantially proportional to the grinding pressure. It can be seen that the amount of grinding has increased.

(Example 2) In accordance with the method of Example 1, diamond having a particle diameter shown in Table 2 was used as superabrasive particles, and a particle having an oxide film formed on the surface as a binder was 1 μm to 2 μm.
μm W and a diameter of 30 according to the manufacturing conditions shown in Table 2.
A grindstone sample having a thickness of 0.5 mm and a thickness of 0.5 mm was prepared. The porosity, Young's modulus, and Vickers hardness of this product were measured.
Table 2 shows the results.

(Comparative Example 2) According to the method of Example 2, a diamond having a particle diameter shown in Table 2 was used as superabrasive grains, and Co having a particle diameter shown in Table 2 was used as a binder. A grindstone sample having the same shape as in Example 2 was prepared according to the manufacturing conditions. The porosity, Young's modulus, and Vickers hardness of this product are shown in Table 2 together with Example 2.

[0048]

[Table 2]

From a comparison between Example 2 and Comparative Example 2, the superabrasive grindstone of the present invention has a higher porosity than a conventional superabrasive grindstone using Co as a binder, and furthermore has a high physical property. It can be seen that is also excellent.

Example 3 According to the method of Example 1, diamond having a particle diameter shown in Table 3 was used as superabrasive particles, and a particle having an oxide film formed on the surface as a binder was 1 μm to 2 μm.
μm W and an outer diameter of 92 mm according to the manufacturing conditions shown in Table 3.
mm, an inner diameter of 40 mm, and a 0.4 mm-thick thin blade grindstone sample were prepared. The porosity, Young's modulus, and Vickers hardness of this product were measured. Table 3 shows the results.

(Comparative Example 3) According to the method of Example 2, a diamond having a particle diameter shown in Table 3 was used as superabrasive particles, and Co having a particle diameter shown in Table 3 was used as a binder. A grindstone sample having the same shape as that of Example 3 was prepared according to the manufacturing conditions. The porosity, Young's modulus, and Vickers hardness of this product are shown in Table 3 together with Example 3.

[0052]

[Table 3]

From the comparison between Example 3 and Comparative Example 3, the superabrasive grindstone of the present invention has a higher porosity than the conventional superabrasive grindstone using Co as a binder, and furthermore has a high physical property. It can be seen that is also excellent.

In the superabrasive grinding wheel of the present invention, it is important that an oxide film is formed on the surface of the binder particles. W having a particle size of 1 μm to 2 μm was used as binder particles, and the oxide film was formed and the oxide film was not formed. The amount of oxygen contained in the sample and that which could not be sintered was measured by Auger analysis.
4 (a) and 4 (b) show the measurement results of those which could be sintered, and FIGS. 5 (a) and 5 (b) show the measurement results of those which could not be sintered. Here, FIG. 4 (a) shows that the carbon content is 38.9, respectively.
FIG. 4 (b) shows a carbon content of 7.9 at%, FIG.
(A) shows the case where the carbon content is 32 at%, and FIG. 5 (b) shows the case where the carbon content is 3.2 at%.

That is, regardless of the carbon content in the sample, the oxygen content was as high as 3.2 at% to 6.7 at%.
The samples of (a) and (b) were sinterable at 1260 ° C., whereas the oxygen content was 1.3 at% to 1.9 at.
5 (a) and 5 (b) could not be sintered at the same temperature. It is clear that the oxygen formed an oxide film on the surface of the binder particles, thereby lowering the sintering temperature of the binder particles and enabling sintering.

The superabrasive grindstone of the present invention can be advantageously used for grinding and cutting superhard materials such as ceramics in the form of a cup grindstone or a thin blade grindstone. FIG. 6A shows a state in which a carbide grinding material S such as Al ₂ O ₃ .TiC ceramics is ground using the cup grinding wheel 30 of the present invention. FIG. 6B shows a state in which a material to be ground S such as Al ₂ O ₃ .TiC ceramics is cut using the thin blade whetstone 31 of the present invention.

The superabrasive grindstone of the present invention is particularly suitable for Al ₂ O ₃ .T
It can be advantageously used, for example, when manufacturing a head chip of a magnetic head from an iC ceramics substrate. An example of a method for manufacturing this head chip will be described with reference to FIGS. 7 (a), 7 (b) and 7 (c). As shown in FIG. 7A, first, Al ₂ O ₃ .Ti
A magnetic head element 44 including a core 41, a coil 42, and a connection pad 43 is formed on a C ceramics substrate 40 by a thin film method. Next, a wafer-shaped Al ₂ O ₃ .TiC ceramics substrate 40 in which a number of the magnetic head elements 44 are formed in parallel is combined with the magnetic head elements 44 in parallel.
Is cut using the diamond thin blade grinding wheel of the present invention along the lines 45 on both sides of. As a result, FIG.
As shown in (1), a rod-shaped body 47 having a cross section 46 serving as a slide rail (46) of the magnetic head is obtained. Next, a groove that becomes a slide surface 48 in the vertical direction is ground on the cross section 46 using the diamond cup grindstone of the present invention. Thus, the slide rail 46 is formed. Next, when the rod-shaped body 47 is vertically cut for each magnetic head element 44 using the diamond thin blade grindstone of the present invention, as shown in FIG. 7C, the magnetic head element 44, the slide rail 46, and the slide surface 48 are formed. Can be manufactured.

In manufacturing the above-mentioned head chip 50, since the thin blade grindstone and the cup grindstone of the present invention are used, the finished surface of grinding and cutting is extremely smooth.
In addition, since the durability of the grindstone is high, the number of times of sharpening is reduced, and a high-quality head chip can be manufactured with high production efficiency.

[0059]

The superabrasive grindstone of the present invention comprises a sintered body of superabrasive grains and binder particles, and the binder particles are formed of a metal having a melting point of 2,000 ° C. or more and having an oxide film formed on the surface. , It can be sintered at a relatively low temperature, and the bonding force between the superabrasive grains and the binder particles is strong, and the strength of the grindstone itself is high. In addition, the sintered structure has a suitable level of disintegration, has good dressing properties while strongly retaining abrasive grains, has a self-generating blade action that is unlikely to be clogged, has a small grinding resistance, and can be used to precisely grind difficult-to-grind materials. And efficient grinding.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an embodiment of a superabrasive grindstone of the present invention.

FIG. 2 is a sectional view showing an example of a spark plasma sintering apparatus.

FIG. 3 is a graph showing a relationship between a grinding pressure and a grinding amount in Examples and Comparative Examples.

FIGS. 4A and 4B are Auger analysis graphs for measuring the oxygen content in a sintered composition, respectively.

FIGS. 5A and 5B are Auger analysis graphs for measuring the oxygen content in a sintered composition, respectively.

FIGS. 6 (a) and 6 (b) are perspective views respectively showing examples of different use forms of the superabrasive grindstone of the present invention.

FIGS. 7A, 7B, and 7C are perspective views showing steps of manufacturing a head chip of a magnetic head as one application example of the superabrasive grindstone of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Super abrasive grain 2 ... Binder material 3 ... Oxide film 4 ... Metal particle 5 ... Pore 6 ... Pocket 10 ... Super abrasive grain grindstone 21 ... Die 22 ... Core 23 ... Top punch 24 ... Lower punch 25: powder mixture 26: thermocouple

Claims (6)

[Claims] 1. A sintered body of superabrasive grains made of diamond or cubic boron nitride having an average particle diameter in a range of 0.5 μm to 60 μm and binder particles, and the binder particles have a surface A superabrasive grindstone comprising a metal particle having a melting point of 2,000 ° C. or more and having an oxide film formed thereon. 2. The method according to claim 1, wherein the metal is W, Os, Ta, Ir,
The superabrasive stone according to claim 1, wherein the superabrasive stone is at least one selected from the group consisting of Mo and Ru. 3. A superabrasive made of diamond or cubic boron nitride having an average particle size in the range of 0.5 μm to 60 μm, and a melting point of 2000 having an oxide film formed on the surface.
A method for producing a superabrasive grindstone, comprising mixing a binder material composed of metal particles having a temperature of at least 0 ° C. and sintering the obtained powder mixture. 4. The method according to claim 3, wherein the sintering is performed using a spark plasma sintering method or a hot isostatic press sintering method. 5. The method according to claim 3, wherein the sintering is performed in an atmosphere having an inert gas or oxygen partial pressure of 0.01 MPa or less. 6. The sintering is carried out at a sintering temperature of 0.5 Tm or less (Tm is a melting point or a liquid phase generation temperature of a binder represented by an absolute temperature ΔK) or less for a period of 30 minutes or less. The method for producing a superabrasive grindstone according to claim 3, wherein: