Vitrified tool and method for manufacturing the same

Abstract

To provide a vitrified tool which employs diamond as abrasive grains, realizes high surface roughness of a material polished therewith, and hardly causes scratches.SOLUTION: The vitrified tool comprises a substrate 15, and a bond layer 5 disposed on the substrate 15 and comprising a vitreous material retaining innumerable abrasive grains 1. Each abrasive grain 1 is of diamond. The bond layer 5 contains 10.6 mol% or more of bismuth oxide.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vitrified tool and a method for manufacturing the same.

Background Art

[0002] A vitrified tool includes a base material and a bond layer made of glassy material holding innumerable abrasive grains. There are cases where the bond layer holding innumerable abrasive grains is manufactured as a chip and the chip is fixed on the base material, and cases where the bond layer holding innumerable abrasive grains is directly fixed on the base material. The bond layer may or may not contain pores. In this vitrified tool, a technique of impregnating resin into pores in the bond layer is disclosed in Patent Document 1 in order to improve the abrasive grain holding force.

[0003] For example, this vitrified tool is embodied as a grinding tool and used in grinding. The vitrified tool has a characteristic that it is easy to adjust the surface density and size of abrasive grains on the polishing surface during manufacturing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the vitrified tool is used for machining difficult-to-machine workpiece materials such as semiconductor wafers, cemented carbide, and ceramics, when diamond with the highest hardness is adopted, the surface roughness of the machined workpiece material is low and scratches are likely to occur. This is because the wettability between diamond and glassy material is low and the holding state between diamond and the bond layer is likely to be different, so diamond is likely to be scattered and the grinding state is likely to vary.

[0006] The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide a vitrified tool that uses diamond as an abrasive grain, has a high surface roughness of the mating material after polishing, and is less likely to generate scratches.

Means for Solving the Problems

[0007] The vitrified tool of the present invention includes a base material and a tip provided on the base material. The tip includes innumerable abrasive grains and a bond layer made of a glassy material that holds each of the abrasive grains. Each of the abrasive grains is diamond. The bond layer contains 10.6 mol% or more of bismuth oxide, SiO 2 4.8 to 25.4 mol% , Al 2 O 3 0.8 to 4.4 mol% , B 2 O 3 21.0 to 31.1 mol% 0.1 to 0.2 mol% of an alkali oxide and 27.0 to 34.4 mol% of an alkaline earth oxide, and is characterized by this.

[0008] According to the inventor's tests, in the vitrified tool of the present invention, although each abrasive grain is diamond, the glassy bond layer contains 10.6 mol% or more of bismuth oxide (Bi 2 O 3 ), and the glassy material contains SiO 2 4.8 to 25.4 mol% , Al 2 O 3 0.8 to 4.4 mol% , B 2 O 3 21.0 to 31.1 mol% 0.1 to 0.2 mol% of an alkali oxide and 27.0 to 34.4 mol% of an alkaline earth oxide. As a result, the bond layer exhibits high wettability with respect to diamond. For this reason, it is difficult for the holding state between the diamond and the bond layer to be different, and since the diamond is likely to be present evenly, variations in the grinding state are less likely to occur.

[0009] The manufacturing method of the vitrified tool of the present invention contains 10.6 mol% or more of bismuth oxide, SiO 2 4.8 to 25.4 mol% , Al 2 O 3 0.8 to 4.4 mol% , B 2 O 3 21.0 to 31.1 mol% , 0.1 to 0.2 mol% of alkali oxide and 27.0 to 34.4 mol% of alkaline earth oxide, and a first step of preparing a mixture containing a composition that forms a glassy substance and innumerable abrasive grains made of diamond; A second step of obtaining a molded body of the mixture; A third step of forming a bond layer in which each abrasive grain is held by the glassy substance made of the composition by firing the molded body in an oxidizing atmosphere, and providing a chip including each abrasive grain and the bond layer on a base material to obtain a vitrified tool. It is characterized by having.

[0010] According to the manufacturing method of the present invention, the vitrified tool of the present invention can be manufactured.

Effects of the Invention

[0011] According to the vitrified tool of the present invention, while adopting diamond as the abrasive grain, the surface roughness of the mating material after polishing is high and scratches are hardly generated.

Brief Description of the Drawings

[0012]

Figure 1

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Figure 10

[0013] As the base material, in addition to a rigid base material, a base material having flexibility such that the bond layer holding innumerable abrasive grains is not deformed can be adopted. As the rigid base material, ceramics such as alumina, silicon nitride, silicon carbide, zirconia, mullite, metals such as iron, SUS, copper, glass having a strain point of 600 °C or higher, etc. can be adopted. As the flexible base material, a sheet made of a woven or non-woven fabric composed of fibers such as natural fiber, synthetic fiber, carbon fiber, or a single-layer or multi-layer film made of a synthetic resin such as polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyimide (PI), polyethylene naphthalate (PEN), aramid, or a metal such as aluminum or copper can be adopted.

[0014] As the bond layer made of glassy material, the composition containing frit such as borosilicate glass can be minimized. The composition can be a slurry or a powder. A mixture containing the composition and innumerable abrasive grains made of diamond can also be a slurry or a powder. By forming the mixture into a molded body, drying the molded body as necessary, and melting and solidifying the composition, the composition constitutes the glassy material.

[0015] The mixing ratio (by volume) of the glassy material and diamond in the bond layer is preferably 80:20 to 10:90, and more preferably 60:40 to 25:75. In order to adjust the porosity of the bond layer, a pore-forming material or the like may be added to the mixture.

[0016] The abrasive grains used in the vitrified tool of the present invention are diamond. The particle size of the diamond is variously set according to the use of the vitrified tool and the like.

[0017] According to the test results of the inventors, if the bond layer contains 10.6 mol% or more of bismuth oxide, the effects of the present invention can be obtained, but it is more preferable that the bond layer contains 28.6 mol% or more of bismuth oxide. In terms of mass%, if the bond layer contains 40.6 mass% or more of bismuth oxide, the effects of the present invention can be obtained, but it is more preferable that the bond layer contains 71.1 mass% or more of bismuth oxide. In this case, the bond layer has high wettability with diamond.

[0018] The bond layer may contain, in addition to bismuth oxide, SiO 2 , Al 2 O 3 , B 2 O 3 , alkali oxides and alkaline earth oxides. SiO 2 is preferably 4.8 mol% or more and 25.4 mol% or less. In terms of mass%, SiO 2 is preferably 1.4 mass% or more and 12.6 mass% or less. Al 2 O 3 is preferably 0.8 mol% or more and 4.4 mol% or less. In terms of mass%, Al 2 O 3 is preferably 0.4 mass% or more and 3.7 mass% or less. B 2 O 3 is preferably 21.0 mol% or more and 31.1 mol% or less. In terms of mass%, B 2 O 3It is preferably 7.8% by mass or more and less than 14.4% by mass. The alkali oxide is preferably 0.1 mol% or more and 0.2 mol% or less. In terms of mass%, the alkali oxide is preferably 0.1% by mass or less. The alkaline earth oxide is preferably 27.0 mol% or more and 34.4 mol% or less. In terms of mass%, the alkaline earth oxide is preferably 10.7% by mass or more and 28.7% by mass or less.

[0019] Also, according to the test results of the inventor, the bond layer preferably has a softening point of 391°C or higher and 549°C or lower. The bond layer preferably has a softening point of 522°C or lower, particularly 436°C or lower. In this case, the bond layer has high wettability with diamond.

[0020] Furthermore, according to the test results of the inventor, the bond layer preferably has a crystallinity of 90% or less. In this case, the bond layer has high wettability with diamond. More preferably, the bond layer has a crystallinity of 70% or less, and even more preferably 8% or less.

[0021] According to the test results of the inventor, in the manufacturing method of the present invention, in the oxidation atmosphere, it is preferable that a reducing gas such as hydrogen is not introduced into the firing chamber and the oxygen concentration is 0.01 to 20%. If a reducing gas is introduced into the firing chamber or the oxygen concentration is less than 0.01%, bismuth oxide in the composition is reduced, and the bond layer cannot exhibit suitable wettability with diamond abrasive grains. If the oxygen concentration exceeds 20%, although it depends on the firing time, diamond as the abrasive grains tends to disappear.

[0022] In the manufacturing method of the present invention, in the third step, it is preferable to fire the base material compact at 585°C or lower. This is because according to the test results of the inventor, the vitrified tool of the present invention was obtained with a composition having a yield point of 585°C. In this case, although it depends on the firing time, diamond as the abrasive grains is difficult to disappear, and the bond layer has high wettability with diamond. In the third step, it is more preferable to fire the base material compact at 467°C or lower.

[0023] Hereinafter, the present invention will be described with reference to Tests 1 to 3, and Examples 1 to 5 and Comparative Examples will also be described.

[0024] (Test 1) In Test 1, the composition of the composition was varied, and as shown in FIG. 1, a chip 20 having diamond as abrasive grains 1 was manufactured. Each chip 20 has innumerable abrasive grains 1 held in a bond layer 5 made of glass. The bond layer 5 contains pores 7 and has the abrasive grains 1 in multiple layers.

[0025] First, as a first step, Compositions 1 to 7, innumerable abrasive grains 1 (diamond, average particle size: 0.5 μm), a binder resin (acrylic resin), and a solvent (alcohol) were prepared. The mol% in terms of glass of Compositions 1 to 7 is shown in Table 1, and the mass% is shown in Table 2. In the lower part of Table 1, the mol% of alkali oxides and alkaline earth oxides is shown, and in the lower part of Table 2, the mass% of alkali oxides and alkaline earth oxides is shown.

[0026] [Table 1]

[0027] [Table 2]

[0028] For each of Compositions 1 to 7, TMA measurement was performed. Since each of Compositions 1 to 7 melts upon heating, as illustrated in FIG. 2, the softening point Tg (°C) and the yield point Ts (°C) are shown. Also, for each of Compositions 1 to 7, as shown in FIG. 3, evaluation was performed using an XRD evaluation apparatus (Rigaku "Smartlab"), and the crystallinity was determined. These results are shown in Table 3.

[0029] [Table 3]

[0030] Compositions 1 to 7 and abrasive grains 1 were put into a ball mill, and the ball mill was rotated. Thus, slurries of Test Specimens 1 to 7 were obtained. The mixing ratio (by volume) of the glassy substance of the bond layer 5 and the abrasive grains 1 was set to 30:70.

[0031] As a second step, each slurry was used to form a chip shape, and the solvent was vaporized to form a molded body.

[0032] As a third step, each molded body was fired for a predetermined time to obtain chips 20. In the slurry of Test Specimen 7, it was impossible to manufacture the chip 20. The gas species, oxygen concentration (%), and atmosphere in the firing chamber at this time are shown in Table 4.

[0033]

Table 4

[0034] As shown in Fig. 4, the chips 20 obtained from the slurries of Test Specimens 1 to 5 were adhered to the base alloy 15 made of an aluminum alloy as a base material to form a grinding tool. In one cutting tool, the chips 20 manufactured from the same slurry were joined.

[0035] (Test 2) In Test 2, the wettability between the abrasive grains 1 and the bond layer 5 was confirmed. First, the slurries of Test Specimens 1 to 6 were applied on an alumina substrate to a thickness of about 10 μm, and the abrasive grains 1 made of diamond with an average particle size of 12 μm were placed on the film, and firing was performed in the same manner as in Test 1. After firing, how much the abrasive grains 1 were embedded in the bond layer 5 composed of the slurries of Test Specimens 1 to 6 was evaluated according to the following criteria. ◎: The bond layer 5 is 50% or more of the diameter of the abrasive grains 1 〇: The bond layer 5 is 10% or more of the diameter of the abrasive grains 1 ×: The bond layer 5 is less than 10% of the diameter of the abrasive grains 1

[0036] The micrograph of the side surface of the bond layer 5 using the slurry of Test Specimen 1 is shown in Fig. 4, and the micrograph of its cross section is shown in Fig. 5. On the other hand, the micrograph of the side surface of the bond layer 5 using the slurry of Test Specimen 6 is shown in Fig. 6, and the micrograph of its cross section is shown in Fig. 7.

[0037] As shown in FIGS. 4 and 5, when the slurry of Test Specimen 1 is used, it can be seen that the abrasive grains 1 made of black diamonds are embedded in the bond layer 5 made of white. Also, when the slurry of Test Specimen 1 is used, it can be seen that the bond layer 5 is well coated around the abrasive grains 1. This is because the bond layer 5 made of the slurry of Comparative Example 1 has high wettability with respect to the abrasive grains 1 made of diamonds. The same applies when the slurries of Test Specimens 2 to 5 are used.

[0038] On the other hand, as shown in FIGS. 6 and 7, when the slurry of Test Specimen 6 is used, it can be seen that the abrasive grains 1 exist exposed from the bond layer 5. Also, when the slurry of Test Specimen 6 is used, it can be seen that there are spots where the abrasive grains 1 are scattered, and it is likely that the grinding state varies.

[0039] (Test 3) Evaluation grinding tools using each chip 20 obtained with the slurries of Test Specimens 1 to 6 were prepared. The evaluation grinding tools using each chip 20 obtained with the slurries of Test Specimens 1 to 5 are the vitrified tools of Examples 1 to 5, and the evaluation grinding tool using each chip 20 obtained with the slurry of Test Specimen 6 is the vitrified tool of the comparative example. Si wafers were ground with each evaluation grinding tool, the surface roughness of the ground wafer was confirmed with a surface roughness meter (Zygo), and evaluation was performed under the following conditions. ◎: Sa < 2 nm 〇: Sa < 3 nm ×: Sa ≥ 3 nm

[0040] Furthermore, it was confirmed whether there were scratches with a depth of 20 nm or more on the ground wafer, and evaluation was performed with 〇 when there were none and × when there were. These results are shown in Table 5.

[0041]

Table 5

[0042] As is clear from Table 5, it can be seen that the bond layer 5 of the grinding tools for evaluation in Examples 1 to 5 is rich in wettability while each abrasive grain 1 is diamond. In particular, the bond layer 5 of the grinding tools for evaluation in Examples 1 and 2, in which the bond layer 5 contains 28.6 mol% or more of bismuth oxide, exhibits excellent wettability. For this reason, it can be seen that the vitrified tools using the chip 20 having these bond layers 5 are excellent in both grindability and scratch resistance while adopting diamond as the abrasive grain 1. This is because it contains a specific amount or more of bismuth oxide. Further, these bond layers 5 have a softening point of 391°C or higher and 549°C or lower, and a crystallinity of 90% or lower.

[0043] The chips 20 of Examples 1 to 5 can also be embodied in the grinding tools of FIGS. 9 and 10. The grinding tool shown in FIG. 9 employs a rod-shaped base metal 17, and a plurality of chips 20 are adhered to the peripheral surface of this base metal 17. The grinding tool shown in FIG. 10 employs a plate-shaped base metal 19, and a plurality of chips 20 are adhered to one surface of this base metal 19.

[0044] Therefore, the vitrified tools of Examples 1 to 5 can be used to process difficult-to-machine materials with a tool rotating at high speed.

[0045] In the above, the present invention has been described with reference to Tests 1 to 3 and Examples 1 to 5. However, it goes without saying that the present invention is not limited to the above Tests 1 to 3 and Examples 1 to 5, and can be appropriately modified and applied without departing from the spirit thereof.

[0046] In the above embodiment, the bond layer 5 holding innumerable abrasive grains 1 is manufactured as the chip 20, and the chip 20 is fixed on the base material. However, in the vitrified tool of the present invention, the bond layer 5 holding innumerable abrasive grains 1 may be directly fixed on the base material. Further, the bond layer 5 may have the abrasive grains 1 in multiple layers on the base material as in the embodiment, or may have only a single layer of the abrasive grains 1 on the base material. Furthermore, in the above embodiment, the bond layer 5 has pores 7, but the bond layer 5 may be configured densely without having the pores 7. In the vitrified tool of the present invention, if only a single layer of abrasive grains is fixed on the base material, it is preferable to adopt a dense bond layer that substantially does not contain pores.

Industrial Applicability

[0047] The present invention can be used for grinding tools and the like.

Explanation of Symbols

[0048] 15…Base material (alloy) 5…Bond layer 1…Abrasive grain

Claims

1. A base material and a chip provided on the base material, The chip includes innumerable abrasive grains and a bond layer made of glassy material holding each of the abrasive grains, Each of the abrasive grains is diamond, The bond layer contains 10.6 mol% or more of bismuth oxide, 4.8 to 25.4 mol% of SiO 2 4, 0.8 to 4.4 mol% of Al 2 O 3 6, 21.0 to 31.1 mol% of B 2 O 3 8, and is characterized by containing 0.1 to 0.2 mol% of alkali oxide and 27.0 to 34.4 mol% of alkaline earth oxide. A vitrified tool

2. The vitrified tool according to claim 1, wherein the bond layer has a crystallinity of 70% or less.

3. The vitrified tool according to claim 2, wherein the bond layer has a crystallinity of 8% or less.

4. The vitrified tool according to any one of claims 1 to 3, wherein the bond layer contains 28.6 mol% or more of bismuth oxide.

5. Bismuth oxide of 10.6 mol% or more, SiO 2 4.8 to 25.4 mol%, Al 2 O 3 0.8 to 4.4 mol%, B 2 O 3 A first step of preparing a mixture containing a composition containing 21.0 to 31.1 mol% of B2O3, 0.1 to 0.2 mol% of an alkali oxide, and 27.0 to 34.4 mol% of an alkaline earth oxide and forming a glassy substance, and innumerable abrasive grains made of diamond. A second step of obtaining a molded body of the mixture, A third step of forming a bond layer holding each of the abrasive grains with the glassy material composed of the composition by firing the molded body in an oxidizing atmosphere, and providing a chip including each of the abrasive grains and the bond layer on a base material to obtain a vitrified tool, characterized in that the method for manufacturing a vitrified tool comprises the steps.

6. The method for manufacturing a vitrified tool according to claim 5, wherein the oxidizing atmosphere has an oxygen concentration of 0.01 to 20%.

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