Vitrified bond superabrasive wheel

Abstract

A vitrified bond superabrasive wheel comprising a superabrasive layer containing diamond abrasive grains, a vitrified bond, and a filler, wherein the filler is made of aluminum oxide. The vitrified bond contains Si, Al, B, F, and alkali metals as its chemical composition, with the total content of Si and B being 50.0 mol% to 80.0 mol%, the Al content being 0.1 mol% to 10.0 mol%, the F content being 0.1 mol% to 10.0 mol%, and the alkali metal content being 15.0 mol% to 25.0 mol%.

Description

[Technical Field]

[0001] The present disclosure relates to a vitrified bond superabrasive wheel. This application claims priority based on Japanese Patent Application No. 2025-002955, filed on January 8, 2025. All the contents described in the said Japanese patent application are incorporated herein by reference. [Background Art]

[0002] Conventionally, vitrified bond superabrasive wheels are described, for example, in Patent Documents 1 to 7. [Prior Art Literature] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2014-61585 [Patent Document 2] Japanese Unexamined Patent Publication No. Hei 9-267264 [Patent Document 3] Japanese Unexamined Patent Publication No. Hei 9-267266 [Patent Document 4] Japanese Unexamined Patent Publication No. Sho 62-57873 [Patent Document 5] Japanese Unexamined Patent Publication No. Sho 62-57874 [Patent Document 6] Japanese Unexamined Patent Publication No. 2017-170554 [Patent Document 7] Japanese Unexamined Patent Publication No. 2015-112685 [Summary of the Invention] [Means for Solving the Problems]

[0004] The vitrified bond superabrasive wheel of this disclosure is a vitrified bond superabrasive wheel comprising a superabrasive layer containing diamond abrasive grains, a vitrified bond, and a filler, wherein the filler is made of aluminum oxide. The vitrified bond contains Si, Al, B, F, and alkali metals as a chemical composition, wherein the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the Al content is 0.1 mol% or more and 10.0 mol% or less, the F content is 0.1 mol% or more and 10.0 mol% or less, and the alkali metal content is 15.0 mol% or more and 25.0 mol% or less, relative to the total content of the chemical composition. [Brief explanation of the drawing]

[0005] [Figure 1] Figure 1 is a photograph of a superabrasive layer 6 having a aggregate cutting edge structure surrounded by lines 7, which consist of a vitrified bond 2, diamond abrasive grains 3, and filler 4. [Figure 2] Figure 2 is a photograph of the superabrasive layer 6 without aggregated cutting edge structure. [Figure 3] Figure 3 is a schematic diagram of the superabrasive layer 6 having the aggregated cutting edge structure shown in Figure 1. [Figure 4] Figure 4 is a side view of the superabrasive layer 6, which is provided with the aggregated cutting edge structure shown in Figure 3. [Figure 5] Figure 5 is a schematic diagram of the superabrasive layer 6 without the aggregate cutting edge structure shown in Figure 2. [Figure 6] Figure 6 is a side view of the superabrasive layer 6 without the aggregate cutting edge structure shown in Figure 5. [Modes for carrying out the invention]

[0006] [Problems the invention aims to solve] Conventional vitrified bond superabrasive wheels had the problem of low grinding performance.

[0007] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described.

[0008] When vitrified bond superabrasive wheels are used for grinding compound semiconductors, the strength of the superabrasive layer is insufficient. This is because conventional vitrified bond superabrasive wheels do not have a structure that can withstand high temperatures and high loads. Specifically, there is no combination of a filler with excellent high-temperature properties and a vitrified bond with a chemical composition that has excellent affinity with that filler. As a result, conventional vitrified bond superabrasive wheels have the problem of high wear rates.

[0009] The vitrified bond superabrasive wheel of this disclosure is a vitrified bond superabrasive wheel comprising a superabrasive layer containing diamond abrasive grains, a vitrified bond, and a filler, wherein the filler is made of aluminum oxide. The vitrified bond contains Si, Al, B, F, and alkali metals as a chemical composition, wherein the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the Al content is 0.1 mol% or more and 10.0 mol% or less, the F content is 0.1 mol% or more and 10.0 mol% or less, and the alkali metal content is 15.0 mol% or more and 25.0 mol% or less, relative to the total content of the chemical composition.

[0010] Superabrasive wheels used for grinding compound semiconductor wafers such as SiC need to withstand high temperatures and heavy loads. In a vitrified bond superabrasive wheel configured as described above, grinding performance can be improved by including aluminum oxide, which is stable at high temperatures, as a filler, and by including aluminum, a constituent element of the filler, and fluorine, which has excellent chemical affinity with aluminum, in the vitrified bond.

[0011] Preferably, the volume percentages of the diamond abrasive grains and the vitrified bond in the superabrasive layer are 10-40% by volume and 10-25% by volume, respectively, and the volume ratio of the filler to the vitrified bond is 2-5. Within this range, grinding performance such as grinding load and wear rate can be maintained at a high level.

[0012] Preferably, the average particle diameter of the diamond abrasive grains is 0.1 to 5.0 µm. Within this range, the grinding load can be kept low while increasing the strength of the superabrasive grain layer.

[0013] Preferably, the average particle diameter of the filler is 0.1 to 5.0 µm. Within this range, the grinding load can be kept low while increasing the strength of the superabrasive grain layer.

[0014] Preferably, the vitrified bond further contains an alkaline earth metal as part of the chemical composition, and the content of the alkaline earth metal relative to the total content of the chemical composition is more than 0.0 mol% and 2.9 mol% or less. Within this range, the glass softening temperature can be adjusted without excessively impairing the strength of the vitrified bond.

[0015] Preferably, the vitrified bond further contains a transition metal as part of the chemical composition, and the content of the transition metal relative to the total content of the chemical composition is more than 0.0 mol% and 0.8 mol% or less. Within this range, the strength can be adjusted without impairing the sinterability of the vitrified bond.

[0016] Preferably, the vitrified bond further contains an alkaline earth metal and a transition metal as part of the chemical composition, the content of the alkaline earth metal relative to the total content of the chemical composition is more than 0.0 mol% and 2.9 mol% or less, and the content of the transition metal relative to the total content of the chemical composition is more than 0.0 mol% and 0.8 mol% or less. Within this range, it is suitable for achieving both the strength and sinterability of the vitrified bond.

[0017] Preferably, the vitrified bond superabrasive wheel has an aggregated cutting edge structure on the working surface of the superabrasive grain layer after grinding, the aggregated cutting edge structure contains the diamond abrasive grains, the vitrified bond and the filler, and has a flattened surface facing the workpiece. This allows the cutting edge to withstand the high temperature and high load generated when grinding a compound semiconductor wafer such as SiC, enabling high-efficiency grinding.

[0018] Preferred embodiments of the present disclosure will be described below. The vitrified bond superabrasive layer of the present disclosure contains at least diamond abrasive grains, a vitrified bond, and a filler. The filler according to the present disclosure is characterized by being made of aluminum oxide. In other words, the filler according to the present disclosure substantially contains only aluminum oxide. The proportion of aluminum oxide in the filler is, for example, 98% by volume or more. The filler may contain silicon oxide or the like in addition to aluminum oxide. The composition of the filler can be determined by structural analysis via XRD and structural analysis via SEM. Further, the vitrified bond according to the present disclosure contains Si, Al, B, F and an alkali metal in its chemical composition, wherein based on the total content of said chemical composition, the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the Al content is 0.1 mol% or more and 10.0 mol% or less, the F content is 0.1 mol% or more and 10.0 mol% or less, and the alkali metal content is 15.0 mol% or more and 25.0 mol% or less.

[0019] When used for surface grinding of compound semiconductor wafers such as SiC wafers, the superabrasive wheel of the present disclosure having the above configuration can exhibit excellent performance in balancing wear resistance and grinding load even under the high temperature and high load generated during grinding. In surface grinding of compound semiconductor wafers, the cutting edge temperature and load are higher than those of silicon semiconductors, and conventional superabrasive layers have the problem of deteriorated wear resistance and increased grinding resistance. In the present disclosure, alumina (aluminum oxide), which has excellent high-temperature properties, is used as the filler, and the vitrified bond composition has excellent chemical affinity with alumina, so the resistance to temperature and load is significantly improved.

[0020] In this disclosure, it is preferable that the volume percentages of diamond abrasive grains and vitrified bond in the entire superabrasive layer, excluding pores, are 10.0 to 40.0 vol% and 10.0 to 25.0 vol%, respectively, and that the volume ratio of filler to vitrified bond is 2.0 to 5.0. This makes it possible to create a superabrasive layer with excellent grinding performance. In ordinary vitrified bond superabrasive wheels, natural pores remaining during sintering and artificial pores consisting of the remnants of pore-forming material are formed, and the superabrasive layer of this disclosure may also contain pores, but in this disclosure, the volume of pores is not counted as part of the structure of the superabrasive layer. Further preferred composition ratios for the superabrasive layer are a volume percentage of abrasive grains of 12.0 to 40.0 vol%, or a volume percentage of abrasive grains of 17.1 to 38.1 vol%, or a volume percentage of abrasive grains of 18.2 to 33.2 vol%. The volume percentage of the vitrified bond should be 12.0 to 20.0 vol%. Alternatively, the volume percentage of the vitrified bond should be 15.0 to 18.0 vol%. The volume ratio of filler to vitrified bond (volume of filler / volume of vitrified bond) should be 2.5 to 4.5. The volume ratio of filler to vitrified bond (volume of filler / volume of vitrified bond) should be 2.9 to 3.9. Furthermore, the volume percentage of the filler should be the remainder of the total volume percentage of the superabrasive layer excluding pores, after subtracting the volume percentage of diamond abrasive grains and the volume percentage of the vitrified bond.

[0021] This disclosure is particularly suitable for application to vitrified bond superabrasive wheels having diamond abrasive grains with an average particle size of 0.1 to 5.0 μm. In vitrified bond superabrasive wheels with relatively fine grains, the strength of the superabrasive layer tends to decrease. As a result, deterioration of grinding performance due to high temperature and high load becomes a problem when grinding compound semiconductor wafers, so the effects of this disclosure are particularly evident. The average particle size of the diamond abrasive grains is preferably between 1.2 μm and 5.0 μm. The average particle size of the diamond abrasive grains is preferably between 0.10 μm and 1.2 μm. The average particle size of the diamond abrasive grains is preferably between 0.10 μm and 0.80 μm.

[0022] Furthermore, the filler according to this disclosure preferably has an average particle size of 0.1 to 5.0 μm. If the average particle size of the filler is 0.1 μm or more, the strength of the superabrasive layer increases and wear resistance improves. If it is 5.0 μm or less, the superabrasive layer is moderately broken down, so grinding resistance can be reduced. The average particle size of the filler is preferably 1.2 μm or more and 5.0 μm or less. The average particle size of the filler is preferably 0.10 μm or more and 1.2 μm or less. filler The average particle size is preferably between 0.10 μm and 0.60 μm.

[0023] Si and B are elements that form the framework of the glass. Too much of them reduces the sinterability of the superabrasive layer and worsens its strength, while too little reduces the glass strength and worsens the strength of the superabrasive layer. Alkali metal elements are elements that regulate the softening point and strength of the glass. Too much of them reduces the glass strength and softening point and worsens its resistance to grinding temperature and load, while too little reduces the sinterability of the superabrasive layer and worsens its strength. Al is a glass framework element and also contributes to the affinity with the filler (alumina). Too much reacts with F (described later) and worsens the affinity between the glass and the filler, while too little results in insufficient affinity with the filler. F is an element that greatly contributes to the affinity with the filler. Too much of it reduces the glass strength and softening point and worsens its resistance to grinding temperature and load, while too little results in insufficient affinity with the filler.

[0024] Furthermore, a more preferable chemical composition range for the vitrified bond according to this disclosure is a total Si and B content of 55.0 to 75.0 mol%, an Al content of 1.0 to 8.0 mol%, an F content of 1.0 to 8.0 mol%, and an alkali metal content of 17.5 to 22.5 mol%. Within this range, the grinding performance of the vitrified superabrasive wheel can be maximized.

[0025] Furthermore, a more preferable chemical composition range for the vitrified bond according to this disclosure is a total Si and B content of 55.0 to 75.0 mol%, an Al content of 1.0 to 8.0 mol%, an F content of 1.0 to 8.0 mol%, and an alkali metal content of 17.5 to 22.5 mol%. Within this range, the grinding performance of the vitrified superabrasive wheel can be maximized. It is preferable if the total content of Si and B is 56.9 mol% or more and 69.0 mol% or less. It is preferable if the total content of Si and B is 70.5 mol% or more and 75.2 mol% or less. It is preferable if the total content of Si and B is 57.5 mol% or more and 69.0 mol% or less. A preferably Al content of 1.6 mol% to 7.5 mol%. A preferably Al content of 3.7 mol% to 6.7 mol%. F included The amount is preferably 1.3 mol% to 7.1 mol%. The F content is preferably 1.7 mol% to 5.5 mol%. Preferably, the alkali metal content is between 18.3 mol% and 22.3 mol%. Preferably, the alkali metal content is between 18.9 mol% and 22.0 mol%.

[0026] A preferably Al content of 1.6 mol% to 7.5 mol%. A preferably Al content of 3.7 mol% to 6.7 mol%.

[0027] A Fl content of 1.3 mol% to 7.1 mol% is preferable. A F content of 1.7 mol% to 5.5 mol% is preferable.

[0028] Preferably, the alkali metal content is between 18.3 mol% and 22.3 mol%. Preferably, the alkali metal content is between 18.9 mol% and 22.0 mol%.

[0029] The vitrified bond further contains alkaline earth metals as part of the chemical composition, and the content of alkaline earth metals relative to the total content of the chemical composition is preferably more than 0.0 mol% and 2.9 mol% or less. Preferably, the content of alkaline earth metals is 0.3 mol% or more and 2.9 mol% or less. Preferably, the content of alkaline earth metals is 0.4 mol% or more and 2.8 mol% or less.

[0030] The vitrified bond further contains a transition metal as part of its chemical composition, and it is preferable that the content of the transition metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 0.8 mol%. Preferably, the content of the transition metal is between 0.1 mol% and 0.8 mol%. Preferably, the content of the transition metal is between 0.3 mol% and 0.7 mol%.

[0031] The vitrified bond further contains alkaline earth metals and transition metals as part of the chemical composition, and it is even more preferable that the content of alkaline earth metals relative to the total content of the chemical composition is greater than 0.0 mol% and 2.9 mol% or less, and the content of transition metals relative to the total content of the chemical composition is greater than 0.0 mol% and 0.8 mol% or less. It is even more preferable that the content of alkaline earth metals relative to the total content of the chemical composition is 0.3 mol% or more and 2.9 mol% or less, and the content of transition metals relative to the total content of the chemical composition is 0.1 mol% or more and 0.8 mol% or less. It is even more preferable that the content of alkaline earth metals relative to the total content of the chemical composition is 0.4 mol% or more and 2.8 mol% or less, and the content of transition metals relative to the total content of the chemical composition is 0.3 mol% or more and 0.7 mol% or less. The vitrified bond preferably contains Si, B, Al, F, alkali metals, optionally alkaline earth metals, and optionally transition metals as part of its chemical composition, with the remainder being unavoidable impurities.

[0032] Next, another aspect of this disclosure will be described. Another aspect of the present disclosure is a superabrasive wheel comprising diamond abrasive grains, a vitrified bond, and a filler, wherein the working surface after grinding a workpiece (particularly a compound semiconductor wafer) has a aggregate cutting edge structure in which the diamond abrasive grains, vitrified bond, and filler are included and the workpiece-facing surface is flattened.

[0033] In a superabrasive layer having a clustered cutting edge structure, premature detachment of the cutting edge can be suppressed during surface grinding of compound semiconductor wafers, where high temperature and high load are problematic. In conventional superabrasive layers, the strength of the vitrified bond supporting the cutting edge (abrasive grains) is insufficient, resulting in poor wear resistance. In this disclosure, the vitrified bond, reinforced with fillers, can retain the diamond abrasive grains for a long time, thus improving wear resistance. The central portion of the clustered cutting edge structure is rubbed and flattened by the workpiece (semiconductor wafer).

[0034] Figure 1 is a photograph of a superabrasive layer 6 having a cluster cutting edge structure enclosed by lines 7, which consist of a vitrified bond 2, diamond abrasive grains 3, and filler 4. Figure 2 is a photograph of a superabrasive layer 6 without the cluster cutting edge structure. Figure 3 is a schematic diagram of the superabrasive layer 6 with the cluster cutting edge structure shown in Figure 1. Figure 4 is a side view of the superabrasive layer 6 with the cluster cutting edge structure shown in Figure 3. Figure 5 is a schematic diagram of a superabrasive layer 6 without the cluster cutting edge structure shown in Figure 2. Figure 6 is a side view of the superabrasive layer 6 without the cluster cutting edge structure shown in Figure 5.

[0035] As shown in Figures 1, 3, and 4, when a clustered cutting edge structure (region enclosed by line 7) consisting of vitrified bond 2, diamond abrasive grains 3, and filler 4 is provided, it becomes possible to suppress the shedding of diamond abrasive grains 3 that constitute the cutting edge. In the clustered cutting edge structure, multiple diamond abrasive grains 3 form a plane in the direction facing the wafer (workpiece) indicated by arrow 11. This prevents only one diamond abrasive grain 3 from protruding, and as a result, the shedding of diamond abrasive grains 3 can be suppressed. In contrast, as shown in Figures 2, 5, and 6, when a clustered cutting edge structure is not provided, one diamond abrasive grain 3 constitutes the cutting edge 17. As a result, the diamond abrasive grains 3 are more likely to detach.

[0036] The superabrasive layers of the two embodiments described above can be manufactured by the manufacturing process of a normal vitrified bond superabrasive layer. Diamond abrasive grains of the desired particle size, an alumina filler, and glass frit are prepared. Glass frit is glass powder obtained by crushing glass to an appropriate size. The chemical composition of the glass frit may be the same as the composition of the vitrified bond of this disclosure. These starting materials can be manufactured by means known to those skilled in the art, for example, by wet mixing, cold forming, firing in air, base bonding, and shaping.

[0037] Whether aluminum and fluorine are contained in the vitrified bond within the superabrasive layer can be easily identified using observation methods such as SEM / EDS and TEM / EDS. Further analysis of the glass composition will be described later.

[0038] The volume ratio of diamond abrasive grains, fillers, and vitrified bond in a superabrasive layer can be analyzed from electron microscope images such as those taken with a scanning electron microscope (SEM). As an example, a field of view and magnification containing 50 or more diamond abrasive grains and fillers is selected, and the area ratio of diamond abrasive grains, fillers, and vitrified bond is determined using image analysis software such as WinRoof. The area ratio of diamond abrasive grains, fillers, and vitrified bond can be expressed as the volume ratio. As is obvious to those skilled in the art, in a superabrasive layer using a typical vitrified bond, it is possible to distinguish between abrasive grains, fillers, and vitrified bond from the color tone of the microstructure image. In the example in Figure 1, the black particles can be identified as diamond abrasive grains, the white particles as fillers, and the amorphous material of intermediate color as vitrified bond.

[0039] The average particle size of diamond abrasive grains and fillers within the superabrasive layer can also be analyzed from electron microscope images such as those taken with a scanning electron microscope (SEM). Using image analysis software, the ferret diameter of 50 or more particles is measured using the same procedure as described above for volume ratios, and the median diameter is taken as the average particle size.

[0040] The following procedure is recommended for identifying the detailed composition of the vitrified bond. First, the volume ratio of filler and vitrified bond to the superabrasive layer is determined using the method described above. Next, a predetermined amount of microstructure fragments of the superabrasive layer are collected and crushed using a crushing device. The resulting crushed powder of the superabrasive layer is calcined under air to burn off only the diamond abrasive grains contained in the superabrasive layer, obtaining a residue powder consisting only of vitrified bond and filler. The true specific gravity of this residue powder is measured using a pycnometer, and the specific gravity of the vitrified bond is determined by using the previously determined volume ratio of filler:vitrified bond and the known specific gravity of alumina. From these values, the weight ratio of filler:vitrified bond can be determined.

[0041] Subsequently, the chemical composition of the residue powder is identified by ICP and combustion ion chromatography. More specifically, Si, Al, B, alkali metals, alkaline earth metals, and transition metal elements are analyzed by ICP. Si and F are analyzed by combustion ion chromatography. From these analytical results, the amount of Si analyzed by combustion ion chromatography is calculated as "Si <ic>ICP analysis amount of Si for "Si <icp>The ratio of "Si <icp> / And <ic>The ratio is determined by combustion ion chromatography to obtain the F spectroscopy amount "F <ic>Multiplying by ", the ICP analysis equivalent amount of F "F <icp>On the other hand, for the amount of Al analyzed by ICP, the amount of Al contained in the filler is subtracted from the filler:vitrified bond weight ratio determined in advance. For example, if the filler:vitrified bond weight ratio is 1:1 and the amount of Al analyzed by ICP is 10 parts by weight, then the amount of Al contained in the vitrified bond is assumed to be 5 parts by weight.

[0042] The chemical composition (weight ratio) of the vitrified bond can be determined from the weight ratio of all elements determined by the above procedure, and the chemical composition (molar ratio) of the vitrified bond can be identified by using the atomic weight of each element. This allows for the calculation of the ratio of the number of moles of each component contained in the vitrified bond to the total number of moles of the vitrified bond.

[0043] [Details of the embodiments of this disclosure] (Example 1)

[0044] [Table 1]

[0045] First, diamond abrasive grains and fillers having the average particle sizes listed in Table 1 were prepared. Alumina, silicon carbide, graphite, and h-BN were used as fillers. Resin beads with an average diameter of 1.0 to 5.0 μm were also prepared as pore-forming materials. For the glass frit constituting the vitrified bond, glass frit with a softening temperature of 850°C was prepared. Composition 1 of the vitrified bond for sample number 1 contains Al and F, composition 2 of sample number 201 does not contain Al, and composition 3 of sample number 202 does not contain F.

[0046] The glass frit was processed into a fine powder in a pre-grinding process using a ball mill and a bead mill to achieve an average particle size similar to that of each diamond particle.

[0047] These raw material powders and wax as a molding aid were placed in a pot and mixed for 72 hours using a wet ball mill with zirconia balls.

[0048] After mixing diamond abrasive grains, glass frit powder, and filler, the slurry composed of these mixtures was collected and dried by a water bath. This dried slurry was then sieved and sorted using a sieve with a predetermined mesh size to obtain granulated material.

[0049] This granulated material is filled into a mold, and the temperature is 150°C and the surface pressure is 0.2 tons (0.2 × 1000 × 9.8 N) / cm. 2 The compacted powder was obtained by warm compression molding.

[0050] The compacted powder was charged into an atmospheric furnace, maintained at a maximum temperature of 650-950°C for 2 hours, and then cooled to obtain a sintered body.

[0051] A sintered body was attached to an aluminum base with a wheel diameter of 200 mm, and its inner circumference and surface were processed with a WA grinding wheel with a grit size of #240 to produce vitrified bond superabrasive wheels containing diamond abrasive grains and fillers, as shown in Table 1 (sample numbers 1, 201 to 205). The composition of the vitrified bond was confirmed to be the same as the composition of glass frit, which is the raw material for the vitrified bond.

[0052] These superabrasive wheels from Table 1 were subjected to grinding under the following conditions. The machine used was a Tokyo Seimitsu HRG300, and the workpiece was a commercially available 6-inch single-crystal SiC wafer (dummy grade 4H-N). The machining conditions were: spindle speed 1750 rpm, table speed 300 rpm, wheel feed rate 0.6 μm / s, and machining thickness 25 μm.

[0053] In the evaluation, the wear rate (change in the height of the superabrasive layer 6 before and after wear / change in the thickness of the workpiece (wafer) in the ground portion before and after grinding), load current, and grinding resistance were measured on both the Si side and C side of the SiC wafer, and the average value was calculated.

[0054] Regarding the processing results, it was found that sample number 1, in which alumina was used as a filler and the vitrified bond contained Al and F, showed a low abrasion rate.

[0055] Load current and grinding resistance are generally correlated. Samples with high grinding resistance tended to have high load currents. In sample number 204, which uses silicon carbide as a filler, it is thought that friction between the silicon carbide constituting the workpiece and the filler increased, resulting in higher grinding resistance and load current compared to sample number 1.

[0056] (Example 2)

[0057] [Table 2]

[0058] [Table 3]

[0059] Superabrasive layers for samples 11 to 28 and 111 to 120, having diamond abrasive grains, vitrified bond, and filler as shown in Tables 2 and 3, were prepared in the same manner as in Example 1. The proportions of diamond abrasive grains, vitrified bond, and filler were adjusted by changing the proportions of the raw materials mixed. All fillers were alumina. As the glass frit constituting the vitrified bond, glass frit with a softening temperature of 850°C was prepared. The glass frit contained Si, Al, B, F, alkali metals, and alkaline earth metals as its chemical composition, with the total content of Si and B being 50.0 to 80.0 mol%, Al being 0.1 to 10.0 mol%, F being 0.1 to 10.0 mol%, alkali metals being 15.0 to 25.0 mol%, and alkaline earth metals being more than 0.0 mol% and less than or equal to 2.9 mol%.

[0060] A vitrified bond superabrasive wheel was obtained by attaching a superabrasive layer having a vitrified bond with the composition shown in Tables 2 and 3 to a base metal similar to that in Example 1.

[0061] This was subjected to grinding under the same conditions as in Example 1. The grinding results are shown in Tables 2 and 3. For samples 11 to 28, the volume ratios of diamond abrasive grains and the vitrified bond in the superabrasive layer were 10.0% to 40.0% and 10.0% to 25.0%, respectively, and the volume ratio of filler to vitrified bond was 2 to 5. It was found that a more favorable result in terms of wear rate could be obtained with a vitrified bond superabrasive wheel configured in this way.

[0062] (Example 3)

[0063] [Table 4]

[0064] [Table 5]

[0065] Superabrasive layers for samples 31 to 40 and 131 to 140, having diamond abrasive grains, vitrified bond, and optionally fillers as shown in Tables 4 and 5, were prepared in the same manner as in Example 1.

[0066] Samples 31 to 40 in Tables 4 and 5 have the same filler and vitrified bond composition as sample 1. However, samples 31 to 40 differ from each other in the average particle size of the diamond abrasive grains.

[0067] In samples 231 to 240, compared to samples 31 to 40, super abrasive layer It was found that the wear rate deteriorated because the sample did not contain alumina filler and the vitrified bond did not contain Al or F. Furthermore, samples 33 to 40, in which the average particle size of diamond abrasive grains was between 0.1 μm and 5.0 μm, showed better results in terms of wear rate, load current, and grinding resistance compared to samples 31 and 32. In samples 31 and 32, although the wear rate decreased because the average particle size of the diamond abrasive grains was larger than that of samples 33 to 40, the load current and grinding resistance were inferior to those of samples 33 and 40. It can be said that the average particle size of the diamond abrasive grains was optimized in samples 33 to 40.

[0068] Using materials numbered 31 to 40 and 231 to 240, superabrasive layers were prepared in the same manner as in Example 1. A superabrasive layer having a vitrified bond with the composition shown in Tables 4 and 5 was attached to a base metal similar to that in Example 1 to obtain a vitrified bond superabrasive wheel.

[0069] This was subjected to grinding under the same conditions as in Example 1. The grinding results are shown in Tables 4 and 5.

[0070] In samples 231 to 240, compared to samples 31 to 40, the wear rate was found to be worse because the vitrified bond did not contain alumina filler and did not contain Al or F. Furthermore, samples 33 to 40, with an average diamond abrasive particle size of 0.1 μm to 5.0 μm, showed better results in wear rate, load current, and grinding resistance compared to samples 31 and 32. While samples 31 and 32 showed a lower wear rate due to their larger average diamond abrasive particle size compared to samples 33 to 40, their load current and grinding resistance were inferior. This suggests that the average diamond abrasive particle size was optimized for samples 33 to 40.

[0071] (Example 4)

[0072] [Table 6]

[0073] This was subjected to grinding under the same conditions as in Example 1. The grinding results are shown in Table 6. From Table 6, the average particle size of the filler was 0.1 μm. That's all. It was found that a good balance of wear rate, load current, and grinding resistance can be obtained when the particle size is 5.0 μm or less.

[0074] Samples 41-47 and 141-144 in Table 6 have the same filler and vitrified bond composition as sample 1. Samples 41-47 and 141-144 differ from each other in the average particle size of the filler.

[0075] Using materials numbered 41 to 47 and 141 to 144, superabrasive layers were fabricated in the same manner as in Example 1. A superabrasive layer having a vitrified bond with the composition shown in Table 6 was attached to a base metal similar to that in Example 1 to obtain a vitrified bond superabrasive wheel.

[0076] This was subjected to grinding under the same conditions as in Example 1. The grinding results are shown in Table 6. From Table 6, it was found that if the average particle size of the filler is 0.1 μm to 5.0 μm or less, a good balance can be obtained in terms of wear rate, load current, and grinding resistance.

[0077] (Example 5)

[0078] [Table 7]

[0079] [Table 8]

[0080] Diamond abrasive grains, alumina filler, and vitrified bonds with the compositions shown in Tables 7 and 8 were prepared. A "-" in Tables 7 and 8 indicates a composition of 0.0 mol%.

[0081] Superabrasive layers for samples 51 to 73 and 251 to 257, having diamond abrasive grains, fillers, and vitrified bonds as shown in Tables 7 and 8, were prepared in the same manner as in Example 1.

[0082] A vitrified bond superabrasive wheel was obtained by attaching a superabrasive layer having the composition shown in Tables 7 and 8 to a base metal similar to that in Example 1.

[0083] This sample was subjected to grinding under the same conditions as sample number 1. The grinding results are shown in Tables 9 and 10.

[0084] [Table 9]

[0085] [Table 10]

[0086] Compared to samples 51 to 70, where the total content of Si and B relative to the total content of the vitrified bond was 50.0 mol% to 80.0 mol%, Al content was 0.1 mol% to 10.0 mol%, F content was 0.1 mol% to 10.0 mol%, and alkali metal content was 15.0 mol% to 25.0 mol%, the vitrified bond composition in samples 71 to 73 and 251 to 257 fell outside this range. Consequently, it was found that the wear rate was worse.

[0087] The embodiments and examples disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described above, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of Symbols]

[0088] 2 vitrified bond, 3 diamond abrasive grains, 4 filler, 6 superabrasive layer, 7 lines, 11 arrows, 17 cutting edge.< / icp> < / ic> < / ic> < / icp> < / icp> < / ic>

Claims

1. A vitrified bond superabrasive wheel comprising a superabrasive layer containing diamond abrasive grains, a vitrified bond, and a filler, The filler consists of aluminum oxide, The vitrified bond contains Si, Al, B, F, and alkali metals as its chemical composition, wherein the total content of Si and B is 50.0 mol% to 80.0 mol%, the Al content is 0.1 mol% to 10.0 mol%, the F content is 0.1 mol% to 10.0 mol%, and the alkali metal content is 15.0 mol% to 25.0 mol%.

2. The vitrified bond superabrasive wheel according to Claim 1, wherein the volume ratio of the vitrified bond to the superabrasive layer is 10.0% by volume or more and 25.0% by volume or less.

3. The vitrified bond superabrasive wheel according to claim 1, wherein the volume ratio of the filler to the vitrified bond is 2.0 to 5.

0.

4. The vitrified bond superabrasive wheel according to claim 1, wherein the volume ratio of the diamond abrasive grains to the superabrasive layer is 10.0% by volume or more and 40.0% by volume or less, the volume ratio of the vitrified bond to the superabrasive layer is 10.0% by volume or more and 25.0% by volume or less, and the volume ratio of the filler to the vitrified bond is 2.0 to 5.

0.

5. The vitrified bond superabrasive wheel according to claim 1 or claim 2, wherein the average particle size of the diamond abrasive grains is 0.1 μm or more and 5.0 μm or less.

6. The vitrified bond superabrasive wheel according to claim 1 or claim 2, wherein the average particle size of the filler is 0.1 μm or more and 5.0 μm or less.

7. The vitrified bond further comprises an alkaline earth metal as part of the chemical composition, wherein the content of the alkaline earth metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 2.9 mol%, as described in claim 1 or claim 2.

8. The vitrified bond further comprises a transition metal as part of the chemical composition, wherein the content of the transition metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 0.8 mol%, as described in claim 1 or claim 2.

9. The vitrified bond further comprises an alkaline earth metal and a transition metal as part of the chemical composition, wherein the content of the alkaline earth metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 2.9 mol%, and the content of the transition metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 0.8 mol%, as described in claim 1 or claim 2.

10. A vitrified bond superabrasive wheel according to claim 1 or 2, wherein the working surface of the superabrasive layer after grinding has a aggregate cutting edge structure in which the diamond abrasive grains, the vitrified bond, and the filler are included and the workpiece-facing surface is flattened.

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