MXPA01004012A - Stiffly bonded thin abrasive wheel - Google Patents

Abstract

A straight, thin, monolithic abrasive wheel formed of hard and rigid abrasive grains and a sintered metal bond including a stiffness enhancing metal component exhibits superior stiffness. The metals can be selected from among many sinterable metal compositions. Blends of nickel and tin are preferred. The stiffness enhancing metal is a metal capable of providing substantially increased rigidity to the bond without significantly increasing bond hardness. Molybdenum, rhenium, tungsten and blends of these are favored. The sintered bond is generally formed from powders. A diamond abrasive, nickel/tin/molybdenum sintered bond abrasive wheel is preferred. Such a wheel is useful for abrading operations in the electronics industry, such as cutting silicon wafers and alumina-titanium carbide pucks. The stiffness of the novel abrasive wheels is higher than conventional straight monolithic wheels and therefore improved cutting precision and less chipping can be attained without increase of wheel thickness and concomitant increased kerf loss.

Description

MUELA ABRASIVA DELGADA WITH RIGID UNION DESCRIPTIVE MEMORY This invention relates to thin abrasive wheels for abrasive wear of very hard materials, such as those used in the electronics industry. Abrasive wheels that are very thin and very rigid have great commercial importance. For example, thin abrasive wheels are used in the cutting of thin sections and for performing other operations of friction wear in the processing of silicon wafers and the so-called titanium-alumina carbide composite discs in the production of Electronic products. Silicon wafers are generally used for integrated circuits and titanium-alumina carbide disks are used to make heads for floating thin film to record and reproduce magnetically stored information. The use of thin abrasive wheels for frictional wear of silicon wafers and titanium-alumina carbide discs is explained in U.S. Patent No. 5,313,742, the disclosure of which is incorporated herein by reference. As indicated in the '742 patent, the manufacture of silicon wafers and titanium-alumina carbide discs creates the need for dimentionally accurate cuts with little waste of material from the workpiece. Ideally, cutting knives to make such cuts should be as stiff as possible, and as thin and flat as practical, because the thinner and flatter the knife, the less waste caused by the loss of material Excess width of the cost of the saw will occur and the more rigid the knife, the more straight the cut will be. However these characteristics are in conflict, because the thinner the knife the less rigid it will be. The cutting knives are basically made of abrasive grains and a union that keeps the abrasive grains in the desired shape. Because the hardness of the joint tends to increase with increased stiffness, it will be logical to raise the rigidity of the joint to obtain a more rigid knife. However, a hard joint also has a greater resistance to wear, which can delay the erosion of the joint so that the grains become weaker before being expelled from the knife. In spite of being very rigid, a knife with a hard union requires a strong cover and therefore is less attractive. The industry has evolved to the use of monolithic abrasive wheels, usually mounted together in a spindle. The individual wheels are axially separated from each other by durable spacers that can not be compressed. Traditionally, the individual wheels have a uniform axial dimension from the screw hole of the wheel towards its periphery. Although they are thin, the axial dimension of this teeth is greater than the desired one to provide an adequate rigidity for a good precision in the cut. However, to keep waste generation within acceptable limits, the thickness is reduced. This decreases the stiffness of the wheel to a lower level than the ideal. The conventional straight wheel is then observed to generate a greater waste of the work piece than a thinner wheel and produces more chipping and inadequate cuts than would a more rigid wheel. The '742 patent sought to improve the performance of straight wheels assembled together by increasing the thickness of an inner portion extending radially outwardly from the screw hole. The patent discloses that a monolithic wheel with a thicker internal portion was stiffer than a straight wheel with spacers. However, the patent 742 has the drawback that the inner portion is not used for cutting, and therefore, the volume of abrasive material in the inner portion is wasted. Because thin abrasive wheels, especially those for cutting titanium-alumina carbide, they use very expensive abrasive substances, like diamond, the cost of a wheel of the 742 patent is compared with a straight wheel due to the wasted abrasive volume. Until now, a metal bond has typically been used for straight, monolithic, thin abrasive wheels created to cut hard materials such as silicon wafers and titanium-alumina carbide discs. A variety of metal bonding compositions for containing diamond grains, such as copper, zinc, silver, nickel or iron alloys, for example, is known in the art. U.S. Patent No. 3,886,925 discloses a grinding wheel with an abrasive layer formed of high purity nickel electrolytically deposited from nickel solutions having finely divided divided abrasive material suspended therein. U.S. Patent No. 4,180,048 describes an improvement in the wheel of the '925 patent, wherein a very thin layer of chromium is deposited electrolytically on the nickel matrix. U.S. Patent No. 4,219,004 discloses a knife comprising diamond particles in a nickel matrix that constitutes the sole support for the diamond particles. A very stiff, novel metal bond suitable for bonding diamond grains to an abrasive wheel will be described below. The novel nickel-sphene bonding composition with a metallic component that improves stiffness, preferably tungsten, molybdenum, rhenium or a mixture thereof provides better combinations of stiffness, strength and wear resistance. By keeping the stiffening improver within a suitable proportion to nickel and tin, the desired binding properties can be obtained by concreting without pressure or by hot pressing. In this way, by using conventional powder metallurgical equipment, the novel joint can easily supplant the joints based on traditional less rigid bronze alloys and electrodeposited nickel bonds. In this way, an abrasive wheel comprising an abrasive disk consisting essentially of 2.5 to 50% by volume of abrasive grains and a complementary amount of a concretely bonded joint is provided. of a composition comprising a metal component consisting essentially of nickel and tin, and a metal that improves the stiffness selected from the group consisting of molybdenum, rhenium, tungsten and a mixture thereof. Also provided is a method for cutting a workpiece comprising the step of causing the workpiece to contact at least one abrasive wheel comprising an abrasive disk consisting essentially of about 2.5 to 50% by volume of grains. abrasives and a complementary amount of a concreted bond of a composition comprising a metal component consisting essentially of nickel and tin, and ur: metal for improving rigidity selected from the group consisting of molybdenum, rhenium, tungsten and a mixture of minus two of these. In addition, the present invention provides a method for making an abrasive tool comprising the steps of: a) supplying previously selected amounts of particle ingredients comprising 1) abrasive grains; and 2) a binding composition consisting essentially of nickel powder, tin powder and a metal for improving rigidity selected from the group consisting of molybdenum, rhenium, tungsten and a mixture thereof; b) mixing the ingredients into particles to form a uniform composition; c) placing the uniform composition in a mold with a previously selected shape; d) compressing the mold at a pressure in the range of about 345-690 MPa for an effective duration to form a molded article; e) heating the molded article to a temperature in the range of about 1050-1200 ° C for an effective duration to specify the bonding composition; and f) cooling the molded article to form the abrasive tool. Additionally, a composition for a particular bonding of a monolithic grinding wheel comprising a metal component consisting essentially of nickel and tin, and a metal that improves the stiffness selected from the group consisting of molybdenum, rhenium, tungsten, and a mixing of at least two of these, wherein the concreted joint has a modulus of elasticity of at least 130 GPa and a Rockwell B hardness of less than about 105. The novel connection according to the present invention can be applied to millstones monolithic abrasives. The term "straight" refers to the geometric feature in that the axial thickness of the wheel is completely uniform from the diameter of the screw hole to the diameter of the wheel. Preferably, the uniform thickness is in a range of about 20 to 2500 μm, most preferably, about 20 to 500 μm, and most preferably, about 175 to 200 μm. The uniformity of the thickness of the wheel is maintained in a narrow tolerance to achieve the desired cutting performance, especially to reduce chipping and loss of material in the workpiece. A variability in thickness of less than about 5 μm is preferred. Typically, the diameter of the screw hole is approximately 12 to 90 mm and the diameter of the wheel is approximately 50 to 120 mm. The novel joint can also be used to take advantage of monolithic abrasive wheels having a width that is not uniform, such as the coarse internal section wheels that are described in the patent 742, mentioned in previous paragraphs. The term "monolithic" means that the material of the grinding wheel is a uniform composition completely from the diameter of! , screw hole to the diameter of the wheel. That is, basically the entire body of the monolithic wheel is an abrasive disc comprising abrasive grains embedded in a concreted joint. A monolithic wheel does not have a non-abrasive, integral portion for a structural support of the abrasive portion, so that the metallic core on which the abrasive portion of a grinding wheel is fixed. Basically, the abrasive disc of the present invention comprises three ingredients, namely, abrasive grains, a metal component and a metal component that improves rigidity. The metal component and the metal that improves, the rigidity together form a concreted joint to contain the abrasive grains in the desired shape of the wheel. The concrete union is achieved by subjecting the components to suitable concretion conditions. The preferred metallic component of the present invention is a mixture of nickel and tin, where nickel constitutes the main fraction. The term "metal that improves stiffness" means an element or compound that is capable of allying with the metal component during or prior to concretion to provide a concreted joint having a significantly greater elastic modulus than the concretely bonded metal component alone. Molybdenum, rhenium and tungsten are preferred, having elastic moduli of approximately 324, 460 and 410 GPa, respectively. In this way, the concretely bonded preferably consists essentially of nickel, tin and molybdenum, rhenium, tungsten or a mixture of at least two of molybdenum, rhenium and tungsten. When a mixed stiffness improver is used, molybdenum is preferably present as the main component of the rigidity improving component, while rhenium and / or tungsten each have a smaller fraction. By "main fraction" is meant more than 50% by weight. It has been found that the stiffness of a joint that has been made stiffer for an abrasive article of the aforementioned composition -JJé? ^ A ^? M M? ^^^^ áb ^^ íA ^ i previously, should be improved considerably in relation to conventional wheels. In a preferred embodiment, the elastic modulus of the abrasive wheel with novel rigid joint is at least about 100 GPa, preferably about 130 GPa, and most preferably about 160 GPa. A main point for the selection of the abrasive grain is that the abrasive substance must be stronger than the material to be cut. Usually, the abrasive grains of the thin abrasive wheels will be selected from very hard substances, because these wheels are typically used to abrade extremely hard materials, such as carbon-alumina carbide. Representative hard abrasive substances for use in the present invention are known as superabrasives, such as diamond and cubic boron nitride, and other hard abrasives such as silicon carbide, fuming aluminum oxide, microcrystalline alumina, silicon nitride, carbide boron and tungsten carbide. Mixtures of at least two of these abrasives can also be used. Diamond is preferred. Abrasive grains are usually used in the form of fine particles. Generally, to shorten silicon wafers and titanium-alumina carbide discs, the particle size of the grains will be in a selected range to reduce chipping of the edges of the workpiece. Preferably, the particle size of the grains should be in a range of about 10 to 25 μm, and most preferably, about 15 to 25 μm. The typical diamond abrasive grains suitable The present invention has particle size distributions of 10/20 μm and 15/25 μm, where "10/20" designates that substantially all diamond particles pass through a mesh. with an opening of 20 μm and are retained in a 10 μm mesh. Due to the metal component that improves rigidity, the concreted joint produces an upper elastic modulus, more rigidly than the conventional concreted metal joints used in abrasive applications. Because the novel composition provides a relatively smooth concreted joint, the joint wears at a suitable rate to expel the soft grains during grinding. Consequently, the wheel will cut more freely with a lower tendency to load, and therefore, works with a reduced energy consumption. The novelty of the present invention thus offers the advantages of strong and soft metal bonds coupled with high rigidity for precise cutting and low material loss due to excess width of the saw cost. Both the metal component and the metal component that improves stiffness are preferably incorporated into the particulate bonding composition. The particles must have a small particle size to help achieve uniform concentration at the concreted junction and maximum contact with the abrasive grains to develop a high bond strength with the grains. Fine particles of maximum dimensions of about 44 μm are preferred. The size of The metal powder particle can be determined by the filtration of the particles through a sieve with a specified mesh size. For example, particles with a maximum nominal size of 44 μm will pass through a standard mesh screen 325 U.S. In a preferred embodiment, the rigid rigid joint abrasive wheel comprises a concreted joint of about 38 to 86% by weight of nickel, about 10 to 25% by weight of tin and about 4 to 40% by weight of metal which improves the stiffness, the total sum is 100% by weight, preferably about 43 to 70% by weight of nickel, about 10 to 20% by weight of tin and about 10 to 40% of iTietal which improves rigidity, and most preferably from about 43 to 70% by weight of nickel, about 10 to 20% by weight of tin and about 20 to 40% by weight of metal which improves rigidity. The novel grinding wheel is basically produced by a concreting process of the types known as "cold press" or "hot press". In a cold press procedure, sometimes referred to as "pressureless concretion," a mixture of components is introduced into a mold with the desired shape and a high pressure is applied at room temperature to obtain a compact and friable molded article. Usually, the high pressure is greater than about 300 MPa. Subsequently, the pressure is released and the molded article is removed from the mold, then heated to a concreting temperature. The heating to concretize is normally done while the article M - • "" "" "" • • • • A A A A A "",,,,,,,,,,,,,,,,, ir 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 的 100 100 的 100 100, 100 less than about 50 MPa. During this low pressure concretion, the molded article, such as a disc for a thin abrasive wheel, can be usefully placed in a mold and / or sandwiched between flat plates. In a hot press process, the mixture of the components of the particulate binding composition is placed in the mold, typically graphite, and compressed at high pressure in the cold process. However, the high pressure is maintained while the temperature rises, thus achieving densification while the preform ectá under pressure. An initial step of the grinding wheel process involves packing the components in a mold to shape. The components can be added as a uniform blend of separate abrasive grains, constituent particles of the metal component and particles constituting the metal component to improve stiffness. This uniform mixture can be formed using any suitable mechanical mixing apparatus known in the art to combine a mixture of grains and particles in a previously selected proportion. Illustrative mixing equipment may include double cone rotating drums, double V-shaped rotating drums, ribbon mixers, horizontal rotary drums, and stationary deck / internal screw mixers.

Nickel and tin can be a previous alloy. Another option includes the combination and subsequently mixing to achieve a uniformity of a provision of a particulate composition of a nickel / tin alloy, additional nickel and / or tin particles, metal particles that improves stiffness and abrasive grains. The mixture of components that will be loaded into the mold to shape may include smaller amounts of optional processing aids such as paraffin wax, "Acrowax", and zinc stearate that is used daily in the abrasive industry. Once a uniform mixture is prepared, it is loaded into a suitable mold. In a preferred cold press forming method, although the content of the mold can be compressed with mechanical pressure applied externally at room temperature to about 345-6900 MPa. For example, a platen press can be used for this operation. The compression is usually maintained for about 5 to 15 seconds, after which the pressure is released and the preform is heated to a concreting temperature. Heating should be carried out in an inert atmosphere, for example under vacuum at low absolute pressure or under a cover of inert gas. The content of the mold is subsequently raised to a concreting temperature. The concreting temperature must be maintained for an effective time to specify the components of the joint. The concretion temperature must be high enough to cause the bonding composition to densify but not melt completely. It is important to select the metal and metal bond components that improve stiffness that do not require concreting at such high temperatures that the abrasive grains are adversely affected. For example, the diamond begins to graphitize at a higher temperature of about 1100 ° C. It is usually desired to make diamond abrasive wheels below this temperature. Because nickel and some nickel alloys melt easily, it is usually necessary to concrete the binding composition of the present invention at or above the graffiti corrosion temperature of the incipient diamond, for example at temperatures in a range of 1050 to 1200. ° C. The concretion can be achieved in this temperature range without serious degradation of the diamond in case it is exposed to a temperature above 1100 ° C is limited to short durations, for example less than about 30 minutes, and preferably less than 15 minutes. In a preferred aspect of the present invention, an additional metal component can be added to the binding composition to achieve specific results. For example, a smaller fraction of boron can be added to a nickel-containing joint as a depressant of the concretion temperature, thereby reducing the graffiti corrosion risk of the diamond by lowering the concretion temperature. At most about 4 parts by weight (pep) of boron per 100 parts by weight of nickel is preferred. In a preferred hot pressure forming method, the conditions are generally the same as for cold pressure, with the exception that the pressure is maintained until the completion of the concretion. In any, without pressure or hot pressure, after concretion, the concrencionados products preferably form alloys to cool gradually to room temperature. Preferably, a convection of natural or forced air at room temperature is used for cooling. Shock cooling is not recommended. The products are finished by conventional methods, such as stoning to obtain the desired dimensional tolerances. It is preferred to use from about 2.5 to 50% by volume of abrasive grains and a quantity of binding complement specified in the particular product. Preferably the pores should occupy at most about 10% by volume of the densified product, ie, bond and abrasive, and most preferably, less than about 5% by volume. The concreted joint typically has a Rockwell B hardness of about 100 to 105. The abrasive tool that is preferred according to the present invention is an abrasive wheel. In this way, the typical mold shape is a thin disk. The molds are usually stacked in a vertical stack separated by a graphite plate between the adjacent discs. A solid disk mold can be used, in which case after concretion a central disk portion can be removed to form the screw hole. Alternatively, an annular mold may be used to form the spindle hole in the site. The last mentioned technique avoids wastage because it does not require the loaded central portion of the abrasive of the concreted disc. The present invention is illustrated below by examples of certain representative embodiments thereof, wherein, unless otherwise indicated, all parts, proportions and percentages are given by weight, and particle sizes are established by US standard mesh size designation All the units of weights and measures not originally obtained in SI units have been converted to SI units.

EXAMPLES EXAMPLE 1 Nickel powder (3-7 μm, Acupowder International Co., New Jersey), powdered tin (<325 Acupowder International Co. mesh) and powdered molybdenum (2-4 μm, Cerac Corporation) were combined in 58.8 proportions % Ni, 17.6% Sn and 23.50% Mo. This binding composition was passed through a 165 mesh stainless steel filter to remove the agglomerates and the sieved mixture was thoroughly mixed in a "Turbula" brand blender (Glen Mills Corporation , Clifton, New Jersey) ^ ^ ^ ^ ^ i ^^^^^ m ^ i ^^^ B ^ for 30 minutes. The diamond abrasive grains (15-25 μm) of GE Superabrasives, Worthington, Ohio, were added to the metal mixture to form 37.5% by volume of the diamond and total metal mixture. This mixture was mixed in a tubular mixer for 1 hour to obtain a uniform abrasive and the binding composition. The abrasive composition was placed in a steel mold having a cavity of 119.13 mm in external diameter, 6.35 mm in internal diameter and a uniform depth of 1.27 mm. A "green" wheel was formed by compacting the mold at room temperature under 414 MPa (4.65 tons / cm2) for 10 seconds. The green wheel was removed from the mold and then heated to 1150 ° C under pressure of 32.0 MPa (0.36 Ton / cm2) for 10 minutes between graphite plates in a graphite mold. After an air cooling in the mold, the wheel was processed to a finished size of 114.3 mm in external diameter, 69.88 mm in internal diameter (diameter of screw hole), and 0.178 mm in thickness by conventional methods, including " rectification "in a previously selected execution, and initial sharpening under conditions shown in Table I.

TABLE I Conditions for rectification of examples 1 and 2 Grinding wheel Speed 5593 rev / min. Feed rate 100 mm / min. Flange exposure 3.68 mm Grinding wheel model no. 37C220-H9B4 Composition Silicon carbide Diameter 112.65 mm Speed 3000 rev / min. Rotation rate 305 mm / min. No. of passes A 2.5 μm 40 A 1.25 μm 40 Initial grinding Wheel speed 2500 rev / min. Sharpening stick Type 37C500-GV Sharpening stick width 12.7 mm Penetration 2.54 mm Feed rate 100 mm / min. No. of passes 12.00 EXAMPLE 2 AND COMPARATIVE EXAMPLE 1 The novel wheel produced as described in Example 1 and a commercially available conventional wheel for this application of the same size (comparative example 1) were tested in accordance with the procedure described below. The composition of comparison example 1 was 48.2% Co, 20.9% Ni, 11.5% Ag, 4.9% Fe, 3.1% Cu, 2.2% Sn, and 9.3% diamond of 15/25 μm. The procedure included the completion of multiple cuts in a block of 150 mm long by 150 mm wide by 1.98 mm thick, type 3M-310 (Minnesota Mining and Manufacturing Co., Minneapolis, MinnttíHa) titanium-alumina carbide gummed to a graphite substrate . Prior to each cut, the wheels were sharpened as described in Table I with the exception that only one cutting sharpening pass and 19 mm thickness of the sharpening stick (12.7 mm for comparative example 1) were used. The abrasive wheels were mounted between two metal support spacers of 106.93 mm external diameter. The speed of the wheel was 7500 rev / min. (9000 rev / min for comparative example 1). A feed rate of 100 mm / min and a cutting depth of 2.34 mmr was used. The cut was cooled by a flow of 56.4 l / min. of 5% of an antioxidant substance with stabilized de-mineralized water discharged through a rectangular 1.58 mm x 85 7 mm nozzle at a pressure of 2.8 kg / cm2. The results of the cuts are shown in box II. The innovative wheel worked properly compared to all the performance criteria in the cut. For example, in the second series of cuts, the maximum chipping size was smaller than that of the comparative wheel and continued decreasing to 7 μm in the fourth series of cuts. The straightness of the cut was better with the comparative wheel and the wear of the wheel was in par with the comparative example 1. It should also be noted that the wheel of comparative example 1 necessarily operated at a rotation speed greater by 20% and required approximately a power greater than 52% than the new wheel (approximately 520 W compared to 340 W).

CUADR 11 LongiDesgasPoten¬ Straightness of the piece of Radial cia factor1 tud of the cuts cutting wheel work for cut accum. accum Turn No. Acum. m μm μm μm / m Sliver- Sliver- μm W Nod. prom. μm μm Ex. 1 - 9 9 1.35 5.08 5.08 7.4 13 < 5 < 5 372-328 9 18 2.70 5.08 10.16 7.4 8 < 5 < 5 336- 288 9 27 4.05 2.54 12.70 3.7 8 < 5 < 2.5 288-296 9 36 5.40 2.54 15.24 3.7 7 < 5 < 5 264-296 Ex. 9 9 1.35 5.08 5.08 3.7 11 < 5 < 5 520- compa536 ratios 1 9 18 2.70 10.16 15.24 7.4 9 27 4.05 5.08 20.32 3.7 9 36 5.40 2.54 22.86 1.9 10 < 5 < 5 9 45 6.75 5.08 27.94 3.7 9 54 8.10 2.54 30.48 1.9 9 63 9.45 5.08 35.56 3.7 14 < 5 < 5 560- 576 1 Wear factor = wear of the radial wheel divided by the length of the cut workpiece EXAMPLES 3 AND 4 AND COMPARATIVE EXAMPLES 2 TO 6 The rigidity of various abrasive wheels and bonding compositions were tested. Fine metallic powders with and without diamond grains were combined with proportions shown in Table III and mixed to form a uniform composition as in Example 1. Samples were produced with stress test by compressing the compositions in bone-form molds at room temperature under pressure in a range of 414-620 MPa (30-45 Tons / 2.54cm2) for 10 seconds, followed by concretion under vacuum as described in example 1. The test samples were subjected to a sonic module analysis and a standard voltage module measurement in an Instron model 3404 voltage test machine. The results are shown in Table 3. The modulus of tension of the novel grind sample (Example 3) exceeded by much 100 GPa and was much greater than the modules of conventional thin abrasive wheels (Comparative Examples 2 and 4). Example 4 demonstrates that a stiffening metal containing a particular bond produces a markedly high stiffness with respect to the conventional bonding compositions of comparative examples 3 and 5. It is believed that this high concreted binding composition is responsible for the General high rigidity of the abrasive tool. Additionally, the novel stiffness / nickel / tin improver composition in the present invention provides superior stiffness without sacrifice of bond strength, concrete density or other manufacturing features of the wheel. The novel bond compositions in this manner are useful for making abrasive tools, and especially thin abrasive wheels for cutting extremely hard workpieces.

TABLE III Example Example Example Example Example 3 * 4 ** comparison comparative comparative comparative 2 3 4 5 Copper,% 70 70 62 62 weight Tin,% in 17.6 17.6 9.1 9.1 9.2 9.2 weight Nickel,% in 58.8 58.8 7.5 7.5 15.3 15.3 weight Molybdenum 23.6 23.6 iron,% in 13.4 13.4 13.6 13.5 Diamond weight,% 18.8 18.8 18.8 in volume Module 148 95 99 sonic GPa Module 166 210 106 103 95 GPa tension * cold press < oncrecionada (concretion without pressure) hot press concreted EXAMPLE 5 A sample for a binding composition with 14% tin, 48% nickel and 38% tungsten powder was prepared as in the examples 3 and 4 and its elastic modulus was tested. The voltage module was 303 GPa. For comparison, elemental nickel, tin and tungsten have elastic moduli of 207, 41.3 and 410 GPa, respectively. Although the sample did not contain abrasive grains, this example shows the high modulus that can be obtained by a rigid nickel / tin bond with an amount as low as 38% tungsten. Although specific forms of the invention have been selected for illustration in the examples and the foregoing description is given in specific terms for purposes of describing these forms of the invention, this description was not created with the intention of limiting the scope of the invention that it is defined in the claims below.

Claims (29)

NOVELTY OF THE INVENTION CLAIMS

1. - An abrasive wheel comprising an abrasive disk consisting essentially of about 2.5 to 50% by volume of abrasive grains and an amount of complement of a particular joint of a composition comprising a metal component, the disk having a uniform thickness in a range from 20 to 2500 μm, characterized in that the metal component consists essentially of nickel and tin, and the metal that improves rigidity is selected from the group consisting of molybdenum, rhenium, tungsten or a mixture thereof, and the disk has an elastic modulus of at least about 130 GPa.

2. The abrasive wheel according to claim 1, further characterized in that the metallic component consists essentially of at least 50% by weight of nickel and less than 50% by weight of tin.

3. The abrasive wheel according to claim 2, wherein the concreted joint comprises a) about 38 to 86% by weight of nickel; b) about 10 to 25% by weight of tin; and c) about 4 to 40% by weight of metal that improves stiffness, and where the total of a + b + c is 100% by weight.

4. The abrasive wheel according to claim 3, further characterized in that the metal that improves rigidity is molybdenum.

5. - The abrasive wheel according to claim 3, further characterized in that the metal that improves rigidity is rhenium.

6. The abrasive wheel according to claim 3, further characterized in that the metal that improves rigidity is tungsten.

7. The abrasive wheel according to claim 3, further characterized in that the metal that improves rigidity is a mixture of at least molybdenum, rhenium and tungsten.

8. The abrasive wheel according to claim 7, further characterized in that the molybdenum is a main fraction of the mixture.

9. The abrasive wheel according to claim 1, further characterized in that the concrete connection comprises nickel powder, tin powder and a metal that improves the concrete stiffness powder.

10. The abrasive wheel according to claim 1, further characterized in that the abrasive grains are of a hard abrasive selected from the group consisting of diamond, cubic boron nitride, silicon carbide, fuming aluminum oxide, microcrystalline alumina, nitride of silicon, boron carbide, tungsten carbide and mixtures of at least two of these.

11. The abrasive wheel according to claim 10, further characterized in that the abrasive grains are diamond.

12. - The abrasive wheel according to claim 1, further characterized in that the abrasive grains comprise close to 20 to about 50% by volume of the abrasive disk and the abrasive disk additionally comprises pores occupying at most about 10% by volume of the concreted joint and the abrasive grain.

13. The abrasive wheel according to claim 1, further characterized in that it consists essentially of an abrasive disk having a circumferential edge with a diameter of approximately 40 to 120 mm, which defines an axial screw hole of approximately 12 to 90 mm, having a uniform thickness in a range of about 175 to 200 μm, and which consists essentially of diamond grains and a concreted joint comprising about 18% by weight of tin, about 24% by weight of molybdenum and about 58% by weight of nickel.

14. The abrasive wheel according to claim 1, further characterized in that it consists essentially of an abrasive disk having a circumferential edge with a diameter of approximately 40 to 120 mm, which defines an axial screw hole of approximately 12 to 90 mm, having a uniform thickness in a range of about 175 to 200 μm, and which consists essentially of diamond grains and a concreted joint comprising about 18 wt% of tin, about 24 wt% of tungsten and about 58% by weight of nickel.

15. The abrasive wheel according to claim 1, further characterized in that it consists essentially of an abrasive disk having a circumferential edge of diameter of about 40 to 120 mm, which defines an axial screw hole of about 12 to 90 mm, which has a uniform thickness in a range of about 175. at 200 μm, and which consists essentially of diamond grains and a concreted joint comprising about 18% by weight of tin, about 24% by weight of rhenium and about 58% by weight of nickel.

16. A method for cutting a workpiece comprising the step of the workpiece contacting at least one abrasive wheel comprising an abrasive disk consisting essentially of about 2.5 to 50% by volume of abrasive grains and a quantity of the complement of a specific connection of a composition comprising a metallic component, the disc has a uniform thickness in a range of 20 to 2500 μm, further characterized in that the metallic component consists essentially of nickel and tin, and a metal that it improves the rigidity selected from the group consisting of molybdenum, rhenium, tungsten and a mixture of at least two of these, and the abrasive disk has an elastic modulus of at least about 130 GPa.

17. The method according to claim 16, further characterized in that the abrasive wheel consists essentially of an abrasive disk having a circumferential edge with a diameter of approximately 40 to 120 mm, which defines an axial screw hole of approximately 12 to 90. mm, which has a uniform thickness in a range of about 175 to 200 μm, where the abrasive disk consists essentially Mixture of diamond grains in a specific joint of a composition comprising about 36 to 86% by weight of nickel, 10 to 25% by weight of tin and 4 to 40% by weight of molybdenum, the total nickel, tin and molybdenum being 100% by weight.

18. The method according to claim 16, further characterized in that the abrasive wheel consists essentially of an abrasive disk having a circumferential edge with a diameter of approximately 40 to 120 mm, which defines an axial screw hole of approximately 12 to 90 mm, which has a uniform thickness in a margin 0 of about 175 to 200 μm, where the abrasive disk consists essentially of diamond cvans in a concreted joint of a composition that • comprises about 36 to 86% by weight of nickel, 10 to 25% by weight of tin and 4 to 40% by weight of tungsten, the total nickel, tin and tungsten being 100% by weight. 5.

The method according to claim 16, further characterized in that the abrasive wheel consists essentially of an abrasive disk having a circumferential edge with a diameter of approximately 40 to 120 mm, which defines an axial screw hole of approximately 12 to 90 mm, which has a uniform thickness in a margin 0 of about 175 to 200 μm, wherein the abrasive disk consists essentially of diamond grains in a concreted joint of a composition comprising about 36 to 86% by weight of nickel, from 10 to 25% by weight of tin and from 4 to 40% by weight of rhenium, the total of nickel, tin and rhenium being 100% by weight.

20. The method according to claim 16 wherein the workpiece is selected from titanium-alumina carbide and silicon.

21. A method for making an abrasive tool having a uniform thickness in a range of 20 to 2500 μm, comprising the steps of a) providing previously selected amounts of particulate ingredients comprising 1) abrasive grains; and 2) a binding composition consisting essentially of nickel powder, tin powder and molybdenum, rhenium, tungsten and a mixture thereof; - «b) mix the ingredients into particles to form a uniform composition; c) placing the uniform composition in a mold of a preselected thin disc shape; compressing the mold at a pressure in a range of about 345 to 690 MPa for an effective time to form a molded article; e) heating the molded article to a temperature on a scale of about 1050 to 1200 ° C for an effective time to specify the binding composition; f) cooling the molded article to form the abrasive tool; and g) reducing the pressure in the molded article to a low pressure of less than 100 MPa after the compression step and keeping the pressure low during the heating step.

22. The method according to claim 21, wherein the pressure in the molded article is maintained on a scale of about 25 to 75 MPa during the heating step.

23. - The method according to claim 1, wherein the particle ingredients comprise a) about 38 to 86% by weight of nickel; b) about 10 to 25% by weight of tin; and c) about 4 to 40% by weight of molybdenum, the total of a, b and c being 100% by weight.

24. The method according to claim 1, wherein the particle ingredients comprise a) about 38 to 86% by weight of nickel; b) about 10 to 25% by weight of tin; and c) about 4 to 40% by weight of tungsten, the total of a, b and c being 100% by weight.

25. The method according to claim 1, wherein the particulate ingredients comprise a) about 38 to 86% by weight of nickel; b) about 10 to 25% by weight of tin; and c) about 4 to 40% by weight of rowing, the total of a, b and c being 100% by weight.

26. The method according to claim 21, further characterized in that the abrasive tool is a disk having a uniform thickness on a scale of approximately 175 to 200 μm., a circumferential edge with a diameter of about 40 to 120 mm and whose disk defines an axial screw hole of approximately 12 to 90 mm.

27. The method according to claim 21, further characterized in that the particulate ingredients further comprise about 20 to 50% by volume abrasive grains of a hard abrasive selected from the group consisting of diamond, cubic boron nitride, carbide of silicon, fuming aluminum oxide, microcrystalline alumina, silicon nitride, boron carbide, tungsten carbide and mixtures of at least two of these.

28. The method according to claim 27, further characterized in that the abrasive grains are diamond.

29. The method according to claim 21, further characterized in that the heating step occurs while the molded article is maintained at a pressure of the compression step. siMÉttl K ^ Ugi ¡^ A ^ j ^ gÍ |