JP2016069450A - Hard metallic material polishing abrasive grain, polishing composition, and hard metallic product production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an abrasive grain that efficiently polishes a hard metallic material; a polishing composition containing the abrasive grain; and a hard metallic material production method using the composition.SOLUTION: Provided is a hard metallic material polishing abrasive grain which is an abrasive grain for supplying to a polishing surface plate and polishing a hard metallic material, and in which the average particle size is 2 to 10 μm, and the retention rate with respect to the polishing surface plate is 5 to 60%; from a standpoint of polishing efficiency, an abrasive grain substantially composed of a titanium diboride is particularly preferred; a preferred example of a hard metallic material includes a stainless steel.SELECTED DRAWING: None

Description

  The present invention relates to abrasive grains for polishing hard metal materials and use thereof. Specifically, the present invention relates to the above abrasive grains, a polishing composition containing the abrasive grains, and a method for producing a hard metal product using the polishing composition containing the abrasive grains.

  Hard metal materials such as stainless steel and titanium alloys are generally difficult to polish. For this reason, high-hardness abrasive grains such as diamond, CBN (cubic boron nitride), boron carbide and the like are usually used for lapping of such hard metal materials. For example, Patent Document 1 describes polishing stainless steel using diamond abrasive grains. Patent Document 2 is a technical document relating to polishing of a silicon carbide single crystal rather than a hard metal material.

JP 2006-249536 A Japanese Patent Laid-Open No. 7-80770

  However, high hardness abrasive grains such as diamond are generally expensive. For this reason, it is not easy to reduce the raw material cost while securing a practical polishing efficiency (polishing rate) in the polishing process of the hard metal material.

  This invention is made | formed in view of this condition, Comprising: It aims at providing the abrasive grain which can grind | polish a hard metal material efficiently. Another object of the present invention is to provide a polishing composition containing the above abrasive grains. Another related object is to provide a method of manufacturing a hard metal product using the abrasive grains.

According to the present invention, an abrasive for polishing a hard metal material supplied to a polishing surface plate is provided. The abrasive grains have an average particle diameter of 2 to 10 μm. The abrasive grains have a retention rate of 5 to 60% with respect to the polishing surface plate.
Such abrasive grains have an average particle diameter suitable for polishing (particularly lapping) of the hard metal having the above-mentioned retention rate in an appropriate range, and thereby processing force by the abrasive grains is applied to the hard metal material as an object to be polished. It can be made to act efficiently. Therefore, according to the said abrasive grain, practical polishing efficiency can be achieved, suppressing raw material cost.

  According to the present invention, there is also provided a polishing composition comprising any of the abrasive grains disclosed herein. According to the polishing composition, practical polishing efficiency can be achieved while reducing raw material costs in polishing hard metal materials. The polishing composition typically further includes a solvent for dispersing the abrasive grains.

  In a preferred embodiment of the polishing composition disclosed herein, the concentration of the abrasive grains in the composition is 0.3 to 10% by weight. In the polishing composition having an abrasive grain concentration in the above range, it is possible to more suitably achieve both a reduction in raw material costs and a good polishing efficiency.

  According to the present invention, a method for producing a hard metal product is also provided. The method typically includes setting a hard metal material as an object to be polished in a polishing apparatus equipped with a polishing platen. The method also includes supplying a polishing composition to the polishing surface plate. As the polishing composition, a polishing composition containing any of the abrasive grains disclosed herein can be used. The method further includes polishing the polishing object by moving the polishing platen relative to the polishing object. According to this method, a hard metal product having a polished surface can be efficiently produced while suppressing raw material costs.

  As another aspect of the present invention, a method for polishing a hard metal material is provided. The method typically includes setting a hard metal material as an object to be polished in a polishing apparatus equipped with a polishing platen. The method also includes supplying a polishing composition to the polishing surface plate. As the polishing composition, a polishing composition containing any of the abrasive grains disclosed herein can be used. The method further includes polishing the polishing object by moving the polishing platen relative to the polishing object. According to this method, the hard metal material can be efficiently polished while suppressing the raw material cost.

  The polishing platen in any of the techniques disclosed herein may be surface-adjusted with green silicon carbide abrasive grains (hereinafter also referred to as “GC abrasive grains”) having an average particle diameter of 25 to 120 μm. According to such a polishing surface plate, the processing force by the abrasive grains disclosed herein can be efficiently applied to the hard metal material that is an object to be polished.

  As the polishing surface plate in any of the techniques disclosed herein, one having a cast iron surface can be preferably used. In the polishing using such a polishing surface plate (cast iron surface plate), the effects of the present invention can be suitably exhibited.

  Preferable examples of the abrasive grains in any of the techniques disclosed herein include abrasive grains substantially consisting of titanium diboride. According to such abrasive grains, it is possible to particularly suitably achieve both a reduction in raw material costs and a good polishing efficiency.

  A suitable example of the hard metal material in any of the techniques disclosed herein is stainless steel. That is, the technique disclosed herein can be preferably applied to the polishing of stainless steel. Among these, application to stainless steel wrapping is particularly significant.

  Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

<Polishing object>
The technique disclosed here can be preferably applied to polishing of various hard metal materials. Here, the hard metal material means a material having a relatively high hardness among metal materials, and specifically refers to a metal material having a Vickers hardness exceeding 100 HV. The Vickers hardness indicates the fastness to the indentation pressure, and specifically is a hardness measured by the method described in JIS Z2244: 2009.
The hard metal material may be a simple substance or an alloy. Typical examples of the hard metal material include alloy materials such as titanium alloy, nickel alloy, and stainless steel.

  The titanium alloy is an alloy mainly composed of titanium, and may include at least one selected from the group consisting of aluminum, iron, vanadium, and the like as a metal species other than the main component. The content of metal species other than the main component may be, for example, 3.5 to 30% by weight of the entire titanium alloy. As a titanium alloy, the thing described in JIS H4600: 2012, 11-23 types, 50 types, 60 types, 61 types, and 80 types are mentioned, for example.

  The nickel alloy is an alloy containing nickel as a main component, and may include at least one selected from the group consisting of iron, chromium, molybdenum and cobalt as a metal species other than the main component. The content of metal species other than the main component can be, for example, 20 to 75% by weight of the entire nickel alloy. Examples of the nickel alloy include NCF600, 601, 625, 750, 800, 800H, 825, NW0276, 4400, 6002, 6022 and the like in the alloy number described in JIS H4551: 2000.

  The technique disclosed herein can be particularly preferably applied to the polishing of stainless steel. Stainless steel is an alloy containing iron as a main component, and may include at least one selected from the group consisting of chromium, nickel, molybdenum, and manganese as a metal species other than the main component. The content of metal species other than the main component may be, for example, 10 to 50% by weight of the entire stainless steel. Examples of stainless steel include SUS201, 303, 303Se, 304, 304L, 304NI, 305, 305JI, 309S, 310S, 316, 316L, 321, 347, 384, in the symbols of the type described in JIS G4303: 2005. XM7, 303F, 303C, 430, 430F, 434, 410, 416, 420J1, 420J2, 420F, 420C, 631J1 and the like.

<Abrasive>
In the technique disclosed here, the material of the abrasive grains is not particularly limited. For example, diamond; boride such as titanium diboride, zirconium boride, tantalum boride, chromium boride, molybdenum boride, tungsten boride, lanthanum boride; carbide such as boron carbide, silicon carbide; aluminum oxide, oxidation Abrasive grains substantially composed of any of oxides such as silicon, zirconium oxide, titanium oxide, and cerium oxide; nitrides such as boron nitride (typically cubic boron nitride); and the like. From the viewpoint of polishing efficiency, it is preferable to use abrasive grains having high hardness. As a particularly preferable abrasive grain from such a viewpoint, an abrasive grain substantially composed of either titanium diboride or diamond is exemplified.

  In the present specification, regarding the composition of the abrasive grains, “substantially consisting of X” or “substantially consisting of X” means that the proportion of X in the abrasive grains (the purity of X) is the weight. It is 90% or more on a standard basis, preferably 95% or more, more preferably 97% or more, still more preferably 98% or more, for example 99% or more.

Preferable examples of the abrasive grains in the technology disclosed herein include abrasive grains substantially composed of titanium diboride (hereinafter also referred to as “titanium diboride abrasive grains”). Titanium diboride used as an abrasive is typically a high hardness material having a Vickers hardness (Hv) of 2000 or more. In addition to such high hardness, titanium diboride abrasive grains are also preferable in that they have higher heat resistance (difficult to cause surface alteration due to heat) than diamond abrasive grains.
Known methods for obtaining titanium diboride abrasive grains include a method in which titanium and boron are directly reacted, a method in which titanium oxide and boron oxide are reduced, and a method in which a titanium and boron halide is vapor-phase reacted. (See, for example, JP-A-5-139725). In the technology disclosed herein, as the titanium diboride abrasive grains, titanium diboride powder that can be generally obtained or manufactured can be used without particular limitation without being limited by the manufacturing method and form.

Titanium diboride is a crystalline component that typically has a hexagonal crystal structure. In the titanium diboride abrasive grains disclosed herein, the size of crystals is not limited, and an amorphous component may be included. Further, an element other than titanium and boron, for example, impurities such as carbon, iron, oxygen, nitrogen, silicon, aluminum, and zirconium, may be included as long as the performance of the abrasive grains is not significantly impaired.
Usually, it is advantageous that the purity of titanium diboride in the titanium diboride abrasive grains is higher. Specifically, the purity of titanium diboride is preferably 90% by weight or more, preferably 95% by weight or more, and more preferably 99% by weight or more.
The purity of titanium diboride can be measured by, for example, the measured value of titanium diboride using a fluorescent X-ray apparatus, or by the intensity of a diffraction peak by a powder X-ray diffraction method. In addition, when the purity measured by the fluorescent X-ray apparatus and the purity measured based on the powder X-ray diffraction method are different, the measurement result with higher purity is adopted as the purity of the titanium diboride. Shall.

The average particle diameter of the abrasive grains is typically 1 μm or more, and usually 2 μm or more. As the average particle size of the abrasive grains increases, the polishing efficiency tends to improve. From this viewpoint, the average particle diameter of the abrasive grains is preferably 2.2 μm or more, more preferably 2.5 μm or more, and further preferably 3 μm or more.
In the present specification, unless otherwise specified, the average particle size of the abrasive grains is a particle size (50%) at an integrated value of 50% in a volume-based particle size distribution determined by a laser diffraction / scattering particle size distribution measuring apparatus. Volume average particle diameter). As a laser diffraction / scattering particle size distribution measuring apparatus, for example, “LA-950” manufactured by Horiba, Ltd. can be used.

  Further, the average particle diameter of the abrasive grains is typically 20 μm or less, and it is usually preferably 10 μm or less because the preferable retention disclosed herein is easily obtained. As the average particle size of the abrasive grains decreases, the dispersion stability of the abrasive grains in the polishing composition tends to improve. In addition, the surface accuracy of the hard metal material after polishing tends to be improved. For example, the generation of scratches on the hard metal material due to polishing is suppressed, and the roughness of the hard material surface after polishing (arithmetic average roughness (Ra)) also tends to decrease. From these circumstances, the average particle diameter of the abrasive grains is preferably 8 μm or less, and more preferably 5 μm or less.

The technique disclosed herein can be preferably implemented in a mode in which the retention rate of the abrasive grains with respect to the polishing surface plate is 5% or more. From the viewpoint of obtaining higher polishing efficiency, the retention rate is more preferably 10% or more, and further preferably 15% or more. Note that how to obtain the retention rate will be described later.
Further, the polishing efficiency tends to decrease even if the retention rate of the abrasive grains with respect to the polishing surface plate is too high. Therefore, the retention is suitably 60% or less, preferably 55% or less, more preferably 40% or less, and even more preferably 35% or less.

  As a suitable example of the abrasive grain disclosed here, an abrasive having the above-mentioned retention in the range of 5 to 60% can be mentioned. According to the polishing performed by supplying such abrasive grains to the polishing surface plate, the processing force by the abrasive grains can be efficiently applied to the hard metal material. For this reason, practical polishing efficiency can be achieved not only in the polishing mode using diamond abrasive grains but also in the polishing mode using other abrasive grains such as titanium diboride abrasive grains. Therefore, it is possible to suitably achieve both a reduction in raw material cost and a practical polishing efficiency. Better results can be achieved with abrasive grains having a retention rate in the range of 15-35%.

<Polishing composition>
The polishing composition disclosed herein contains at least abrasive grains, and typically contains abrasive grains and a solvent for dispersing the abrasive grains. As said abrasive grain, 1 type can be used individually or in combination of 2 or more types among the abrasive grains mentioned above. For example, a polishing composition containing at least titanium diboride abrasive grains as abrasive grains is preferable. In such a polishing composition, it is possible to suitably achieve both a reduction in raw material costs and a good polishing efficiency.

The polishing composition disclosed herein may contain a combination of titanium diboride and other abrasive grains. Examples of the other abrasive grains include diamond; borides such as zirconium boride, tantalum boride, chromium boride, molybdenum boride, tungsten boride, and lanthanum boride; carbides such as boron carbide and silicon carbide; Abrasive grains substantially composed of any of oxides such as aluminum, silicon oxide, zirconium oxide, titanium oxide, and cerium oxide; nitrides such as boron nitride (typically cubic boron nitride); Can be mentioned. Quartz etc. are mentioned as an example of the abrasive grain which consists of silicon oxide substantially.
From the viewpoint of polishing efficiency, it is generally advantageous that the proportion of titanium diboride abrasive grains in the entire abrasive grains contained in the polishing composition is high. For example, the proportion of titanium diboride abrasive grains in the entire abrasive grains contained in the polishing composition is preferably 70% by weight or more, and more preferably 90% by weight or more.

  The solvent used in the polishing composition is not particularly limited as long as it can disperse the abrasive grains. As the solvent, water, and organic solvents such as alcohols, ethers, glycols, and various oils can be used. Examples of the oils include mineral oil, synthetic oil, vegetable oil and the like. Such a solvent can be used individually by 1 type or in combination of 2 or more types. From the viewpoints of volatility, detergency, and ease of processing of the polishing waste liquid, water or a mixed solvent containing water as a main component can be preferably employed. Usually, it is preferable that 90 volume% or more of the solvent contained in polishing composition is water, and it is more preferable that 95 volume% or more (typically 99-100 volume%) is water. As water, ion exchange water (deionized water), distilled water, pure water, or the like can be used.

The abrasive grain concentration in the polishing composition is not particularly limited. For example, the abrasive concentration can be 0.05% by weight or more, and usually 0.1% by weight or more is appropriate. As the abrasive concentration increases, a higher polishing efficiency tends to be obtained. From this viewpoint, the abrasive concentration is preferably 0.3% by weight or more, and more preferably 0.5% by weight or more.
From the viewpoint of raw material cost, the abrasive concentration in the polishing composition is usually 20% by weight or less, preferably 10% by weight or less. In a preferred embodiment, the abrasive concentration can be 5% by weight or less, and may be 3% by weight or less. For example, the abrasive concentration of the polishing composition is preferably 0.5 to 5% by weight, and more preferably 0.5 to 3% by weight.
According to the technique disclosed here, as described above, the processing force by the abrasive grains can be efficiently applied to the hard metal material. In a preferred embodiment, the abrasive concentration can be 2% by weight or less (for example, 0.5 to 2% by weight), further 1% by weight or less (for example, 0.5 to 1% by weight). In this case, a practical polishing efficiency can be achieved. According to this aspect, it is possible to achieve both high cost reduction and raw material cost reduction.

  A dispersing agent may be added to the polishing composition as necessary for the purpose of improving dispersion stability. Examples of the dispersant include polyphosphates such as sodium hexametaphosphate and sodium pyrophosphate. Other examples of the dispersant include water-soluble polymers and salts thereof.

  Examples of water-soluble polymers that can be used as dispersants include polycarboxylic acids, polycarboxylic acid salts, polysulfonic acid, polysulfonic acid salts, polyamines, polyamides, polyols, polysaccharides, and their derivatives and copolymers. Etc. More specifically, polystyrenesulfonic acid and its salt, polyisoprenesulfonic acid and its salt, polyacrylic acid and its salt, polymaleic acid, polyitaconic acid, polyvinyl acetate, polyvinyl alcohol, polyglycerin, polyvinylpyrrolidone, isoprenesulfonic acid And acrylic acid copolymer, polyvinylpyrrolidone-polyacrylic acid copolymer, polyvinylpyrrolidone-vinyl acetate copolymer, salt of naphthalenesulfonic acid formalin condensate, copolymer of diallylamine hydrochloride and sulfur dioxide, carboxymethylcellulose Carboxymethylcellulose salts, hydroxyethylcellulose, hydroxypropylcellulose, pullulan, chitosan, chitosan salts and the like.

  The weight average molecular weight (Mw) of the water-soluble polymer is not particularly limited. From the viewpoint of sufficiently exhibiting the effect of improving the dispersion stability, it is usually appropriate to be about 10,000 or more (for example, more than 50,000). The upper limit of Mw is not particularly limited, but it is usually about 800,000 or less (eg, 600,000 or less, typically 300,000 or less) from the viewpoints of filterability and detergency. In addition, as the Mw of the water-soluble polymer, a value based on gel permeation chromatography (GPC) (aqueous, converted to polyethylene oxide) can be adopted.

  Although not particularly limited, in a polishing composition containing a dispersant, it is appropriate that the content of the dispersant is, for example, 0.001% by weight or more, preferably 0.005% by weight. Above, more preferably 0.01% by weight or more, still more preferably 0.02% by weight or more. The content is usually suitably 10% by weight or less, preferably 5% by weight or less, for example 1% by weight or less.

  Various types of surfactants may be added to the polishing composition as necessary. The surfactant here is typically a compound having a lower molecular weight than that of the dispersant, and preferably a compound having a molecular weight of less than 10,000. The surfactant in the polishing composition is adsorbed on the surface of abrasive grains and hard metal materials to change their surface state, change the dispersibility of abrasive grains, and form a protective film on the surface of hard metal materials You can make it. By this, the effect of suppressing generation | occurrence | production of the defect in the surface of a hard metal material or preventing the expansion of a defect may be exhibited.

As the surfactant, any of anionic, nonionic, and cationic surfactants can be used. Usually, either one or both of an anionic surfactant and a nonionic surfactant can be preferably used.
Examples of the nonionic surfactant include a polymer having a plurality of the same or different types of oxyalkylene units, and a compound in which an alcohol, hydrocarbon or aromatic ring is bonded to the polymer. More specifically, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene polyoxybutylene alkyl ether, polyoxyethylene polyoxypropylene polyoxybutylene alkyl ether, polyoxyethylene carboxylic acid ester, polyoxyethylene Oxyethylene carboxylic acid diester, polyoxyethylene polyoxypropylene carboxylic acid ester, polyoxyethylene polyoxybutylene carboxylic acid ester, polyoxyethylene polyoxypropylene polyoxybutylene carboxylic acid ester, polyoxyethylene polyoxypropylene copolymer, polyoxyethylene Polyoxybutylene copolymer, polyoxyethylene polyoxypropylene polyoxybutylene copolymer , Polyoxyethylene sorbitan fatty acid ester and polyoxyethylene sorbite fatty acid ester, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoleic trioleate Examples thereof include oxyethylene sorbitan, polyoxyethylene sorbitan monocaprylate, polyoxyethylene sorbitol tetraoleate and the like.

  Examples of anionic surfactants include sulfonic acid surfactants, and more specifically alkyl sulfonic acids, alkyl ether sulfonic acids, polyoxyethylene alkyl ether sulfonic acids, alkyl aromatic sulfonic acids, alkyl ether aromatics. Examples thereof include sulfonic acid and polyoxyethylene alkyl ether aromatic sulfonic acid.

  Although not particularly limited, in a polishing composition containing a surfactant, it is appropriate that the content of the surfactant is, for example, 0.001% by weight or more, preferably 0.005. % By weight or more, more preferably 0.01% by weight or more, still more preferably 0.02% by weight or more. In addition, the content is usually suitably 10% by weight or less, preferably 5% by weight or less, for example 1% by weight or less.

  The pH of the polishing composition is not particularly limited. Usually, it is appropriate to adjust the pH of the polishing composition to 1 or more and 14 or less. When the pH of the polishing composition is within the above range, practical polishing efficiency is easily achieved. It is preferable to use a polishing composition having an appropriate pH in consideration of the vulnerability of the polishing object to pH. For example, in the case of stainless steel, the pH of the polishing composition can be 1 or more and 8 or less, and more preferably 1 or more and 5 or less (for example, 2 or more and 4 or less).

  Various acids, bases, or salts thereof can be used to adjust the pH of the polishing composition. Specifically, for example, organic acids such as citric acid and other organic carboxylic acids, organic phosphonic acids and organic sulfonic acids, inorganic acids such as phosphoric acid, phosphorous acid, sulfuric acid, nitric acid, hydrochloric acid, boric acid and carbonic acid, tetramethoxyammonium One or more selected from organic bases such as oxide, trimethanolamine and monoethanolamine, inorganic bases such as potassium hydroxide, sodium hydroxide and ammonia, and salts thereof can be used.

  Among the above acids and bases, in particular, when a weak acid and a strong base, a strong acid and a weak base, or a combination of a weak acid and a weak base, a buffering action of pH can be expected. Moreover, when it is set as the combination of a strong acid and a strong base among said acids and bases, not only pH but electrical conductivity can be adjusted with a small amount.

The polishing composition can contain components other than those described above, if necessary. Examples of such components include anticorrosives, chelating agents, preservatives, antifungal agents and the like.
Examples of the corrosion inhibitor include amines, pyridines, tetraphenylphosphonium salts, benzotriazoles, triazoles, tetrazoles, benzoic acid and the like.
Examples of chelating agents include carboxylic acid chelating agents such as gluconic acid, amine chelating agents such as ethylenediamine, diethylenetriamine, and trimethyltetraamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, triethylenetetraminehexaacetic acid. , Polyaminopolycarboxylic chelating agents such as diethylenetriaminepentaacetic acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetrakis (methylenephosphonic acid), diethylenetriaminepenta ( Methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-to Organic phosphonic acid chelating agents such as carboxylic acid, phenol derivatives, 1,3-diketones and the like.
Examples of preservatives include sodium hypochlorite and the like. Examples of the antifungal agent include oxazolines such as oxazolidine-2,5-dione.

  The manufacturing method of polishing composition disclosed here is not specifically limited, A well-known method is employable suitably. For example, a polishing composition can be produced by mixing abrasive grains, a solvent, and other components used as necessary.

  The polishing composition as described above is typically used in the polishing of a hard metal material as an object to be polished in the form of a polishing liquid containing the polishing composition. The polishing liquid may be prepared, for example, by diluting a polishing composition. Or you may use polishing composition as polishing liquid as it is. That is, the concept of the polishing composition in the technology disclosed herein includes both the polishing liquid (working slurry) supplied to the object to be polished and the concentrated liquid diluted and used as the polishing liquid. .

The polishing composition disclosed herein may be in a concentrated form (in the form of a concentrated liquid) before being supplied to the object to be polished. Such a polishing composition in the form of a concentrated solution is advantageous from the viewpoints of convenience, cost reduction, etc. during production, distribution, storage and the like. The concentration factor can be set to about 1.5 to 50 times, for example. From the viewpoint of the storage stability of the concentrate, a concentration factor of about 2 to 20 times (typically 2 to 10 times) is usually appropriate.
Thus, the polishing composition in the form of a concentrated liquid can be suitably used in a mode in which a polishing liquid is prepared by diluting at a desired timing and the polishing liquid is supplied to a polishing object.

  The abrasive grains disclosed herein or the polishing composition containing the abrasive grains can be used for polishing an object to be polished (here, a hard metal material) using a general polishing apparatus. The present invention can be applied to both polishing using a single-side polishing apparatus and polishing using a double-side polishing apparatus. In a single-side polishing apparatus, a polishing object is held by using a holder called a carrier, and the surface plate is rotated by pressing the surface plate against one side of the polishing object while supplying the polishing composition. Polish one side. In a double-side polishing apparatus, a polishing object is held using a holder called a carrier, a surface plate is pressed against the opposite surface of the polishing object while supplying the polishing composition from above, and they are rotated in a relative direction. Thus, both surfaces of the object to be polished are polished simultaneously. At this time, the method of directly polishing the polishing object using the surface of the surface plate is called lapping. A polishing pad is attached to the surface of the surface plate, and polishing is performed between the attached polishing pad surface and the polishing object. This method is called policing.

<Polishing surface plate>
The abrasive grains disclosed herein or a polishing composition containing the abrasive grains are typically supplied to a metal polishing platen for polishing a hard metal material, that is, used for wrapping a hard metal material. It is done. The polishing surface plate used for lapping is required to have a property that can be easily processed in order to maintain the accuracy of the surface surface (surface facing the object to be polished). For this reason, a polishing surface plate in which at least the surface plate surface is made of a metal such as cast iron, tin, copper, or a copper alloy is preferably used. As the polishing platen, a plate having a groove on the surface of the platen may be used for the purpose of stably supplying the polishing composition and adjusting the processing pressure. The shape and depth of the groove are arbitrary, and for example, a groove in which a groove is engraved in a lattice shape or a radial shape can be used.

The surface of the polishing surface plate (surface plate surface) preferably has a surface state in which the retention rate of abrasive grains applied to the polishing of the hard metal material by the polishing surface plate is in the above-described preferable range. The retention rate is a guideline for determining how much of the fine grooves on the surface plate have a shape and size suitable for holding abrasive grains (hereinafter also referred to as “effective grooves”) on the surface plate surface. As a useful index. The shape of the minute groove is not particularly limited. For example, the aspect ratio of the fine groove is not particularly limited. The concept of the microgroove here may include a shape generally called a dent or a dent.
In the technique disclosed herein, a fine groove having a width of an average particle diameter + 0.1 μm or more and a depth of an average particle diameter / 2 or more in relation to the average particle diameter of the abrasive grains is used as the abrasive grains. It is recognized as an “effective groove” for If the width of the minute groove is equal to or larger than the average particle diameter +0.1 μm, it is considered that the opening has a sufficient opening size to fit the abrasive grains. In addition, if the depth of the minute groove is equal to or greater than the average particle diameter / 2, the fitted abrasive can be held to a certain degree of stability, and the abrasive power of the abrasive can be effectively applied to the object to be polished. It is thought to get. Specifically, the retention rate is determined according to “retention rate measurement” described in Examples described later.

In addition, the width | variety of the micro groove | channel recognized as an effective groove | channel should just be an average particle diameter +0.1 micrometer or more, and the upper limit in particular of a width | variety is not restrict | limited. From the viewpoint of the stability of holding the abrasive grains, a fine groove having a width of 7 times or less (preferably 5 times or less, for example, 3 times or less) of the average particle size +0.1 μm is preferable.
Further, the depth of the fine groove to be recognized as an effective groove may be an average particle diameter / 2 or more (that is, 0.5 times or more of the average particle diameter), and the upper limit of the depth is not particularly limited. From the viewpoint of the stability of holding the abrasive grains and the polishing efficiency, the depth of the fine grooves is preferably 0.5 times or more and 1.5 times or less of the average particle diameter, and is 0.5 times or more and less than 1 time. More preferably, it is 0.5 times or more and less than 0.9 times.
The technology disclosed herein is particularly effective for fine grooves having a width of 1 to 5 times the average particle diameter +0.1 μm and a depth of 0.5 to 1 time less than the average particle diameter. It is recognized as a groove suitable for holding (hereinafter also referred to as “highly effective groove”), and the retention calculated for the highly effective groove can be preferably implemented in a preferable range described above.

  The retention rate can be adjusted to be within a preferable range disclosed herein, for example, by changing one or both of the average particle diameter of the abrasive grains used and the surface condition of the polishing surface plate. As a method of changing the average particle diameter of the abrasive grains, a method of changing the abrasive grains used to one having a different average particle diameter or a method of blending two or more kinds of abrasive grains having different particle diameters at an appropriate ratio Etc. can be adopted. The surface state of the polishing surface plate can be changed by adjusting the surface state of the polishing surface plate (that is, performing surface adjustment).

  The surface adjustment of the polishing surface plate can be performed, for example, by polishing the surface of the polishing surface plate using a surface adjustment slurry containing abrasive grains having an appropriate average particle diameter and roughening the surface to a certain roughness. it can. Therefore, it is desirable to use a material that easily roughens the polishing surface plate as the abrasive. Examples of abrasive grains that can be preferably used for surface adjustment of the polishing surface plate include high-hardness abrasive grains such as GC abrasive grains, titanium diboride abrasive grains, and boron carbide abrasive grains. Among these, GC abrasive grains are preferable.

  The size of the abrasive grains used for the surface adjustment of the polishing surface plate can be selected according to the average particle diameter of the abrasive grains used for polishing the hard metal material and the target retention value. Although not particularly limited, in one embodiment of the technology disclosed herein, abrasive grains (for example, GC abrasive grains) having an average particle diameter of 25 to 120 μm, more preferably 45 to 75 μm, are used for the surface adjustment abrasive. It can employ | adopt preferably as a grain. As the surface-adjusting abrasive grains, two or more kinds of abrasive grains having different one or both of size and material may be blended and used.

  The abrasive concentration in the surface adjustment slurry and the polishing conditions in the surface adjustment of the polishing surface plate using the slurry are not particularly limited, and can be appropriately set so as to obtain a desired surface state. For example, the abrasive concentration in the surface conditioning slurry can be about 5 to 20% by weight (for example, 10 to 15% by weight).

  As will be understood from the above description and examples described later, the matters disclosed by the present specification include abrasive grains used for surface adjustment of the polishing surface plate in any of the techniques disclosed herein. . Moreover, the slurry for surface adjustment containing this abrasive grain is contained. As the surface-adjusting abrasive, an abrasive having an average particle diameter of 25 to 120 μm (more preferably 45 to 75 μm) can be preferably used. The abrasive grains may include at least one of GC abrasive grains, titanium diboride abrasive grains, and boron carbide abrasive grains. Among these, GC abrasive grains are preferable. The method for producing a hard metal product disclosed herein may further include a step of adjusting the surface of the polishing surface plate using the surface adjustment slurry. Also disclosed in the present specification is a hard metal material polishing comprising any of the hard metal material polishing compositions disclosed herein and any of the surface conditioning slurries disclosed herein. A composition set is included. This polishing composition set may be an embodiment containing abrasive grains constituting the composition instead of the hard metal material polishing composition. Further, the hard metal material polishing composition set may include an abrasive grain constituting the slurry instead of the surface conditioning slurry.

<Polishing method>
In the technique disclosed here, the polishing conditions of the object to be polished (hard metal material) are not particularly limited. For example, from the viewpoint of polishing efficiency, the polishing pressure per 1 cm ² of the processing area of the object to be polished is preferably 50 g or more, more preferably 100 g or more. Further, from the viewpoint of preventing deterioration of the surface of the polishing object and deterioration of the abrasive grains due to excessive heat generation accompanying an increase in load, it is usually appropriate that the polishing pressure per processing area of 1 cm ² is 1000 g or less.

  In general, the linear velocity may vary due to the influence of the platen rotation speed, the carrier rotation speed, the size of the polishing object, the number of polishing objects, and the like. In the technique disclosed herein, the linear velocity is preferably 10 m / min or more, and more preferably 30 m / min or more. Higher polishing efficiency tends to be obtained by increasing the linear velocity. Further, from the viewpoint of preventing damage to the polishing object and excessive heat generation, the linear velocity is usually preferably 300 m / min or less, and more preferably 200 m / min or less.

  The supply amount of the polishing composition at the time of polishing is not particularly limited. The supply amount is preferably set so that the polishing composition is sufficiently supplied between the object to be polished and the polishing surface plate so as to be supplied to the entire surface without unevenness. A suitable supply amount may vary depending on the material of the object to be polished, the configuration of the polishing apparatus, and other polishing conditions. A person skilled in the art can find an appropriate supply amount without undue burden based on the description in the present specification and common general technical knowledge.

  The polishing composition disclosed herein may be recovered after use and reused (circulated). More specifically, the used polishing composition discharged from the polishing apparatus may be once collected in a tank and supplied from the tank to the polishing apparatus again. In this case, the amount of the used polishing composition as a waste liquid can be reduced. This is preferable from the viewpoint of reducing environmental burden and cost.

  In circulating use of the polishing composition, at least one of the components (for example, abrasive grains) consumed or lost by being used for polishing among the components originally contained in the polishing composition You may make it supplement a part or all of the reduction | decrease about an ingredient. The replenishing components may be added individually to the used polishing composition, or may be added to the used polishing composition in the form of a mixture containing two or more components in any concentration. .

  Among the hard metal materials, when a material requiring particularly high surface accuracy such as an electronic material substrate or a crystal material manufacturing substrate is used as an object to be polished, any of the abrasive grains disclosed herein or the abrasive grains It is preferable to perform further polishing after polishing (lapping) with a polishing surface plate using a polishing composition containing. The abrasive grains of the polishing composition used for the polishing are preferably those having an average particle diameter of 0.30 μm or less, more preferably from the viewpoint of reducing waviness, roughness, defects, etc. of the surface of the object to be polished. It is 0.25 μm or less, more preferably 0.20 μm or less. From the viewpoint of improving the polishing efficiency (polishing rate), the average particle size of the abrasive grains contained in the polishing composition is preferably 0.01 μm or more, more preferably 0.02 μm or more. Abrasive grains suitably used in the polishing composition can be colloidal oxide particles such as colloidal silica. The average particle diameter of the abrasive grains in the polishing composition can be measured by a dynamic light scattering method using, for example, “Nanotrac UPA-UT151” manufactured by Nikkiso Co., Ltd.

  The pH of the polishing composition is not particularly limited, but is preferably 1 to 4 or 8 to 11. The pH of the polishing composition can be adjusted using various acids, bases or salts thereof as in the polishing composition used for polishing (lapping) with a polishing platen. The polishing composition may contain additives such as a chelating agent, a water-soluble polymer, a surfactant, an antiseptic, an antifungal agent, and an antirust agent as necessary. The polishing composition may be prepared by diluting a stock solution of the composition with water.

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples.

<Surface adjustment of polishing surface plate>
Under the following conditions A to E, the surface of a cast iron polishing surface plate (without grooves) used for a polishing experiment described later was adjusted. The size of each part of the polishing surface plate is 20 cm in diameter, 2.8 cm in diameter at the center, 8.6 cm in radius (excluding the center), and the effective area is 307.8456 cm ² .

(Adjustment condition A)
As a polishing machine for adjusting the surface of the polishing surface plate, a lens polishing machine “AL-2” manufactured by Udagawa Seiko Co., Ltd. was used. The polishing surface plate as a processing object was set on the cast iron surface plate of the polishing machine, and the surface plate was rotated while supplying the surface adjustment slurry to adjust the surface. As the slurry for surface adjustment, a slurry containing GC abrasive grains having an average particle diameter of 48 μm and GC abrasive grains having an average particle diameter of 74 μm at a weight ratio of 1: 1 at a total concentration of 13% by weight was used. The slurry supply rate was 14 mL / min, and the platen speed was 130 rpm. The surface adjustment time was set in a range of 1.5 hours to 2 hours so that the in-plane flatness of the polishing platen was within ± 5 μm. In-plane flatness of the polishing surface plate is measured along four lines intersecting at an angle of 45 degrees through the center of the object to be processed using a micro gauge “HYPREZ DIVISION” manufactured by Nippon Engis Co., Ltd. It was evaluated by performing.

(Adjustment conditions B to E)
The surface adjustment of the polishing surface plate was performed in the same manner as in the adjustment condition A, except that the average particle diameter of the abrasive grains contained in the surface adjustment slurry was changed as follows. All the abrasive grains used were GC abrasive grains manufactured by Fujimi Incorporated Co., Ltd., and the concentration of the abrasive grains in the surface adjustment slurry was 13 wt%.
Adjustment condition B: average particle size 74 μm
Adjustment condition C: average particle size 100 μm
Condition D: Average particle size 48 μm
Condition E: Average particle size 15 μm

(Retention rate measurement)
The surface of the polishing surface plate adjusted under the above conditions was observed with a shape measurement laser microscope “VK-X200” manufactured by Keyence Corporation. The observation locations were selected so that the portions other than the central portion of the polishing surface plate were increased along the radial direction of the polishing surface plate by 5 points and the distance from the center increased at substantially equal intervals. Within these five observation fields, the width and depth of the microgrooves existing on the surface of the polishing surface plate were measured for a range on a line segment having a length of 100 μm along the radial direction of the polishing surface plate. For the average particle diameter of each abrasive grain used in Examples 1 to 23 below, the width of the micro grooves is an average particle diameter +0.1 μm or more and the depth is an average particle diameter / 2 or more. Grooves were detected as effective grooves, and the ratio of the total width of these effective grooves to the total measured length (that is, 500 μm) in the five observation fields was calculated. In addition, the width | variety of each microgroove was measured along the said line segment.

<Polishing experiment>
(Preparation of polishing liquid)
As abrasive grains, four types of titanium diboride (TiB ₂ ) powders having an average particle diameter of 2.1 μm, 2.6 μm, 3.7 μm, and 7.7 μm were prepared. After adding a certain amount of 20 g / L citric acid and 5 g / L polyacrylic acid as additives to these abrasive grains, the abrasive grains were added at a concentration of 0.2 to 20% by weight (respective concentrations shown in Table 1). It was prepared so that it might become the polishing liquid contained in. The pH of the polishing liquid thus prepared was about 3.3 to 3.5. In addition, each average particle diameter of the said titanium diboride powder is a measured value by the laser diffraction / scattering type | formula particle size distribution measuring apparatus "LA-950" by Horiba, Ltd.

(Examples 1 to 23)
A polishing platen whose surface was adjusted under the conditions shown in Table 1 was attached to a polishing machine “Fact 200” manufactured by Nanofactor. Three stainless steel plates (disks made of SUS304 and having a diameter of 25.4 mm) as an object to be polished were set in this polishing machine. The polishing liquid having the composition shown in Table 1 was supplied to the polishing machine, and lapping was performed under the following conditions.
[Wrapping conditions]
Polishing load: 170 g / cm ²
Surface plate rotation speed: 75 rpm (linear speed 47 m / min)
Polishing liquid supply rate: 7 mL / min

(Examples 24-26)
A polishing pad was attached to a polishing surface plate whose surface was not adjusted, and polishing liquids having the compositions shown in Table 1 were supplied from the polishing liquids prepared above, and lapping was performed under the above conditions. As a polishing pad, a hard urethane pad “NP-3100N / perforation” manufactured by Toyo Advanced Technology Co., Ltd. was used.

(Performance evaluation)
The weight of the object to be polished was measured before and after the lapping, and the polishing efficiency was calculated from the difference in weight. Further, the surface roughness (arithmetic average roughness (Ra)) of the surface after lapping was measured using a shape measurement laser microscope “VK-X200” manufactured by Keyence Corporation. The results are shown in Table 1.

As shown in Table 1, clearly higher polishing efficiency was obtained in Examples 1 to 17 than Examples 18 to 20 having a retention rate of less than 5% and Examples 21 to 23 having a retention rate of more than 60%. Moreover, it can be seen from Table 1 that when the other conditions are similar, if the retention rate is in the range of 15 to 35%, a better polishing efficiency tends to be obtained.
On the other hand, in Examples 24-26 using the polishing pad, the polishing efficiency was reduced by half in Example 24 using the polishing liquid having the same composition as Example 10, and even if the abrasive concentration was increased to 20% by weight, Examples 1- The polishing efficiency of 17 was not reached.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

Claims (9)

Abrasive grains for polishing a hard metal material supplied to a polishing surface plate,
The average particle size is 2 to 10 μm,
An abrasive for polishing a hard metal material, having a retention rate of 5 to 60% with respect to the polishing surface plate.   The abrasive grain of claim 1 consisting essentially of titanium diboride.   Polishing composition containing the abrasive grain of Claim 1 or 2, and the solvent which disperse | distributes this abrasive grain.   The polishing composition according to claim 3, wherein the concentration of the abrasive grains is 0.3 to 10% by weight. A method of manufacturing a hard metal product comprising:
Setting a hard metal material as an object to be polished in a polishing apparatus equipped with a polishing surface plate;
Supplying a polishing composition to the polishing surface plate; and polishing the polishing object by moving the polishing surface plate relative to the polishing object;
Here, the hard metal product manufacturing method using the polishing composition according to claim 3 or 4 as the polishing composition.   The method according to claim 5, wherein the polishing surface plate is surface-adjusted with green silicon carbide abrasive grains having an average particle diameter of 25 to 120 μm.   The method according to claim 5 or 6, wherein the polishing surface plate comprises a cast iron surface.   8. A method according to any one of claims 5 to 7, wherein the abrasive grains consist essentially of titanium diboride.   The method according to claim 5, wherein the hard metal material is stainless steel.