Ultra-low temperature vitrified bond and its preparation method, ceramic diamond wheel containing ultra-low temperature vitrified bond and its preparation method

Abstract

To provide an ultra-low temperature vitrified bond capable of having relatively high porosity and maintaining completeness of a tissue structure of pores by keeping a satisfactory mechanical strength, decreasing a sinter temperature to 400°C at a minimum, decreasing a softening point temperature of a bond to 320°C at a minimum and keeping actions of binding and fixing of a vitrified bond before burning down a polymer pore-forming agent and a polymer temporary binding agent.SOLUTION: An ultra-low temperature vitrified bond contains as components in mass percentage: Bi2O3 in 40 to 80%; B2O3 in 5 to 15%; ZnO in 10 to 35%; SiO2 in 0 to 5%; Li2O in 0.5 to 3%; TiO2 in 0 to 5%; CaF2 in 2 to 10%; and Y2O3 in 0 to 5%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to the technical field of ultra-precision machining preparation of hard and brittle materials, and more particularly to a vitrified bond for ultra-low temperature sintering and a method for preparing an ultra-fine abrasive diamond wheel using the same for ultra-precision machining of hard and brittle materials. [Background technology]

[0002] Vitrified-bond wheels (wheels using vitrified bonds) are widely used due to their excellent grinding ability, excellent shape retention, high grinding accuracy, resistance to clogging, ease of maintenance and shaping, and excellent resistance to high temperatures, acids, and alkalis. They are suitable for grinding with various coolants and for various processing precision requirements. Ultrafine abrasive wheels (with abrasive grain sizes of 10 μm or less) are typically used in ultra-precision processing, particularly in the fields of integrated circuits, semiconductor power devices, and optoelectronic devices. These fields use hard and brittle materials such as single-crystal silicon, sapphire, silicon carbide, lithium tantalate, and gallium nitride, and require very high wafer flatness and surface quality. Therefore, precision grinding using ultrafine abrasive vitrified-bond diamond wheels (diamond wheels using vitrified bonds) is an essential part of the process, and the quality of this processing determines the product yield rate.

[0003] Vitrified-bond diamond wheels are often prepared by melting the vitrified bond and bonding the diamonds through sintering to form a diamond wheel with a consistent strength and shape. However, diamond is a carbon-based material that oxidizes at high temperatures when sintered in air (the oxidation temperature of coarse-grained diamonds is generally around 700°C in air). Fine-grained diamonds, in particular, oxidize at temperatures as low as 600°C when sintered in air, resulting in a deterioration in wheel performance. Current vitrified bonds for diamonds typically have a sintering temperature of 700-800°C, which does not meet the sintering requirements for ultrafine-grained ceramic diamond wheels. Previously, vitrified bonds for diamonds with sintering temperatures below 600°C were developed, but these bonds contained large amounts of PbO as a melting promoter to lower the sintering temperature. The heavy metal lead, known to be a significant threat to the ecological environment and human health, has led to restrictions or bans on their use worldwide. As a result, these bonds have not been widely used. For this reason, there is a strong demand for the development of a contamination-free vitrified bond that is suitable for ultra-low temperatures (sintering temperatures below 600°C) and for the preparation of diamond wheels with ultra-fine abrasive grains.

[0004] The sintering temperature of a vitrified bond is the temperature range that allows the vitrified bond to melt sufficiently and spread on the surface of the abrasive while still maintaining the bonding performance of the abrasives. In production, a standard flow block prepared with the bond, i.e., a cylinder with a diameter and height of 15 mm, is typically used. The deformation of this standard flow block at different temperatures is measured to demonstrate the bond's ability to flow and spread on the surface of the abrasive. Specifically, the fluidity of the bond is measured by measuring the percentage of the diameter of the sintered sample relative to the initial diameter of the standard flow block. The sintering temperature range is typically defined as the temperature at which the fluidity of the bond is 90% to 160%, and the temperature at which the corners of the sample begin to curve upon heating is defined as the bond's melting initiation temperature T1. This temperature is the lower limit at which the vitrified bond can be used to prepare wheels, and the fluidity at this point is typically around 90%. When the temperature reaches T2, the sample becomes hemispherical, its height being approximately 2 / 3 of the original sample height. T2 is the melting temperature of the bond. At this point, the bond has already melted and is in a viscous, fluid state, with a fluidity of approximately 120%. When heated to temperature T3, the sample flows and expands, its height being approximately 1 / 3 of the original sample height. T3 is the flowing temperature for glazes, with a fluidity of approximately 160%. This is shown in Figure 1. The temperature range from T1 to T3 is the sintering temperature range of the bond.

[0005] Furthermore, the finer the grit size of the wheel abrasive, the poorer the cutting ability and self-sharpening ability of the abrasive tool. To ensure the continuity of cutting ability during wafer planarization and to avoid wafer warpage, deformation, and processing damage caused by grinding stress on the wafer grinding surface, in addition to forming a certain pore structure through the natural deposition of abrasive grains, pore-forming materials are generally added to form additional pore structure, moderately weakening the structural strength and improving the self-sharpening ability of the wheel. The internal pores formed by conventional pore-forming agents are irregular in shape, with large variations in pore size, making it difficult to effectively control the porosity, making it difficult to design and control the pore structure of ultrafine abrasive wheels. Later, the addition of polymeric spherical pore-forming agents was adopted, and because pore size and porosity are positively correlated with the particle size and amount of the added pore-forming agent, controlling the particle size and amount of the added polymeric pore-forming agent allowed for the creation of spherical wheel pores and effectively mitigated the negative impact of shortened service life due to the pore structure. However, this process only resulted in pore structures with porosities of 50 vol% or less. This is because a large amount of spherical polymer material must be added to achieve a highly porous structure, and the frictional force between the powder materials is relatively small, so the polymeric pore-forming agent burns out at high temperatures and the structure cannot be maintained without a binder. Although press molding can be achieved using a temporary polymer binder, the polymer binder and pore former completely decompose and burn away at a temperature of 450°C, losing their ability to support the temporary binding and skeletal structure. At this temperature, not all of the vitrified bonds have reached their melting point, preventing the structure from solidifying, resulting in the molded body collapsing and becoming unusable (see Figure 2). Therefore, the preparation of a wheel structure with a high volume fraction of porosity is not determined solely by the pore former. Because the vitrified bond exerts a bonding effect on the structure with a high volume fraction of porosity, it is necessary to lower the melting point of the bond so that the vitrified bond retains adequate binding and adhesion strength and maintains the macrostructure of the body after the temporary polymer binder and pore former materials have lost their binding ability or burned away at a temperature of 450°C.

[0006] Therefore, the key technical issues in ultrafine abrasive ceramic diamond wheels for ultra-precision planarization of semiconductor hard and brittle wafer materials are how to scientifically design the components of the vitrified bond to lower the sintering temperature range of the bond while maintaining good mechanical strength and maximally protecting the strength of the diamond particles themselves, and how to design and control the high porosity pore structure of ultrafine abrasive wheels using vitrified bonds.

[0007] To solve the above problems, the following patent technologies have been developed: (1) The composition (by mass) of the low-temperature vitrified bond described in Patent Document 1, "Low-Temperature Sintering Vitrified Bond and Preparation Method Thereof," includes 30-35 parts silica sol, 45-50 parts bismuth(III) oxide, 5-7 parts boric acid, and 12-20 parts additives (3-5 parts zinc oxide, 3-5 parts manganese dioxide, 3-5 parts iron(III) oxide, and 3-5 parts divanadium pentoxide). This patent technology mainly emphasizes the low-temperature sintering performance of the vitrified bond, which can effectively prevent oxidation of diamond due to high temperatures, but does not mention the effects on the strength performance of the bond or the pore-forming process. (2) Patent Document 2, "Low-Temperature Vitrified Bond Diamond Wheel and Its Preparation Method," also uses a low-temperature glass system of bismuth (III) oxide-boron oxide (Bi2O3-B2O3), and the composition (molar percentage) of the low-temperature vitrified bond includes 30%-50% bismuth (III) oxide, 30%-50% boron oxide, 2%-10% silicon dioxide, and 2%-10% aluminum oxide. This patented technology also emphasizes the low-temperature sintering characteristics of the vitrified bond. While this patented technology uses walnut shells as a pore-forming agent, it employs conventional material selection and does not discuss the relationship between the bond and the pore-forming process. (3) Patent Document 3, "Vitrified Bond Wheel and Method for Preparing the Same," describes a method for preparing an ultrafine abrasive vitrified bond wheel with a high porosity of 75 to 95% by volume. The sintering temperature of the vitrified bond used is 700°C, which can prevent high-temperature oxidation of ordinary coarse-grain diamond. However, the sintering temperature is still relatively high for ultrafine abrasive diamond. Therefore, by using 30 to 100 μm polystyrene particles as a pore-forming agent and adding sodium silicate as a medium-temperature (approximately 400 to 600°C) binder, the shape of the base body can be maintained at high temperatures, and the base body can be prevented from collapsing after sintering due to the polymer molding binder losing its binding ability at high temperatures (450°C or higher).However, since a relatively large amount of sodium silicate (Na2O·nSiO2) is used, a relatively large amount of Na2O is introduced into the bond. In this case, the strength of the bond is reduced, which is detrimental to the life of the wheel. In addition, abnormalities in the abrasive grains are likely to occur and they may suddenly come out, which will cause accidental scratches in ultra-precision machining, which is unacceptable for practical use. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent CN201711006994.8 [Patent Document 2] Patent CN202210952515.6 [Patent Document 3] Patent CN200510072858.X Summary of the Invention [Problem to be solved by the invention]

[0009] Previous patent applications for ultrafine abrasive ceramic diamond wheels, especially those with high porosity, have focused solely on the low-temperature vitrified bond or pore-forming process, rather than on a comprehensive solution design. Wheels prepared in this manner have difficulty achieving a balance between sharpness and durability, making it difficult to meet the technical requirements for high efficiency, low damage, and long life required for ultra-precision planarization of semiconductor wafers. In light of the above, the present invention has been devised. [Means for solving the problem]

[0010] The present invention overcomes the drawbacks of the prior art and aims to provide an ultra-low temperature vitrified bond. This ultra-low temperature vitrified bond maintains good mechanical strength, has a sintering temperature of at least 400°C, and a bond softening point of at least 320°C, so that the binding and fixing functions of the vitrified bond can be maintained before the polymeric pore-forming agent and polymeric temporary binder are burned off. This allows for a relatively high porosity and maintains the integrity of the pore structure. Furthermore, by using this vitrified bond and a suitable polymeric pore-forming agent, spherical pores can be formed in which the microscopic gaps between the pores are interconnected, and the pore size can be controlled during preparation.

[0011] The present invention further provides a method for preparing an ultrafine abrasive ceramic diamond wheel using the above-mentioned ultra-low temperature vitrified bond.

[0012] To achieve the above objectives, the present invention adopts the following technical solutions.

[0013] The raw materials of ultra-low temperature vitrified bond are mainly composed of Bi2O3: 40-80%, B2O3: 5-15%, ZnO: 10-35%, SiO2: 0-5%, Li2O: 0.5-3%, TiO2: 0-5%, CaF2: 2-10%, and Y2O3: 0-5% by mass fraction. Preferably, the mass ratio of Bi2O3 to ZnO is 1.5 to 5.5:1.

[0014] The present invention provides a cryogenic vitrified bond containing, by mass fraction, 40-80% Bi2O3, 5-15% B2O3, 10-35% ZnO, 0-5% SiO2, 0.5-3% Li2O, 0-5% TiO2, 2-10% CaF2, and 0-5% Y2O3.

[0015] The Bi2O3 component of the ultra-low temperature vitrified bond of the present invention lowers the softening point of the bond, improves bond fluidity, and lowers the temperature for crystal precipitation. At high temperatures, B2O3 exists as a boron-oxygen triangle, reducing viscosity and favoring melting. At low temperatures, B2O3 forms a boron-oxygen tetrahedron, resulting in a compact structure and favoring improved strength. Li2O reduces the linear expansion coefficient and devitrification tendency of the glass. ZnO lowers the glass melting temperature of the bond and adjusts the thermal expansion coefficient. When used in combination with optional TiO2, it facilitates the precipitation of small equiaxed crystals. CaF2 lowers the melting point of the glass, favoring improved impact resistance. Optional SiO2 reduces the crystallization tendency of the glass, favoring grain refinement. Optional Y2O3 is a rare earth oxide that suppresses devitrification of the glass and achieves grain refinement.

[0016] The ultra-low temperature vitrified bond according to the present invention contains, as components, by mass fraction, Bi2O3: 40-70%, B2O3: 5-12.5%, ZnO: 12.5-35%, SiO2: 1-5%, Li2O: 0.5-3%, TiO2: 0-5%, CaF2: 2-10%, and Y2O3: 0-5%.

[0017] The ultra-low temperature vitrified bond according to the present invention has a mass ratio of Bi2O3 to ZnO of 1.5 to 5.5:1.

[0018] As the Bi2O3 / ZnO value of the components of the ultra-low temperature vitrified bond according to the present invention increases, the improving effect of lowering the sintering temperature of the bond becomes weaker and weaker, so it is preferable to keep the Bi2O3 / ZnO value within the above range.

[0019] The ultra-low temperature vitrified bond according to the present invention satisfies at least one of the following characteristics a to c: a. 10 to 20 μm; b. softening point temperature is 320 to 395°C, optionally 320 to 385°C; c. sintering temperature is 400 to 485°C, optionally 400 to 470°C.

[0020] The present invention provides a method for preparing a vitrified bond at ultra-low temperature, which includes the following steps:

[0021] Step (1): Mix the raw materials uniformly in the following mass fractions to obtain a mixed material: Bi2O3: 40-80%, B2O3: 5-15%, ZnO: 10-35%, SiO2: 0-5%, Li2O: 0.5-3%, TiO2: 0-5%, CaF2: 2-10%, and Y2O3: 0-5%. Step (2): The mixed material is melted in a high-temperature smelting furnace using a quartz crucible at a temperature of 900 to 1100°C for 40 to 120 minutes to obtain molten glass. Step (3): The molten glass is water quenched, polished using a stirring mill, and dried to obtain an ultra-low temperature vitrified bond with a particle size of 10 to 20 μm.

[0022] The sintering temperature range of the prepared ultra-low temperature vitrified bond is 400-470°C. The softening point of the vitrified bond is as low as 320°C, which is lower than the decomposition temperature of some polymer pore formers and polymer binders. The bond has good wettability with diamond (see Figure 3). Strength test pieces prepared using this bond and diamond have a flexural strength of 50-65 MPa and an impact strength of 8-15 KJ / m. 2 is.

[0023] In one embodiment of the present invention, the mass fractions of the raw materials are Bi2O3: 40-70%, B2O3: 5-12.5%, ZnO: 12.5-35%, SiO2: 1-5%, Li2O: 0.5-3%, TiO2: 0-5%, CaF2: 2-10%, and Y2O3: 0-5%.

[0024] In one embodiment of the present invention, the mass ratio of Bi2O3 to ZnO in the raw materials is 1.5-5.5:1.

[0025] In one embodiment of the present invention, the raw materials Bi2O3, ZnO, SiO2, TiO2, CaF2, and Y2O3 are analytical grade compounds themselves, the raw material for B2O3 is analytical grade boric acid, and the raw material for Li2O is analytical grade lithium carbonate.

[0026] When boric acid is used as the initial raw material instead of B2O3, the amount of boric acid used is 1.8 times that of B2O3. When lithium carbonate is used as the initial raw material instead of Li2O, the amount of lithium carbonate used is 2.47 times that of Li2O.

[0027] When at least one of boric acid and lithium carbonate is used as the initial raw material, in step (2), the mixed material is subjected to decrystallization at a temperature of 350 to 450°C (for about 40 to 60 minutes), and then melted in a high-temperature smelting furnace using a quartz crucible at a temperature of 900 to 1100°C for 40 to 120 minutes to obtain molten glass.

[0028] More preferably, in step (3), the parameters for polishing using an agitation mill are a rotation speed of the agitation mill of 800 to 900 rpm, wet milling is used, the mass ratio of water to material is 1 to 1.5:1, the polishing medium is zirconia balls (diameter 5 to 7 mm), the mass ratio of balls to material is 2 to 4:1, and ball milling is performed for 0.5 to 2 hours.

[0029] The present invention further provides an ultrafine abrasive ceramic diamond wheel prepared using the above-mentioned ultra-low temperature vitrified bond, which is prepared from raw materials consisting mainly of 15-35% ultra-low temperature vitrified bond, 20-75% diamond abrasive, and 10-55% polymeric pore-forming agent by mass fraction.

[0030] Specifically, the polymeric pore-forming agent is one or two of polyethylene particles, polytetrafluoroethylene particles, etc., and the amount and particle size thereof can be adjusted according to needs. The particle size of the polymeric pore-forming agent is 20 to 400 μm.

[0031] Furthermore, the particle size of the diamond abrasive is 0.5 to 5 μm.

[0032] The present invention provides a ceramic diamond wheel comprising the above-described ultra-low temperature vitrified bond.

[0033] In one embodiment of the present invention, the ceramic diamond wheel contains, as its components, 15 to 35 parts by mass of ultra-low temperature vitrified bond and 20 to 75 parts by mass of diamond abrasive, and the porosity of the ceramic diamond wheel is 35 to 95 vol %.

[0034] In one embodiment of the present invention, the diamond abrasive has a particle size of 0.5 to 5 μm.

[0035] In one embodiment of the present invention, the porosity of the ceramic diamond wheel is 40 to 95 vol%, optionally 70 to 95 vol%, optionally 75 to 95 vol%, and / or the pore size is 20 to 800 μm, and can be controlled as needed.

[0036] The present invention further provides a method for preparing the ultrafine grain ceramic diamond wheel, which is specifically as follows:

[0037] A mixed material is obtained by uniformly mixing, by mass, 15-35% ultra-low temperature vitrified bond, 20-75% diamond abrasive, and 10-55% polymer pore-forming agent. 5-10% of a phenolic resin alcohol solution is added to the mixed material, so that the mass concentration of the phenolic resin alcohol solution is 25%-35%. The mixed material is then wetted, sieved, and granulated. The granulated mixed material is press-molded and dried, and then sintered at a temperature of 400-485°C in an air atmosphere. The temperature is maintained for 3.5-5 hours to obtain the ultrafine abrasive ceramic diamond wheel.

[0038] In one embodiment of the present invention, the ultrafine abrasive grain ceramic diamond wheel is obtained by sintering at a temperature of 400 to 470°C in an air atmosphere and keeping the temperature for 3.5 to 5 hours.

[0039] We prepare an ultrafine abrasive ceramic diamond wheel with spherical pores, controllable porosity (35-95 vol%), and pore size (20-800 μm).

[0040] Specifically, the polymeric pore-forming agent is one or two of polyethylene particles, polytetrafluoroethylene particles, etc., and the amount and particle size thereof can be adjusted according to needs. The particle size of the polymeric pore-forming agent is 20 to 400 μm.

[0041] In particular, the present invention uses polytetrafluoroethylene particles, which have a relatively high decomposition temperature, to prepare wheels using an ultrafine abrasive vitrified bond diamond wheel with a porosity of over 75 vol%. The decomposition temperature of polytetrafluoroethylene particles is 420°C, which is higher than the softening point of the bond of the present invention, which is 320-395°C. This effectively prevents the ceramic body from collapsing after the polymer material is burned away. Furthermore, preparing a wheel with an ultrahigh porosity requires a temperature curve longer than the conventional heating time. In the present invention, heating is performed for 3.5-5 hours, allowing the preparation of an ultrafine abrasive vitrified bond diamond wheel with a porosity of 95 vol%. [Effects of the Invention]

[0042] (1) The ultra-low temperature vitrified bond of the present invention has an ultra-low sintering temperature range of 400 to 485°C. This effectively prevents high-temperature oxidation of the ultrafine abrasive diamond grains during the sintering process in an air atmosphere. The softening point of the vitrified bond of the present invention is low, reaching a minimum of 320°C, which is lower than the decomposition temperature of some polymeric pore formers and polymeric binders. This allows the vitrified bond to maintain its binding and fixing properties before the polymeric pore formers and polymeric temporary binders are burned away. This bond can be used to prepare wheels using an ultrafine abrasive grain vitrified bond with a high porosity and controllable pore size.

[0043] (2) The ultra-low temperature vitrified bond according to the present invention has good wettability and bond strength with diamond, and also has relatively good impact strength, so that it can be used for grinding under severe operating conditions involving impact.

[0044] (3) The vitrified bond of the present invention has a low sintering temperature and does not contain heavy metal oxides such as As2O3, PbO, BaO, and V2O5 that are harmful to the environment, making it environmentally friendly.

[0045] (4) In the present invention, a polytetrafluoroethylene pore former material with a relatively high decomposition temperature (melting point: 327°C, decomposition temperature: 420°C) is used, which is compatible with the softening and sintering temperatures of the ultra-low temperature bond of the present invention. This makes it possible to prepare an ultra-fine abrasive ceramic diamond wheel with a porosity of 75 vol% or more and controllable pore size.

[0046] (5) The ultra-low temperature vitrified bond of the present invention has good mechanical strength and can bond well with diamond. Furthermore, the spherical pores contribute to ensuring the strength of the macrostructure. Therefore, when used in the ultra-precision planarization of semiconductor wafers, the surface processing quality is relatively high, the processing damage is relatively low, and the wheel has a good service life. [Brief explanation of the drawings]

[0047] [Figure 1] FIG. 2 is a schematic diagram showing the change in vitrified bonds at high temperatures. [Figure 2] A comparison of the body of a conventional wheel block with high porosity before and after sintering. (a) The wheel block with high porosity has a perfectly formed body, while (b) the wheel block with high porosity collapses after sintering. [Figure 3] 1 is a photomicrograph showing the wetting bond between the ultra-low temperature vitrified bond and diamond according to the present invention. [Figure 4] 1 is a photograph showing the flow state of the ultra-low temperature vitrified bond according to Example 1 of the present invention. [Figure 5] 1 is a micrograph of the structure of an ultrafine abrasive ceramic diamond wheel according to Example 1 of the present invention. [Figure 6] 10 is a photograph showing the flow state of the ultra-low temperature vitrified bond according to Example 2 of the present invention. [Figure 7] 1 is a micrograph of the structure of an ultrafine abrasive ceramic diamond wheel according to Example 2 of the present invention. [Figure 8] 10 is a photograph showing the flow state of the ultra-low temperature vitrified bond according to Example 3 of the present invention. [Figure 9] 1 is a micrograph of the structure of an ultrafine abrasive ceramic diamond wheel according to Example 3 of the present invention. [Figure 10] 1 is a micrograph of the structure of an ultrafine abrasive grain ceramic diamond wheel according to Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0048] The technical solution of the present invention will be further described in detail with reference to the following examples, but the scope of protection of the present invention is not limited thereto.

[0049] Unless otherwise specified, "A and / or B" in this specification means "at least one of A and B." In the following examples, unless otherwise specified, all raw materials used are commercially available or can be prepared by conventional methods (for example, phenolic resin can be directly purchased and diluted with alcohol to a suitable concentration to obtain a phenolic resin alcohol solution with a mass concentration of 25% to 35%), and any operations or steps not described in detail (for example, granulation, etc.) can be performed using conventional techniques in the art.

[0050] As used herein, unless otherwise specified, the term "low-temperature vitrified bond" refers to a vitrified bond with a relatively low sintering temperature. Generally, the term "low-temperature vitrified bond" refers to a vitrified bond with a sintering temperature of 850°C to 1050°C. As used herein, unless otherwise specified, the term "ultra-low temperature vitrified bond" as used herein refers to a vitrified bond with an ultra-low sintering temperature. Generally, an ultra-low temperature vitrified bond refers to a vitrified bond with a sintering temperature of less than 600°C.

[0051] In this specification, the terms "particle size," "particle size," and "particle size" refer to the size of particles, and unless otherwise specified, these terms are used interchangeably. In this specification, unless otherwise specified, the particle size, particle diameter, or pore size all refer to particle size distribution, which is generally measured using a laser particle size measuring device.

[0052] In this specification, "flexural strength" refers to the strength value obtained by performing a three-point bending test on a test piece manufactured from a vitrified bond and diamond. The measurement method involves mixing a vitrified bond sample with a mass fraction of 18% and a mass fraction of diamond, pressing the mixture, and then bending the mixture to a density of 1.85 g / cm. 3 A test piece having dimensions of 50 mm x 6 mm x 5 mm is manufactured, and after sintering the test piece at a predetermined sintering temperature, the flexural strength is measured using a triaxial bending strength tester. As those skilled in the art will appreciate, since the vitrified bond and diamond function together as a wheel, the strength of the vitrified bond can be measured using a test piece made of the vitrified bond and diamond. Without wishing to be bound by any theory, the flexural strength of the diamond strength test piece shows a positive correlation with the strength of the vitrified bond itself.

[0053] In the examples, the Bi2O3, ZnO, SiO2, TiO2, CaF2, and Y2O3 used are analytical grade compounds themselves, the raw material for B2O3 is analytical grade boric acid, and the raw material for Li2O is analytical grade lithium carbonate. As will be understood by those skilled in the art, when using boric acid water, B2O3 is obtained by removing water of crystallization. When using lithium carbonate, Li2O is obtained in a high temperature environment. The other components and contents do not change before and after the preparation of the bond.

[0054] [Example 1] 1. Preparation of Bond The raw materials were mixed according to the mass fractions shown in Table 1 below, and the mixed materials were uniformly mixed using a three-dimensional mixer. The mixed materials were then dehydrated in a high-temperature oven at 400°C for 60 minutes. The mixture was then melted in a quartz crucible in a high-temperature smelting furnace at 1100°C for 40 minutes to obtain molten glass. The molten glass was then quenched in water and finely ground using a stirring mill (the stirring mill rotation speed was 840 rpm, wet milling was used, the mass ratio of water to material was 1:1, the grinding medium was zirconia balls with a diameter of 5 to 7 mm, and the ball to material ratio was 3:1). Ball milling was performed for 1 hour, and the mixture was dried at 150°C for 10 hours to obtain an ultra-low-temperature vitrified bond with a particle size of 10 to 20 μm.

[0055] [Table 1]

[0056] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 385°C and a sintering temperature of 470°C. The fluidity at 470°C is shown in Figure 4, where the fluidity was 130%, and the bond was in a molten state, showing good fluidity. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 65 MPa and an impact strength of 15 KJ / m 2 It was.

[0057] 2. Preparation of Ceramic Diamond Wheel The mass fraction of the prepared ultra-low temperature vitrified bond was 15%, diamond abrasive with a particle size of 2-4 μm was 70%, and polymer pore former (polyethylene particles and polytetrafluoroethylene particles with a mass ratio of 1:3) with a particle size of 20-50 μm was 15%. The above materials were uniformly mixed to obtain the mixed material for the wheel. The mixed material was then wetted for 10 minutes with 5% phenolic resin alcohol solution (concentration was 25%) and passed through a 60 mesh sieve five times. The mixture was filtered to mix uniformly and granulate, and the granulated mixed material was molded and pressed, dried (12 hours at room temperature and 12 hours in an oven at 50°C, for a total of 24 hours, same below), and then placed in a furnace and sintered in an air atmosphere at a sintering temperature of 470°C and a heat retention time of 3.5 hours. This resulted in an ultra-fine abrasive ceramic diamond wheel (see Figure 5) with spherical pores, a porosity of 45 vol%, and a pore size of 20 to 50 μm.

[0058] [Example 2] 1. Preparation of Bond The raw materials were mixed according to the mass fractions shown in Table 2 below, and the mixed materials were uniformly mixed using a three-dimensional mixer. The mixed materials were then dehydrated in a high-temperature oven at 400°C for 60 minutes. The mixture was then melted in a quartz crucible in a high-temperature smelting furnace at 1000°C for 90 minutes to obtain molten glass. The molten glass was then quenched in water and finely ground using a stirring mill (rotation speed of the stirring mill: 840 rpm, wet milling was used, the mass ratio of water to material was 1:1, the grinding medium was zirconia balls with a diameter of 5-7 mm, and the ball to material ratio was 3:1). Ball milling was performed for 1 hour, and the mixture was dried at 150°C for 10 hours to obtain an ultra-low-temperature vitrified bond with a particle size of 10-20 μm.

[0059] [Table 2]

[0060] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 340°C and a sintering temperature of 440°C. The fluidity at 440°C is shown in Figure 6, where the fluidity was 130%, and the bond was in a molten state, showing good fluidity. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 55 MPa and an impact strength of 12 KJ / m 2 It was.

[0061] 2. Wheel Preparation The mass fraction of the prepared ultra-low temperature vitrified bond, 35% diamond abrasive with a particle size of 1-2 μm, and 30% polymeric pore former (polyethylene particles and polytetrafluoroethylene particles in a 1:2 mass ratio) with a particle size of 20-400 μm were weighed out. The above materials were uniformly mixed to obtain the wheel mixture. An 8% phenolic resin alcohol solution (30% concentration) was added to the mixture and wetted for 10 minutes. The mixture was then passed through a 60-mesh sieve five times to uniformly mix and granulate. The granulated mixture was then molded and dried, and then placed in a furnace and sintered in air at a sintering temperature of 440°C for 4 hours. This produced an ultra-fine abrasive ceramic diamond wheel with spherical pores, a porosity of 70 vol%, and a pore size of approximately 35-470 μm (see Figure 7).

[0062] [Example 3] 1. Preparation of Bond The raw materials were mixed according to the mass fractions shown in Table 3 below, and the mixed materials were homogeneously mixed using a three-dimensional mixer. The mixed materials were then dehydrated in a high-temperature oven at 400°C for 45 minutes. The mixture was then melted in a quartz crucible in a high-temperature smelting furnace at 900°C for 120 minutes to obtain molten glass. The molten glass was then quenched in water and finely ground using a stirring mill (rotation speed of the stirring mill: 840 rpm, wet milling was used, the mass ratio of water to material was 1:1, the grinding medium was zirconia balls with a diameter of 5-7 mm, and the ball to material ratio was 3:1). Ball milling was performed for 1 hour, and the mixture was dried at 150°C for 10 hours to obtain an ultra-low-temperature vitrified bond with a particle size of 10-20 μm.

[0063] [Table 3]

[0064] The ultra-low temperature vitrified bond prepared in this example has a softening temperature of 320°C and a sintering temperature of 400°C. The fluidity at 400°C is shown in Figure 8, where the fluidity is 110% and the melting start state is close to the molten state, so the fluidity meets the requirements. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 50 MPa and an impact strength of 8 KJ / m 2 It was.

[0065] 2. Wheel Preparation The mass fraction of the prepared ultra-low temperature vitrified bond, 25%, diamond abrasive with a particle size of 0-0.5 μm, and polytetrafluoroethylene polymer pore former with a particle size of 30-300 μm were weighed out, and the above materials were uniformly mixed to obtain the wheel mixture. A 10% phenolic resin alcohol solution (concentration: 35%) was added to the mixture, and the mixture was wetted for 10 minutes. The mixture was then passed through a 60-mesh sieve five times to uniformly mix and granulate. The granulated mixture was then molded and pressed, dried, and then placed in a furnace and sintered in air at a sintering temperature of 400°C for 5 hours. This resulted in an ultra-fine abrasive ceramic diamond wheel with spherical pores, a porosity of 95 vol%, and a pore size of approximately 50-350 μm (see Figure 9).

[0066] [Example 4] 1. Preparation of Bond The raw materials were blended according to the mass fractions shown in Table 4 below, and an ultra-low temperature vitrified bond with a particle size of 10 to 20 μm was obtained according to the preparation process and parameters of the bond according to Example 1.

[0067] [Table 4]

[0068] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 395°C and a sintering temperature of 485°C. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 53 MPa and an impact strength of 8 KJ / m 2 It was.

[0069] 2. Preparation of Ceramic Diamond Wheel According to the preparation process and parameters of the ceramic diamond wheel according to Example 1, an ultrafine abrasive ceramic diamond wheel was obtained with spherical pores, a porosity of 45 vol%, and pore sizes of 20-50 μm.

[0070] [Example 5] 1. Preparation of Bond The raw materials were blended according to the mass fractions shown in Table 5 below, and the preparation process and parameters of the bond according to Example 1 were followed to obtain an ultra-low temperature vitrified bond with a particle size of 10-20 μm.

[0071] [Table 5]

[0072] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 370°C and a sintering temperature of 460°C. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 55 MPa and an impact strength of 7 KJ / m 2 It was.

[0073] 2. Preparation of Ceramic Diamond Wheel According to the preparation process and parameters of the ceramic diamond wheel according to Example 1, an ultrafine abrasive ceramic diamond wheel was obtained with spherical pores, a porosity of 45 vol%, and pore sizes of 20-50 μm.

[0074] [Example 6] 1. Preparation of Bond The steps were the same as in Example 3, but the only difference from Example 3 was the mass fraction of the raw materials, which are shown in Table 6.

[0075] [Table 6]

[0076] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 330°C and a sintering temperature of 415°C. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 48 MPa and an impact strength of 7 KJ / m 2 It was.

[0077] 2. Wheel Preparation A ceramic diamond wheel was prepared according to the process and parameters of Example 3. An ultrafine abrasive ceramic diamond wheel was obtained with spherical pores, a porosity of 90 vol%, and pore sizes of approximately 50 to 350 μm.

[0078] [Example 7] 1. Preparation of Bond The raw materials were blended according to the mass fractions shown in Table 7 below, and the preparation process and parameters of the bond according to Example 1 were followed to obtain an ultra-low temperature vitrified bond with a particle size of 10-20 μm.

[0079] [Table 7]

[0080] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 390°C and a sintering temperature of 475°C. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 57 MPa and an impact strength of 9 KJ / m 2 It was.

[0081] 2. Preparation of Ceramic Diamond Wheel Using the above-mentioned ultra-low temperature vitrified bond prepared in mass fraction, and according to the ceramic diamond wheel preparation process and parameters of Example 2, an ultra-fine abrasive ceramic diamond wheel was obtained with spherical pore shape, a porosity of 60 vol%, and a pore size of 35 to 470 μm.

[0082] [Example 8] 1. Preparation of Bond The raw materials were blended according to the mass fractions shown in Table 8 below, and the preparation process and parameters of the bond according to Example 1 were followed to obtain an ultra-low temperature vitrified bond with a particle size of 10-20 μm.

[0083] [Table 8]

[0084] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 335°C and a sintering temperature of 425°C. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 48 MPa and an impact strength of 7 KJ / m 2 It was.

[0085] 2. Preparation of Ceramic Diamond Wheel Using the above-mentioned ultra-low temperature vitrified bond prepared in mass fraction, and according to the ceramic diamond wheel preparation process and parameters of Example 2, an ultra-fine abrasive ceramic diamond wheel was obtained with spherical pore shape, a porosity of 70 vol%, and a pore size of 35 to 470 μm.

[0086] [Example 9] 1. Preparation of Bond The raw materials were blended according to the mass fractions shown in Table 9 below, and the preparation process and parameters of the bond according to Example 1 were followed to obtain an ultra-low temperature vitrified bond with a particle size of 10-20 μm.

[0087] [Table 9]

[0088] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 350°C and a sintering temperature of 445°C. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 49 MPa and an impact strength of 7 KJ / m 2 It was.

[0089] 2. Preparation of Ceramic Diamond Wheel Using the above-mentioned ultra-low temperature vitrified bond prepared in mass fraction, and according to the ceramic diamond wheel preparation process and parameters of Example 2, an ultra-fine abrasive ceramic diamond wheel was obtained with spherical pore shape, a porosity of 70 vol%, and a pore size of 35 to 470 μm.

[0090] [Comparative Example 1] 1. Preparation of Bond The raw materials were blended according to the mass fractions shown in Table 10 below, and the blended materials were homogeneously mixed using a three-dimensional mixer. The blended materials were then dehydrated in a high-temperature oven at 400°C for 60 minutes. The mixture was then melted in a quartz crucible in a high-temperature smelting furnace at 1100°C for 40 minutes to obtain molten glass. The molten glass was then poured into water for water quenching, and then finely ground using a stirring mill (the stirring mill rotation speed was 840 rpm, wet milling was used, the mass ratio of water to material was 1:1, the grinding medium was zirconia balls with a diameter of 5 to 7 mm, and the ball to material ratio was 3:1). Ball milling was performed for 1 hour, and the mixture was dried at 150°C for 10 hours to obtain an ultra-low-temperature vitrified bond with a particle size of 10 to 20 μm.

[0091] [Table 10]

[0092] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 610°C and a sintering temperature of 720°C. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 40 MPa and an impact strength of 2 KJ / m 2 It was.

[0093] 2. Preparation of Ceramic Diamond Wheel According to the method and process for preparing the wheel in Example 2, the wheel materials were blended, mixed, granulated, molded, and dried, and then placed in a furnace for sintering in an air atmosphere at a sintering temperature of 720°C and a holding time of 3.5 hours. The sintered body had a collapsed structure and was unusable, as shown in Figure 2(b).

[0094] Comparative Example 2 1. Preparation of Bond In this comparative example, a vitrified bond prepared by the same process as in Comparative Example 1 was used.

[0095] 2. Preparation of Ceramic Diamond Wheel According to the wheel preparation plan and process of Example 1, the wheel materials were blended, mixed, granulated, molded, and dried, and then placed in a furnace and sintered in an air atmosphere at a sintering temperature of 720°C with a holding time of 3.5 hours, resulting in an ultrafine abrasive ceramic diamond wheel with a wheel porosity of only 30 vol% and pore size of 10-40 μm. This is because the sintering temperature of the bond is much higher than the burn-off temperature of the pore-forming agent, so after the pore-forming agent is burned off, the pore structure at that location is no longer maintained in large quantities; the higher the sintering temperature of the bond than that of the pore-forming agent, the lower the resulting porosity.

[0096] Comparative Example 3 1. Preparation of Bond The raw materials were blended according to the mass fractions shown in Table 11 below, with a Bi2O3 to ZnO mass ratio of 9.6:1. The blended materials were homogeneously mixed using a three-dimensional mixer and dehydrated in a high-temperature oven at 400°C for 60 minutes. The mixture was then melted in a quartz crucible in a high-temperature smelting furnace at 900°C for 120 minutes to obtain molten glass. The molten glass was then quenched in water and finely ground using a stirring mill (rotation speed of the stirring mill: 840 rpm, wet milling: water to material mass ratio: 1:1, grinding medium: zirconia balls with a diameter of 5-7 mm, ball to material ratio: 3:1). Ball milling was performed for 1 hour, and the mixture was dried at 150°C for 10 hours to obtain an ultra-low-temperature vitrified bond with a particle size of 10-20 μm.

[0097] [Table 11]

[0098] The ultra-low temperature vitrified bond prepared in this example had a softening temperature of 340°C, a sintering temperature of 430°C, and a fluidity of 90% at 430°C, which was in the melting start state and had normal fluidity. The strength test piece made of the ultra-low temperature vitrified bond and diamond prepared in this example has a flexural strength of 45 MPa and an impact strength of 5 KJ / m 2 It was.

[0099] 2. Wheel Preparation The prepared ultra-low temperature vitrified bond was weighed out as 25% by mass, diamond abrasive with a particle size of 0-0.5 μm was weighed out as 20% by mass, and polytetrafluoroethylene polymer pore former with a particle size of 30-300 μm was weighed out as 55% by mass. The above materials were uniformly mixed to obtain the mixed material for the wheel. Then, 10% of the mixed material was added to the alcohol solution of phenolic resin (concentration 35%) and wetted for 10 minutes. The mixed material was passed through a 60 mesh sieve five times to uniformly mix and granulate. The granulated mixed material was After molding and drying, the wheel was placed in a furnace and sintered in air at a sintering temperature of 400°C for 5 hours. The resulting wheel had a porosity of 80 vol% and a normal pore structure (see Figure 10). There was significant pore fusion and the local pore structure was incomplete. This was because the sintering temperature of the bond was higher than the burnout temperature of the pore-forming agent, and the structure of the local area was no longer maintained after the pore-forming agent was burned out.

[0100] Application test: Grinding performance of ultra-fine grain vitrified bond diamond wheels The ultrafine grain vitrified bond diamond wheels prepared in Examples 1, 2, 3, 4, 5, 6, and 7 and Comparative Examples 2 and 3 were subjected to grinding performance tests using a wafer grinding machine. 8-inch silicon wafers were ground with the wheels, and the current value, wear, surface roughness, and damaged layer were measured when the silicon wafer was ground to a depth of 15 μm. The measurement results are shown in Table 12 below.

[0101] [Table 12]

[0102] As can be seen from Table 12, the ultrafine abrasive vitrified bond diamond wheel according to the present invention has spherical pores that are advantageous for the structural strength of the wheel, and therefore, when grinding silicon wafers, it exhibits good grinding performance, a relatively fast feed rate, and relatively low processing damage. The wheel with a grain size of M2 / 4 according to Example 1 had a feed rate of 2 μm / s and a damage layer thickness of 2.6 μm or more. The wheel with a grain size of M1 / 2 according to Example 2 had a feed rate of 0.5 μm / s and a damage layer thickness of 1.2 μm or more. The wheel with a grain size of M0 / 0.5 according to Example 3 had a feed rate of 0.4 μm / s and a damage layer thickness of 0.6 μm or more. In contrast, the wheel of Comparative Example 2, although having a grain size of M2 / 4, had a relatively high bond sintering temperature, much higher than the burnout temperature of the pore-forming agent, resulting in a relatively low porosity and poor grinding performance. The feed rate was 0.6 μm / s, and the damage layer thickness was 8.40 μm, significantly different from Examples 1, 4, 5, and 6. Comparative Example 1 used the same vitrified bond as Comparative Example 2, but the sintering temperature of the vitrified bond used was relatively high, making it impossible to prepare a wheel with a high porosity of 70% or more, and therefore making it impossible to conduct a comparative grinding performance test. The wheel of Comparative Example 3, having a grain size of M0 / 0.5, had a lower bond strength and a higher sintering temperature than Example 3. The wheel prepared had an unideal pore structure, a feed rate of 0.15 μm / s, and a damage layer thickness of 1.42 μm, significantly different from Example 3.

Claims

1. As a component, by mass fraction, Bi ２ O ３ : 40-80%, B ２ O ３ : 5-15%, ZnO: 10-35%, SiO ２ : 0 to 5%, Li ２ O: 0.5-3%, TiO ２ : 0-5%, CaF ２ : 2 to 10% and Y ２ O ３ : 0 to 5% included Ultra-low temperature vitrified bond.

2. As a component, by mass fraction, Bi ２ O ３ : 40-70%, B ２ O ３ : 5-12.5%, ZnO: 12.5-35%, SiO ２ : 1 to 5%, Li ２ O: 0.5-3%, TiO ２ : 0-5%, CaF ２ : 2 to 10% and Y ２ O ３ : 0 to 5% included 2. The ultra-low temperature vitrified bond according to claim 1.

3. Bi ２ O ３ and ZnO in a mass ratio of 1.5 to 5.5:

1.

2. The ultra-low temperature vitrified bond according to claim 1.

4. a. particle size of 10-20 μm; b. A softening point temperature of 320 to 395°C; c. The sintering temperature is 400 to 485°C; Satisfy at least one of the characteristics a to c 2. The ultra-low temperature vitrified bond according to claim 1.

5. Bi ２ O ３ : 40-80%, B ２ O ３ : 5-15%, ZnO: 10-35%, SiO ２ : 0 to 5%, Li ２ O: 0.5-3%, TiO ２ : 0-5%, CaF ２ : 2 to 10% and Y ２ O ３ : Step (1) of uniformly mixing raw materials at a mass fraction of 0 to 5% to obtain a mixed material; Step (2) of melting the mixed material at a temperature of 900 to 1100°C for 40 to 120 minutes to obtain molten glass; (3) water quenching the molten glass, grinding it using a stirring mill, and drying it to obtain an ultra-low temperature vitrified bond with a particle size of 10-20 μm; A method for preparing a vitrified bond at ultra-low temperatures, comprising:

6. a. The mass fraction of the raw material is Bi ２ O ３ : 40-70%, B ２ O ３ : 5-12.5%, ZnO: 12.5-35%, SiO ２ : 1 to 5%, Li ２ O: 0.5-3%, TiO ２ : 0-5%, CaF ２ : 2-10%, Y ２ O ３ : 0 to 5%; b. Bi of the raw material ２ O ３ and ZnO in a mass ratio of 1.5 to 5.5:1; c.B ２ O ３ Instead of B, boric acid is used as the initial raw material, and the amount of boric acid used is B ２ O ３ It is 1.8 times d. Li ２ Lithium carbonate is used as the initial raw material instead of O, and the amount of lithium carbonate used is Li ２ It is 2.47 times that of O. e. Using at least one of boric acid and lithium carbonate as an initial raw material, removing water of crystallization from the mixed material at a temperature of 350 to 450°C, and melting the mixed material at a temperature of 900 to 1100°C for 40 to 120 minutes to obtain molten glass; Satisfy at least one of the characteristics a to e 6. The method for preparing a vitrified bond at ultra-low temperatures according to claim 5.

7. In step (3), the polishing parameters using the agitation mill are: the rotation speed of the media agitation mill is 800-900 rpm; wet milling is used; the mass ratio of water to material is 1-1.5:1; the polishing medium is zirconia balls; the mass ratio of balls to material is 2-4:1; and ball milling is performed for 0.5-2 hours.

6. The method for preparing a vitrified bond at ultra-low temperatures according to claim 5.

8. The ultra-low temperature vitrified bond according to any one of claims 1 to 4 is included. Ceramic diamond wheel characterized by:

9. The ceramic diamond wheel contains 15 to 35 parts by mass of ultra-low temperature vitrified bond and 20 to 75 parts by mass of diamond abrasive, and the porosity of the ceramic diamond wheel is 35 to 95 vol%.

9. The ceramic diamond wheel according to claim 8.

10. The particle size of the diamond abrasive is 0.5 to 5 μm.

10. The ceramic diamond wheel according to claim 9.

11. a. The porosity of the ceramic diamond wheel is 40 to 95 vol%, 70 to 95 vol%, or 75 to 95 vol%, b. The pore size is 20 to 800 μm and can be controlled as needed; Satisfy at least one of the characteristics a to b 9. The ceramic diamond wheel according to claim 8.

12. 10. A method for preparing a ceramic diamond wheel according to claim 9, comprising: The raw materials are uniformly mixed in mass fractions of 15 to 35% of the ultra-low temperature vitrified bond, 20 to 75% of the diamond abrasive, and 10 to 55% of the polymer pore former to obtain a mixed material, which is then wetted with 5 to 10% of a phenolic resin alcohol solution based on the mass of the mixed material, sieved, and granulated. The granulated mixed material is press-molded and dried, and then sintered at a temperature of 400 to 485°C in an air atmosphere, and the temperature is maintained for 3.5 to 5 hours to obtain a ceramic diamond wheel.

1. A method for preparing a ceramic diamond wheel, comprising:

13. The polymeric pore-forming agent is one or both of polyethylene particles and polytetrafluoroethylene particles, and the particle size of the polymeric pore-forming agent is 20 to 400 μm.

13. The method for preparing a ceramic diamond wheel according to claim 12.

Images