A silicon carbide ceramic drilling metal grinding wheel and its preparation method

Abstract

This invention pertains to machining tools, specifically relating to a metal grinding wheel for drilling silicon carbide ceramics and its preparation method. Copper powder, tin powder, nano-titanium powder, diamond, and resin are ball-milled and then mixed with copper-tin alloy powder and resin to obtain a powder. This powder is then cold-pressed and sintered to obtain a metal grinding wheel for drilling silicon carbide ceramics. Previously, sintered metal grinding wheels used for processing ceramics such as zirconia and alumina could not meet the requirements for lifespan and quality when dealing with the harder and more brittle silicon carbide ceramics. This invention utilizes nano-titanium powder to achieve strong holding force and easy sintering, while adding a copper-tin alloy to improve the toughness of the binder, enhance the self-sharpening property of the product, increase cutting force, and ensure product quality and lifespan.

Description

Technical Field

[0001] This invention pertains to machining tools, specifically relating to a silicon carbide ceramic drilling metal grinding wheel and its preparation method. Background Technology

[0002] Silicon carbide ceramic materials are not only a new generation of semiconductor materials, but also have wide applications in 5G communications, national defense, aerospace, and electronic products due to their high strength, high hardness, and high temperature resistance. Currently, the global silicon carbide semiconductor industry market is developing rapidly and has entered a period of explosive growth, making silicon carbide processing and processing tools essential for its development. Previously used metal sintered grinding rods for processing ceramics such as zirconia and alumina cannot meet the requirements for lifespan and quality when dealing with the harder and more brittle silicon carbide ceramics. CN112756613A discloses a grinding wheel for processing high-strength, high-hardness ceramics and its preparation method. The metal matrix is ​​obtained by mixing copper powder, tin powder, iron powder, and nano-titanium powder. The copper powder, tin powder, iron powder, and nano-titanium powder are ball-milled and then mixed with diamond to obtain the material. The material is then cold-pressed, sintered, and processed to obtain a grinding wheel for processing high-strength, high-hardness ceramics. This grinding wheel exhibits a low cracking rate and long processing life when drilling high-strength, high-hardness, and brittle ceramics. However, this grinding wheel encounters a problem when drilling silicon carbide, where it cannot be ground. Therefore, it is necessary to improve the formula of metal grinding wheels to prepare grinding wheels that can perform high-quality silicon carbide drilling. Summary of the Invention

[0003] This invention uses copper powder and tin powder as a base. While utilizing nano-titanium powder to achieve strong holding force and easy sintering, it adds copper-tin alloy to improve the toughness of the binder, enhance the self-sharpening property of the product, increase the cutting force, and ensure product quality and lifespan.

[0004] The present invention adopts the following technical solution:

[0005] A method for preparing a silicon carbide ceramic drilling metal grinding wheel includes the following steps: ball milling copper powder, tin powder, nano titanium powder, diamond, and resin glue, then mixing them with copper-tin alloy powder and resin glue to obtain a powder; then cold pressing the powder and sintering it to obtain a silicon carbide ceramic drilling metal grinding wheel.

[0006] In this invention, copper powder, tin powder, nano-titanium powder, and copper-tin alloy powder constitute the metal matrix, and the mass percentages of each component are as follows:

[0007] Copper powder 50-70%

[0008] Tin powder 15-25%

[0009] Nano titanium powder 10-20%

[0010] copper-tin alloy balance

[0011] Preferred,

[0012] Copper powder 55-65%

[0013] 15-20% tin powder

[0014] Nano titanium powder 10-15%

[0015] copper-tin alloy powder balance

[0016] Further optimization:

[0017] Copper powder 60-65%

[0018] Tin powder 15-17%

[0019] Nano titanium powder 10-13%

[0020] copper-tin alloy powder balance

[0021] Preferably, in this invention, copper powder, tin powder, nano-titanium powder and copper-tin alloy powder constitute the metal matrix, and the mass percentage of copper-tin alloy powder is 10-15%.

[0022] In this invention, the volume ratio of the metal matrix to diamond is 60%:(35-45)%; preferably 60%:40%.

[0023] In this invention, copper powder, tin powder, and nano-titanium powder are dispersed and mixed before being ball-milled with diamond and resin adhesive. Preferably, ultrasonic treatment is used to disperse and mix the copper powder, tin powder, and nano-titanium powder. Preferably, the ultrasonic treatment time is 3-8 minutes, and the temperature is 50-70°C. Preferably, the ball milling is carried out in the presence of an organic solvent such as acetone or alcohol, and the ball-to-powder ratio is 5:1.

[0024] In this invention, the cold pressing pressure is 2 ± 0.5 t / cm. 2 The pressure is maintained for 5-10 seconds. Preferably, the cold pressing is performed twice. After the first cold pressing, the device is rotated 90° for the second cold pressing.

[0025] In this invention, during sintering, the heating rate is 10-30℃ / min; the temperature is raised from room temperature to 300℃ and held for 60-120 min, then raised to the sintering temperature of 700-800℃ and held for 40-80 min, then raised to the highest temperature of 880-950℃ and held for 60-90 min, and then cooled naturally to complete the sintering, thus obtaining a silicon carbide ceramic drilling metal grinding wheel rod.

[0026] Silicon carbide ceramic materials are a new generation of semiconductor materials, and their high strength, high hardness, and high temperature resistance make them widely used in 5G communications, defense, aerospace, and electronic products. Currently, the global silicon carbide semiconductor industry market is developing rapidly and has entered a period of explosive growth, making silicon carbide processing and processing tools essential for its development. Traditional metal sintered grinding rods used for processing ceramics such as zirconia and alumina cannot meet the requirements for lifespan and quality when dealing with the harder and more brittle silicon carbide ceramics. This invention utilizes nano-titanium powder to achieve strong holding force and easy sintering, while adding a copper-tin alloy to improve the toughness of the binder, enhance the product's self-sharpening properties, and increase cutting force, thus ensuring product quality and lifespan. Attached Figure Description

[0027] Figure 1 This is a picture of an actual grinding wheel. Detailed Implementation

[0028] The metal matrix composition and content of the silicon carbide ceramic drilling metal grinding wheel disclosed in this invention are as follows:

[0029] Copper powder 50-70%

[0030] Tin powder 15-25%

[0031] Nano titanium powder 10-20%

[0032] copper-tin alloy balance

[0033] Preparation method of silicon carbide ceramic drilling metal grinding wheel rod:

[0034] (1) Raw material preparation: Copper powder, tin powder, and nano-titanium powder are accurately weighed according to the formula requirements of a certain proportion. First, the accurately weighed nano-titanium powder is placed in a beaker, and 200% of the total volume of copper powder, tin powder, and nano-titanium powder in alcohol is added. The mixture is ultrasonically dispersed for 5 minutes at 60℃. Then, copper powder and tin powder are added and ultrasonically treated until the alcohol evaporates completely. The ultrasonically treated powder, diamond, and epoxy resin are ball-milled in acetone solution. Then, stainless steel balls are added with a ball-to-material ratio of 5:1 (wt.%) and a mass ratio of large and small balls (2mm and 1mm) of 4:1. The ball mill is run at 200 rpm for 60 minutes. The material is then removed, dried, and sieved. The balls and material are separated, and the powder is crushed and granulated. Then, the granulated diamond-containing powder, 200# copper-tin alloy powder, and a small amount of resin are mixed in a three-dimensional mixing mill for 30 minutes, dried, and sieved.

[0035] (2) Pressing: The powder is evenly poured into a conventional mold, and the pressure applied to the mold is 2±0.5t / cm. 2 The pressure is maintained for 5-10 seconds. The mold is rotated 90° for the second pressure application, and the same pressure is applied again for pressing. After demolding, a cold-pressed blank with uniform density is obtained.

[0036] (3) Sintering and shaping: Place the cold-pressed blank from step (2) into the sintering furnace, raise the temperature at a rate of 10-30℃ / min, raise the temperature to 300℃ and hold for 60-120min; raise the temperature to the sintering temperature of 700-800℃ and hold for 40-80min, then raise the temperature to the highest temperature of 880-950℃ and hold for 60-90min, and cool down naturally to complete the sintering.

[0037] Standard shape processing: According to the drawings, the shape is machined to size by electrical discharge machining or grinding, then mounted on a machine and polished with a 400# oilstone for 30 seconds to remove the sharp edge and loose sand. The grinding wheel prepared by the above method has the characteristics of long life and good quality. Due to the strong holding force of the bonding agent on the diamond and good self-sharpening properties, the quality is excellent while ensuring a life of 1.5-2 times that of conventional grinding wheels.

[0038] This invention utilizes existing raw materials and creatively proposes a new formula to obtain a high-quality, long-life grinding wheel for silicon carbide drilling. The specific preparation operation and processing testing are conventional techniques. The copper powder is 500#, the tin powder is 500#, the nano titanium powder is 60nm (D90), the copper-tin alloy powder is 200#, and the tin content is 20%. The resin is epoxy resin E-20, and the amount of epoxy resin is 1% of the total metal powder. The diamond is 180#.

[0039] Example 1

[0040] Weigh out 61% copper powder, 17% tin powder, 12% nano titanium powder, and 10% copper-tin alloy powder by mass percentage; the volume ratio of metal powder to diamond is 60%:40%. Weigh the molding material according to the unit weight requirement, put the molding quantity into the mold cavity, and perform pressing, sintering, and dimensional processing. Figure 1 This is a picture of the actual grinding wheel. Silicon nitride drilling produces no chipping, has a lifespan of up to 350 holes, and uses up all the metal rod.

[0041] Example 2

[0042] Weigh out 60% copper powder, 15% tin powder, 10% nano titanium powder, and 15% copper-tin alloy powder by mass percentage; the volume ratio of metal powder to diamond is 60%:40%. Weigh the molding material according to the unit weight requirement, put the molding quantity into the mold cavity, and perform pressing, sintering, and dimensional processing. Silicon nitride drilling can achieve a life of up to 260 holes.

[0043] Example 3

[0044] Weigh out 65% copper powder, 15% tin powder, 15% nano titanium powder, and 5% copper-tin alloy powder by mass percentage; the volume ratio of metal powder to diamond is 60%:40%. Weigh the molding material according to the unit weight requirement, put the molding quantity into the mold cavity, and perform pressing, sintering, and dimensional processing. Silicon nitride drilling can achieve a life of up to 170 holes.

[0045] The preparation methods of the above embodiments are as follows:

[0046] (1) Raw material preparation: Copper powder, tin powder, and nano-titanium powder were accurately weighed according to the formula requirements of a certain proportion. First, the accurately weighed nano-titanium powder was placed in a beaker, and 200% of the total volume of copper powder, tin powder, and nano-titanium powder in alcohol was added. The mixture was ultrasonically dispersed for 5 minutes at 60°C. Then, copper powder and tin powder were added and ultrasonically treated until the alcohol evaporated. The ultrasonically treated powder, diamond, and epoxy resin (70% of the total amount of resin) were ball-milled in acetone solution. Then, stainless steel balls were added with a ball-to-material ratio of 5:1 (wt.%) and a mass ratio of large and small balls (2mm and 1mm) of 4:1. The ball mill was run at 200 rpm for 60 minutes. The material was removed, dried, and sieved. The balls and material were separated, and the powder was crushed and granulated. Then, the granulated diamond-containing powder, copper-tin alloy powder, and a small amount of resin (30% of the total amount of resin) were mixed in a three-dimensional mixer for 30 minutes, dried, and sieved.

[0047] (2) Pressing: The powder is evenly poured into a conventional mold, and the pressure applied to the mold is 2 t / cm. 2 The pressure is maintained for 8 seconds. The mold is rotated 90° for the second pressure application, and the same pressure is applied again for pressing. After demolding, a cold-pressed blank with uniform density is obtained.

[0048] (3) Sintering and shaping: Place the cold-pressed blank in step (2) into the sintering furnace, raise the temperature at a rate of 20℃ / min, raise the temperature to 300℃ and hold for 100min; raise the temperature to 750℃ and hold for 60min; raise the temperature to the highest temperature of 900℃ and hold for 80min; cool down naturally to complete sintering.

[0049] After routine machining, a metal grinding wheel with an outer diameter of 8 mm is obtained for drilling. When drilling with silicon carbide ceramic, the rotation speed is 20,000 rpm, the feed rate is 300 mm / min, the depth of cut is 0.02 mm per pass, and the hole diameter is 10 × 4 mm.

[0050] The lifespan is measured by the point at which the drill bit chips or the metal grinding wheel is used up.

[0051] Comparison Example

[0052] The best-performing product of its kind currently available on the market, silicon nitride drilling produces no chipping, has a lifespan of up to 210 holes, and uses up all the metal rods.

[0053] The high-strength, high-hardness ceramic grinding wheel disclosed in CN112756613A cannot be used for drilling silicon carbide ceramics, resulting in a phenomenon where it cannot be ground.

[0054] Comparative Example

[0055] Based on Example 1, the copper-tin alloy is omitted; instead, 69% copper powder, 19% tin powder, and 12% nano-titanium powder are weighed by mass percentage; the volume ratio of metal powder to diamond is 60%:40%. The molding material is weighed according to the unit weight requirement, and the molding quantity is put into the mold cavity for pressing, sintering, and dimensional processing. It has high toughness, which is not conducive to blade removal and has a short lifespan. Silicon nitride is used for drilling, with 125 holes.

Claims

1. A method for preparing a silicon carbide ceramic drilling metal grinding wheel, comprising the following steps: ball milling copper powder, tin powder, nano-titanium powder, diamond, and resin adhesive, then mixing them with copper-tin alloy powder and resin adhesive to obtain a powder; then cold pressing the powder and sintering it to obtain a silicon carbide ceramic drilling metal grinding wheel; the copper powder, tin powder, nano-titanium powder, and copper-tin alloy powder constitute the metal matrix, and the mass percentage of each component is as follows: 60% copper powder 15% tin powder 10% nano titanium powder copper-tin alloy powder balance The metal matrix is ​​composed of copper powder, tin powder, nano-titanium powder, and copper-tin alloy powder, with a volume ratio of 60% to 40% for the metal matrix and diamond. The pressure of cold pressing is 2±0.5t / cm. 2 Maintain pressure for 5-10 seconds; during sintering, the heating rate is 10-30℃ / min; heat from room temperature to 300℃ and hold for 60-120 minutes, then heat to the sintering temperature of 700-800℃ and hold for 40-80 minutes, then heat to the highest temperature of 880-950℃ and hold for 60-90 minutes, then cool naturally to complete sintering.

2. The method for preparing the silicon carbide ceramic drilling metal grinding wheel according to claim 1, wherein copper powder, tin powder, and nano titanium powder are dispersed and mixed, and then milled with diamond and resin ball mill.

3. The silicon carbide ceramic metal grinding wheel prepared by the method for preparing silicon carbide ceramic drilling metal grinding wheel according to claim 1.

4. The application of the metal grinding wheel for drilling silicon carbide ceramics as described in claim 3 in the processing of silicon carbide ceramics.

5. A method for machining silicon carbide ceramics using the metal grinding wheel for drilling silicon carbide ceramics as described in claim 3, characterized in that, The silicon carbide ceramic is drilled using the metal grinding wheel for drilling silicon carbide ceramics as described in claim 3.

Images