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CN-122010571-A - Pressureless sintered silicon carbide grinding medium and preparation method thereof

CN122010571ACN 122010571 ACN122010571 ACN 122010571ACN-122010571-A

Abstract

The invention belongs to the technical field of ceramic tube preparation, and particularly relates to a pressureless sintered silicon carbide grinding medium and a preparation method thereof. The preparation method of the pressureless sintered silicon carbide grinding medium comprises the specific steps of proportioning, preparing a base material of the silicon carbide grinding medium, wherein the base material comprises 98-99wt% of submicron silicon carbide and 1-2wt% of boron carbide, ball milling and mixing, spray granulating, forcefully stirring and mixing and granulating, biscuit drying, biscuit wax removal and high-temperature sintering, thus the preparation is completed. The preparation method has simple process flow, avoids the use of large forming equipment such as a dry press, a cold isostatic press and the like, greatly reduces the production input cost, and has the advantages of good sphericity degree, high density, high strength, high toughness, ultrahigh wear resistance, long service life, high temperature resistance and good chemical stability.

Inventors

  • ZHENG DEKUN
  • XIAO HUI
  • WEI HUI
  • LI YUQING
  • LI SILONG

Assignees

  • 陕西科谷新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20251230

Claims (8)

  1. 1. The preparation method of the pressureless sintered silicon carbide grinding medium is characterized by comprising the following steps: S1, preparing a base material of a silicon carbide grinding medium, wherein the base material comprises 98-99wt% of submicron silicon carbide and 1-2wt% of boron carbide according to the weight ratio; S2, ball milling and mixing, wherein the specific process is as follows: s21, putting the base material obtained in the step S1, tetramethyl ammonium hydroxide and deionized water into a ball mill for stirring and ball milling, wherein the tetramethyl ammonium hydroxide accounts for 0.2-1.5wt% of the total weight of the base material, and the deionized water accounts for 65-75wt% of the total weight of the base material until stirring is uniform; S22, adding water-soluble phenolic resin until stirring is uniform, wherein the water-soluble phenolic resin accounts for 5-8wt% of the total weight of the base material; S23, adding PEG400, wherein the PEG400 accounts for 1-3wt% of the total weight of the base material, stirring until the mixture is uniform, and then unloading, sieving, stirring and ageing; s3, spray granulation; s4, strongly stirring, mixing and granulating; s5, drying the biscuit, wherein the concrete process is as follows: Placing the prepared grinding medium biscuit balls into a hot air oven, preserving heat at 50-60 ℃ for 1-2 hours, and then heating to 120 ℃ for preserving heat for 1-3 hours; s6, removing wax from the biscuit, wherein the specific process is as follows: the dried grinding medium biscuit is put into a wax removal furnace, the temperature is raised to 850 ℃ at 1-5 ℃ per min, the temperature is kept for 1-4h, flowing argon is filled for protection, and the biscuit is cooled along with the furnace after the temperature is kept; and S7, sintering at high temperature to finish the preparation.
  2. 2. The method of preparing pressureless sintered silicon carbide grinding media according to claim 1, wherein in step S21, the rotation speed of the ball mill is in the range of 5-10r/min.
  3. 3. The method for preparing pressureless sintered silicon carbide grinding media according to claim 1, wherein in the step S23, the specific process of unloading, sieving, stirring and aging is that sieving is carried out by adopting a 250-mesh screen, and then the sieved slurry is poured into a paddle bucket for slow stirring and aging, and the rotation speed of a stirring shaft is 10-25r/min.
  4. 4. The method for preparing pressureless sintered silicon carbide grinding media, as set forth in claim 1, characterized in that in the step S3, spray granulation is performed by adopting a centrifugal spray granulation tower, the aged slurry is poured into a storage tank, the inlet temperature is set to be 200-250 ℃, the outlet temperature is set to be 80-120 ℃, the rotating speed of an atomizing disk is set to be 6000-10000r/min, the speed of a material pump is set to be 18-20HZ, spray granulation is performed, the prepared spray granulation powder is subjected to 80-mesh sieving, and then sealed aging is performed for standby.
  5. 5. The method for preparing pressureless sintered silicon carbide grinding medium according to claim 1, wherein in the step S4, the powder is mixed and granulated by strong stirring, the spray granulation powder prepared in the step S3 is added into a mixer, deionized water is added into a container bottle, air pressure is regulated, water is atomized into fine liquid, the fine liquid is sprayed onto the surface of the granulation powder, strong mixed granulation is started, after the designed particle size is reached, atomization water spraying is stopped, and the granulated grinding medium biscuit is continuously operated for 10-30min, so that densification is enhanced.
  6. 6. The method for preparing pressureless sintered silicon carbide grinding medium according to claim 1, wherein in step S5, the biscuit is dried by placing the prepared grinding medium biscuit ball into a hot air oven, preserving heat at 50-60 ℃ for 1-2 hours, and then heating to 120 ℃ for preserving heat for 1-3 hours.
  7. 7. The method for preparing pressureless sintered silicon carbide grinding media according to claim 1, wherein in the step S7, sintering is performed at high temperature, the method comprises the steps of loading a biscuit after wax removal into a graphite crucible, loading the graphite crucible into a sintering furnace, starting a vacuum pump to vacuum, heating to 900 ℃ at 1-5 ℃ per minute, preserving heat for 1-2h, heating to 1500 ℃ at 1-3/minute, preserving heat for 1-2h, closing the vacuum, filling argon gas to a pressure gauge to display 0.1bar, heating to 2150 ℃ at 1-2 ℃ per minute, preserving heat for 0.5-1.5h, closing a heating system, and cooling to room temperature along with furnace cooling to open the furnace, thereby completing the preparation.
  8. 8. The pressureless sintered silicon carbide grinding medium is prepared by the preparation method of the pressureless sintered silicon carbide grinding medium according to claim 1, and is characterized in that the pressureless sintered silicon carbide grinding medium has a particle size ranging from 3mm to 20mm, a volume density of not less than 3.10g/cm < 3 >, a crushing strength ranging from 8KN to 20KN, an abrasion value ranging from 0.275 to 0.350 g/(kg.h) and a Vickers hardness ranging from 22 to 30Gpa.

Description

Pressureless sintered silicon carbide grinding medium and preparation method thereof Technical Field The invention relates to a pressureless sintered silicon carbide grinding medium and a preparation method thereof. Background With the development of the sanding superfine grinding technology, the sand mill is widely applied to industries such as paint, printing ink, high-quality automobile paint, pigment and dye, environment-friendly heat insulation materials, nano ceramic, electronic materials, lithium batteries, barium carbonate, barium sulfate, food processing, chocolate, abrasives, biological agents, suspending agent pesticides, papermaking, submicron grinding, pharmacy and the like. The principle is that a solid-liquid phase mixed material after pre-dispersing and wetting treatment of a stirrer is input into a cylinder body by a material pump, and the material and a grinding medium in the cylinder body are stirred by a disperser rotating at high speed, so that solid particles in the material and the grinding medium generate stronger collision, friction and shearing actions with each other, and the purposes of accelerating grinding of the particles and dispersing of aggregates are achieved. The materials after grinding and dispersing are separated by a dynamic separator to grind mediums, and flow out from a discharging pipe. As the sand mill runs, the purpose of accelerating grinding of fine particles and dispersing aggregates is achieved mainly by the stronger collision, friction and shearing actions of solid particles and grinding media, the abrasion of the grinding media is very serious, the grinding media has high grinding efficiency for reducing the abrasion of the grinding media and the pollution to materials, and generally, the higher the hardness and toughness of the grinding media are, the better the smaller the sphere diameter is. Silicon carbide has hardness inferior to that of diamond and cubic boron nitride, good chemical stability, strong acid and alkali resistance, high thermal conductivity and small thermal expansion coefficient, and is the optimal material for manufacturing grinding media. Chinese patent CN1552936a, which relates to a grinding ball used in ball mill and its manufacturing method, mainly solves the problems of low fracture toughness value and easy occurrence of chipping in grinding process of the existing grinding medium. The product comprises 55-99 parts of silicon carbide and boron carbide powder, 0.5-25 parts of Al-Y additive and 0.5-30 parts of CeO2 or La2O 3. The manufacturing method comprises the steps of preparing a biscuit ball by dry press molding or cold isostatic pressing molding, placing the biscuit ball in a vacuum sintering furnace, flushing with argon, heating and sintering, wherein the heating rate is 5-30 ℃ per minute, heating to 1750-2100 ℃, preserving heat for 240-480 minutes, and sintering in argon. The hardness of the product is adjustable from HV 2420-3000, the wear resistance is improved by 10-50% compared with the prior art, the cost is reduced by 20-40%, the toughness can be improved to 7MPa/cm < 1 >/2, and the toughness is improved by about 30% compared with the prior art, so that the anti-crushing performance of the material is improved. The method is suitable for preparing grinding balls with a diameter of >5mm or more, and there is no mention of preparing grinding balls with a diameter of 0.2-5 mm. The invention relates to a production process for manufacturing silicon carbide ceramic microbeads, belonging to the field of powder grinding. The ceramic raw material is prepared by the following components, by mass, 75% -90% of alpha-SiC powder, 5% -7% of SiO 23%-7%,Al2O3%, 0.1% -3% of TiN, 0.5% -1% of phenolic resin, 0.4% -5% of HT resin, 0.1% -1% of oleic acid and 0.9% -1% of B 4 C, injecting adhesive PVA into the ceramic raw material in the same rotary table, balling and solidifying the adhesive PVA in a medium, directly molding compact blank beads with the particle size of 0.1-2mm, cold isostatic pressing the blank beads filled in the sponge for 2-10 minutes, placing the blank beads after cold isostatic pressing in a degumming furnace to finish the degumming procedure, sintering the obtained blank beads in a crucible in a vacuum high-temperature sintering furnace to produce ceramic microsphere blank balls, and grinding and polishing the obtained ceramic microsphere blank balls to produce the ceramic microsphere balls. The silicon carbide ceramic microbeads produced by the method are firstly rolled to be formed and then subjected to cold isostatic pressing treatment, so that the production process is complex, the production cost is high, and the selling price is high. Disclosure of Invention In view of the above problems, an object of the present invention is to provide a pressureless sintered silicon carbide grinding medium and a method for preparing the same. The technical scheme of the invention is that the preparation method of the pressure