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CN-121990841-A - Porous graphite and preparation method thereof

CN121990841ACN 121990841 ACN121990841 ACN 121990841ACN-121990841-A

Abstract

A porous graphite and a preparation method belong to the technical field of semiconductors. The preparation method comprises the steps of placing mixed raw materials comprising 30-60 parts of carbon fibers with the average length of 100-300 mu m and the average diameter of 10-20 mu m and 35-70 parts of carbonizable graphitized organic precursor substances under the pressure of 2-80MPa for cold press molding, and sequentially carbonizing and graphitizing, wherein the obtained porous graphite has the heat conductivity coefficient of 6-20 w/(m.K) at the test temperature of 1000 ℃ and the bending strength of 6-50Mpa, is not easy to fall off powder, has small secondary pollution, is not easy to be deformed by strong airflow impact, is beneficial to controlling the temperature gradient, relieves the thermal shock property, and improves the growth quality of silicon carbide crystals when being applied to the growth of silicon carbide crystals.

Inventors

  • XIN WEI
  • CHEN MIN
  • WANG YONGFU
  • XIE ZHANBIN
  • JIANG WEIMING
  • Dai Aixin
  • XIA JIANQIANG

Assignees

  • 江苏青昀碳基创新材料有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (20)

  1. 1. The porous graphite is characterized in that the heat conductivity coefficient of the porous graphite at the testing temperature of 1000 ℃ is 6-20 w/(m.K), and the bending strength is 6-50MPa.
  2. 2. The porous graphite of claim 1, wherein the porous graphite has a thermal conductivity of 12.9-14.6 w/(m.k) at 1000 ℃ test temperature.
  3. 3. The porous graphite of claim 1, wherein the porous graphite has a thermal conductivity of 14.6-16.6 w/(m.k) at 1000 ℃ test temperature.
  4. 4. The porous graphite of claim 1, wherein the porous graphite has a flexural strength of 14.5 to 24.1MPa.
  5. 5. The porous graphite of claim 1, wherein the porous graphite has a flexural strength of 24.1-34.1MPa.
  6. 6. The porous graphite of claim 1, wherein the porous graphite has a flexural strength of 34.1-46.1MPa.
  7. 7. The porous graphite according to claim 1, wherein the porous graphite has a bulk density of 0.7-1.25g/ml and a total pore area of 0.05-1.8m 2 /g.
  8. 8. The porous graphite of claim 7, wherein the porous graphite has a bulk density of 0.92-1.02g/ml.
  9. 9. The porous graphite of claim 7, wherein the porous graphite has a bulk density of 1.02-1.12g/ml.
  10. 10. The porous graphite according to claim 7, wherein the porous graphite has a total pore area of 0.05-0.5m 2 /g.
  11. 11. The porous graphite according to claim 7, wherein the porous graphite has a total pore area of 0.5-1.0m 2 /g.
  12. 12. The porous graphite according to claim 7, wherein the porous graphite has a total pore area of 1.0-1.5m 2 /g.
  13. 13. The porous graphite according to claim 7, wherein the porous graphite has a total pore area of 1.5-1.8m 2 /g.
  14. 14. The porous graphite of claim 1, wherein the porous graphite has an apparent density of 1.725-1.814g/ml.
  15. 15. The porous graphite of claim 1, wherein the porous graphite has a median pore diameter of 8.05-47.16 μm and an average pore diameter of 0.476-30.89 μm.
  16. 16. The porous graphite of claim 15, wherein the porous graphite has a median pore diameter of 15.84-25.44 μm.
  17. 17. The porous graphite of claim 15, wherein the porous graphite has a median pore diameter of 25.44-34.44 μm.
  18. 18. The porous graphite of claim 15, wherein the porous graphite has an average pore size of 0.843-8.17 μm.
  19. 19. The porous graphite of claim 15, wherein the porous graphite has an average pore size of 8.17-16.17 μm.
  20. 20. The porous graphite of claim 15, wherein the porous graphite has an average pore size of 16.17-24.17 μm.

Description

Porous graphite and preparation method thereof Technical Field The application relates to the technical field of semiconductors, in particular to porous graphite and a preparation method thereof. Background Silicon carbide has the properties of wide forbidden band, high thermal conductivity, high electron saturation mobility, high breakdown electric field and the like, and is considered to be an ideal semiconductor material for manufacturing optoelectronic devices, high-frequency high-power devices, high-temperature electronic devices and the like. Currently, porous graphite is typically used to separate the silicon carbide source powder from the silicon carbide seed crystals during the growth process of the silicon carbide crystalline material. During the crystal growth process, the silicon carbide source powder is sublimated after being heated to a certain temperature to form gas-phase substances. These sublimated vapor phase materials pass through the porous graphite and are transported to the surface of the seed crystal for deposition and crystal growth. However, silicon carbide crystals prepared by using the current porous graphite are easy to crack and have poor growth quality. Disclosure of Invention Based on the defects, the application provides porous graphite and a preparation method thereof, so as to solve the problem of poor growth quality of silicon carbide crystals in the related art. The application is realized in the following way: in a first aspect, examples of the present application provide a porous graphite having a thermal conductivity of 6-20 w/(m.K) and a flexural strength of 6-50MPa at a test temperature of 1000 ℃. In the implementation process, the porous graphite has the heat conductivity coefficient of 6-20 w/(m.K) and the bending strength of 6-50MPa at the test temperature of 1000 ℃, has higher bending strength and lower heat conductivity coefficient, and has high bending strength, difficult powder falling, small secondary pollution and difficult strong airflow impact deformation when being applied to the growth of silicon carbide crystals, and the lower heat conductivity coefficient can meet the requirement of accurate control of the growth temperature gradient of the silicon carbide crystals, can keep the temperature stability of a crystal growth area and relieve the thermal shock resistance caused by temperature change, thereby improving the growth quality of the silicon carbide crystals. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a thermal conductivity of 12.9-14.6 w/(m.k) at a test temperature of 1000 ℃. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a thermal conductivity of 14.6-16.6 w/(m.k) at a test temperature of 1000 ℃. With reference to the first aspect, in an alternative embodiment of the present application, the flexural strength of the porous graphite is 14.5 to 24.1MPa. With reference to the first aspect, in an alternative embodiment of the present application, the flexural strength of the porous graphite is 24.1 to 34.1MPa. With reference to the first aspect, in an alternative embodiment of the present application, the flexural strength of the porous graphite is 34.1 to 46.1MPa. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a bulk density of 0.7-1.25g/ml and a total pore area of 0.05-1.8m 2/g. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a bulk density of 0.92-1.02g/ml. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a bulk density of 1.02-1.12g/ml. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a total pore area of 0.05-0.5m 2/g. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a total pore area of 0.5-1.0m 2/g. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a total pore area of 1.0-1.5m 2/g. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has a total pore area of 1.5-1.8m 2/g. With reference to the first aspect, in an alternative embodiment of the present application, the porous graphite has an apparent density of 1.725-1.814g/ml. In the implementation process, the porous graphite with the volume density of 0.7-1.2g/ml provided by the example has the apparent density of 1.725-1.814g/ml, the apparent density is basically stable along with the increase of the volume density, and the heat transmission path of the porous graphite in the heat transmission process and the force transmission path of the porous graphite under the stress can be influenc