Patent EA-003437-B1 (EA)
Title: Method of manufacturing a diamond-silicon carbide-silicon composite and composite produced by this method
Inventor: GORDEEV SERGEY
IPC: C04B35/573
Filed: 1998-07-16
Abstract: 1. A method for manufacturing a diamond-silicon carbide-silicon composite from diamond particles, comprising the steps of forming a work piece from diamond drains and bonding them by infiltrating of silicon under the pressure of 1000mm of mercury and heating the temperature at least to 1000 degree C wherein the forming a work piece is with a porosity of 25 60 vol-%, heating the work piece and controlling the heating temperature and heating time so that a certain desired amount of graphite is created by graphitization of diamond particles, thereby creating an intermediate body, wherein the amount of graphite created by graphitization is 1-50 wt-% of the amount of diamond, and infiltrating silicon into the intermediate body. 2. A method according to Claim 1, wherein intermediate body is formed by graphitization of diamond. 3. A method according to Claim 2, wherein the amount of graphite created by graphitization is 6-30 wt-% of the amount of diamond. 4. A method according to Claim 2 or 3, wherein the heating temperature during graphitization is lower than 1700 degree C. 5. A method according to Claim 4, wherein the heating temperature and heating time needed for the graphitization is empirically determined for the heating equipment used. 6. A method according to any one of Claims 1, wherein a certain amount of carbon is deposited in the work piece by exposing it to a gaseous hydrocarbon or gaseous hydrocarbons at a temperature exceeding the decomposition temperature for hydrocarbon or hydrocarbons. 7. A method according to Claim 1- 6, wherein the intermediate body is machined into the desired shape and size of the final body before the step of infiltration of liquid silicon. 8. A method according to Claim 7, wherein the intermediate body is heated in the presence of vaporous silicon and then machined into the desired shape and size of the final body before the step of infiltration of liquid silicon. 9. A method according to any one of Claims 1-8, wherein the work piece is formed with a non-uniform distribution of diamond particles with various sizes and qualities. 10. A method according to any one of Claims 1-8, wherein the work piece is formed from a homogeneous mixture of diamond particles of various sizes eventually with the addition of a binder. 11. A method according to any one of Claims 1-8, wherein the diamond particles in the work piece is distributed in successively decreasing sizes from the surface of the work piece towards the center thereof. 12. A method according to any one of Claims 1-11, wherein two or more work pieces are made separately and thereafter being brought together before the heat treatment and the infiltration steps. 13. A method according to any one of Claims 1-11, wherein the forming of the work piece is made in a mould, the heat treatment and the infiltration of silicon being made after the work piece has been taken out of the mould. 14. A composite material diamond- silicon carbide - silicon comprising diamond particles placed in matrix containing silicone carbide, and silicone wherein body comprises 20-75 vol-% of diamond particles, at least 5 vol-% of silicon carbide, the Young's modulus exceeding 450 GPa. 15. A composite material, diamond- silicon carbide - silicon by Claim 14, wherein material contains at least 15 vol-% of silicon carbide. 16. A body by Claim 14, said body comprising at least 29 vol-% of diamond particles, at least 14 vol% of silicon carbide, and silicon, the Young's modulus exceeding 540 GPa. 17. A body by Claim 14, wherein said body comprises at least 46 vol% of diamond particles having sizes of about 30 mum at the most, the Young's modulus exceeding 560 GPa. 18. A body by Claim 14, wherein said body comprises at least 54 vol% of diamond particles, at least 60 % of the diamond particles having sizes of at least 50 mum, the Young's modules exceeding 650 GPa. 19. A body by Claim 14, wherein diamond particles of sizes of about 10 mum or less are embedded and included in the matrix, the Vickers micro hardness of the matrix measured in an area between diamond particles being greater than 30 GPa for a load of 20 N. 20. A body according to Claim 19, wherein diamond particles of sizes of about 10 mum or less are embedded and included in the matrix, the Knoop micro hardness of the matrix being greater than 36 GPa for a load of 20 N. 21. A body by Claim 14, wherein the diamond particles have one size fraction of particles being larger than 50 mum and one sizes fraction of particles having a size of 50 mum at the most, the mass ratio falling in the range of 0.25 to 2.5 and the mean particle size being larger than 10mum, preferably larger than 20mum. 22. A body by Claim 14, wherein diamond particles having sizes less than 20 mum, the abrasion rate being less than 26, preferably less than 10 mum3/m. 23. A body according to Claim 14, wherein the diamond particles having sizes less than 20 mum, the erosion rate being less than 0.34, preferably 0.25 mg/g. 24. A body by Claim 14, wherein a surface of the body is coated with diamond film. 25. A body by Claim 14, wherein the body comprises large diamond particles of a size larger than 20 mum, the matrix comprising 0-50 vol-% of small diamond particles having sizes less than 20 mum, 20-99 vol-% of silicon carbide and 1-30 vol-% silicon, the matrix hardness being 20-63 GPa. 26. A body by Claim 25, wherein the matrix hardness is 20-30 GPa. 27. A body by Claim 25, wherein the matrix hardness is 50-63 GPa. 28. A body by Claim 25, wherein the matrix hardness is 30-50 GPa.