| 摘要 |
1. A method of producing dense silicon carbide articles by sintering without pressure, in which a) a silicon carbide powder which is at least in major part of the crystalline alpha form, having a specific surface equal to at least 2 m**2 /g, is submitted to a purifying heat treatment under vacuum at a temperature higher than 1 200 degrees C, b) the purified powder is mixed to a nitride which contains aluminium as well as to boron or a compound containing boron, in a quantity corresponding to less than 0,15% by weight of boron as compared with the weight of silicon, the nitride and the boron or the compound which contains boron being equally in the powder state, c) the powdery mixture is suspended in a volatile organic solvent and is submitted to a crushing, d) the metal impurities coming from the crushing are eliminated by a diluted acid, e) a carbonisable organic material which produces by its carbonisation during the sintering step 0,2 to 4% by weight of amorphous carbon compared to the weight of silicon carbide is added to the powdery mixture, f) a moulded article is formed from the powdery mixture and the carbonisable organic material, g) the moulded article is submitted to sintering under neutral atmosphere at a temperature lying between 1 900 and 2 250 degrees C, characterized in that the nitride which contains aluminium is the product obtained by nitriding a mixture of silicon and aluminium powders. |
