| 摘要 |
Silicon carbide whiskers are prepared by reaction, in nonoxidising atmosphere, at a temperature of at least 1300 DEG C, of a charge consisting of a mixture of carbon black and of a source of silicon oxide, according to which process the carbon black has an oxidisability ratio (measured by heating in air for 30 minutes at 600 DEG C) of at least 85%, in that the source of silicon oxide has a particle size of less than 100 mu m and in that the rate of temperature rise between 1300 and 1600 DEG C is lower than 3 DEG C min<-><1> per minute if the operation is carried out in a static atmosphere and not more than 25 DEG C min<-><1> if the operation is carried out with gas percolation. A plateau of 5 min to 5 h at 1600 DEG C is optionally carried out. …<??>The carbon is preferably introduced into the reaction mixture in superstoichiometric quantity relative to the silicon. …<??>The excess carbon is removed at the end of the reaction by oxidation in air at approximately 600 DEG C. …<IMAGE>… |
