Process for making pitch-free graphitic articles

摘要

High density composites consisting of graphite and metal borides by pressing blended powders of pitch-free coke and boride powder. The pressing may be hot pressing at temperatures of about 2200 DEG C. and pressure of about 1500 psi or cold pressing at about room temperature followed by high temperature sintering. Some of the boron from the boride diffuses substitutionally into the structure at the processing temperatures promoting graphitization; whereby densification and bonding the resulting degree of graphitization of the shapes is comparable to that of conventional graphite articles processed at temperatures in excess of 2800 DEG C. The mechanical strength of these composites is equivalent to and often exceeds the strength of conventional graphites and the oxidation resistance in dry air is much superior at temperatures as high as 800 DEG C. Overall processing time is reduced from months to days thus improving the economics of the process.