Abstract: A definitive investigation of the boron-carbon equilibrium system is being made by X-ray diffraction, metallographic, and thermal analytical techniques. Additional baron-carbon alloys have been prepared by sintering and arc-melting compacts prepared from boron and high-purity graphite. Metallographic examinations of these alloys are in agreement with alloys previously preapred from lampblack. X-ray investigation of sintered compacts indicates that the solubility range of boron carbide extends almost to pure boron. Boron of various purities has been annealed for times up to four hours, but no structure other than beta-rhombohedral has been detected. Very high purity boron (10 ppm impurity) has been obtained for the study of allotropy and the equilibrium relationships at very dilute carbon contents.

Abstract: A definitive investigation of the boron-carbon equilibrium system is being made by X-ray diffraction, metallographic, and thermal analytical techniques. Alloys are being produced by sintering pressed powder aggregates with subsequent arc melting. Alloys have been made at two atomic percent intervals up to thirty atomic per cent carbon. In the future, higher carbon compositions are to be investigated. Techniques have been worked out for the metallographic preparation of the extremely hard and friable alloys.