Metal-ceramics based on nanostructured boron carbide

Abstract

Boron carbide has unique physicochemical and mechanical properties such as: high modulus of elasticity, high value of a strength-to-density ratio, heightened wear-resistance in unfriendly environment, etc., however dense product of boron carbide is not widely used in the area of engineering due to low impact strength, brittleness and low thermal conductivity of this material. Recent efforts of the scientists working in this area are focused on creating the so-called hetero-modulus metal-ceramic composite materials comprised of high-modulus ceramic and a metallic phase as an elastic binder. Creation of effective boron carbide based hetero-modulus materials is possible when a) boron carbide has a high degree of dispersion; b) metallic binder has a high adhesion ability and low reactivity toward boron carbide. The technology developed for producing boron carbide based metal-ceramic materials provides pyrolysis (900–1100 °C) of the precursors comprised of amorphous boron, carbon-chain polymers and appropriate metal salts. Each particle of the obtained powder contains both – nanostructured components of boron carbide and of a binding metallic phase. The fabricated metal-ceramic product has heightened parameters of impact strength and thermal conductivity in parallel with the retained unique properties of boron carbide.