boron carbide boron carbide

noun Chemistry.

1. a black, crystalline, extremely hard, water-insoluble solid, B4C, used chiefly as a moderator in nuclear reactors, as an abrasive, and as a refractory.

noun

1. a black extremely hard inert substance having a high capture cross section for thermal neutrons. It is used as an abrasive and refractory and in control rods in nuclear reactors. Formula: B 4 C