Name of a commodity Average particle size Purity Crystal type Color MH-Bi 50 nm 99.5% Sub structure of spherical Black Appearance. Different size of bismuth nanoparticles showed a dark gray to black, no other color mix, spherical, without obvious agglomeration。 Use: Metal nanoparticles as lubricating additives: 0.1~0.3% to grease added, so that the formation of self lubrication, the self repairing surface of friction pairs in the friction process, significantly improve the performance of greases. Metallurgical Industry: can be used as additive of cast iron, steel and aluminum alloy, improve the machinability of alloy. Magnetic materials: thermal neutron absorption cross section of bismuth is small and the end of the melting point, high boiling point, heat transfer medium used for nuclear reactor.