Boride-sarja

Fysikaaliset ja kemialliset ominaisuudet

Boron is a binary compound formed with metals and certain nonmetals (such as carbon). It can be represented by the general formula MmBn, which is generally an intermediate compound and does not follow the valence rules. In addition to zinc (Zn), cadmium (Cd), mercury (Hg), gallium (Ga), indium (In), thallium (Tl), germanium (Ge), tin (Sn), lead (Pb), and bismuth (Bi) Besides, other metals can form boride. They are crystals with high hardness and melting point. They are chemically stable and cannot be dissolved by hot concentrated nitric acid. They can be produced by direct combination of elements or by reducing oxides with active metals. They are used as refractory, grinding and superconducting materials.

Hakemus

Borides have the characteristics of high conductivity, high melting point, high hardness and high stability.

Borides are soluble in molten alkali. Borides of rare earth and alkaline earth metals are not corroded by moist air or dilute hydrochloric acid, but are soluble in nitric acid. Almost all borides have metallic appearance and properties, with high electrical conductivity and positive temperature coefficient of resistance. Borides of Ti, Zr, and Hf have better electrical conductivity than their metals.

Borides have very good creep resistance, which is of great significance for gas turbines, rockets, etc. that require materials to work at high temperatures for a long time, maintain strength, resist deformation, resist corrosion, and resist thermal shock. Various alloys or cermets based on boride, carbide, and nitride can be used to manufacture rocket structural components, aviation device components, turbine components, sample clamps of high-temperature material testing machines, components of instruments, bearings, and components for measuring high temperatures. Cone heads for hardness and some structural parts of nuclear energy devices, etc.