Beryllium is a light, light gray metal. The crystal structure
of a-Be (269-1254 ° C) is hexagonal; I-Be (1254-1284 ° C) -
body-centered, cubic. Density 1844 kg / m3, melting point 1287 ° С,
boiling point 2507 ° С. It has the highest heat capacity of all metals
1.80 kJ / kg o K, high thermal conductivity 178 W / m o K at 50 ° C, low
specific electrical resistance (3.6-4.5) o 10 Ohm o m at 20 ° FROM;
coefficient of thermal linear expansion 10.3-13.1 o 10-6 deg-1 (25-100 °
C). Beryllium is a brittle metal; impact strength 10-50 kJ / m2.
Beryllium has a small thermal neutron capture cross section.
Application of beryllium
Beryllium and its compounds are used in technology (over 70% of total metal consumption) as an alloying addition to alloys based on Cu, Ni, Zn, Al, Pb and other non-ferrous metals. In nuclear technology, Be and BeO are used as reflectors and moderators of neutrons, as well as as a source of neutrons. Low density, high strength and heat resistance, high modulus of elasticity and good thermal conductivity make it possible to use beryllium and its alloys as a structural material in aircraft, rocketry and space technology. Alloys of beryllium and beryllium oxide meet the requirements for strength and corrosion resistance as materials for fuel element cladding. Beryllium is used for making X-ray tube windows, applying a hard diffusion layer on the surface of steel (beryllization), and as an additive to rocket fuel. Consumers of Be and BeO are also electrical engineering and radio electronics; BeO is used as a material for housings, heat sinks and insulators for semiconductor devices. Due to its high refractoriness and inertness with respect to most molten metals and salts, beryllium oxide is used for the manufacture of crucibles and special ceramics.