Магний борид

Описание

Magnesium diboride (MgB₂) is a simple ionic binary compound that has proven to be an inexpensive and useful superconducting material.

Химические свойства

Magnesium Boride is brown solid, by reaction of boron oxide and magnesium powder ignited.

Физические свойства

Its molecular weight is 45.9325 g/mol. Magnesium Boride melts at 830°C and is hexagonal with space group P6/mmm and lattice constants of a=3.0864? , c=3.5215 ?. The density is 2.625 g/cm³ and the hardness is 1260 kg/mm².

Использование

Magnesium Boride exhibits super conducting properties and utilized in MRI superconducting magnet, which is a closed-loop cryocooler. It is used as propellants, pyrotechnics and explosives. It can be used as high temperature boron-based thermoelectric materials. It is also used in superconducting transformers, rotors, transmission cables, superconducting radio frequency cavities to minimize energy loss.

Подготовка

Magnesium boride can be formed directly from the elements. Mg melts at 650 °C and boron melts at 2076 °C. Therefore, if a vapor of Mg metal at >750°C (red-heat) is passed over crystals of boron, reaction forms the desired boride. However, to obtain a stoichiometric compositions, it is better to heat the well-mixed powders of Mg and B to obtain specific compounds:
Mg + 2B→MgB₂

Общее описание

Magnesium boride (MgB₂) powder is a superconductive material which has a critical temperature (Tc) = 39K. It can be used for a variety of applications such as hydrogen storage, high energy fuel and high field superconductors.