What Is a Bolide?

A binary compound of boron with metals and certain non-metals such as carbon. It can be represented by the general formula M _m B _n , which is generally a meso-filled 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) In addition, other metals can form borides. They are all crystals with very high hardness and melting point. They are chemically stable and cannot be dissolved by hot concentrated nitric acid. They can be directly combined with elements or made from active metal reduction oxides. They are used as refractory, abrasive and superconducting materials.

Boron (B) is

Structural units in the form of single bonds, double bonds, networks and space skeletons are formed between boron atoms in the boride lattice. As the relative content of boron in the boride increases, the structural unit becomes more complicated. (as the picture shows)

The main method for making refractory metal borides is

Boride has the characteristics of high conductivity, high melting point, high hardness and high stability: boride has relatively high thermal conductivity and strength, so it has better thermal stability. The oxidation resistance of boride at high temperatures is based on Group IVB metals. Boride is best.

Borides are soluble in molten alkali. Borides of rare earths and alkaline earth metals are not attacked by humid air or dilute hydrochloric acid, but are soluble in nitric acid. Almost all borides have the appearance and properties of a metal, with high electrical conductivity and a positive temperature coefficient of resistance. Ti, Zr, Hf borides are more conductive than their metals.

Boride has very good creep resistance, which is very important for gas turbines and rockets that require materials to work at high temperatures for a long time and can maintain strength, resistance to deformation, corrosion, and thermal shock. Various alloys or cermets based on borides, carbides, and nitrides, which can be used to manufacture rocket structural elements, aviation device components, turbine components, specimen holders for high-temperature material testing machines and instrument components, bearings, and high temperature Cone heads for hardness and certain structural parts of nuclear energy devices. ^[2]