Crystal structure and Uses of Iron boride
Iron boride has properties of ceramics such as high hardness, and properties of metal properties, such as thermal conductivity and electrical conductivity. Boride coatings on iron are superior mechanical, frictional, and anti-corrosive. Iron mono boride is a grey powder that is insoluble in water.
Crystal structure
Iron boride has a tetragonal crystal structure, has zig-zag chains of boron atoms that are coordinated by seven iron atoms. Boron atoms have a slightly distorted mono-capped trigonal prismatic iron atom coordination and two boron atom neighbors.
B-B single bond distance is 178 pm, Fe-B distance is 215–220 pm, and Fe-Fe distance is 240–272 pm. Each trigonal prism shares two rectangular faces with the nearby prisms, forming infinite prism columns.
Properties
Iron boride is a soft ferromagnetic compound that becomes paramagnetic above ~325 °C (617 °F).In air, FeB powders begin to react with the ambient oxygen above 300 °C, though bulk FeB materials are expected to be stable in air to much higher temperatures. FeB is an extremely hard compound (15-22 GPa as measured by Vickers indentation) but is not sought after on bored steels because FeB layers are brittle and prone to spalling of the steel or iron.
Uses
Iron boride is often used to improve abrasion resistance, corrosion resistance, wear resistance, and oxidation resistance. It is used in oil and gas refineries, chemical extraction, automotive, stamping, textile extrusion, and injection molding industries.
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