Boron compounds are employed as protective slag forming agents and melting catalysts in non-ferrous metal industry thanks to their smooth, sticky, protective and burr-free liquid forming properties at high temperatures.
In fluxing applications, boron is used in melting of copper alloys, analysis and refining of gold, brazing of steel and gas soldering.
Boron doping increases the hardness and strength of steel. Steel may contain up to 50 ppm of boron. Boron-steel has superior hardening ability. Boron can also be added to stainless steel.
Ferroboron is employed in the production of steel, cast iron, permanent magnets and amorphous metals. More than 50% of the global ferroboron output is dedicated to the steel industry. 10% of the overall yield is employed to produce Nd-Fe-B permanent magnets.
Another application of boron compounds is boronizing. Boronizing improves the hardness of the steel surface. Thanks to its high resistance to corrosion and abrasion, boronized steel is used particularly in surface finishing of hydraulic equipment and oil-well drills. Moreover, boronized materials are employed in the automotive industry for reducing friction coefficient and protecting the moving parts.
Boron nitride is extensively used in surface coating for its friction-reducing effect. The coating process is performed by evaporating h-BN and obtaining c-BN films under high vacuum and appropriate temperature.
Boron chemicals are also employed as cleaners and buffers in electroplating. While boric acid and flouroborates are used in very limited amounts to reduce pores and pits of bearings, flouroboric acid is used at a rate of 10% in cleaning (pickling) process for tin-plated wires.
Boron fibres can be used in a vast variety of applications ranging from sports equipment (fisheries, golf, skiing, bicycles) to aerospace and air vehicles. Boron fibre composites consist of boron fibres and reinforced polymer resins. Boron fibre composites represent the maiden advanced composite materials employed in the construction of aerospace and air vehicles. High costs of boron fibre restricts its application extent.
Aeronautics and Space
Boron use in the aeronautics and space industry demonstrates a progressive rise. Advancements in aerodynamics, high speed wing applications, airframes resistant to high temperatures, R&D efforts on low-weight and high-capacity projects have fairly broadened the use of composite materials in the aeronautics and space industry.
Inflammability accompanied with high ignition temperature, capability to yield solid products that can easily be transferred after combustion, and no pollutant emissions are basic strengths of the material in the design of transportation vehicles.
Boron chemicals can also be used as rocket fuel and various studies on the use of borohydrides such as diboran (B2H6) and pentaboran (B5H9) as a high performance potential fuel additive in aircrafts are underway.