Basic Properties, Synthesis and Typical Properties of Boron Carbide

What is boron caride?

Boron carbide is a part of the trigonal crystal system. Unit cell contains 12 B and 3 C elements. C atoms within a unit cell are connected in a stereo diagonal arrangement. This configuration can be changed by B atoms.

B4C’s molecular weight is 52.25, B21.74% and B78.25%. It can be found in a range of colors, from gray to black to a dense 2.519g/cm3, and a microhardness around 49GPa. The grinding efficiency is about 60%-70% higher than SiC and 1-2 times as high as corundum.


B4C powder’s melting point is 2450. At 1000°C, the coefficient for expansion is 4.5×10-6degC-1. Thermal conductivity at 1000degC is 121.4W/m*k (100degC) and 62.79W/m*k (707degC). Although B4C is most commonly used for abrasives and hot-pressed B4C can also be used to make heat-resistant, wear-resistant, or heat-resistant parts. B4C can also be used in the refractory industries as an additive. For example, it is added to carbon-bonded materials to act an antioxidant. A body with unshaped materials has a higher strength and greater resistance to corrosion.

The typical properties and synthesis of Boron Carbide

A common method of synthesizing B4C in industry is to reduce the boronanhydride with excessive carbon.

2B2O3+7C-B4+6CO|


You can either use an electric arc furnace or a muffle oven to perform the reaction. The resistance furnace can synthesize B4C by heating the mixture B2O3-carbon C at a temperature below B4C. (sometimes with Free B 1%-2%) is another better method. B4C is broken down into a carbon-rich phase at 2200 when it’s synthesized using an electric arc furnace. The quality of B4C produced is affected by the volatilization of some of its components, which can result in a high level of C (between 20% and 30%).


Boric acid, artificial graphite, fixed carbon greater that 95 %, and petroleum coke are used to synthesize B4C using an electric arc furnace. The theoretical dosage of B4C is determined according to the reaction equation. About 2% is the theoretical amount. 50 percent of the total carbon addition amount comes from petroleum coke and artificial graphite. This is about 3%-4% higher than the theoretical value. By reducing or carbonizing the furnace between 1700-2300, you can mix the three ingredients in a mill. To obtain different particle sizes of B4C, the frit must be separated, washed, pickedled, sedimentation, and classified.


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