Basic Properties, Synthesis and Typical Properties of Boron Carbide

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What is Boron Carbide?

Boron Carbide Powder belongs to the trigonal system. The unit cell contains 12 B and 3 C. The unit cell’s stereo diagonally connected C atoms are in an active configuration. They can be substituted by B atoms, forming a solid solution replacement.

B4C’s molecular weight is 52.25 with C21.74% & B78.25%. The color is usually gray or black. It has a hardness of Mohs 9.35, a microhardness around 49GPa and is only second to cubic boron.

B4C Powder has a melting temperature of 2450°C (decomposition). The coefficient for expansion at 1000degC (4.5×10-6degC-1) is 4.5×10-6degC-1. Thermal conductivity is 121.4W/m*k for 100degC, and 62.79W/m*k for 700degC. B4C powder can be used primarily as an abrasive. B4C hot-pressed products are suitable for wear-resistant or heat-resistant parts. B4C is mostly used in the refractory industries as an anti-oxidant additive. Unshaped materials enhance the strength and resistance to corrosion of the body.

The properties of Boron Carbide and their Synthesis

B4C is commonly synthesized by reducing boron ahydride with carbon.


The synthesis reaction may be carried out either in an electric arc or a muffle oven. In a resistance-type furnace, the mixtures of boron hydride B2O3 with carbon C are heated to a lower decomposition temperature than B4C. This is an effective way to synthesize B4C. B4C is broken down into boron and carbon rich phase in the electric-arc furnace because of the high temperature. The reaction product may contain a lot of free C (20%-30%). As a result, the B4C obtained is of slightly inferior quality.

In order to synthesize B4C using an electric arc, boric acids (with a content greater than 92%), artificial graphite with a fixed carbon of greater than 95%, and petroleum coke with 85% fixed carbon are used. The theoretical dosage is calculated based on the reaction formula. The theoretical amount is approximately 2% higher. Each of artificial graphite and petroleum coke accounts for 50% of total carbon addition, which is then 3%-4% more than the theoretical amount. Add the three prepared raw materials to a ball-mill and then add them to the arc. B4C can then be obtained by reducing and Carbonizing the furnace from 1700-2300. Finaly, the frit will be sorted and cleaned, then crushed, ground, picked, sedimented, classified, etc. to produce B4C in various particle sizes.

(aka. Technology Co. Ltd., a trusted global chemical materials supplier & manufacturer has over 12 years experience in providing high-quality nanomaterials and chemicals. B4C powder manufactured by our company is of high purity with fine particles and low impurity. If you need lower, please call us.