Preparation of novel carborane-containing boron carbide precursor and its derived ceramic hollow microsphere

High melting point and hardness of boron carbide make it extremely difficult to be directly prepared as hollow microsphere. However, precursor derived method is an effective approach to prepare ceramic materials with complex shape. Therefore, in this work a novel boron carbide precursor, poly[1,7-bis(4-chlorophenyl)-m-carborane] (P4CB), was synthesized. The ceramic yield of the precursor P4CB reached as high as 90.25% at 900 degrees C in nitrogen. Oxidation of P4CB in air was barely observed below 500 degrees C, and a passive oxidation was exhibited beyond 700 degrees C. The P4CB/PAN slurry was prepared and coated on a polyoxymethylene (POM) ball substrate. After air crosslinking, substrate decomposition and heat-treatment at 1100 degrees C in Ar atmosphere, boron carbide hollow microsphere with diameter of approximate 1.34 mm and average shell thickness of 30 mu m was finally obtained. The novel precursor could be also utilized to fabricate boron carbide ceramics with different shapes due to its high ceramic yield.

Automated summary

A novel boron carbide precursor, P4CB, was synthesized and used to prepare boron carbide hollow microspheres with high ceramic yield. The precursor showed excellent oxidation resistance and the ability to fabricate ceramics of different shapes.