Towards a large-scale production of boron carbide nano particles from poly (vinyl alcohol) and boric acid by a solid-state reaction-pyrolysis process (SRPP)

摘要

The aim of the present work is to develop a solid-state reaction-pyrolysis process (SRPP) of poly (vinyl alcohol) PVA and boric acid for the synthesis of boron carbide. PVA and boric acid in a molar ratio of (4:1) were dry-mixed, solid-state reacted by heating at (200250) degrees C in air, and were directly pyrolyzed at (700800) degrees C in air to obtain preceramic precursors. By varying the holding time at 250 degrees C from 210 to 270 min, its effects on the purity of the final product were investigated. The preceramic precursors were ground and heat treated at 1475 degrees C for 120 min in a flow of Ar. The XRD & FE-SEM analyses show that a high purity boron carbide powder with nanosized particles was obtained using this promising approach.