Investigation of boron carbide powder production parameters by dynamic carbotermal reduction

Keywods: Boron Carbide, Boron Oxide, Dynamic Carbothermal Reduction, Powder Production The Carbothermal Reduction (CR) is one of the methods used in the synthesis of advanced ceramics. In this thesis, the method of carbothermal reduction has been optimized by realizing the synthesis in a moving system using the novel method of Dynamic Carbothermal Reduction (DCR). In this method, the raw powders are in move throughout the reaction, which consequently increases the quality of the advanced technical ceramic's powders. Furthermore, both the synthesis temperature and duration are decreased. Boron oxide (B2O3) and carbon black were used as starting raw powders in this study. The mixing of raw powders was adapted in the appropriate stochiometric conditions and boron carbide (B4C) synthesis was examined. Moreover, the effects of yttrium oxide (Y2O3) and alumina (Al2O3) additives on the product properties and the process, were investigated. Granules of the powder mixtures were obtained using a granulator, at a speed varying between 300 and 6000 rpm. B4C powders were obtained from the prepared granules in graphite reactor under Ar atmosphere, at a 4 rpm reactor rotation. The reaction temperatures investigated were 1400°C, 1450°C and 1500°C, whereas the reaction times were 1, 60, 120 min. various parameters such as gas mixtures (Ar and C3H8) and additives (Y2O3 and Al2O3) were investigated. The synthesized powders were characterized by XRD and SEM analysis and the optimum conditions were determined.