Synthesis of strontium hexaboride via condensed precursor technique: in situ formation of B4C as reductant

Journal article, 2022

The divalent alkaline earth borides have received great attention owing to their superior properties for energy-related applications. Among these borides, SrB6 is very popular owing to its excellent magnetic and IR-absorbing properties. In the present study, the synthesis parameters such as temperature and dwell time to synthesize strontium hexaboride were investigated. Strontium hexaboride powders were synthesized via boro/carbothermal reduction (BCTR) by using the condensed product obtained from boric acid, polyol, and strontium carbonate. Two different methods were tried to prepare an optimum condensed product which was used as a raw material for boride synthesis. The condensed products prepared with different methods were characterized to reveal the thermal behavior of the products by simultaneous thermal analysis (STA). The phase formations were examined via X-ray diffractometer (XRD) to investigate the effect of boro/carbothermal reduction temperature and dwell time. The elemental analysis and powder morphology of the final product synthesized via the optimum condensed product were carried out via scanning electron microscopy-energy dispersive X-ray analysis (SEM–EDX). The transitional phases were identified as strontium-rich borates, carbon, and boron carbide (B4C). The optimum synthesis condition of strontium hexaboride via the condensed precursor technique was determined as 1500 °C for 8 h under an Ar flow.