Optimum temperature, time and atmosphere of precursor pyrolysis for synthesis of B۴C ceramics

In this paper, the variables of the pyrolysis operation such as temperature, time, and atmosphere were studied and optimized. At first, the effect of increasing pyrolysis time at lower temperatures was investigated to understand the mutual influence of pyrolysis time and temperature in enhancing the efficiency of B۴C synthesis. Then, three pyrolysis atmospheres were selected to find the optimal conditions: burial method in a box furnace (air), pyrolysis in a tubular furnace (argon), and pyrolysis in a box furnace (air). The pyrolyzed powders were finally located inside the tubular furnace at ۱۵۰۰ °C for ۴ h under an argon atmosphere to synthesize B۴C ceramics. X-ray diffractometry (XRD) was employed to determine the optimal processing conditions. The temperature of ۶۰۰ °C and the holding time of ۲ h were selected as the optimal pyrolysis conditions. Meanwhile, the burial method was chosen as the best atmosphere despite having a higher percentage of impurity because of the much lower cost compared to the argon atmosphere.