Boron carbide is the third hardest material in the world after diamond and cubic boron nitride, which is one of the most strategic engineering ceramics in various industrial applications. The aim of this research is to synthesize B4C by reacting boric acid as boron source with polymers from the saccharide family as carbon sources, and to determine the best saccharide as precursor. For this purpose, glucose (monosaccharide), sucrose (disaccharide), and cellulose (polysaccharide) were used and examined. The samples were prepared by appropriate mixing of the starting materials, pyrolysis at 700 °C, and synthesis at 1500 °C. The results of Fourier transform infrared (FT-IR) spectroscopy and X-ray diffractometry (XRD) showed that among the studied saccharide polymers, glucose is the best carbon source candidate for the synthesis of B4C. To describe precisely, the specimen prepared with glucose and boric acid had more boron carbide and less hydrocarbon.

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 B4C synthesis. Then, three pyrolysis atmospheres were selected to find the optimal conditions: burial method in box furnace (air), pyrolysis in tubular furnace (argon), and pyrolysis in box furnace (air). The pyrolyzed powders were finally located inside the tubular furnace at 1500 °C for 4 h under argon atmosphere to synthesize B4C ceramics. X-ray diffractometry (XRD) was employed to determine the optimal processing conditions. The temperature of 600 °C and the holding time of 2 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.

In this paper, mechanical activation and tartaric acid addition were employed to reduce the residual carbon and intensify the efficiency of B4C synthesis using glucose and boric acid as starting materials. To investigate the role of mechanical activation on synthesis performance, one sample was subjected to high-energy ball milling before pyrolysis and the other after pyrolysis. To study the role of additives, in the precursor production stage, on synthesis efficiency and residual carbon reduction, different amounts of tartaric acid (0, 5, 10, 25, and 50 wt%) were tested. FT-IR and XRD analyses were used to characterize the bonds created in the precursors and the phases formed during the pyrolysis and synthesis steps, respectively. The results confirmed that mechanical activation before synthesis can improve the synthesis efficiency, but ball milling before pyrolysis did not significantly affect the final synthesis product. The addition of tartaric acid enhanced the formation of B–C bonds; hence, it increased the efficiency of B4C synthesis. The optimum additive amount was 25 wt% and higher amounts weakened the synthesis performance.

In this research, the effects of synthesis temperature, holding time, and furnace atmosphere on the synthesizability of B4C ceramics using glucose and boric acid as the starting materials were scrutinized. Three temperatures of 1300, 1400, and 1500 °C were selected as synthesis temperatures. The synthesis process was carried out in a tubular furnace for 4 h in Ar atmosphere. To scrutinize the interactive effect of synthesis temperature and holding time, three samples were synthesized at 1500, 1400, and 1300 °C for 4, 8, and 12 h, respectively. Moreover, two types of controlled atmospheres, traditional Ar and an innovative CO/CO2 setup, were considered to optimize the synthesis process. X-ray diffraction (XRD) patterns were employed to determine the optimum synthesis temperature and atmosphere based on the detection of B4C peaks as the desired product and undesirable hydrocarbon and carbon byproducts. The results showed that B4C synthesized at 1500 °C for 4 h in Ar atmosphere contained the least byproduct impurities, so this temperature was chosen as the optimal choice. However, the sample fabricated at 1400 °C for 8 h is a good choice in cases where lower manufacturing temperatures are desired. The efficiency of the innovative setup was similar to the traditional one; therefore, considering the economic aspects, the CO/CO2 atmosphere was chosen as an acceptable option for B4C synthesis.

Synthesis of boron carbide (B4C) as one of the hardest materials on planet Earth is of particular importance due to its wide range of industrial and engineering applications. For this purpose, boric acid and polymers can be used as the boron and carbon sources, respectively. From the family of saccharides in polymeric materials, glucose has shown the best performance for the synthesis of B4C. In this research, untreated and pretreated (caramelized by heating) glucose precursors were selected and mixed with boric acid for subsequent pyrolysis and synthesis processes. X-ray diffractometry and Fourier transform infrared spectroscopy confirmed that heat-treated glucose is a better carbon precursor for B4C synthesis. In order to evaluate the effect of the amount of boric acid, more than its stoichiometric ratio, additional amounts of boric acid (10-40%) were also examined and the excess amount of 30% was determined as the optimal value.