The features of combustion synthesis of aluminum and carbon doped magnesium diboride

We report the results of synthesizing the MgB2-based material in the layerwise combustion and thermal explosion modes. For the initial temperature of 500 °C, the combustion temperatures in the layerwise combustion and thermal explosion modes are identical. The sample surface after the synthesis is coated with a friable white coating, up to 10 µm thick, consisting of whisker-like MgO crystals 1.5 µm long and 200 nm in diameter. It is possible to dope MgB2 with aluminum and carbon atoms. Time-resolved X-ray diffraction studies demonstrate that the (Mg,Al)B2 phase emerges without formation of any intermediate compounds. The absence of Al demonstrates that it is contained in MgB2. Aluminum and carbon doping of MgB2 alters the lattice parameters, while its structural type remains unchanged. Doping of MgB2 with carbon black is found to be a more effective method than graphite doping. Superconducting properties of the synthesized samples were studied.