Results on Testing New Process to Make Nitrogen- and Carbon-Containing Precursor Based on Vanadium and Aluminum to Smelt V–Al–N–C Master Alloy

A new process to make complex nitrogen- and carbon-containing precursor materials V(51–43)–Al(30–36)–N(13.4–16.4)–C(2.7–6.0) is developed involving nitriding mixtures of powder of industrial alloys V(65–50)–Al with graphite using self-propagating high-temperature synthesis. The results of pilot tests are encouraging. The ratio of nitrogen to carbon can vary in precursors over a wide range: N/C = 5.5–2.2. X‑ray diffraction analysis confirms that in these materials nitrogen has the form of AlN and VN nitrides, and carbon has the form of double V2C and VC and triple V2Al0.96C1.1 carbides. It is proved experimentally that graphite can be replaced by alternative precursor V(51)–Al(30)–N(15)–C(2.7) in the charge of ladle aluminothermic smelting master alloy V–Al–N–C. The comparison is made between phase composition and distribution of nitride and carbide inclusions in master alloy V–Al–N–C ingots and in those of master alloys smelted using other carbon-containing materials. The comparison involves X-ray diffraction analysis, electron microscopy, and X-ray spectral microanalysis. Matching results are obtained. The nitrogen, carbon, and oxygen content in the ingot meets the requirements set forth in the technical specifications for the master alloys of grade V–Al–N–C.