A thermal explosion process to fabricate an intermetallic matrix composite coating on a steel

The thermodynamic analysis and thermal explosion tests in an argon atmosphere for the Ti–C–3Ni–Al system were carried out. An intermetallic matrix composite coating on a steel was fabricated by the thermal explosion reactions of the Ti–C–3Ni–Al system in melt. The thermal explosion products and coatings were examined using XRD and SEM. TiC and Ni3Al were the final products of the thermal explosion reactions of the Ti–C–3Ni–Al system in argon or melt. The addition of 2 wt.% Mg was helpful to reduce the incubation time at the ignition temperature and the size of TiC. But the excess amount of Mg led to the formation of inclusions. During the thermal explosion reactions of the Ti–C–3Ni–Al system in melt, Ni–Al as an ignition agent and Mg as an active agent ensured the ignition and completion of the reactions. The formation of the intermetallic matrix composite coatings on the steel was closely related with the weight ratio of TiC. The microstructure and the interface in the coatings turned to be dense with increasing the weight ratio of TiC. The sound composite coatings firmly bonded with the steel were achieved as the weight ratio of TiC reached 35 wt.% or above.