In situ synthesis of NiAl–NbB2 composite powder through combustion synthesis

Synthesis of a novel NiAl matrix composite powder reinforced with 0–40 wt.% NbB2 by combustion synthesis in thermal explosion mode was investigated. The elemental powders of Ni, Al, Nb, and amorphous boron were used as starting material. For all compositions final products consisted of only the NiAl and NbB2 phases. Coarser NbB2 with a relatively uniform distribution in NiAl matrix was formed with rising NbB2 content. Microhardness of NiAl considerably increased from 377 ± 13 HV0.05 to 866 ± 81 HV0.05 for NiAl with 40 wt.% NbB2. High microhardness, proper size and distribution of NbB2 in NiAl matrix make it a good candidate as precursor for thermal spray application.

► A Novel NiAl matrix composite powder with 0–40 wt.% NbB2 was synthesized. ► Composite powders were synthesized by thermal explosion reaction of Ni–Al–Nb–B system. ► Microhardness of NiAl considerably increased with raising NbB2 content. ► Synthesized composite powders is a good candidate as precursor for thermal barrier application.