Applying SHS for the Fabrication of the Ti3SiC2–Ni Composite

Abstract

The results of applying self-propagating high-temperature synthesis (SHS) for fabricating high-temperature nickel alloys and composites based on titanium carbide (TiC) and nickel are reviewed. To reduce brittleness, it is proposed to replace the TiC phase by Ti₃SiC₂ titanium silicon carbide and apply the SHS process to fabricate the Ti₃SiC₂–Ni skeleton composite. Nickel, for infiltrating the Ti₃SiC₂ skeleton, is introduced in three variants: with the addition into the reaction mixture, in the form of a briquette arranged between two SHS charge briquettes, and similarly to the second variant, but with barrier paper layers between nickel and SHS charge briquettes. It is shown that, in all variants, the Ni melt prevents the formation of the titanium silicon carbide MAX phase, thus leading to its degradation. The introduction of Ni into the reaction mixture according to the first variant makes it possible to form a homogeneous composite material, the porosity of which decreased almost to zero with an increase in the Ni concentration to 50%. If the Ni briquette is arranged between two compacted SHS charge briquettes, it is possible to melt a relatively small amount of nickel (23–29% of the weight of samples of synthesized composites), which is insufficient to completely fill the porous layered Ti₃SiC₂ skeletons. When adding 20% Si into the Ni briquette, the infiltration depth increased; the degree of degradation of the MAX phase in the infiltration place decreased; and a more homogeneous composite consisting of the porous skeleton of TiC, TiSi₂, and Ti₃SiC₂ phases partially filled with metallic nickel during the infiltration of the Ni(Si) melt is formed.