A Complete Study of MAX Phases Ti₃Si_1–xCu_xC₂ (0 ≤ x ≤ 1) Formation: Ab Initio Calculations and Sustainable Synthesis

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Using density functional theory calculations, we simulated the substitution of silicon by copper in Ti₃SiC₂ with the formation of Ti₃Si_1–xCu_xC₂ (x = 0.0; 0.125; 0.25; 0.5; 0.75; 0.875; 1.0). We found that the Si–Cu substitution was possible up to half, with the formation of Ti₃Si_0.5Cu_0.5C₂. The elastic matrices for Ti₃SiC₂, Ti₃Si_0.5Cu_0.5C₂, and Ti₃CuC₂ were calculated to determine the effect of substitution on the mechanical properties of the materials. It has been confirmed that the presence of copper leads to a decrease in elastic moduli and an increase in thermal resistivity. In this regard, Ti₃Si_0.5Cu_0.5C₂ may be a promising thermal barrier coating material with a thermal conductivity of about 1.6 W m^–1K^–1. According to the electronic structure, both compounds have zero band gaps. In addition, an attempt to synthesize the Ti₃Si_1–xCu_xC₂ material was carried out using high-temperature self-propagating synthesis. As a result, a sample with more than 70% yield of Ti₃SiC₂ content was obtained through rapid and environmentally friendly synthesis, and then a 20% yield of Ti₃Si_0.929Cu_0.071C₂ composition was achieved, which was confirmed by the X-ray diffraction and energy-dispersive X-ray spectroscopy investigations.