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In this study, a high-density ZrN/ZrSi 2 composite reinforced with ZrO 2 as an inert phase was synthesized under vacuum starting with a Zr-Si 4 N 3 -ZrO 2 blend using combustion-synthesis methodology accompanied by compaction. The effects of ZrO 2 additions (10-30 wt%) and compression loads (117-327 MPa) on the microstructure, porosity and hardness of the samples were studied. The process was monitored using XRD, SEM, EDS, porosity, density and hardness measurements. Thermodynamic calculations of the effect of ZrO 2 addition on the combustion reaction were performed including the calculation of the adiabatic temperatures and the estimation of the fractions of the liquid phase. The addition of up to 20 wt% ZrO 2 improved the hardness and reduced the porosity of the samples. Using 20 wt% ZrO 2 , the sample porosity was reduced to 1.66 vol%, and the sample hardness was improved to 1165 ± 40.5 HV at 234 MPa.

In ferromagnetic semiconductors, the coupling of magnetic ordering with semiconductor character accelerates the quantum computing. The structural stability, Curie temperature (T c ), spin polarization, half magnetic ferromagnetism and transport properties of ZnX 2 Se 4 (X = Ti, V, Cr) chalcogenides for spintronic and thermoelectric applications are studied here by density functional theory (DFT). The highest value of T c is perceived for ZnCr 2 Se 4 . The band structures in both spin channels confirmed half metallic ferromagnetic behavior, which is approved by integer magnetic moments (2, 3, 4) μ B of Ti, V and Cr based spinels. The HM behavior is further measured by computing crystal field energy ΔE crystal , exchange energies Δ x ( d ), Δ x ( pd ) and exchange constants (N o α and N o β). The thermoelectric properties are addressed in terms of electrical conductivity, thermal conductivity, Seebeck coefficient and power factor in within a temperature range 0-400 K. The positive Seebeck coefficient shows p-type character and the PF is highest for ZnTi2Se4 (1.2 × 10 11 W/mK 2 ) among studied compounds.

Vanadium carbide is known, for its hardness and other unique properties, as a refractory material. The synthesis of vanadium carbide is always associated with the utilization of expensive active metals, such as aluminum, calcium and magnesium, as a reducing agent to extract the vanadium metal from its corresponding oxide, followed by carbidization. The carbidization of reduced vanadium requires a complicated process and elevated temperature. Mechanical activation to synthesize vanadium carbide from its corresponding oxide and carbon source represents a promising, straightforward and less energy-intensive route. In the present study, vanadium carbide is synthesized by the carbothermic reduction of a mechanically activated mixture of V 2 O 5 and carbon black as reducing agents without any additives. The reduction process is monitored by means of thermogravimetric analysis. The reduction products are characterized by X-ray diffraction and field emission scanning electron microscope. It is found that V 8 C 7 with an average crystallite size of 88 nm can be synthesized from a V 2 O 5 -C mixture after milling for 15 h and further heating at 1050 °C for 1 h in an inert atmosphere.