Microstructure investigation of V2AlC MAX phase synthesized through spark plasma sintering using two various sources V and V2O5 as the starting materials

Autor: Mansour Razavi, Hamidreza Mohammadian-Semnani, Omid Mirzaee, Mohsen Hosseinzadeh
Rok vydání: 2019
Předmět:
Zdroj: Ceramics International. 45:23902-23916
ISSN: 0272-8842
DOI: 10.1016/j.ceramint.2019.07.236
Popis: In this present study, V2AlC MAX phases were prepared successfully using elemental V and V2O5 compound as the starting materials through the spark plasma sintering process. V and V2O5 alongside the carbon source with stoichiometric ratio and non-stoichiometric molar ratios of Al were mixed in a high energy mixer mill for 10 min. The sintering processes were performed at 1350 °C for both prepared mixtures with the initial and final applied pressure of 10 and 30 MPa, respectively. The XRD results indicated that the dominant phase was V2AlC in the sample synthesized with the elemental V powders; while in the case of samples using V2O5, the XRD investigation showed the formation of V2AlC participant Al2O3 as the reduction product of V2O5. The thermodynamic investigations with the proposed reaction approved the formation of V2AlC and Al2O3 as the final products of V2O5–Al–C system. The microstructure study also revealed lath-like and spherical shape of V2AlC MAX phase prepared samples containing V and V2O5 compounds, respectively. The high bending strength amount of 347 ± 12 MPa was obtained for the sample consisting of V2AlC, while the V2AlC–Al2O3 composite showed the Vickers hardness value of11.24 ± 0.26 GPa. It seemed that using V2O5 as the cheaper source of V could lead to producing the V2AlC–Al2O3 composite; however, the microstructure and bending strength of the prepared sample did not demonstrate the accepted results in comparison to V2AlC produced by the direct reaction of V, Al and C as the conventional preparation method.
Databáze: OpenAIRE
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