Synthesis, Characterizations, And Evaluation Of Mechanical Properties Of (Mg-Co-Ni-Cu-Zn)O High-Entropy Oxide

Abstract

High-Entropy Oxides (Heos) Are Among The Novel Family Of Advanced Ceramic Materials With Attractive And Unexpected Functional Properties In A Specific Area. Even Though High-Entropy Binary Oxides Are Very Important For Energy Applications, The Mechanical Properties And Thermal Stability Of These Classes Of Materials Are Not Well Investigated. Therefore, In This Work, Heo Systems Were Synthesized By Using A Solid-State Reaction Method At High Temperatures, From Binary Oxides Of Mgo, Coo, Nio, Cuo, And Zno, Where These Individual Oxides Were Synthesized From Their Respective Precursors Through Co-Precipitation Methods. The Binary Oxides Were Mixed According To Their Stoichio metric Ratio And Ball-Milled For 10 H; Followed By Filtering And Drying At 100 ???. The Dried Powder Of The Mixture Was Calcined Sequentially At The Temperature Ranges From 750 To 1100 ???, With 50 ??? Increments, To Obtain Optimum Temperature For The Resulting Single-Phase Heos. To Avoid Phase Separation, Samples Were Quickly Removed From The Furnace And Followed By Air Cooling. The Phase-Stability And Compositional Analysis Of The Calcined Powder Were Performed Using X-Ray Powder Diffraction (Xrd). Thus, The Sample Calcined At 950 ??? Can Be Easily Indexed With A Single Phase, Rock-Salt Structure With The Space Group Of Fm-3m. Then, The Uncalcined Powder Was Uniaxially Pressed Into Pellets Under A Pressure Of 45 Mpa And Subjected To Sintering At Various Temperatures In The Ranges From 900 To 1200 ??? With Sintering Times From 3-15 H To Obtain A Single Phase Of Heos (Mg-Co-Ni-Cu-Zn)O. Consequently, The Phase-Stability Of Sintered Pellets Was Confirmed Using Xrd, And As The Result Shown That Pure Single-Phase Heos Were Obtained At 1200 ???Which Are Well-Matched With Powder Calcined At 950 ???. The Micro structural And Elemental Analysis Of The Sintered Pellet Was Characterized Using Scanning Electron Microscopy (Sem) And Energy Dispersive X-Ray Spectroscopy (Edx). Thermal Stability Analysis Of The Heo Powder Samples Was Analyzed Using Thermo-Gravimetric Analysis (Tga) And Differential Thermal Analysis (Dta). Finally, The Mechanical Properties Such As Compressive Strength And Vickers Hardness Tests, Which Are Directly Correlated With The Microstructure Of The Samples, Were Performed On The Sintered Heo Samples. The Sample Sintered At 1200 ??? For 15 H Showed A Maximum Compressive Strength And Vickers Hardness Of About 270.09 Mpa And 15.10 Gpa Respectively, With A Corresponding Relative Density Of About 99.20 %. Hence, These Single-Phase Heo Materials Could Be A Potential Candidate For Structural Applications.