Impact of MgO Additions on the Oxidation Resistance and Compression Behavior of Vanadium Alloys
A novel route for the fabrication of core–shell structured V–MgO alloys via in situ MgO formation is developed. Spark plasma sintering is employed to obtain fully dense V– x MgO ( x = 1, 2.5, 5 wt.%) samples. The sintered alloys consist of vanadium grains with finely dispersed MgO particles uniformly distributed along the grain boundaries. An increase in oxidation resistance at 600 °C is achieved for alloys containing more than 2.5 wt.% MgO. XRD analysis shows that during oxidation, V 2 O 5 reacts with MgO, leading to the formation of MgO 6 V 2 and Mg 2 O 7 V 2 oxides. However, these compounds formed at high temperature are not stable in ambient air with atmospheric CO 2 since it forms MgCO 3 . For further development of this concept, other more stable vanadate formers need to be investigated. The room temperature compressive strength increases from 1350 MPa for pure vanadium to 2180 MPa for the V–5MgO alloy, while at 600 °C it increases from 300 to 350 MPa.