The production of binary Mg-Ni alloys and ternary Mg-Ni-based alloys: The structural and corrosion properties

This study produced binary Mg-Ni and ternary Mg-Ni-Ag, Mg-Ni-Fe, and Mg-Ni-Ti alloys using vacuum arc melting and characterized. Binary Mg-Ni alloys were initially prepared, and their evaporation behaviors and structural properties were investigated. Significant evaporation losses were observed during melting due to Mg's low evaporation temperature, and the phase formations within the alloy were evaluated. Subsequently, ternary alloys were produced by adding different amounts of Ag, Fe, and Ti elements to the Mg-Ni binary alloy. X-ray diffraction (XRD) analyses revealed the formation of various phases, such as Ag17Mg54, and Ni3Ti as well as Mg, Mg2Ni, MgNi2 phases. Scanning electron microscopy (SEM) images demonstrated the distribution of these phases within the microstructure. Corrosion tests conducted through electrochemical measurements evaluated each alloy's corrosion potential (Ecorr) and corrosion current density (icorr) values. In alloys substituted with Ag, increasing Ag content resulted in more negative Ecorr values (from -0.611 V to -0.852 V) and higher icorr values (from 3.14 x10-5 A/cm2 to 5.95 x10-degrees A/cm2), indicating reduced corrosion resistance. Conversely, in Fesubstituted alloys, increasing Fe content caused Ecorr values to become less negative (from -1.001 V to -0.794 V) and icorr values to decrease (from 5.52 x10-3 A/cm2 to 2.61 x10-degrees A/cm2), signifying improved corrosion resistance. For Ti-substituted alloys, higher Ti content led to decreased Ecorr values (from -0.976 V to -0.807 V) and reduced icorr values (from 4.55 x10-3 A/cm2 to 1.55 x10-degrees A/cm2), indicating enhanced corrosion resistance. After the corrosion tests, the surface images of the alloys demonstrated intergranular corrosion.