<p>This work investigates the effect of applied voltage on the plasma characteristics of an Al–Ni alloy using optical emission spectroscopy (OES). The alloy, composed of 80% aluminum and 20% nickel by weight, was locally fabricated using a gas furnace to ensure compositional uniformity. Argon gas was used to sustain the plasma discharge, and a DC voltage ranging from 5 to 13 kV was applied. Emission spectra were recorded using an S3000-UV-NIR spectrometer. The results revealed a linear increase in both electron temperature and electron density with rising voltage, indicating that voltage plays a critical role in tuning plasma properties. Prominent spectral lines were observed at 811.53 nm (argon), 296.12 nm (aluminum), and 52.263 nm (nickel). The electron temperature increased from 0.108 eV to 0.662 eV, while electron density rose from 4.80 × 10¹⁷ cm⁻³ to 9.88 × 10¹⁷ cm⁻³. Additionally, the combined influence of gas flow rate and voltage on plasma flame length was examined, revealing a direct and interactive relationship that contributes to producing a more stable and homogeneous plasma. These findings emphasize the importance of optimizing operating conditions to generate controlled plasma suitable for industrial, technological, and medical applications.</p>