Luminescence of the B1Σ+-X1Σ+ band system of MgO during plasma electrolytic oxidation of magnesium alloy

► Plasma electrolytic oxidation (PEO) of magnesium alloy in solution containing Na2SiO3 and KOH. ► Luminescence of the B1Σ+ → X1Σ+ band system of MgO during PEO. ► The measured intensity distributions are employed to estimate the plasma temperature. ► The composition of plasma containing magnesium, oxygen, and hydrogen is calculated.