  Plasma electrolytic oxidation (PEO) is a surface processing for oxide
coatings formation with advanced properties. Mostly, PEO is performed in an
aqueous solution electrolyte which limits the dimension of treated parts due to
the system heating up. Therefore, treatment of large surfaces cannot be applied
in aqueous electrolyte. In current work an alternative approach of PEO
treatment applied in aluminum 1050 alloy in nitrate molten salt was
investigated. The structure, phase and chemical compositions, and
micro-hardness were examined using XRD, SEM, EDS and micro-hardness tests. The
obtained results showed that formed coating contains from two phases of
{\alpha}- Al2O3 and {\gamma}- Al2O3. It was found that formed coating is free
of any contaminants originated from the electrolyte and has no damages, which
are usually present in coatings formed in PEO treatment in aqueous solution
electrolyte.
