Evaluation of Fracture Toughness of Plasma Electrolytic Oxidized Al2O3-ZrO2 Coatings Utilizing Nano-Scratch Technique

Al2O3 coatings, which can be produced by plasma electrolytic oxidation (PEO) on aluminum substrates, provide an excellent protection against corrosion and wear. However, due to the brittle nature of oxide ceramic, fracture toughness is limited. One approach enhance tolerance incorporation ZrO2 form zirconia toughened alumina (ZTA). In addition its use as a bulk material, application coating material enables broader field application. this study, Al2O3-ZrO2 composite was applied 6082 alloy using aluminate-phosphate-based solution containing Zr-based salt. Polarization measurement indicator passivability given system revealed that salt improves passivation alloy. The coatings’ characteristics were evaluated SEM, EDS, XRD. incorporated into metastable high-temperature modification led thicker with new morphologies including lamellar dendritic structures. Nano-indentation showed Zr increase average hardness compact layer from 16 GPa 18 GPa. coatings investigated locally nano-scratches outer cross-sections. Zr-containing resulted in significantly higher (6.9 MPa∙m1/2) comparison Zr-free (4.6 MPa∙m1/2). Therefore, it shown, PEO process stabilized allotrope at room temperature without need for rare-earth dopants such Y2O3. Furthermore, demonstrated nano-scratch method suitable accurate technique investigation inherent cracks.