Influence of Plasma Electrolytic Oxidation of Cast Al-Si Alloys on Their Phase Composition and Abrasive Wear Resistance

The microhardness and abrasive wear resistance of cast Al-Si alloys after plasma-electrolytic oxidation (PEO) in a weakly alkaline basic electrolyte (3 g/L KOH + 2 Na2SiO3), as well with the addition H2O2, were determined. X-ray analysis showed that PEO layer comprises two oxide phases, namely α-Al2O3 γ-Al2O3, sillimanite -Al2O3 · SiO2 small percentage mullite -3 Al2O3 2SiO2. Silicon is present structure layer, its greater than their initial state. It has been shown characteristics layers on AK9 AK12 silumins synthesized an composition increase (microhardness up to 900–1000 HV by 14–57 times). formation base 3 hydrogen peroxide intensifies synthesis process promotes high-temperature phases (in particular, corundum). both such increases 30–70%.