Effects of electrolytes variation on formation of oxide layers of
6061 Al alloys by plasma electrolytic oxidation
(1. School of Nano & Advanced Materials Engineering, Changwon National University,
Changwon, 641-773, Korea;
2. Surface Technology Research Center, Korea Institute of Materials Science,
Changwon, 641-010, Korea)
Changwon, 641-773, Korea;
2. Surface Technology Research Center, Korea Institute of Materials Science,
Changwon, 641-010, Korea)
Abstract: Plasma electrolytic oxidation(PEO) processes were carried out to produce ceramic layers on 6061 aluminum substrates in four kinds of electrolytes such as silicate and aluminate solution with and without sodium fluorosilicate. The PEO processes were carried out under a hybrid voltage (260 V DC combined with 200 V, 60 Hz AC amplitude) at room temperature for 5 min. The composition, microstructure and element distribution analyses of the PEO-treated layers were carried out by XRD and SEM & EDS. The effect of the electrolyte contents on the growth mechanism, element distribution and properties of oxide layers were studied. It is obvious that the layers generated in aluminate solutions show smoother surfaces than those in silicate solutions. Moreover, an addition of fluorine ion can effectively control the layer porosity; therefore, it can enhance the properties of the layers.
Key words: plasma electrolytic oxidation; oxide layer; Al alloy; alkaline electrolyte