›› 2015, Vol. 23 ›› Issue (9): 1572-1578.doi: 10.1016/j.cjche.2015.06.004

• Materials and Product Engineering • Previous Articles    

Influence of surface etching pretreatment on PEO process of eutectic Al-Si alloy

Kang Li1, Wenfang Li1, Guoge Zhang1, Min Wang1,2, Peng Tang1,3   

  1. 1 School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641, China;
    2 College of Mechanical Engineering, Guangdong Polytechnic Normal University, Guangzhou 510635, China;
    3 School of Materials Science and Engineering, Guangxi University, Nanning 530004, China
  • Received:2014-10-12 Revised:2015-05-20 Online:2015-09-28 Published:2015-10-24
  • Supported by:
    Supported by the Natural Science Foundation of Guangdong Province, China (S2013010015211).

Abstract: To solve the problems generally encountered during the plasma electrolytic oxidation (PEO) of Al alloys with high Si content, a pretreatment of chemical etching was applied before the process. The influence of such pretreatment was studied by SEM, EDS and XRD. The pretreatment presents a significant effect on positive voltage at the beginning stage of PEO, leading to higher voltage over thewhole process. The difference between the positive voltages of non-etched and etched specimens decreases graduallywith the increase of processing time. The pretreatment exhibitsmuch less influence on the negative voltage. For the sample with surface pretreatment, the average growth rate of PEO coating is increased from 0.50 to 0.84 μm·min-1 and the energy consumption is decreased from 6.30 to 4.36 kW·h·μm-1·m-2. At the same time, both mullite and amorphous SiO2 contents are decreased in the coating.

Key words: Plasma electrolytic oxidation, Eutectic Al-Si alloy, Pretreatment, Etching