کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1657968 | 1517657 | 2013 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Effects of electrical parameters on plasma electrolytic oxidation of aluminium Effects of electrical parameters on plasma electrolytic oxidation of aluminium](/preview/png/1657968.png)
The plasma electrolytic oxidation (PEO) of aluminium alloys is investigated for different electrical working conditions using a pulsed bipolar current supply. A particular attention is paid to the effect of the anodic current density (from 10 to 90 A dm− 2) and current pulse frequency (from 100 to 900 Hz) on the resulting oxide layer. Micro-discharges are characterized during the process by means of fast video imaging with a time and a space resolution of 8 μs and 0.017 mm2, respectively. Correlations are established between the micro-discharge characteristics (surface density, lifetime and size) and the elaborated oxide layers (morphology, growth rate and surface roughness). The highest coating growth rate measured (2.1 μm min− 1) is achieved with the combination of the highest current density (75.7 A dm− 2) and the highest current pulse frequency (900 Hz). Within these specific current conditions it is concluded that the detrimental effects of numerous micro-discharges are minimized. The results also show that the surface roughness may be largely affected by the presence of long-lived and large micro-discharges which develop over the processed surface. The strongest micro-discharges (live duration up to 0.3 ms and cross-sectional area up to 1 mm2) are mainly observed with the combination of the highest current density (75.7 A dm− 2) and the lowest current pulse frequency (100 Hz).
► Effects of anodic current density and pulse frequency in PEO process are investigated.
► Fast-video (8 μs/0.017 mm2 resol.) is used to characterize micro-discharges (MDs).
► Characteristics of MD and some properties of PEO coatings are discussed.
► Growth kinetic and roughness are correlated with strength of MDs (lifetime/size).
Journal: Surface and Coatings Technology - Volume 221, 25 April 2013, Pages 70–76