| Al-1050 위에 플라즈마 전해 산화법으로 형성된 Al2O3 피막 특성에 미치는 듀티사이클의 영향 |
| 남경수, 문정인, 피마봉 껑씨, 송정환1, 임대영1 |
배재대학교 대학원 재료공학과
1배재대학교 정보전자소재공학과 |
| Influence of the Duty Cycle on the Characteristics of Al2O3 Coatings Formed on the Al-1050 by Plasma Electrolytic Oxidation |
| Kyung-Su Nam, Jung-In Moon, Phimmavong Kongsy, Jeong-Hwan Song1, Dae-Young Lim1 |
Departmemt of Materials Engineering, Graduate School of PaiChai University
1Departmemt of Information & Electronic Materials Engineering, PaiChai University |
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| ABSTRACT |
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Oxide coatings were prepared on Al-1050 substrates by an environment-friendly plasma electrolytic oxidation (PEO) process using an electrolytic solution of $Na_2SiO_3$ (8 g/L) and NaOH (3 g/L). The effects of three different duty cycles (20%, 40%, and 60%) and frequencies (50 Hz, 200 Hz, and 800 Hz) on the structure and micro-hardness of the oxide coatings were investigated. XRD analysis revealed that the oxides were mainly composed of ${alpha}-Al_2O_3$, ${gamma}-Al_2O_3$, and mullite. The proportion of each crystalline phase depended on various electrical parameters, such as duty cycle and frequency. SEM images indicated that the oxide coatings formed at a 60% duty cycle exhibited relatively coarser surfaces with larger pore sizes and sintering particles. However, the oxides prepared at a 20% duty cycle showed relatively smooth surfaces. The PEO treatment also resulted in a strong adhesion between the oxide coating and the substrate. The oxide coatings were found to improve the micro-hardness with the increase of duty cycle. The structural and physical properties of the oxide coatings were affected by the duty cycles. |
| Key words:
PEO, Duty cycle, $Al_2O_3$ coating, Al-1050, Micro-hardness |
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