Effects of Different Electrolyte Systems on the Formation of Micro-Arc Oxidation Ceramic Coatings of 6061 Aluminum Alloy
Ceramic coatings on 6061 aluminum alloy were prepared by micro-arc oxidation in Na2SiO3 electrolyte system, NaAlO2 electrolyte system and Na (PO3)6 electrolyte system. The breakdown voltage, thickness and hardness of ceramic coatings in different electrolyte systems were comparatively studied. The surface morphology and phase composition of ceramic coatings were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the breakdown voltage is decreased with increase of concentration of electrolyte, and in Na2SiO3 electrolyte system it is the lowest, NaAlO2 takes the second place and Na (PO3)6 is the highest. There is no significant relationship between breakdown voltage and current density in different electrolyte systems. In constant-current model, the thickness of ceramic coatings shows linear increase with the increment of oxidation time in three kinds of electrolyte systems, growth rate remains essentially constant. In the same oxidation time (<80 min), the thickness in Na2SiO3 electrolyte system is the thickest, NaAlO2 takes the second place and Na (PO3)6 is the thinnest. The ceramic coatings in different electrolyte systems are mainly composed of α-Al2O3 and γ-Al2O3, the relative content of α-Al2O3 and γ-Al2O3 in NaAlO2 electrolyte system is higher than that in the other electrolyte systems. The hardness of dense layer is relatively high, the hardness of loose layer is rather low. The distance from substrate interface is 15 um, hardness reaches the highest (1270 HV), then it begins to reduce gradually in NaAlO2 electrolyte system.
LIU Yajuan XU Jinyong LIN Wei GAO Cheng ZAHNG Jingchun CHEN Xiaohe
School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin Guangxi Youjiang Bureau of Mines, Tiandong 531501, China
国际会议
桂林
英文
1-6
2010-11-16（万方平台首次上网日期，不代表论文的发表时间）