| 摘要 |
A coating method by plasma electrolytic oxidation according to the invention is to coat a metal surface with electrolyte. The electric current with 50 mA/ to 100 mA/ of electric current density is applied with 350 V to 600 V of voltage, higher voltage than voltage applied during the remaining process is applied in early plasma electrolytic oxidation process, the rate of number of times between a positive voltage pulse and a negative voltage pulse is 1 : 1 to 2 : 1 in early plasma electrolytic oxidation process and is 30 : 1 to 50 : 1 after middle process when applying the voltage for the positive electrode and the negative electrode in a plasma electrolytic oxidation bath. The surface coating according to the invention has a coating thickness of 0.5 to 5, a surface roughness Ra50 of 0.5 to 10, and maintains a breakdown voltage of 1,000V or higher. Moreover, the invention can be efficiently applied when coating the upper part in a way to apply the electricity such as paint, Teflon, electro deposition coating, silane or coating solution using silane as a main component, coating or electro deposition coating of glass-ceramic, PVD, electroplating, etc.. In addition, the coating has an excellent physical property such as pencil hardness of 8H or greater, 5% NaCl salt water resistant spraying of 96 hours or longer, excellent cohesive property (KS M ISO 2409) (no separation), excellent impact resistance (KS D 6711) (no abrasion). |
