| 摘要 |
PURPOSE:To detect a pinhole without damaging a coating by immersing conductive material coated with an insulation in a conductive liquid and by checking conductivity between the conductive material and the conductive liquid. CONSTITUTION:An impeller 22 as conductive material to which an insulating coating was provided is immersed in an aqueous electrolytic solution 24 in a vessel 23. In the aqueous electrolytic solution 24 a counter electrode 25 is provided and an end part 18 and the electrode 25 are connected with a power source 26 and an ammeter 27. In the case where the coated film has a pinhole, the electrode 25 and the end part 18 are shortted through the solution 24, so the ammeter 27 conducts. On the other hand, when the coating has not a pinhole, the electrode 25 and the end part 18 are insulated with the coating, so that ammeter does not conduct. When a test is performed, it is preferable to give ultrasonic vibration in order to remove foam within the pinhole. |
