AC CONDUCTIVITY OF NON MAGNETIC METALLIC ALLOYS

摘要

AC and DC conductivity measurements on AA3003 aluminum alloy are considered using several inductive methods and the well-known 4-wire method. Samples with conductivity from 2.70×107 to 2.95×107 S/m are produced by cold rolling and subsequent recrystallization. Conductivity obtained varies from 1 to 10% relative to initial conductivity (0% recrystallization). Reference materials are used to calibrate standard eddy current impedance diagram equipment, in the range 5-15 kHz. Besides impedance equipment, other two methods are used in order to compare sensitivity to small conductivity changes: force between flat circular coil to sample and transmission between coils at either sides of the sample. In both cases senoidal current are applied to circular flat coils placed at prescribed distance from sample. Measurements are compared with numerically simulated behavior for each physical system, accordingly with Maxwell equations. A procedure for Non-destructive measurement of AC conductivity is proposed and validated.