ASTM International Standard Practice for Thermoelectric Sorting of Electrically Conductive Materials ASTM E977-05

This practice covers the procedure for sorting electrically conductive materials using the thermoelectric method, which is based on the seebeck effect. The procedure relates to the use of direct- and comparator-type thermoelectric instruments for distinguishing variations in materials which affect the thermoelectric properties of those materials. The two techniques that are primarily used in thermoelectric sorting are direct and comparative instrumentation. In the direct instruments, equipment is standardized by placing materials with known chemistry and metallurgical structure in the test system. In the comparative instruments, the thermoelectric response of the test piece is compared with that of a known standard(s) and the response indicates whether the piece is within the acceptance limits. The electronic apparatus shall be capable of maintaining a sufficient temperature differential across the electrodes to produce a suitable thermoelectric voltage. The different procedures for sorting electrically conductive materials are presented in details.