ProfessorMember of ASTM, State University of New York at Buffalo, Buffalo, NY
A short-range, lattice-ordering mechanism has been used extensively to explain the anomalous thermoelectric properties of such alloys as Chromel® and Nicrosil®. This concept appears to have had its origin in early crystallographic work that postulated this mechanism to explain experimentally observed changes in the relative electrical resistance of nickel-chromium alloys. Later crystallographic work, confirmed by several additional investigators, shows no evidence for the existence of short-range order in nickel-chromium alloys containing less than 25 At % Cr. Other investigators, reviewing the short-term thermoelectric deviations of these alloys, describe this mechanism as “much circumstantial evidence of a hypothesis that the short-term emf changes are due to short-range ordering in the Ni-Cr atomic structure of the Type KP thermoelement.” Since short-range ordering has not been established as being responsible for the thermoelectric properties of nickel-chromium alloys, this mechanism may not arbitrarily be considered as the sole rationale for their behaviors.
Paper ID: JTE10684J