https://doi.org/10.1351/goldbook.G02574
An @E01935@ difference between points in the bulk of two phases. It is measurable only when the two phases have identical composition (e.g. two copper wires). It is the difference of @I03046@ in two phases. Symbol: \(\Delta _{\unicode[Times]{x3B1} }^{\unicode[Times]{x3B2} }\phi \).
Source:
Green Book, 2nd ed., p. 59 [Terms] [Book]