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Corrosion‐Free EMF Measurements of Zinc‐Based Intermetallic Compounds at Ambient Temperature
Author(s) -
Kriegel René,
Armbrüster Marc
Publication year - 2020
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201901218
Subject(s) - intermetallic , electromotive force , zinc , electrolyte , inert gas , electrochemistry , corrosion , chemistry , atmospheric temperature range , metal , inert , materials science , anhydrous , inorganic chemistry , chemical engineering , metallurgy , thermodynamics , electrode , organic chemistry , alloy , physics , quantum mechanics , engineering
Material development requires in many cases information about the necessary stability of the materials against oxidation, which is encoded in the chemical activity of the constituting elements. Determination of the chemical activity is tedious, especially for metallic materials at or close to ambient temperature. To determine the chemical activity of Zn at ambient temperature, electromotive force (EMF) measurements on the intermetallic compounds ZnPd, ZnPt and Cu 5 Zn 8 within their respective homogeneity range were conducted. The single‐phase nature of the samples was confirmed by powder X‐ray diffraction, light microscopy as well as SEM/EDX analysis. To exclude oxidation, and therefore faulty determination of the electrochemical potentials, a method was developed to conduct the electrochemical measurements under non‐corrosive conditions in inert atmosphere. Corrosion by the electrolyte was avoided using anhydrous dimethylformamide as aprotic solvent. From the EMF the respective intrinsic activities of zinc in the corresponding intermetallic compounds was determined. Measurements on Cu 5 Zn 8 and comparison to available data in literature verified the developed method allowing to retrieve thermodynamic data of ZnPd and ZnPt for the first time at ambient temperature. The herein developed and easy‐to‐use methodology is applicable to a wide range of metallic material by choosing appropriate compositions of the electrolyte and has the potential to boost material development.