Morphology and conductivity investigations of nickel-molybdenium alloy by means of Scanning Spreading Resistance Microscopy

Electrolytically deposited nickel-molybdenum alloys are interesting materials because of their high corrosion resistance and low over-potential for hydrogen evolution. Despite many studies devoted to the deposition of these alloys, the mechanism of co-deposition is not fully understood [1]. The aim of the research was to preserve the electrochemically deposited layers under the conditions of exposure to the aggressive factor in the form of a brine solution of various concentrations. Additionally, it was noticed that the applied material does not arrange homogeneously with a distinct occurrence of a different electrochemical nature. This was confirmed by the detection of significant changes in electrical conductivity appearing locally in the structure of the material and visualized using the scanning technique of the scattering resistance microscopy. Additionally, the structural heterogeneity of the alloy was confirmed by correlating changes in electrical conductivity with the distribution of areas of different morphology. The scans were made with the CDT-NCHR conductive probe. The collection contains 12 maps of topography and electrical conductivity as well as 11 spectroscopic curves showing changes in the nature of conductivity in selected places of the sample.
[1] L.S. Sanches, S.H. Domingues, C.E.B. Marino, L.H. Mascaro, Characterisation of electrochemically deposited Ni-Mo alloy coatings, Electrochem. Commun. 6 (2004) 543–548. doi:10.1016/j.elecom.2004.04.002.