Abstract In real construction that are designed to atmosphere where is a possibility of galvanic contacts between two or more metals/alloys with different electrochemical properties. Then the corrosion rate change and is not the same as the single metal exposition. However basic electrochemical characteristics will serve as input data for observation of corrosion degradation before exposition of metals and their bimetallic joints in atmospheric conditions. Research in the field of potential and current density distribution at contact zones of two or more metals is very important for solution of geometrical shape of components, which are applicable mainly under atmospheric conditions. The contribution deals with development of new methodology for measuring gradient potential maps in the corrosion research. The method was tested and evaluated on steel and zinc alloys surfaces with corrosion products. These maps help for better visualization of measured values of distributed potential on corroded surfaces of metals. Method reflects an electrochemical behaviour of corrosion layers in different areas of samples with very good correlation. Simultaneously they provide quantification of potential and for steel also determination of protection character of corrosion products created during exposition, Pourbaix diagrams take into account. Method is easy adaptable for “in-situ”, e.c. during exposition, directly on construction of interest and do not require previous destruction of samples, thus there is in majority of corrosion measurements.