METHOD OF MONITORING CONTACT CORROSION OF DIFFERENT METALS AND CORROSION RESISTANCE TESTER

摘要

PURPOSE:To rapidly decide the corrosiveness of a bi-metal can by immersing an anode sample metal and a cathode nobler than said metal into a test soln. and determining the anode polarization resistance on the surface of the sample metal by increasing or decreasing the cathode area by a specific means and by using the specific equation. CONSTITUTION:The sample electrode (anode) 3 consisting of an Al alloy material and the 1st cathode 4 consisting of an iron material are immersed into the test soln. 2 in an electrolytic cell 1 at the time of deciding the contact corrosion of the bi-metal can having a can body which consists of the iron material and a can cap which consists of the Al alloy material. The 2nd cathode 4 having the same nature as the nature of the 1st cathode 4 is simultaneously so provided as to be electrically turned on-off with the 1st cathode 4 to increase or decrease the cathode area. The displacement of galvanic current (Ig) and sample metal potential (Em) is calculated and recorded by a recorder 26 and the anode polarization resistance (Ha) on the surface of the sample metal is determined from the equation by a personal computer 27 and is displayed on an X-Y plotter 26. The corrosion resistance of the different metals to the contact corrosion is easily and rapidly decided with high accuracy in this way.