Electrochemical characterisation of the corrosion properties of aluminium brazing sheet

摘要

A new electrochemical technique is presented that can rapidly assess the corrosion performance of different aluminium brazing sheet alloys. It is an electrochemical technique that uses anodic polarisation to stimulate and accelerate the dissolution of aluminium. Because the core, the diffusion zone and the re-solidified clad after brazing all have different corrosion potentials, the polarisation is chosen in such a way that it resembles the polarisation that the different parts of the sheet have on each other while freely corroding. The corrosion potential may change during the measurement when different parts and surface areas of the sheet become exposed to the electrolyte. Therefore the anodic polarisation is interrupted at regular time intervals to determine the corrosion potential.