Microstructural characterization of degradation in a high-chromium alloy in the sugar industry.

A new high (24%)-chromium alloy was experimentally manufactured by combining the particular chemical composition of various materials with the use of thermal treatments to produce pump impellers for the sugar industry. The alloy metal was tested in situ in a sugar medium and then evaluated by electrochemical measurements; the two former procedures were associated with a nontraditional method to assess the susceptibility and resistance to corrosion. Potentiostatic and atomic absorption measurements were carried out to characterize the degradation and damage morphology by scanning electron microscopy (SEM) observations. The trials proved a good performance for the new alloy in the sugar medium in spite of nonsignificant localized damages involving erosion-corrosion mechanisms and surface microcrackings of the material.

Scanning electron microscopy analysis of corrosion degradation on tinplate substrates.

The degradation of electrolytic tinplate used in food containers was analysed and evaluated, using scanning electron microscopy and electrochemical measurements of microcorrosion and ion dissolution by atomic absorption to prevent food contamination caused by metal traces and to increase the durability of such tinplates.