Chromia Scale Thermally Grown on Pure Chromium Under Controlled p(O2) Atmosphere: IISpallation Investigation Using Photoelectrochemical Techniques at a Microscale

Pure chromium oxidized at 900 degrees C at low oxygen partial pressure (10(-12)atm) gives duplex Cr2O3 scale with an internal part made of equiaxed grains and exhibiting an n-type conduction, and an external part made of columnar grains and exhibiting a p-type conduction. Spalled regions occurring during cooling have been studied with photoelectrochemical techniques at a microscale. New information in the form of a specific image (structural quality image) could be obtained and revealed a level of structural defect density in the internal chromia subscale higher than that measured in the non-spalled region. The results complement the spallation scenario proposed in part I of this work.