In situ monitoring of structural changes in boron carbide under electric fields

In situ monitoring of the transformation of B4C under electric field using Raman spectroscopy is reported. Application of electric fields up to 5000 V/cm leads to local segregation of carbon, indicated by the appearance of Raman D and G peaks. At low electric fields (< 3000 V/cm) the segregated carbon is amorphous, while at higher fields aromatic sp(2) clustering is observed. Electrical measurements as a function of temperature are used to complement the Raman measurements. The results demonstrate that it is possible to induce transformations in boron carbide using electric fields that are comparable with those obtained under shock and nanoindentation.