The increasing use of ion exchange resins in the industry presents the need to determine the main mechanism of loss of efficacy for dry-electropolishing applications. Ion exchange resins for the polishing process of titanium alloys are used to study the effectivity reduction in terms of surface quality and therefore reduce the polishing cycles. Two different resins will be employed, one new (considered as a reference) and the other after reaching the end-life (around 100 hours of dry-electropolishing). Along the process, the electrochemical activity of the solid particles decreases, due to several factors; as: moisture retention, saturation of the ionic exchange points, closure of the porosity due to Joule’s effect, among others.

The main goal behind this study, is to evaluate the degradation process of cationic-based ion exchange resins to highlight the chemical, physical and thermal properties along the life-time of the electrolyte. Furthermore, the functional groups evolution as well as the mean decomposition temperature of the solid/liquid part of the ion exchange resins investigated will be characterized by using Fourier Transformed Infrared (FT-IR) and thermogravimetric analysis, respectively. Finally, the microstructure of the ionic exchange porosity will be evaluated by means of scanning electron microscopy.

To conclude, after the dry-electropolishing process is possible to appreciate, a reduction of the acid and water content filled in the internal porosity due to the Joule’s effect induced during the dry-electropolishing process. The dehydration process presents two different rates: (1) high-dehydration rate induced during the initial dry-electropolishing process mainly attributed to the local temperature change near the surface of the resin and (2) at lower dehydration rates, mainly attribution to a diffusion process of the liquid media, from the central to external part of the resin. These hypotheses agree with the O-H groups present in the FT-IR spectra.