Chemical Analysis of Solid Insulation Degradation using the AFM-IR Technique

To enable the continued development of power transmission cabling, an understanding of the processes which result in their failures is essential. In order to do so, powerful analysis techniques are required. However, those which consider chemical degradation are lagging behind those for visible degradation. This paper presents the Atomic Force Microscopy - Infrared Spectroscopy (AFM-IR) chemical analysis technique, which can provide surface chemical analysis with resolution of ~50 nm across the infrared spectrum. Two cases are considered: interfacial tracking between epoxy and silicone rubber, and the degraded region formed in front of a needle tip in the electrical tree initiation process. The results obtained using AFM-IR are compared to the outcomes from other techniques. It is found that AFM-IR offers a unique and powerful insight into visible and non-visible degradation of solid dielectrics.