A High-Resolution Study of Chemical Aging Prior to Electrical Tree Growth

A study of chemical aging prior to electrical tree initiation has been undertaken using a high-resolution chemical analysis technique, AFM-IR (atomic force microscopy-infrared spectroscopy). This technique has provided chemical characterisation with a spatial resolution of around 50 nm. It is seen that the use of tests on this scale provide information and insight which was not previously observable using lower resolution techniques. Previously unobserved degradation products are observed in epoxy resin prior to tree initiation with ethers (C-O) and methyl groups (CH
₃
) appearing to form alongside carbonyls (C=O), each occurring in different locations around the needle tip. Such spatial resolution of aging chemistry will allow improved models of tree initiation and growth to be developed.