Aging and Durability of High Temperature Electrical Insulation
Abstract
The objectives of this program are to investigate the long-term aging processes which occur in typical high temperature polymeric systems. The primary system of interest is irradiated ethylene tetrafluoroethylene (ETFE) coated over silver plated copper. The two specific goals of this research are: (1) To determine thermal oxidative degradation of a high temperature polymer such as ETFE in the presence of metal surfaces, and (2) To determine the effect of the polymer on the overall stability and morphology of the metal surface. The kinetics of the ETFE degradation process as a function of radiation dose (used to cross-link the polymer, thereby enhancing its mechanical properties), temperature and catalytic metal surface were studies by several different thermal oxidative methods. Kinetic parameters, temperature coefficients (i.e., activation energies), and degradation rates as a function of temperature, radiation dose, and catalytic surfaces were investigated. Analytical procedures were used to determine the most accurate and reproducible method for kinetic analysis. The diffusion and subsequent surface reactions of copper through a thin silver plate (silver plated copper conductor) were studied by scanning Auger electron and optical spectroscopies. The kinetics of the copper diffusion are evaluated in order to correlate changes in the polymer degradation reactions with the change in surface chemistry and morphology of the metal. The initial silver surface slowly changes to an oxidized copper surface of the general stoichiometry Cu 27 o as the copper diffuses through the silver layer. The diffusion is more rapid and the copper surface layer is thicker when the conductor is covered with polymer. In this case the ratio of copper to oxygen at the surface is approximately 3:1.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1999
- Accession Number
- ADA376633
Entities
People
- Clarence J. Wolf
Organizations
- Washington University in St. Louis