Stretched exponential behavior of degradation in oxide cathodes

We investigated degradation behavior of oxide cathodes in CRTs. The excess (or free) Ba enrichment process on the surface of oxide cathode, which starts to be induced from activation process, is a complex phenomenon which includes electrolytic transport, chemical reduction, and boundary diffusion, etc. We reveal that degradation behavior of oxide cathodes, which is directly related with the free Ba enrichment process, is able to be described by the stretched exponential model that has been successfully used to describe the complex dynamics of various systems. We derive a simple longevity equation, which depends on two parameters of stretched exponential model: i) characteristic life and ii) stretched exponent. We demonstrate that degradation factors, for example, temperature, can significantly affect the two parameters and in turn longevity. It is interesting that oxide cathodes, which have been applied as electron sources for ∼100 years, can be described as dynamics of complex systems in modern physics.