Abstract
The integrity of coating can exert a major influence on the first-stage bucket life of gas turbines. This paper clarifies the role of coating and then describes the degradation mechanisms of Platinum-modified aluminide diffusion coating and vacuum plasma sprayed Co-Cr-Al-Y coating based on the investigated results of macro- and micro-structural degradation behaviors for the buckets exposed in service for 11000 and 25000 hours. The life exhaustion concept of the first-stage bucket with that of the coating are also described.
