Evaluation of Hot Corrosion Properties for Nano-coated Superalloy

Abstract

The purpose of this study is to optimize the hot corroded pack coated Ni-based super alloy K417G using composite desirability. Pack cementation parameters optimization was performed using quality characteristics of diffusion coatings for pack cementation process, i.e. salt activator, Nano-powders master alloy powder and wt.% Ge. Analysis of variance (ANOVA) was used for observing the most influencing pack cementation parameters on the quality characteristics, i.e. Na2So4-6% wt. V2O5 (kp1), 100 wt% NaSO4 (kp2), and 75 wt. % NaSO4-25 wt % NaCl (kp3). The optimal process parameters were calculated using composite desirability analysis, a confirmation test performed. Based on analysis of variance results, the wt.% of Ge is the most significant controllable diffusion coating factor for the hot corroded pack coated K417G at optimum setting conditions (A2, B1, C3) i.e. activator (NaCl), master alloy (90Cr-10Al) and wt.% of Ge (2%) according to the quality characteristics. Composite desirability was successfully applied on optimization of hot corroded pack coated K417G using multi-performance characteristics.