Effect of γ' Phase Elements on Oxidation Behavior of Nanocrystalline Coatings at 1050 °C.

Jinlong Wang,Yixuan Jia,Yanxin Qiao,Fuhui Wang,Shasha Yang,Minghui Chen,Pingyi Guo,Lanlan Yang,Shenglong Zhu

doi:10.3390/ma14010202

Abstract

To study the effect of γ′ phase elements on the oxidation behavior of nanocrystalline coatings, two comparable nanocrystalline coating systems were established and prepared by magnetron sputtering. The oxidation experiments of the nanocrystalline coatings on the K38G and N5 superalloys were carried at 1050 °C for 100 h, respectively. The chemical composition of the above coatings is the same as the substrate alloy, including the γ′ elements, such as Al, Ta, and Ti. After serving at a high temperature for certain periods, their oxides participated and then affected the oxidation behavior of the coatings. The Al2O3 scale can be formed on the N5 coating, which cannot be formed on the K38G coating. Tantalum and titanium oxides can be detected on the oxide scale, which ruin its purity and integrity.

Highlights

Nickel-based superalloys are widely used in aeroengines and gas turbines due to their excellent high-temperature mechanical properties [1,2,3]
It is ensured that the beneficial anti-oxidation elements in the sub-state superalloy will not be consumed excessively, and no structural degradation will occur during the oxidation process
The chemical composition of the two coatings were similar to nanocrystalline coatings

Summary

Introduction

Nickel-based superalloys are widely used in aeroengines and gas turbines due to their excellent high-temperature mechanical properties [1,2,3]. They are mainly composed of γ and γ0 phases. After the coating is prepared, the main purpose is to quickly form a protective alumina scale on the alloy surface to achieve protection [16,17] In this way, it is ensured that the beneficial anti-oxidation elements in the sub-state superalloy will not be consumed excessively, and no structural degradation will occur during the oxidation process. The effect of γ0 phase elements in the nanocrystalline coating on its oxidation behavior was studied

Experiment

Discussion

Isothermal

Ellingham

Conclusions