Atomic‐Scale Structural and Chemical Study of Columnar and Multilayer Re–Ni Electrodeposited Thermal Barrier Coating

Rhenium alloys exhibit a unique combination of chemical, physical, and mechanical properties that makes them attractive for a variety of applications. Herein, we present atomic‐scale structural and atomic part‐per‐million level three‐dimensional (3D) chemical characterization of a Re–Ni coating, combining aberration‐corrected scanning transmission electron microscopy (STEM) and atom‐probe tomography (APT). A unique combination of a columnar and multilayer structure is formed by single‐bath dc‐electroplating and is reported here for the first time. Alternating thicker Re‐rich and thinner Ni‐rich layers support a mechanism in which Ni acts as a reducing agent. The multilayers exhibit hetero‐epitaxial growth resulting in high residual shear stresses that lead to formation of corrugated interfaces and an outer layer with mud‐cracks.