Nanomechanical characterization of nanostructured Lu₂SiO₅ environmental barrier coatings by nano-indentation

Nanostructured rare-earth silicates are widely considered as environmental barrier coatings for the new generation of silicon-based composites. In current work, the nanostructured Lu₂SiO₅ coatings were deposited successfully using nanostructured Lu₂SiO₅ feedstocks by atmospheric plasma spraying (APS). Moreover, the nanomechanical properties of Lu₂SiO₅ coatings were characterized systematically by nano-indentation. Results indicate that the grain growth of Lu₂SiO₅ coatings is not obvious compared to Lu₂SiO₅ feedstocks. The nanostructured Lu₂SiO₅ coatings exhibit bi-modal nanomechanical properties. The elastic modulus and nanohardness of Lu₂SiO₅ coatings are 148.84 ± 28.00 GPa and 8.51 ± 4.12 GPa, respectively. In addition, the elastic work and plastic work of Lu₂SiO₅ coatings are 10.387 ± 1.283 nJ and 18.437 ± 6.823 nJ, respectively. The proportion of consumption of energy of Lu₂SiO₅ coatings is 0.636 ± 0.099 during indentation, which means that nanostructured Lu₂SiO₅ coatings process an excellent wear resistance.