Achieving improved compression plasticity/strength in plasma sprayed Al2O3–GAP amorphous ceramic coatings by regulating spray powder phase compositions

Abstract

In this work, Al2O3–GdAlO3 (GAP) amorphous ceramic coatings were prepared via plasma spraying. A novel method of regulating spray powder phase compositions was provided to obtain the different amorphous phase contents in Al2O3–GAP coatings. The α-Al2O3/c-Gd2O3 and α-Al2O3/GAP sprayable powders were individually applied to deposit the coatings, namely Coating 1# and Coating 2#. Their amorphous phase contents were 91.8 wt% and 55.4 wt%, respectively. X-ray diffraction, scanning electron microscope, electron backscattered diffraction, X-computed tomography, atom probe tomography and micropillar compression tests combined with finite element method were applied to analyze microstructural features and mechanical performance of the coatings. The results showed that Coating 2# possessed higher compressive strength (3.42 GPa) and greater compression plasticity (21.8 %) than Coating 1#. Compared with nearly 40 amorphous materials, Coating 2# had an excellent compression plasticity, which was better than almost all amorphous alloy materials, showing extremely attractive engineering application potential.