Compositional Grading of Al<sub>2</sub>O<sub>3</sub>/ZrO<sub>2</sub>/SUS304 Hybrid Materials Using Centrifugal Slurry Methods and Spark Plasma Sintering

Abstract

Ceramic/ metal functionally graded materials (FGMs) have been promising to sustain coating structures working under super high temperature as well as high temperature gradient conditions. Compositional gradients in the FGMs can be engineered according to functional performance requirements. This study aims to fabricate Al2O3/ZrO2/SUS304 hybrid FGMs with continuous compositional gradient manners using a combination of centrifugal slurry methods and spark plasma sintering (SPS). The compositional gradients in the FGMs were investigated on microstructures with elemental distributions and hardness on the cross sections of the FGMs. It was demonstrated that the compositions of ZrO2 and SUS304 continuously varied in the FGMs, while Al2O3 resided only on ZrO2-rich sides, which can effectively enhance the fracture toughness of the ZrO2-rich layer. Ball milling treatments can make the Al2O3 layer more formed in the ZrO2-rich layer. With increasing the amount of Al2O3, the Al2O3 layer resided closer to the top of the ZrO2 surfaces in the FGMs subject to ball milling treatments, which can prevent the crack propagation from the ZrO2 top surfaces.