Nanoparticles Application in Promoting the Growth of a More Protective Oxide Scale at High Temperatures

Integrated Laser Additive Manufacturing of α-Al2O3 Nanoparticle-Seeded β/γ’ Ni-Al Intermetallic Alloy with Enhanced High-Temperature Oxidation Performance

“…Based on the aforementioned results and interpretations, the enhanced oxidation resistance of the LAM β/γ' dual-phase alloy can be attributed to the promotion of the thermal growth of α-Al 2 O 3 , which is fundamentally induced by surface-seeded α-Al 2 O 3 NPs. Peng et al [48] proposed that θ-Al 2 O 3 rather than α-Al 2 O 3 preferentially grows on M x Al y (M = Ni, Fe, Co) such as β-NiAl due to the fact that a higher energy barrier is needed for oxidation through the route of α-Al 2 O 3 direct growth in comparison to the conventionally observed route of θ-Al 2 O 3 preferential growth and subsequent transformation to α-Al 2 O 3 through a "synchro-shear" mechanism [48]. When M x Al y is dispersed with NPs of metal oxide with either a hcp structure or a hcp O sublattice structure, these oxide NPs would exert a "template" effect, catalyzing the direct growth of corundum α-Al 2 O 3 .…”