Controlling the surface texture of nickel for high temperature oxidation inhibition

The possibility of controlling the crystallographic texture of a Ni surface to increase the resistance against high-temperature oxidation is studied. Polycrystalline Ni coatings and foils with the [100], [110] and [211] textures were manufactured using an electrodeposition technique. The initial textures and microstructures of Ni were modified using annealing in an inert atmosphere of argon. Textures of a variety of NiO scales grown on the electrodeposits at 1073 K in air were measured and compared to the textures of the corresponding Ni substrates. It was found that NiO grown on as-deposited Ni has a random distribution of grain orientations for all types of the substrate textures. When Ni electrodeposits were annealed prior to oxidation, there was a strong influence of substrate texture on the texture of NiO. In particular, a surface treatment composed of the electrodeposition of Ni primer with a strong [100] texture followed by annealing leads to an Ni layer with a [111] texture and a low density of structural defects. Such a substrate of Ni promotes the formation of epitaxially oriented, slow growing and highly protective NiO scales with the [111] texture. (C) 1999 Elsevier Science Ltd. All rights reserved.