Coating and near‐surface modification design strategies for protective and functional surfaces

Abstract

This paper discusses strategies for controlling the surface chemistry and microstructure of materials to form protective and functional surfaces through controlled gas-metal reactions. Potential applications range from oxidation, corrosion, and wear resistance to electrochemical devices such as fuel cells to catalysts. Phenomenological examples are presented for coatings designed to self-grade under oxidizing conditions, and for the growth of simple and complex (binary and ternary) nitride and carbide phase surface layers by nitridation and carburization reactions. Specific systems discussed include environmental barrier coatings (EBCs) for Si-based ceramics such as Si 3 N 4 and SiC, the growth of continuous, protective CrN/Cr 2 N, TiN, VN, NiNbVN, and related simple nitride layers on Fe-and Ni-base alloys, the possible formation of ternary nitride and carbide surface phases (e.g. Ti 3 AlC 2 and related MAX-phases) on intermetallic surfaces to improve oxidation resistance, and the formation of composite near-surface structures in Ag-SiO 2 and Co(Mo)-Co 6 Mo 6 C 2 systems.

Protecting Peroxidase Activity of Multilayer Enzyme-Polyion Films Using Outer Catalase Layers

“…Two strategies have been used to protect enzymes from damage by peroxide: (1) an impermeable barrier on the biosensor surface to prevent H 2 O 2 from diffusing into the films; (2) a functional protection layer on the biosensor surface to react with H 2 O 2 to protect enzymes from damage. − The latter approach shows obvious advantages in selectivity and efficiency, since with the former method the barrier may also completely isolate the device from substrates. In this aspect, Shchukin and co-workers 35 assembled layer-by-layer films containing catalase on the outermost surface of polyelectrolyte capsule microcontainers that encapsulated bovine serum albumin (BSA).…”

The formation of protective nitride surfaces for PEM fuel cell metallic bipolar plates

“…50 Both continuous external nitride layer formation and internal nitride formation were evident. Efforts to form an NbN layer on binary Ni-Nb alloys were not successful, with very little reaction with nitrogen observed.…”

Advanced ceramics and coatings for erosion‐related applications in mineral and oil and gas production: A technical review

“…Functionally graded materials with high hardness and toughness of the "front" layer, especially if compressive residual stresses may occur on the surface, can be considered the prospective route if components with desirable shapes and sizes can be produced and if the layers are well bonded with minimal delamination. This approach also suited for advanced coatings, [237][238][239] including for the iron boride coatings with a double-layered architecture. [142][143][144][145] In these materials, where one hard coating layer is supported by another hard coating layer but with higher toughness, crack propagation is reduced.…”

“…Protective coatings with multilayered architectures could be essential and highly beneficial for the wear and corrosion application conditions. The benefits of this architectures were considered elsewhere 66,143,[237][238][239] with the schematic presented in Figure 30. 143 The thermal diffusion boronized coatings with two sub-layers where each layer has high hardness, chemical inertness, and good bonding between the layers and the steel substrate can be a very good example.…”