MULTI-LAYER COATING FOR METAL CONTAINING SURFACES

摘要

A multi-layer coating for protection of metals and alloys against oxidation at high temperatures in general is provided. The invention utilizes a multi-layer ceramic coating on metals or alloys for increased oxidation-resistance, comprising at least two layers, wherein the first layer (3) which faces the metal containing surface and the second layer facing the surrounding atmosphere (4) both comprise an oxide, and wherein the first layer (3) has a tracer diffusion coefficient for cations Mm+, where M is the scale forming element of the alloy, and the second layer (4) has a tracer diffusion coefficient for oxygen ions O2- satisfying the following formula: wherein p(O2)in is the oxygen partial pressure in equilibrium between the metallic sub-strate and MaOb, p(O2)ex is the oxygen partial pressure in the reaction atmosphere, DM is the tracer diffusion coefficient of the metal cations Mm+ in the first layer (3), and DO is O2- tracer diffusion coefficient in the second layer (4). The coating may be used in high temperature devices, particularly for coating intercon- nect materials in solid oxide electrolytic devices, including solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs).