| 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 M m+ , where M is the scale forming element of the alloy, and the second layer (4) has a tracer diffusion coefficient for oxygen ions O 2- satisfying the following formula: ˆ« ln €‰ p ( O 2 �¢ ) in ln €‰ p ( O 2 �¢ ) ex D o + m 2 �¢ D M �¢ d €‰ ln €‰ p O 2 < 2 ‹ 10 - 13 €‰ cm 2 / s
wherein p(O 2 ) in is the oxygen partial pressure in equilibrium between the metallic substrate and M a O b , p(O 2 ) ex is the oxygen partial pressure in the reaction atmosphere, D M is the tracer diffusion coefficient of the metal cations M m+ in the first layer (3), and Do is O 2- tracer diffusion coefficient in the second layer (4). The coating may be used in high temperature devices, particularly for coating interconnect materials in solid oxide electrolytic devices, including solid oxide fuel cells (SOFCs) and solid oxide electrolysis cells (SOECs). |
