| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1600026 | Intermetallics | 2015 | 14 Pages |
•Comprehensive comparison of coating concepts for the environmental protection of intermetallic γ-TiAl alloys.•Evaluation of the long-term performance of the different coatings during exposure between 800 and 1050 °C.•The main evaluation criterion is based on the mass gain after at least 1000 h of high temperature exposure.•Detailed overview of the chemical stability of the different coating types (overlay, diffusion and halogen based) is included.•Assessment of the coatings processing routes along with their advantages and drawbacks.
Alloys based on γ-TiAl are lightweight materials with attractive mechanical properties at high temperatures. Although these alloys reveal a superior resistance against environmental attack compared to titanium and 2-based alloys, efficient protection is required for industrial applications at temperatures between 800 and 1050 °C. Extensive research in order to solve this problem started more than 30 years ago. This review provides a summary of the different concepts based on surface modification techniques developed for the environmental protection of γ-TiAl alloys at high temperatures, including overlay and diffusion coatings, as well as the halogen effect. The discussion includes a comparison between the most promising coating types under long-term high temperature exposure and an assessment of their processing routes from a technological point of view. Therefore, a mass gain of 1 mg/cm2 after at least 1000 h of exposure was set as a benchmark to evaluate these protection systems.
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