Details
| Original language | English |
|---|---|
| Article number | 725 |
| Journal | COATINGS |
| Volume | 11 |
| Issue number | 6 |
| Publication status | Published - 16 Jun 2021 |
Abstract
Turbine blades must withstand severe loading conditions and damage can occur during operation due to heat, pressure, foreign objects and hot gas corrosion, despite the protective coatings applied onto the turbine blades. Instead of replacing the damaged components, maintenance, repair and overhaul are key to extend the total service life. Besides welding, the repair of turbine blades by brazing is an established repair process in the industry and involves many individual steps that often require a high degree of manual work. In the present study, a hybrid joining and coating technology was developed to shorten the state-of-the-art process chain for repairing turbine blades. With this approach, a repair coating, which consists of a filler metal, a hot gas corrosion protective layer and an aluminum top layer, is applied by atmospheric plasma spraying. The coated turbine blade then undergoes a heat-treatment so that a brazing and aluminizing process is carried out simultaneously. Due to diffusion and segregation processes, pores can occur in the heat-treated coating. In the present study, a full factorial design of experiment was performed to reduce the pores in the coating. The microstructure of the repair coating was investigated by optical-and scanning electron microscopy (SEM), and the impact of the process parameters on the resulting microstructure is discussed.
Keywords
- Aircraft overhaul, Aluminizing, High-temperature brazing, Hybrid technology, Protective coatings
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Materials Science(all)
- Surfaces, Coatings and Films
- Materials Science(all)
- Materials Chemistry
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In: COATINGS, Vol. 11, No. 6, 725, 16.06.2021.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Thermally sprayed nickel-based repair coatings for high-pressure turbine blades
T2 - Controlling void formation during a combined brazing and aluminizing process
AU - Nicolaus, Martin
AU - Möhwald, Kai
AU - Maier, Hans Jürgen
N1 - Funding Information: Funding: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project number 119193472.
PY - 2021/6/16
Y1 - 2021/6/16
N2 - Turbine blades must withstand severe loading conditions and damage can occur during operation due to heat, pressure, foreign objects and hot gas corrosion, despite the protective coatings applied onto the turbine blades. Instead of replacing the damaged components, maintenance, repair and overhaul are key to extend the total service life. Besides welding, the repair of turbine blades by brazing is an established repair process in the industry and involves many individual steps that often require a high degree of manual work. In the present study, a hybrid joining and coating technology was developed to shorten the state-of-the-art process chain for repairing turbine blades. With this approach, a repair coating, which consists of a filler metal, a hot gas corrosion protective layer and an aluminum top layer, is applied by atmospheric plasma spraying. The coated turbine blade then undergoes a heat-treatment so that a brazing and aluminizing process is carried out simultaneously. Due to diffusion and segregation processes, pores can occur in the heat-treated coating. In the present study, a full factorial design of experiment was performed to reduce the pores in the coating. The microstructure of the repair coating was investigated by optical-and scanning electron microscopy (SEM), and the impact of the process parameters on the resulting microstructure is discussed.
AB - Turbine blades must withstand severe loading conditions and damage can occur during operation due to heat, pressure, foreign objects and hot gas corrosion, despite the protective coatings applied onto the turbine blades. Instead of replacing the damaged components, maintenance, repair and overhaul are key to extend the total service life. Besides welding, the repair of turbine blades by brazing is an established repair process in the industry and involves many individual steps that often require a high degree of manual work. In the present study, a hybrid joining and coating technology was developed to shorten the state-of-the-art process chain for repairing turbine blades. With this approach, a repair coating, which consists of a filler metal, a hot gas corrosion protective layer and an aluminum top layer, is applied by atmospheric plasma spraying. The coated turbine blade then undergoes a heat-treatment so that a brazing and aluminizing process is carried out simultaneously. Due to diffusion and segregation processes, pores can occur in the heat-treated coating. In the present study, a full factorial design of experiment was performed to reduce the pores in the coating. The microstructure of the repair coating was investigated by optical-and scanning electron microscopy (SEM), and the impact of the process parameters on the resulting microstructure is discussed.
KW - Aircraft overhaul
KW - Aluminizing
KW - High-temperature brazing
KW - Hybrid technology
KW - Protective coatings
UR - http://www.scopus.com/inward/record.url?scp=85108870921&partnerID=8YFLogxK
U2 - 10.3390/coatings11060725
DO - 10.3390/coatings11060725
M3 - Article
AN - SCOPUS:85108870921
VL - 11
JO - COATINGS
JF - COATINGS
SN - 2079-6412
IS - 6
M1 - 725
ER -