Industrial Gas Turbines:
Gas Turbine Parts endure high temperatures and mechanical pressure whilst in use. This high pressure and temperature of gases and contamination of fuels will eventually cause the wear and corrosion of parts. One way to deal with these surface degradations is to coat the different parts via the thermal spraying method. Application of these coatings will not only increase the life span of the components but also facilitate the proper operation of parts at higher temperatures.
Previously, gas turbine parts and blades were made of nickel based alloys. These alloys, although seemed to have good oxidation resistance, but they were not resistant to corrosion and wear mechanisms at high temperatures. In addition in the case of cobalt based alloys, despite their corrosion resistance at high temperatures they performed poorly against oxidation. In recent years, researchers have found a new coating material with the commercial name of MCrAlY which can overcome these problems. In this type of coating, M any of the elements Co, Ni and Fe or a combination of them can be used depending on the application. This alloy has good resistance to oxidation and wear and corrosion mechanisms at high temperatures.
In general, the use of MCrAlY coating on gas turbine parts has the following benefits:
- Resistance to oxidation and corrosion at high temperatures
- Reduced thermal conductivity
- Improved wear resistance
- Increased efficiency and lifetime of parts
- Reduces the temperature of the metal base, thereby reducing the occurrence of thermal shocks and the phenomenon of creep
- Increases work temperatures and thus increases thermal efficiency
- Reduces NOx outputs