Experimental Study on Reducing Wear Damage of Gas Turbine Combustor Components Using Hardface Coatings at Elevated Temperatures

Wear is one of the main damage mechanisms in gas turbine combustor components. The mating surfaces experience surface degradation affected by wear. A new wear test machine has been designed and constructed to characterize wear behavior of various candidate hardface coatings. The test rig consists of a stationary flat surface and a moving plate loaded against this surface. Various material pairs and hardface coatings can be tested under different operating conditions. The setup allows heating of the contact area up to 1000˚C. Constant contact load is applied by hanging weights through a lever system. Sliding motion is generated by a shaker that can provide a frequency range from 1 to 6500 Hz. The test conditions are established according to the combustor components under operating conditions. This paper provides the results of an extensive sliding wear testing program to evaluate wear resistance of several conventional coatings for high-temperature applications such as gas turbines. Nickel and cobalt-base superalloys and iron base stainless steels were tested in different combinations, and their wear rates compared to determine optimal wear-resistant coating. The results show that an alloy s wear resistance is highly dependent on the operating temperature and its coupling with another material.