Erosion resistance of superalloys and different coatings exposed to particulate flows at high temperature

Abstract

Abstract The design and development of high performance turbomachinery operating in an ambient with solid particles require a thorough knowledge of the fundamental phenomenon associated with particulate flows. Because of the serious consequences of turbomachinery erosion on their performance and life, it is important to have reliable methods for predicting their erosion when solid particles are ingested with the incoming flow. Several studies, which are essential to predicting blade surface erosion intensity and pattern, have been conducted at the University of Cincinnati's Propulsion Laboratory over the past 25 years. This paper describes only some of the work done on erosion testing at high temperatures and velocities for different materials and coatings. The testing has been performed with a special high temperature erosion wind tunnel, which simulates the aerodynamic conditions on the blades. The coatings investigated are produced by chemical vapor deposition (CVD), physical vapor deposition (PVD), and other methods. Experimental studies were conducted at the University's high temperature erosion wind tunnel to investigate the erosion behavior of coatings exposed to different types of solid particles. Some of the following coatings were evaluated: rhodium platinum aluminized, SDG-2207 (super D-gun product), CVD coatings, including TiC, TiN, Al2O3 and PVD coatings. The erosive wear of the samples was studied experimentally by exposing them to a particle-laden flow at velocities from 180 to 305 m s−1, temperatures from ambient to 815°C and impingement angles from 15 to 90°.