Investigation of the wear resistance properties of Cr/CrN multilayer coatings against sand erosion
(2015)
The wear of metallic components used in gas and steam turbines due to erosive sand particles lead to a tremendous decrease in their lifetime. This wear can be reduced by the use of suitable erosion resistant coatings resulting in lower maintenance costs. In this context, multilayer Cr/CrN PVD coatings using an industrial coater was designed and applied on Inconel 718, a material which finds its application in gas turbines. A variation in the bimodal period has been induced in order to achieve an optimal coating architecture providing optimum properties needed for the erosion resistant coatings. The coating was deposited using a single Cr- target with an induction of N2 during the nitriding phase at a temperature of 480-500 °C and the coating thickness of 24-26 µm was kept constant throughout. The erosion tests were conducted at angles of 30°, 60° and 90°. The sand used for the test is an irregular shaped SiO2. The erosion tests were followed by a detailed microscopic examination of the eroded coating structure in combination with nanoindentation and scratch tests.
This research work provides information about the influence of Ti2AlC MAX phase coatings on the
erosion resistance of Ti624 2alloy.Flat specimens were coated witha20 µm Ti2AlC film using an industrial siz emagnetron sputtering coater and annealed at 800 °C for 1h in vacuum for the formation of the MAX phase.The erosion resistance of the specimens was tested using high velocity particles at room
temperature.The results indicate that the erosion resistance of Ti6242 has been significantly enhanced
by the employment of MAX-phase coatings. This demonstrates the capability of using MAX phase
coatings as erosion protective medium for engine components exposed to similar damage conditions.
Additionally,the results show that uncoated Ti6242 samples with duplex microstructure have a better
durability against erosion attack compared to uncoated samples with globular microstructure.