Cyclic Oxidation Behavior Of Bare And Cr3C2-25 (NiCr) Coated Super Alloy At Elevated Temperature

Department of Metallurgical & Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India

Adv. Mater. Lett., 2013, 4 (10), pp 754-761

DOI: 10.5185/amlett.2013.2428

Publication Date (Web): Oct 13, 2013

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Abstract

High temperature oxidation is the main cause for the degradation of materials used at elevated temperature which is responsible for the major shut down of turbines, boilers and incinerators used in large units. An attempt has been made to use Cr₃C₂-25%NiCr coating deposited by D-gun technique on Superni 600 alloy. These coatings are generally used for wear applications. This coating has been studied for oxidation at 900C under cyclic conditions. Sound and adherent coatings of 150-250 μm can be obtained by D-gun process. The bare and coated alloys were subjected to cyclic oxidation in air for 100 cycles. Weight change/area has been plotted against number of cycles and to monitor the oxidation kinetics. The scale formed after oxidation both on the bare and coated alloys has been examined using FESEM/EDX, XRD, and Cross-sectional/Mapping analysis. The weight gain by coated Superni 600 was found to be about 80% less than that of bare Superni 600. D-gun sprayed Cr₃C₂-NiCr coating has contributed to increase in the oxidation resistance of coated superalloy. These types of coatings can be developed for high temperature applications for both corrosion and erosion resistance.

Keywords

Oxidation, Ni-based superlloys, D-gun, Cr₃C₂-NiCr coating.