Table of Contents
Indian Journal of Materials Science
Volume 2014 (2014), Article ID 453607, 5 pages
http://dx.doi.org/10.1155/2014/453607
Research Article

Hot Corrosion Behaviour of Detonation Gun Sprayed Al2O3-40TiO2 Coating on Nickel Based Superalloys at 900°C

Mechanical Engineering Department, Motilal Nehru National Institute of Technology Allahabad, Allahabad 211004, India

Received 25 November 2013; Accepted 24 December 2013; Published 11 February 2014

Academic Editors: M. Jayachandran and F. Zafar

Copyright © 2014 N. K. Mishra et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Hot corrosion is the major degradation mechanism of failure of boiler and gas turbine components. These failures occur because of the usage of wide range of fuels such as, coal and oil at the elevated temperatures. Nickel based superalloys having excellent mechanical strength and creep resistance at elevated temperature are used under such environment but they lack resistance to hot corrosion at high temperature. To overcome these problems hot corrosion resistant coatings are deposited on these materials. In the current investigation Al2O3-40%TiO2 powder has been deposited on Superni 718 and AE 435 superalloys by Detonation Gun method. The hot corrosion performance of Al2O3-40%TiO2 coated as well as uncoated Superni 718 and AE 435 alloys has been evaluated in aggressive environment Na2SO4-82%Fe2(SO4)3 under cyclic conditions at an elevated temperature of 900°C. The kinetics of the corrosion is approximated by weight change measurements made after each cycle for total duration of 50 cycles. Scanning electron microscopy was used to characterize the hot corrosion products. The coated samples imparted better hot corrosion resistance than the uncoated ones. The AE 435 superalloy performed better than Superni 718 for hot corrosion in a given environment.