Oxidation and hot corrosion in sulphate, chloride and vanadate environment of a cast nickel base superalloy are discussed. Weight gain studies are carried out in air for the uncoated and coated samples. The corrosion products are analysed and the possible mechanisms of corrosion based on the corrosion compounds are discussed. The variation of weight gain with time indicated a parabolic growth of oxides. The outer layers consisted of oxides and in case of hot corrosion, in addition to oxide outer layer, internal sulphidation was also noticed.

D. Deb

Vellore Margabandhu Radhakrishnan

Chlorine compounds

Coated materials

High temperature effects

Metal castings

Nickel alloys

oxidation

SULFUR COMPOUNDS

superalloys

Vanadium Compounds

Corrosion products

corrosion

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

A comparative study of oxidation and hot corrosion of a cast nickel base superalloy in different corrosive environments

Materials Letters

The main aim of the present work is to investigate the high-temperature corrosion behavior of bare, high-velocity oxy-fuel coated on iron-based superalloy A-286. Ni-20%Cr and Cr3C2-25%NiCr powders are deposited on the Fe based superalloy A-286 material by high-velocity oxy-fuel (HVOF) process. Surface roughness and coating thickness of the coated specimen is evaluated using surface roughness tester and optical microscope (OM). The hot corrosion study was performed on bare, and HVOF coated Fe-based superalloy A-286 in Na2SO4-50%V2O5-10%NaCl environment at 700 °C under cyclic conditions. Kinetics of corrosion has been determined by thermo-gravimetric analysis using mass change measurement; Cr3C2-25%NiCr coating shows the better corrosion resistance due to the formation of stable Cr2O3 layer. The uncoated superalloy is severely suffered by spallation and sputtering of oxide scales during hot corrosion study. The surface microstructure, chemical composition and phase identification of coatings before and after hot corrosion are analyzed using scanning electron microscope/ energy dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis. Depth of corrosion attack and oxide scales are characterized using EDS compositional analysis and elemental mapping technique. The result of the cross-sectional image shows that uncoated material was severely suffered by hot corrosion to a depth of 200 µm. © 2019 Elsevier Ltd

Engineering Failure Analysis

Investigations of hot corrosion resistance of HVOF coated Fe based superalloy A-286 in simulated gas turbine environment

Hot corrosion behavior of solution precursor plasma spray (SPPS) thermal barrier coating (TBC) in molten salt mixtures of 90wt.% Na<inf>2</inf>SO<inf>4</inf>+5wt.% V<inf>2</inf>O<inf>5</inf>+5wt.% NaCl and 50wt.% Na<inf>2</inf>SO<inf>4</inf>+50wt.% V<inf>2</inf>O<inf>5</inf> at 900°C is compared vis-à-vis atmospheric plasma spray (APS) coating. APS TBCs show better hot corrosion resistance than SPPS TBCs in both the salt mixtures. The vertical cracks in SPPS coatings, meant for strain tolerance and high thermal cycling life, serve as channels for transporting salts across the coating to bond coat/top coat interface and accelerate failure. © 2015 Elsevier Ltd.

Corrosion Science

Hot corrosion behavior of solution precursor and atmospheric plasma sprayed thermal barrier coatings

Journal of the American Society for Naval Engineers

EXTERNAL DEPOSITS AND CORROSION IN BOILERS AND GAS TURBINES

Who Was Who

Elliot, James Robert McDowell, (1 Jan. 1896–28 July 1980)

Pure and Applied Chemistry

Hot corrosion of materials

Materials Science and Engineering: A

High-temperature corrosion of several commercial FeCrNi alloys under a molten sodium sulphate deposit in oxidizing gaseous environments

Oxidation of Metals

Behavior of oxide scales on 2.25Cr-1Mo steel during thermal cycling. II. Scales grown in water vapor

Journal	Data powered by TypesetMaterials Letters
Publisher	Data powered by TypesetElsevier
ISSN	0167577X
Open Access	No