Evaluations of Hot Corrosion Behavior of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Thermal Spray Coatings with ZrO&lt;sub&gt;2&lt;/sub&gt; Reinforcements on T-91 Steel

Indermeet Singh,Khushdeep Goyal,Rakesh Goyal

doi:10.13189/ujme.2019.070411

Evaluations of Hot Corrosion Behavior of Al2O3 Thermal Spray Coatings with ZrO2 Reinforcements on T-91 Steel

Indermeet Singh, Khushdeep Goyal + Show 1 more

Open Access

https://doi.org/10.13189/ujme.2019.070411

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Abstract

Different coating with varying quantities of Al2O3 and ZrO2 were fabricated on the SA213 T-91 steel using plasma spray method to study hot corrosion resistance behavior. Experiment was conducted under the molten salt environment of 60% Na2SO4-40%V2O5 at a temperature of 900℃ inside a furnace for 50 cycles. Each cycle consisted of 1hr heating and 20 min cooling at room temperature. Results were examined using the visual inspection, weight change measurement, X-ray diffraction technique and Scanning Electron Microscopy/ Energy Dispersive X-Ray Spectroscopy (SEM/ EDS) analysis. Results showed that uncoated T-91 steel was more prone to hot corrosion as compared to coated steel specimens. It was noticed that ZrO2 reinforcements in Al2O3 coating matrix helped to enhance corrosion resistance of these coatings. The corrosion resistance increased with increase in ZrO2 content in coating matrix.

Highlights

At elevated temperature, accelerated oxidation is experienced by metal and alloys when they are exposed to corrosive environment which leads to deposition of thin film of fused salt on the surface of metal
Different coating with varying quantities of Al2O3 and ZrO2 were fabricated on the SA213 T-91 steel using plasma spray method to study hot corrosion resistance behavior
The following conclusions have been drawn from this research work: 1. Using plasma spray process, different coatings of

Summary

Introduction

At elevated temperature, accelerated oxidation is experienced by metal and alloys when they are exposed to corrosive environment which leads to deposition of thin film of fused salt on the surface of metal. Fabrication of ceramic coating using plasma spray method leads to higher inherent porosity which helps the electrolyte to attack on substrate which in turn leads to corrosion To overcome this issue bilayered coatings of Al2O3 and ZrO2 has been used in recent past [10, 11]. Exhaust manifold handles high temperature and different contents of harmful gases causes the material to develop thermal stress and Universal Journal of Mechanical Engineering 7(4): 224-230, 2019 corrosion [13] It is clear from the literature study that Al2O3 and ZrO2 bilayered coating effectively reduced the boiler steel corrosion at higher temperature but there is a chance of inherent porosity in the substrate. It was decided to fabricate different composite coatings by reinforcing ZrO2 in Al2O3 coating matrix Subsequently, their hot corrosion behavior has been studied at high temperature (900°C) in molten salt environment. Very few research have done on reinforced coating ZrO2 with Al2O3

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