KCl-Induced High Temperature Corrosion Behavior of HVAF-Sprayed Ni-Based Coatings in Ambient Air

Jafari, RezaTarbiat Modares University, Department of Material Science and Engineering, Tehran, Iran (author)

This article is an invited paper selected from presentations at the 2017 International Thermal Spray Conference, held June 7–9, 2017, in Düsseldorf, Germany, that has been expanded from the original presentation.
KCl-induced high temperature corrosion behavior of four HVAF-sprayed Ni-based coatings (Ni21Cr, Ni5Al, Ni21Cr7Al1Y, and Ni21Cr9Mo) under KCl deposit has been investigated in ambient air at 600°C up to 168h. The coatings were deposited onto 16Mo3 steel - a widely used boiler tube material.Uncoated substrate, 304L and Sanicro25 were used as reference materials in the test environment.SEM/EDS and XRD techniques were utilized to characterize the as-sprayed and exposed samples.The results showed that the small addition of KCl significantly accelerated degradation to the coatings. All coatings provided better corrosion resistance compared to the reference materials. The alumina-forming Ni5Al coating under KCl deposit was capable of forming a more protective oxide scale compared to the chromia-forming coatings as penetration of Cl through diffusion paths was hindered. Both active corrosion and chromate formation mechanisms were found to be responsible for Page 1 of 23ASM the corrosion damages. The corrosion resistance of the coatings based on the microstructure analysis and kinetics had the following ranking (from the best to worst): Ni5Al >Ni21Cr> Ni21Cr7Al1Y>Ni21Cr9Mo.

Sadeghimeresht, Esmaeil,1985-Högskolan Väst,Avdelningen för avverkande och additativa tillverkningsprocesser (AAT),PTW(Swepub:hv)esasad (author)
Shahrabi Farahani, TaghiTarbiat Modares University, Department of Material Science and Engineering, Tehran, Iran (author)
Huhtakangas, MattiM. H. Engineering AB, Karlskoga, Sweden (author)
Markocsan, Nicolaie,1967-Högskolan Väst,Avdelningen för avverkande och additativa tillverkningsprocesser (AAT),PTW(Swepub:hv)tnm (author)
Joshi, Shrikant V.,1960-Högskolan Väst,Avdelningen för avverkande och additativa tillverkningsprocesser (AAT),PTW(Swepub:hv)shrjos (author)
Tarbiat Modares University, Department of Material Science and Engineering, Tehran, IranAvdelningen för avverkande och additativa tillverkningsprocesser (AAT) (creator_code:org_t)

In:Journal of thermal spray technology (Print): Springer Science and Business Media LLC27:3, s. 500-5111059-96301544-1016

By the author/editor: Jafari, Reza; Sadeghimeresht, ...; Shahrabi Farahan ...; Huhtakangas, Mat ...; Markocsan, Nicol ...; Joshi, Shrikant ...

About the subject

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Materials Engine ...; and Manufacturing Su ...

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Materials Engine ...; and Metallurgy and M ...

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Materials Engine ...; and Composite Scienc ...

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