Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

Oksa, Maria; Metsäjoki, Jarkko; Kärki, Janne

doi:10.1007/s11666-014-0155-5

Cited by 15 publications

(22 citation statements)

References 22 publications

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“…The corrosion mechanism appeared to be the same in both temperatures: sulfidation, possibly preceded by chlorine corrosion. The formation of such types of corrosion products cause by chlorine corrosion have also been reported by Oksa et al [17]. Alkali chlorides in deposits may cause accelerated corrosion well below the melting point of KCl [18].…”

Section: Discussionsupporting

confidence: 59%

“…In addition, nitrogen permeability test buttons and plates for cross sectioning were coated. The test buttons for nitrogen permeability are porous discs that allow gas to freely flow though, but dense enough to be coated without issues [17]. The used torch was DJ Hybrid (Diamond Jet Hybrid) and the -45 μm sieved chamber fraction was used as the powder.…”

Section: Methodsmentioning

confidence: 99%

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Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

et al. 2015

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Oxy-fuel combustion combined with CCS (carbon capture and storage) aims to decrease CO2 emissions in energy production using fossil fuels. Oxygen firing changes power plant boiler conditions compared to conventional firing. Higher material temperatures and harsher and more variable environmental conditions cause new degradation processes that are inadequately understood at the moment. In this study, an Fe-Ni-Cr-Al alloy was developed based on thermodynamic simulations. The chosen composition was manufactured as powder by gas atomization. The powder was sieved into two fractions: The finer was used to produce thermal spray coatings by high velocity oxy-fuel (HVOF) and the coarser to manufacture bulk specimens by hot isostatic pressing (HIP). The high temperature corrosion properties of the manufactured FeNiCrAl coating and bulk material were tested in laboratory conditions simulating oxy-combustion. The manufacturing methods and the results of high temperature corrosion performance are presented. The corrosion performance of the coating was on average between the bulk steel references Sanicro 25 and TP347HFG. OPEN ACCESSCoatings 2015, 5 710

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Section: Discussionsupporting

confidence: 59%

Section: Methodsmentioning

confidence: 99%

Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

et al. 2015

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“…20. Alloying elements like Ni or protective scale-forming elements such as Al or/and Cr can alter the corrosion mechanism (Ref 115 [121][122][123][124][125][126]. However, the coating features associated with the above techniques, such as splat boundaries, pores, and in situ formed oxides (Ref 75), lead to the formation of a discontinuous oxide scale, which motivates to seek even more efficient protective barriers.…”

Section: High-temperature Corrosion In Thermal Spray Coatingsmentioning

confidence: 99%

Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants. Part I: Effect of Composition and Microstructure

2019

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Power generation from renewable resources has attracted increasing attention in recent years owing to the global implementation of clean energy policies. However, such power plants suffer from severe high-temperature corrosion of critical components such as water walls and superheater tubes. The corrosion is mainly triggered by aggressive gases like HCl, H 2 O, etc., often in combination with alkali and metal chlorides that are produced during fuel combustion. Employment of a dense defect-free adherent coating through thermal spray techniques is a promising approach to improving the performances of components as well as their lifetimes and, thus, significantly increasing the thermal/electrical efficiency of power plants. Notwithstanding the already widespread deployment of thermal spray coatings, a few intrinsic limitations, including the presence of pores and relatively weak intersplat bonding that lead to increased corrosion susceptibility, have restricted the benefits that can be derived from these coatings. Nonetheless, the field of thermal spraying has been continuously evolving, and concomitant advances have led to progressive improvements in coating quality; hence, a periodic critical assessment of our understanding of the efficacy of coatings in mitigating corrosion damage can be highly educative. The present paper seeks to comprehensively document the current state of the art, elaborating on the recent progress in thermal spray coatings for high-temperature corrosion applications, including the alloying effects, and the role of microstructural characteristics for understanding the behavior of corrosion-resistant coatings. In particular, this review comprises a substantive discussion on high-temperature corrosion mechanisms, novel coating compositions, and a succinct comparison of the corrosion-resistant coatings produced by diverse thermal spray techniques.

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“…Flexibility of coating technologies allows manufacturing of dense and highly adherent coatings which can meet the critical protection requirements of such a boiler environment. The rapid development of thermal spray processes offers attractive and cost-effective routes to avoid degradation of low alloy tubes by selecting appropriate coating chemistry and manufacturing process (Ref 16,17). A variety of thermal spray methods including atmospheric plasma spray (APS), arc spray and high-velocity air-fuel (HVOF) have been already used to fabricate corrosion resistant coatings (Ref [18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

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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 168 h. The coatings were deposited onto 16Mo3 steel-a widely used boiler tube material. Uncoated substrate, 304L and Sanicro 25 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 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):

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Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

Cited by 15 publications

References 22 publications

Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

Advances in Corrosion-Resistant Thermal Spray Coatings for Renewable Energy Power Plants. Part I: Effect of Composition and Microstructure

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

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