Argon Shrouded Plasma Spraying of Tantalum over Titanium for Corrosion Protection in Fluorinated Nitric Acid Media

Vetrivendan, E.; Jayaraj, J.; Ningshen, S.; Mallika, C.; Mudali, U. Kamachi

doi:10.1007/s11666-017-0678-7

Cited by 14 publications

(4 citation statements)

References 27 publications

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“…Regarding the oxidation of droplets during thermal spraying, scholars have conducted a lot of research on vacuum thermal spraying, nitrogen or argon atmosphere protection spraying, and cold spraying technologies. E. Vetrivendan et al [9] used argon shielded plasma spraying (ASPS) technology to prepare a tantalum coating on the Cp-Ti substrate. The coating can be stored for up to 240 h in 11.5 M HNO 3 + 0.05 M NaF solution, showing excellent corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

Corrosion Behavior of the CoNiCrAlY-Al2O3 Composite Coating Based on Core-Shell Structured Powder Design

et al. 2021

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The oxidation of the metal powder during the thermal spraying process usually leads to significant deterioration of the microstructure and performance of the coating. In order to isolate the metal powder from oxygen during the spraying process, the CoNiCrAlY-Al2O3 core-shell structured powder with Al2O3 as the shell was designed in this study. The influence of the core-shell structured powder on the microstructure and corrosion resistance of the HVOF coating has been studied in detail. The results show that the temperature field of the molten CoNiCrAlY powder during the spraying process is significantly changed by the Al2O3 shell. The poor deformability of the CoNiCrAlY-Al2O3 droplets leads to an increase in the porosity and unmelted particles of the coating. In addition, the significant difference is that the coating also maintains a high content of β-NiAl phase. The lower oxide content in the CoNiCrAlY-Al2O3 coating indicates that the core-shell structured powder significantly inhibits the oxidation of the CoNiCrAlY core powder during the spraying process. The CoNiCrAlY-Al2O3 coating exhibits high corrosion potential, passive film resistance, charge transfer resistance, and low corrosion current density in 3.5 wt.% NaCl solution, indicating that the coating has excellent corrosion resistance.

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Section: Introductionmentioning

confidence: 99%

Corrosion Behavior of the CoNiCrAlY-Al2O3 Composite Coating Based on Core-Shell Structured Powder Design

et al. 2021

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“…The shroud attachment physically shields the plasma flame as it exits the plasma gun. Meanwhile, an inert gas from the end of the shroud attachment is introduced to envelops the plasma flame, which isolates the molten particles from encountering oxygen from the ambient air [16][17][18][19][20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Effect of Shroud in Plasma Spraying on Chemical Composition and Thickness of Titanium Coatings

Zhou

Peng

2021

Coatings

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Titanium and its alloys are wildly used in industries. Shrouded plasma spray can be considered as a useful technology to produce low oxide containing titanium coatings. In this paper, the effect of shroud in plasma spraying on chemical composition and thickness of titanium coatings were investigated. Shrouded plasma-sprayed titanium coatings were deposited onto mild steel substrates. Air plasma-sprayed titanium coatings were also deposited for comparison under the same spraying parameters. Those titanium coatings were then studied in terms of microstructure, oxygen and nitrogen contents and coating’s thickness. The titanium coatings were assessed by scanning electron microscopy and quantitative chemical analysis. The results showed that the shroud played a key role in protecting the particles from oxidation in flight. The shrouded titanium coatings exhibited lower oxygen content and an enhanced microstructure. The reduction in air entrainment with the shroud resulted in better heating of the particles and increases in deposition efficiency and coating thickness.

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“…Surface modification by air oxidation has been proposed to improve the corrosion resistance of Ti in the vapor phase of boiling nitric acid [23]. Also, argon-shrouded plasmasprayed tantalum coating has been developed as an overlay to improve the corrosion behavior of the Ti in nitric acid containing fluoride ions [24]. When compared to other surface modification techniques, air oxidation of Ti in a furnace at high temperatures is the simplest method to generate a protective TiO 2 barrier layer.…”

Section: Introductionmentioning

confidence: 99%

Studies on Corrosion of Titanium and Air-Oxidized Titanium in Fluorinated Nitric Acid

Jayaraj

Padinhateeri

Ningshen

et al. 2019

Trans Indian Inst Met

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Titanium (Ti) is a lustrous transition metal which possesses excellent corrosion resistance in several aggressive environments but is attacked by acidic fluoride media. In this work, the addition of fluoride ion to nitric acid on the corrosion behavior of Ti and air-oxidized Ti was studied. Air oxidation of Ti at 800°C for 5 h resulted in the formation of an intact rutile TiO 2 layer with a thickness of about 35 lm. The corrosion resistance was investigated from the polarization resistance (R P ) values which were obtained from linear polarization and electrochemical impedance spectroscopy (EIS) measurements. A decrease in the R P value of Ti with the addition of fluoride ion in nitric acid was observed, and this indicated the formation of an unstable layer, which resulted in accelerated dissolution. The several order increase in the R P value of air-oxidized Ti in nitric acid containing fluoride ions pointed the improved resistance to corrosion. The diffusivity of species through the air-oxidized TiO 2 layer was estimated from the electrochemical equivalent circuit (EEC) analysis of EIS data. Even though the diffusivity increased by several orders with the addition of fluoride ions, air-oxidized Ti provided better protection against nitric acid containing fluoride ions than Ti. The corrosion rates of Ti and air-oxidized Ti in boiling nitric acid containing fluoride ions were also estimated from weight loss experiments. Even in boiling fluorinated nitric acid, airoxidized Ti provided better corrosion protection, with corrosion rates of about 1000 times less than that of Ti.

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Argon Shrouded Plasma Spraying of Tantalum over Titanium for Corrosion Protection in Fluorinated Nitric Acid Media

Cited by 14 publications

References 27 publications

Corrosion Behavior of the CoNiCrAlY-Al2O3 Composite Coating Based on Core-Shell Structured Powder Design

Corrosion Behavior of the CoNiCrAlY-Al2O3 Composite Coating Based on Core-Shell Structured Powder Design

Effect of Shroud in Plasma Spraying on Chemical Composition and Thickness of Titanium Coatings

Studies on Corrosion of Titanium and Air-Oxidized Titanium in Fluorinated Nitric Acid

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