Influence of oxidation related structural defects on localized corrosion in HVAF-sprayed Fe-based metallic coatings

Wu, Jing; Zhang, S.D.; Sun, Wenyao; Wang, J.Q.

doi:10.1016/j.surfcoat.2017.12.038

Cited by 46 publications

(8 citation statements)

References 49 publications

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“…As the pitting proceeds, the accumulation of chloride or hydrogen ion, which provokes the depassivation of the passive film and dissolution of the oxide layer [46], is promoted at the interface and in the cavities since the replenishment of the solution is not easy in the shallow areas. The concentration of chloride or hydrogen ion from the hydrolysis of metal ions increases gradually [47]. Moreover, the oxide contours formed between the lamellar particles can become the diffusion channels for the electrolyte, affecting the formation of the passive film and causing corrosion of the coatings [48].…”

Section: Discussionmentioning

confidence: 99%

Effect of Oxidation and Crystallization on Pitting Initiation Behavior of Fe-Based Amorphous Coatings

Zhang

Wang

et al. 2022

Coatings

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Fe-based amorphous coatings are typically fabricated by high-velocity oxygen-fuel spraying using industrial raw materials. The bonding mode between the coating particles and the corrosion mechanism of the coating in the chloride-rich environment were studied. The results indicate that some fine crystallites such as α-Fe and Fe3C tend to precipitate from the amorphous matrix as the kerosene flow rate increases or the travel speed of spraying gun decreases. Moreover, some precipitates of the (Cr, Fe)2O3 nanocrystal were detected in the metallurgical interfaces of the amorphous coating. The relationship among the amorphous volume fraction, porosity, and spraying parameters, such as the kerosene flow rate and the travel speed of the spray gun, were established. Due to an oxidation effect during spraying process, atomic diffusion, crystallite precipitation and regional depletion of Cr occur in the area along the pre-deposited side near the metallurgical bonding interface, leading to the initiation of pitting. A model of pitting initiation and expansion of Fe-based amorphous coatings is proposed in this paper.

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Section: Discussionmentioning

confidence: 99%

Effect of Oxidation and Crystallization on Pitting Initiation Behavior of Fe-Based Amorphous Coatings

Zhang

Wang

et al. 2022

Coatings

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“…The schematic diagram of the corrosion process and fitted equivalent circuits of Coating D and the LA141 magnesium alloy are shown in Figure 9c,d. The equivalent circuit of Coating D consists of the electrolyte solution resistance (R s ), the sum of the coating resistance and the solution resistance at the unavoidable pores or cracks of coating (R c ), the CPE of coating (CPE c ), the CPE related to the electric double layer of the electrolyte/coating interface in the pores or cracks (CPE dl ), and the charge transfer resistance across the electric double layer of the electrolyte/coating interface (R t ) [32]. In the equivalent circuit of the LA141 magnesium alloy, R L and L are related to the resistance of a Mg+ reaction and the inductance of a Mg+ reaction on the breaking area of the discontinuous protective film, respectively.…”

Section: Discussionmentioning

confidence: 99%

High-Performance HVOF-Sprayed Fe-Based Amorphous Coating on LA141 Magnesium Alloy via Optimizing Oxygen Flow and Kerosene Flow

et al. 2021

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To solve the problem of poor corrosion and wear resistance of Mg-Li alloys, Fe-based amorphous coatings were prepared by high velocity oxygen-fuel spraying technology (HVOF) on the LA141 magnesium alloy substrate with a Ni60 intermediate layer. The microstructure and performance of Fe-based amorphous coatings with different oxygen flow and kerosene flow were characterized and analyzed. The results demonstrate that there is an optimal oxygen/kerosene ratio where the porosity of Fe-based amorphous coating is the lowest. Moreover, the amorphous content increases with the decrease in the oxygen/kerosene ratio. In particular, when the oxygen flow is 53.8 m3/h and the kerosene flow is 26.5 L/h, the Fe-based amorphous coating possesses the lowest porosity (0.87%), the highest hardness (801 HV0.1), the highest bonding strength (56.9 MPa), and an excellent corrosion and wear resistance. Additionally, it can be seen that the Fe-based amorphous coating is composed of amorphous splats and amorphous oxides, but the Ni60 intermediate layer exhibits an amorphous and crystalline multi-phase structure. The high bonding strength of the coating is attributed to the low porosity of Fe-based amorphous coating and the localized metallurgical bonding between different layers. Finally, the mechanisms on corrosion and wear of Fe-based amorphous coatings are also discussed.

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“…Oxide contours. In the context of the structure of thermal sprayed coatings, another important aspect is the evolution of oxide contours along with the particle/ particle interface during the deposition process [135,151,[240][241][242]. For instance, Guo et al [135] observed that HVAF-sprayed coating showed better corrosion resistance than HVOF one, reflected by a higher E corr and E pit , lower i pass with the wider passive region (Figure 17).…”

Section: Structure Of the Coatingmentioning

confidence: 99%

Fe-based metallic glass coatings by thermal spraying: a focused review on corrosion properties and related degradation mechanisms

Nayak

Kumar

Laha

2022

International Materials Reviews

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Among various materials available for alleviating the corrosion-related degradation, thermal sprayed Fe-based metallic glass coatings (MGCs) have received huge attention from the scientific community due to the exceptional combination of mechanical and corrosion properties, along with commercially attractive low material cost of this particular alloy system. Emerging reports on the thermal sprayed Fe-based MGCs outperforming conventional corrosion-resistant materials and coatings have accelerated further exploration of this domain, resulting in an immense increase of research activities over the last few decades producing fascinating results. This review takes a holistic approach encompassing an in-depth assessment of all the relevant salient work till date, including corrosion properties, corresponding degradation mechanisms, metallurgical and environmental factors with reference to passive film dynamics and/or formation of corrosion products. Moreover, various strategies for improved corrosion properties and recent research progress have been reviewed with an attempt to identify the present knowledge gaps and the future research directions.

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Influence of oxidation related structural defects on localized corrosion in HVAF-sprayed Fe-based metallic coatings

Cited by 46 publications

References 49 publications

Effect of Oxidation and Crystallization on Pitting Initiation Behavior of Fe-Based Amorphous Coatings

Effect of Oxidation and Crystallization on Pitting Initiation Behavior of Fe-Based Amorphous Coatings

High-Performance HVOF-Sprayed Fe-Based Amorphous Coating on LA141 Magnesium Alloy via Optimizing Oxygen Flow and Kerosene Flow

Fe-based metallic glass coatings by thermal spraying: a focused review on corrosion properties and related degradation mechanisms

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