Influence of substrate roughness and temperature on the adhesion/cohesion of alumina coatings

Mellali, M.; Fauchais, Pierre; Grimaud, A.

doi:10.1016/0257-8972(95)02540-5

Cited by 133 publications

(54 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Another factor that appeared to be related to porosity and its higher concentration close to the steel surface was the low temperature at which the substrate was preheated prior to the niobium coating application. The results obtained by Mellali 26 have shown that the initial deposited layers are more influenced by preheating because the contact occurs directly between the substrate and the deposited material in this case.…”

Section: Methodsmentioning

confidence: 78%

Niobium and niobium-iron coatings on API 5LX 70 steel applied with HVOF

et al. 2014

View full text Add to dashboard Cite

The present study aimed to create and characterize niobium and niobium-iron60% coatings applied to steel API 5L X70 using the hypersonic thermal spray process (HVOF). The morphologies of the coatings were analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and profilometry, while the coatings' hardnesses was evaluated using the Vickers hardness test. The coatings' corrosion resistance was evaluated by monitoring their open circuit potential and potentiodynamic polarization and performing electrochemical impedance spectroscopy in a 0.05 M NaCl solution. The results showed that the niobium-iron coating contained minor porosity regions, while such defects occurred over large regions of the niobium coating. In terms of corrosion resistance, the coatings obtained in this work promoted a reduction in the substrate's corrosion rate, but the presence of discontinuities such as porosity compromised the barrier effects of these coatings.

show abstract

Section: Methodsmentioning

confidence: 78%

Niobium and niobium-iron coatings on API 5LX 70 steel applied with HVOF

et al. 2014

View full text Add to dashboard Cite

show abstract

“…It was also observed that the PVD layer did not significantly change the roughness of the underlying substrate. Therefore, the positive effect of the substrate roughness can be preserved [11].…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, substrate roughening, e.g., by grit blasting is a common practice in thermal spraying. In general, higher substrate roughness leads to higher adhesion [11][12][13]; this has been observed both for the deposition of fully molten (plasma sprayed) and semi-molten (HVOF-sprayed) particles [14]. However, for higher roughness range (>50 µm), adhesion was also found to decrease with increasing roughness [15].…”

Section: Introductionmentioning

confidence: 99%

“…Even in the case of mutually insoluble materials (e.g., W and Cu) where no reaction interlayer forms, local melting promotes closer contact of the two materials and thus improves the bonding [16]. For the above reasons, higher deposition temperatures generally lead to improved adhesion, but they may also induce or increase oxidation of metallic materials, which generally hinder adhesion [10,11]. Therefore, a compromise has to be made for a specific material combination.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Influence of Interface Characteristics on the Adhesion/Cohesion of Plasma Sprayed Tungsten Coatings

et al. 2013

View full text Add to dashboard Cite

Abstract:Tungsten is the prime candidate material for plasma facing components of future fusion devices. Plasma spraying, with its ability to coat large areas, including non-planar surfaces, with a significant thickness, is a prospective fabrication technology for components subject to moderate heat loads, e.g., the first wall of the Demonstration Reactor (DEMO). The functionality of such coatings is critically dependent on their adhesion to the underlying material. This in turn, is influenced by a variety of processing-related factors, chief among them being the state of the interface. In this study, the effects of two factors-surface roughness and the presence of thin interlayers-were investigated. Two different levels of roughness of steel substrates were induced by grit blasting, and two thin interlayers-titanium (Ti) and tungsten (W)-were applied by physical vapor deposition prior to plasma spraying of W by a Water Stabilized Plasma (WSP) torch. Coating adhesion was determined by a shear adhesion test. The structures of the coatings and the interfaces, as well as the characteristics of the fractured surfaces, were observed by SEM.

show abstract

“…[1][2][3][4][5] This technique provides thick coating layers over a large surface at a high deposition rate and improves surface properties of substrates such as appearance, adhesion, wettability, wear resistance, and thermal resistance. While many factors affecting coating quality and corresponding reliability have been reported in the literature, [6][7][8][9] detailed technologies and fundamentals to control those factors are not comprehensively understood yet. In the thermal spray coating process, adhesive and cohesive quality between molten droplets and target substrates can be sufficiently controlled by three representative factors as follows; thermal properties, impact dynamics and operating conditions, and surface characteristics.…”

Section: Introductionmentioning

confidence: 99%

Flattening Characteristics of Ni<SUB>20</SUB>Cr Thermal-Sprayed Coating Layers on Preheated SCM415 Substrates

Shin

Lee

Wi³

et al. 2011

Mater. Trans.

View full text Add to dashboard Cite

The preheating effect of SCM415 steel substrates on the flattening behavior of Ni 20 Cr flame-sprayed particles was investigated in a temperature range from 278 K to 523 K. In the present study, we calculated the particle temperature and velocity distributions of the continuous and discrete phases before collision with the substrate by using a computational fluid dynamics (CFD) code of Fluent (ver. 6.3.26). Particle velocity and gas temperature decreased rapidly in the radial direction while the particles traveled toward the substrate, suggesting that substrate size and distance from the nozzle should be carefully controlled to improve coating quality. The conventional flame spray gun was used to accelerate molten particles and K-type thermocouples were used to monitor the substrate temperature during a preheating process. Commercially available nickel-based Ni 20 Cr particles with a mean diameter of 45 mm and 20 mm were used for experiments to examine the particle size effect on the coating characteristics. Herein we present FE-SEM images of coated layers on the substrates. As the substrate preheating temperature increased, the flatter surface morphology was seen at the interface between substrate and coating layer because of better wetting and corresponding higher shear adhesion strength. Moreover, the splat morphology was significantly dependent on the particle size.

show abstract

Influence of substrate roughness and temperature on the adhesion/cohesion of alumina coatings

Cited by 133 publications

References 14 publications

Niobium and niobium-iron coatings on API 5LX 70 steel applied with HVOF

Niobium and niobium-iron coatings on API 5LX 70 steel applied with HVOF

The Influence of Interface Characteristics on the Adhesion/Cohesion of Plasma Sprayed Tungsten Coatings

Flattening Characteristics of Ni<SUB>20</SUB>Cr Thermal-Sprayed Coating Layers on Preheated SCM415 Substrates

Contact Info

Product

Resources

About