Deposition and Characterization of HVOF Thermal Sprayed Functionally Graded Coatings Deposited onto a Lightweight Material

Hasan, Mohammed Adnan; Stokes, Joseph; Looney, L.; Hashmi, M.S.J.

doi:10.1007/s11665-008-9251-3

Cited by 10 publications

(8 citation statements)

References 21 publications

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“…The coatings quality can be controlled by the control of the particles in-flight temperature [98]. Moreover, in case of FGC it is suggested to control the powder with the lowest melting point in order to avoid excessive evaporation [99]. Prchlik et al [91] compared behavior of atmospheric plasma-sprayed Mo-Mo2C/stainless steel and HVOF-sprayed WC-Co/stainless steel functionally graded coatings.…”

Section: High Velocity Oxy-fuel and High Velocity Air-fuel Sprayingmentioning

confidence: 99%

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Review of Functionally Graded Thermal Sprayed Coatings

et al. 2020

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The paper briefly describes major thermal spray techniques used to spray functionally graded coatings such as atmospheric plasma spraying, high velocity oxy-fuel spraying, suspension and solution precursor plasma spraying, and finally low and high pressure cold gas spray method. The examples of combined spray processes as well as some examples of post spray treatment including laser and high temperature treatments or mechanical one, are described. Then, the solid and liquid feedstocks used to spray and their properties are shortly discussed. The reviewed properties of functional coatings include: (i) mechanical (adhesion, toughness, hardness); (ii) physical (porosity, thermal conductivity and diffusivity, thermal expansion, photo-catalytic activity), and; (iii) bioactivity and simulated body fluid (SBF) corrosion. These properties are useful in present applications of functionally graded coatings as thermal barriers, the bioactive coatings in prostheses, photo-catalytic coatings in water treatment, coatings used in printing industry (anilox and corona rolls). Finally, some of the future possible fields of functional thermal sprayed coatings applications are discussed, e.g., to coat polymer substrates or to use the cheap technology of low pressure cold gas spray method instead of expensive technology of vacuum plasma spraying to obtain bond coatings.

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Section: High Velocity Oxy-fuel and High Velocity Air-fuel Sprayingmentioning

confidence: 99%

Section: High Velocity Oxy-fuel and High Velocity Air-fuel Sprayingmentioning

confidence: 99%

Review of Functionally Graded Thermal Sprayed Coatings

et al. 2020

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“…Therefore, it may directly or indirectly affect the oxide content and distribution, phase changes, and coating porosity. In addition, the very fast droplet solidification at cooling rates of about 10 6 -10 7 Ks −1 was found to be the reason for the formation of the amorphous phases [18] and the initiation of higher tensile residual stresses in the TWAS sprayed coatings [19][20][21]. Therefore, it is common that TWAS sprayed coatings require a post-treatment to achieve the required coating microstructure.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Argon as Atomization Gas on the Microstructure, Machine Hammer Peening Post-Treatment, and Corrosion Behavior of Twin Wire Arc Sprayed (TWAS) ZnAl4 Coatings

et al. 2021

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In the twin wire arc spraying (TWAS) process, it is common to use compressed air as atomizing gas. Nitrogen or argon also are used to reduce oxidation and improve coating performance. The heat required to melt the feedstock material depends on the electrical conductivity of the wires used and the ionization energy of both the feedstock material and atomization gas. In the case of ZnAl4, no phase changes were recorded in the obtained coatings by using either compressed air or argon as atomization gas. This fact has led to the assumption that the melting behavior of ZnAl4 with its low melting and evaporating temperature is different from materials with a higher melting point, such as Fe and Ni, which also explains the unexpected compressive residual stresses in the as-sprayed conditions. The heavier atomization gas, argon, led to slightly higher compressive stresses and oxide content. Compressed air as atomization gas led to lower porosity, decreased surface roughness, and better corrosion resistance. In the case of argon, Al precipitated in the form of small particles. The post-treatment machine hammer peening (MHP) has induced horizontal cracks in compressed air sprayed coatings. These cracks were mainly initiated in the oxidized Al phase.

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“…This research will discuss the potential of using the HVOF technique to produce FGMs. Hence a functionally graded coating in which the composition, microstructure and properties vary gradually from the bond coat to the topcoat reported by Hasan et al (2009); Dussoubs et al (2001) resembles the graded coating of material R and S is shown in Figure 1 (b).…”

Section: Introductionmentioning

confidence: 99%

Development of a semi automated dual feed unit to produce FGM coatings using the HVOF thermal spray process

Kabir¹,

Stokes²

2014

S. Pac. J. Nat. App. Sci.

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The application of functionally graded materials (FGMs) is quite difficult, but thermal spray processes like Plasma spray have demonstrated their unique potential in producing graded deposits, where researchers have used twin powder feed systems to mix different proportions of powders. FGMs vary in composition and/or microstructure from one boundary (substrate) to another (top service surface), and innovative characteristics result from the gradient from metals to ceramics or non-metallic to metals. The present study investigates an innovative modification of a high velocity oxy-fuel (HVOF) thermal spray process to produce functionally graded thick coatings. In order to deposit thick coatings, certain problems have to be overcome. Graded coatings enable gradual variation of the coating composition and/or microstructure, which offers the possibility of reducing residual stress build-up with in coatings. In order to spray such a coating, modification to a commercial powder feed hopper was required to enable it to deposit two powders simultaneously which allows deposition of different layers of coating with changing chemical compositions, without interruption to the spraying process. Various concepts for this modification were identified and one design was selected, having been validated through use of a process model, developed using ANSYS Flotran finite element analysis. In the current research the mixing of different proportions of powders were controlled by a computer using LabVIEW software and hardware, which allowed the control and repeatability of the microstructure when producing functionally graded coatings.

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Deposition and Characterization of HVOF Thermal Sprayed Functionally Graded Coatings Deposited onto a Lightweight Material

Cited by 10 publications

References 21 publications

Review of Functionally Graded Thermal Sprayed Coatings

Review of Functionally Graded Thermal Sprayed Coatings

The Effect of Argon as Atomization Gas on the Microstructure, Machine Hammer Peening Post-Treatment, and Corrosion Behavior of Twin Wire Arc Sprayed (TWAS) ZnAl4 Coatings

Development of a semi automated dual feed unit to produce FGM coatings using the HVOF thermal spray process

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