Effect of Substrate Roughness on Splatting Behavior of HVOF Sprayed Polymer Particles: Modeling and Experiments

Ivosevic, M.; Gupta, Vikas; Knight, Richard; Cairncross, Richard A.; Baldoni, J.A.; Twardowski, T. E.

doi:10.1361/105996306x146839

Cited by 31 publications

(20 citation statements)

References 10 publications

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“…Fundamental studies of thermally sprayed plastic coatings have been carried out using the above-mentioned materials, which aim to clarify the particle deposition mechanism [51,52] and relate it to coating performance such as wear resistance [53]. To improve adhesion between a plastic coating and a substrate, polymers and 0 500 1000 1500 10 copolymers with functional groups were investigated, e.g.…”

Section: Plasticsmentioning

confidence: 99%

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Katayama

Kawakita

Watanabe

et al. 2008

Science and Technology of Advanced Materials

156

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In recent years, coating processes based on the impact of high-velocity solid particles such as cold spraying and aerosol deposition have been developed and attracting much industrial attention. A novel coating process called 'warm spraying' has been developed, in which coatings are formed by the high-velocity impact of solid powder particles heated to appropriate temperatures below the melting point of the powder material. The advantages of such process are as follows: (1) the critical velocity needed to form a coating can be significantly lowered by heating, (2) the degradation of feedstock powder such as oxidation can be significantly controlled compared with conventional thermal spraying where powder is molten, and (3) various coating structures can be realized from porous to dense ones by controlling the temperature and velocity of the particles. The principles and characteristics of this new process are discussed in light of other existing spray processes such as high-velocity oxy-fuel spraying and cold spraying. The gas dynamics of particle heating and acceleration by the spraying apparatus as well as the high-velocity impact phenomena of powder particles are discussed in detail. Several examples of depositing heat sensitive materials such as titanium, metallic glass, WC-Co cermet and polymers are described with potential industrial applications.

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Section: Plasticsmentioning

confidence: 99%

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Katayama

Kawakita

Watanabe

et al. 2008

Science and Technology of Advanced Materials

156

View full text Add to dashboard Cite

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“…With such a criteria, only the grit-blasted specimen would be considered high roughness. However, the microstructure of the splats observed for all four rough specimens (Al1005_R, Al1005_GB, Al5052_E, and Al5052_ET) appears to correspond to the effects described for surfaces which exhibit a high roughness, that is disturbance of the flow of the spreading molten splat by the irregularities of the interface (Ref 14, 19), creating very irregularly shaped splats (Ref [20][21][22], occurrence of substrate melting ( Ref 27,28), especially for the peaks of the surface, etc. Accurate quantification of the effects is difficult because of the relatively limited number of FIB and TEM cross sections that were prepared for each specimen.…”

Section: Effects Of the Substrate Roughness On The Splat Formation Prmentioning

confidence: 56%

“…3b) and voids located for instance within the splat, denote the chaotic spreading of the splat upon its formation. Many studies have reported that the presence of high-scale roughnessinduced instabilities in the spreading of plasma-sprayed splat, causing the formation of features such as splashed fingers or voids ( Ref 14,[20][21][22]. The presence of hot oxidizing gases is also evident by the presence of layers of oxides observed on the walls on the voids.…”

Section: Splat Microstructure and Formation For The Roughened And Grimentioning

confidence: 99%

Effects of Substrate Roughness on Splat Formation for Ni-Cr Particles Plasma Sprayed onto Aluminum Substrates

et al. 2010

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Roughening of the substrate, for instance by grit-blasting or etching, is often used before plasma spraying in order to provide a high degree of roughness that promotes mechanical interlocking of the sprayed coating and consequently improved adhesion. This study investigates the morphology and microstructure of NiCr splats formed on such rough Al substrates, where roughness was generated by a number of methods including grinding and etching. Cross sections of the splats and the splat-substrate interface were examined using a range of electron microscopy techniques. Localized substrate melting and chemical mixing with the splat material was observed, forming very particular structures. The formation of various oxides phases and voids was also noted and found to increase, along with the degree of the substrate melting, with increasing substrate roughness. The structures observed were related to the spray conditions and substrate morphology.

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“…In recent years, 3D mathematical models of acceleration, heating, and deformation of the particles have been developed to predict the particle transport and splatting on impact with a �at substrate were discussed. A 3D model for the splatting of high-velocity oxyfuel (HVOF) sprayed polymer particles on rough surfaces has been also developed recently [106]; the results indicated that an increase in the magnitude of the mean substrate roughness promoted splat instability and formation of radial �ngers, while an increase in general surface roughness may result in a lower spreading ratio of thermally sprayed polymer particles. ree-dimensional molecular dynamics simulation with considering the in�uence of the impact parameters to clarify at an atomic level the �attening process of a high-temperature droplet impacting a substrate at high speed [104], the �attening ratio increases in proportion to the droplet velocity and the droplet diameter in their study.…”

Section: Numerical Modeling On Splat Formation Processmentioning

confidence: 99%

Recent Developments in the Research of Splat Formation Process in Thermal Spraying

Yang

Liu

Zhou

et al. 2013

Journal of Materials

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Thermal spraying is a well-established surface modification technology which has been widely used in industrial applications. As the coating properties were mainly determined by the flattening nature of each splat, much attention has been increasingly paid to the study on the splat formation process of thermal sprayed particles. This paper is concerned with the development in the research of the splat formation process of the individual splat deposited by thermal spraying during the past few decades, including the experimental and numerical simulations up to today; some classical splashing models were also reviewed. As a simulation of the actual thermal spray process, the development of the flattening behavior of free falling droplet has been mentioned as well. On the basis of the current investigation, some recommendations for the future work have been advised.

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Effect of Substrate Roughness on Splatting Behavior of HVOF Sprayed Polymer Particles: Modeling and Experiments

Cited by 31 publications

References 10 publications

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Warm spraying—a novel coating process based on high-velocity impact of solid particles

Effects of Substrate Roughness on Splat Formation for Ni-Cr Particles Plasma Sprayed onto Aluminum Substrates

Recent Developments in the Research of Splat Formation Process in Thermal Spraying

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