On the Reproducibility of Air Plasma Spray Process and Control of Particle State

Srinivasan, V.; Sampath, Sanjay; Vaidya, A.; Streibl, T.; Friis, Martin

doi:10.1361/105996306x147199

Cited by 43 publications

(20 citation statements)

References 16 publications

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“…This is a notable finding that suggests a pathway for process control strategy based on injection optimization. Additional information can be found in reference [5,[16][17][18].…”

Section: Reduced Overall Process Variabilitymentioning

confidence: 99%

Particle Injection in Direct Current Air Plasma Spray: Salient Observations and Optimization Strategies

Srinivasan

Friis

Vaidya

et al. 2007

Plasma Chem Plasma Process

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External injection of high-melting point low thermal conductivity ceramics orthogonal to a typical direct current thermal plasma jet plays a vital role in determining the in-flight state of the particles and the process downstream. The interactions between low density ceramic particles and high temperature plasma jet is quite complex, which influences the spray process and associated deposition. Detailed in-flight particle diagnostics as well as spray stream visualization have significantly enhanced our capability to diagnose and control the process. In this paper we present some salient observations on the role of key variables on particle injection. A number of experiments were conducted using a 7MB torch (Sulzer Metco, Westbury, NY) with both Ar-H 2 and N 2 -H 2 plasma gases, where the carrier gas flow to inject Yttria Stabilized Zirconia (YSZ) was varied systematically and the resulting in-flight particle state was captured using an array of particle and spray stream sensors arranged in a 3D set-up. A notable observation is the existence of a ''sweet-spot'' in the plasma jet where the particle temperatures and velocities achieved a maximum. This sweet-spot can be characterized by the plume position (location of centroid of the spray stream) rather than carrier gas flow rate and is independent of primary gas flows and other process/material conditions. This result suggests a possible approach to optimize particle injection independent of plasma-forming-torch-parameters. Controlling particle injection at this sweet-spot has shown to benefit the overall process efficiency (in terms of melting) and process reliability (both in-flight measurement and coating build-up) with concomitant application benefits.

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“…This is a notable finding that suggests a pathway for process control strategy based on injection optimization. Additional information can be found in reference [5,[16][17][18].…”

Section: Reduced Overall Process Variabilitymentioning

confidence: 99%

Particle Injection in Direct Current Air Plasma Spray: Salient Observations and Optimization Strategies

Srinivasan

Friis

Vaidya

et al. 2007

Plasma Chem Plasma Process

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“…Online diagnostics using SprayWatch 2i equipment were carried out at different spray conditions to measure the particle temperature and velocity. Primary gas flow (Ar) strongly influences the average particle velocity whereas secondary gas flow (H 2 ) and current strongly influence the average particle temperature [12]. These three parameters are varied to achieve adequate temperature and velocity of melted agglomerates.…”

Section: Online Particle Diagnosticsmentioning

confidence: 99%

“…Hence, it is imperative to have a control over the particle state in order to achieve reproducible microstructure and properties in coatings. It is evident from literature that both performance and characteristics of coatings are influenced by microstructure, which in turn, are affected by the particle state along with substrate and spray conditions [12]. Hence, controlling each parameter and evaluating its role in performance of coatings becomes difficult.…”

Section: Introductionmentioning

confidence: 99%

Influence of in-flight particle state diagnostics on properties of plasma sprayed YSZ-CeO₂nanocomposite coatings

Mantry

Jha

Mandal

et al. 2014

International Journal of Smart and Nano Materials

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This article describes the influence of controlling in-flight hot particle characteristics on properties of plasma sprayed nanostructured yttria stabilized zirconia (YSZ) coatings. This article depicts dependence of adhesion strength of as-sprayed nanostructured YSZ coatings on particle temperature, velocity and size of the splat prior to impact on the metallic substrate. Particle temperature measurement is based on two-color pyrometry and particle velocities are measured from the length of the particle traces during known exposure times. The microstructure and adhesion strength of as-sprayed nano-YSZ coatings were studied. Field emission scanning electron microscopy results revealed that morphology of coating exhibits bimodal microstructure consisting of nano-zones reinforced in the matrix of fully melted particles. The coating adhesion strength is noticed to be greatly affected by the melting state of agglomerates. Maximum adhesion strength of 42.39 MPa has been experimentally found out by selecting optimum levels of particle temperature and velocity. The enhanced bond strength of nano-YSZ coating may be attributed to higher interfacial toughness due to cracks being interrupted by adherent nano-zones.

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“…For this purpose, new techniques for visualisation and diagnostics of the injected powder particles during their flight to the coated surface have been developed (Moreau et al, 2005;Srinivasan et al, 2006;Streibl et al, 2006). New methods for non-destructive control, including statistical evaluation of the collected data, together with prognosis of the coating parameters as a function of the technological conditions have been offered as well (Zhu & Ding, 2000).…”

Section: Plasma-spraying Of Bioceramic Coatingsmentioning

confidence: 99%

“…New methods for non-destructive control, including statistical evaluation of the collected data, together with prognosis of the coating parameters as a function of the technological conditions have been offered as well (Zhu & Ding, 2000). Some work has already been done to characterise the following main dependencies that play an important role for successful performance of the discussed biomedical coatings (Azarmi et al, 2008;Boulos et al, 1993;Celik et al, 1999;Chen et al, 1993;Choi et al, 1998;Dyshlovenko et al, 2005;Fan et al, 2005;Gueorguiev et al, 2008aGueorguiev et al, , 2008cIordanova & Forcey, 1997;Khor et al, 2004;Kreye et al, 2007;Kuroda & Clyne, 1991;Leigh & Berndt, 1997;Li & Khor, 2002;Liu et al, 2005;Lugscheiber et al, 1993;Mawdsley et al, 2001;Montavon et al, 1997;Moreau et al, 2005;Neufuss et al, 2001;Ohmori & Li, 1991;Parizi et al, 2007;Sampath et al, 2003;Sarikaya, 2005;Srinivasan et al, 2006;Staia et al, 2001;Streibl et al, 2006;Toma et al, 2003;Tong et al, 1996;Wallace & Ilavsky, 1998;Zhu & Ding, 2000):…”

Section: Plasma-spraying Of Bioceramic Coatingsmentioning

confidence: 99%

Plasma Sprayed Bioceramic Coatings on Ti-Based Substrates: Methods for Investigation of Their Crystallographic Structures and Mechanical Properties

Iordanova¹,

Antonov²,

Sprecher³

et al. 2012

Advanced Plasma Spray Applications

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On the Reproducibility of Air Plasma Spray Process and Control of Particle State

Cited by 43 publications

References 16 publications

Particle Injection in Direct Current Air Plasma Spray: Salient Observations and Optimization Strategies

Particle Injection in Direct Current Air Plasma Spray: Salient Observations and Optimization Strategies

Influence of in-flight particle state diagnostics on properties of plasma sprayed YSZ-CeO₂nanocomposite coatings

Plasma Sprayed Bioceramic Coatings on Ti-Based Substrates: Methods for Investigation of Their Crystallographic Structures and Mechanical Properties

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On the Reproducibility of Air Plasma Spray Process and Control of Particle State

Cited by 43 publications

References 16 publications

Particle Injection in Direct Current Air Plasma Spray: Salient Observations and Optimization Strategies

Particle Injection in Direct Current Air Plasma Spray: Salient Observations and Optimization Strategies

Influence of in-flight particle state diagnostics on properties of plasma sprayed YSZ-CeO2nanocomposite coatings

Plasma Sprayed Bioceramic Coatings on Ti-Based Substrates: Methods for Investigation of Their Crystallographic Structures and Mechanical Properties

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Influence of in-flight particle state diagnostics on properties of plasma sprayed YSZ-CeO₂nanocomposite coatings