Suspension Plasma Spraying Process Research Articles

Fabrication and characterization of thermal barrier coatings for internal combustion engines via suspension plasma spray with high solid loading

Suspension plasma spraying (SPS) technique producing thermal barrier coatings (TBCs) with high porosity and good thermal shock resistance has great potential to improve the thermal efficiency of internal combustion (IC) engines. However, its wide usage is limited by the immature fabrication technology and low spraying efficiency. Therefore, this study optimized the SPS process with high solid loading and characterized the properties of the coating to obtain TBCs suitable for IC engines. Suspension composition optimization revealed that polyethylenimide (PEI) has the best dispersion effect, and a suspension with high solid loading of 35 wt% was obtained. Furthermore, the effects of the spraying distance, feeding speed and spraying power on the coating microstructure were investigated, and the porosity and thermal shock resistance of the coatings were characterized to determine the optimal spraying process. Thermal shock failure of SPS coatings primarily arises from the propagation of horizontal cracks originating from vertical intercolumn cracks. The SPS coating with a feathery columnar structure has the best thermal shock resistance. By optimizing the spraying process, a coating with porosity up to 24.16 %, bonding strength of 41.69 MPa, and good thermal shock resistance is successfully achieved.

A Comparative Study of the Self-Cleaning and Filtration Performance of Suspension Plasma-Sprayed TiO2 Ultrafiltration and Microfiltration Membranes.

This study investigated the performance of photocatalytic titanium dioxide microfiltration membranes with an average pore size of approximately 180 nm and ultrafiltration membranes with an average pore size of around 40 nm fabricated with the suspension plasma spray process. The membranes were evaluated for their filtration performance using SiO2 particles of different sizes and polyethylene oxide with molecular weights of 20 kDa to 1000 kDa, and the fouling parameters were characterized. The rejection rate was enhanced by increasing the thickness of the membranes. This effect was more pronounced with the ultrafiltration membranes. The rejection rate of the ultrafiltration membrane was improved significantly after filling the larger pores on the surface with agglomerates of titanium dioxide nanoparticles. The self-cleaning performance of the membranes was assessed under visible light. Both ultrafiltration and microfiltration membranes showed a flux recovery under visible light illumination due to the photocatalytic activity of titanium dioxide. The membranes also show a flux recovery of more than 90%.

High-quality TbF3 coating prepared by suspension plasma spraying technique for improving the grain boundary diffusion efficiency of sintered Nd-Fe-B magnets

High-quality TbF3 coating used for the grain boundary diffusion process (GBDP) of sintered Nd-Fe-B was prepared by the suspension plasma spraying (SPS) technique. The obtained TbF3 coating with SPS process showed a dense and continuous structure with the uniform distribution as well as a good adhesion with the Nd-Fe-B substrate. Compared with the uncoated Nd-Fe-B magnet without heavy rare earth, the coercivity of TbF3 coated Nd-Fe-B magnet enhanced from 1160 kA/m to 1824 kA/m after the GBDP heat treatment. The microstructure and composition analysis indicated that the (Nd, Tb)2Fe14B shell formed at the periphery of Nd2Fe14B grains throughout the whole sample magnet. The shell with high magnetocrystalline anisotropy effectively suppressed the nucleation of reverse domain and repaired the defects on the grain surface of the sintered Nd-Fe-B magnets, thus enhancing the coercivity. As a consequence, the SPS technology has advantage of high depositing rate, flexible production process, good boundary adhesion and homogeneous-dense structure, which is expected to become a promising candidate way of depositing diffusion coating for the GBDP of sintered Nd-Fe-B in industrial production.

Superhydrophobic ceramic coatings with lotus leaf-like hierarchical surface structures deposited via suspension plasma spray process

In this work, superhydrophobic yttria-stabilized zirconia coatings were deposited via the suspension plasma spray process using a new water-based suspension. The new water-based suspension was prepared with the addition of surfactant, which showed a much lower surface tension than the conventional water-based suspension, and meanwhile was much cheaper and safer, and more environmentally friendly than the ethanol-based suspension. The coatings exhibited lotus leaf-like hierarchical surface structures of micron-sized protuberances with superimposed nanometer-sized splats/particles. After chemical modification, the coatings showed excellent water repellency with a water contact angle of ∼157°, a roll-off angle of ∼5°, and complete droplet rebound behaviors. The ethanol-based suspension and conventional water-based suspension were also prepared and used for coating deposition. Comprehensive characterizations of the suspension properties (surface tension, viscosity, atomization behaviors), surface structures, and wetting behaviors of different coatings were conducted for comparative investigation. The formation mechanism of different surface structures was elaborated by investigating the properties of suspensions and plasma gas flow, the aerodynamic breakup behaviors of suspensions, and the motion of impinging particles. The different wetting behaviors of coatings were correlated with the surface structures and wetting states. The study provides a rapid and cost-effective way to deposit hierarchically-structured superhydrophobic ceramic coatings via the water-based suspension plasma spray process.

EBM Technique Study on Microstructural Characterization of Al-Zr-N Coating

Through the implementation of the electron beam physical vapour deposition (EB-PVD) technique, an aluminium zirconium nitrate (Al-Zr-N) coating has been created in the current work on high speed steel (E19) substrates. Through the use of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), nano indentation, and scratch tests, the structural morphological and mechanical properties of the substrate are investigated. The cause of tension relaxation and vacancy concentration is explained by the fluorite phase's lattice constant decreasing with rising deposition temperature. As the temperature of the substrate rises, the coating's increased surface roughness is explained by an increase in crystallite size [1]. TBCs are frequently applied to metal substrates using the Atmospheric Plasma Spraying (APS) and Electron Beam Physical Vapour Deposition (EB-PVD) methods. For the next generation of turbine engines, the high costs and relatively high thermal conductivities of EB-PVD coatings, as well as the short thermal lifetime of APS coatings, are significant drawbacks. Suspension Plasma Spraying (SPS) was evaluated in this study to enhance the thermal properties of TBC. The SPS process enables the creation of columnar micro-structures that are easily adjustable in terms of thermal conductivity and columnar structure compaction.

Obtention, Characterization and Deposition of Hydroxyapatite Obtained from Scales of the Amazonian Fish Pirarucu (Arapaima gigas) Using the High Velocity Suspension Plasma Spray (HVSPS) Process

Obtention, Characterization and Deposition of Hydroxyapatite Obtained from Scales of the Amazonian Fish Pirarucu (Arapaima gigas) Using the High Velocity Suspension Plasma Spray (HVSPS) Process

Evaluation of major factors influencing the TBC topcoat formation in axial suspension plasma spraying (SPS)

AbstractSuspension plasma spraying (SPS) is ideally suited to produce porous or dense columnar, strain‐tolerant thermal barrier coatings (TBCs) and also offers the possibility of producing other microstructures such as feathery and dense vertically cracked coatings. The specific properties of the TBC are significantly influenced by the formed microstructure, that is, affected by feedstock material and process parameters. In this work, the effects of various process parameters in the SPS process are investigated. It was found that the suspension feed rate has a significant effect on the microstructure, especially on the column density of the coating, whereas the suspension solids content mainly affects the coating porosity. Additionally, the surface roughness and topography of the bond coat are crucial for the formation of columnar coatings and were therefore investigated. Despite comparable roughness values for as‐sprayed bond coats for high velocity oxy fuel and vacuum plasma spray produced coatings, the surface structures differ significantly from each other and affect the microstructure of the deposited topcoat. Characterization of mechanical properties by means of micro‐indenter can be suitable for columnar coatings to determine Young's modulus within a column. However, due to the heterogeneity of the coating, the method is not suitable to describe the mechanical properties of the topcoat.

TiO2 Photocatalytic Ultrafiltration Membrane Developed with Suspension Plasma Spray Process

The suspension plasma spray process was used to fabricate photocatalytic ultrafiltration membranes for potential water and wastewater treatment applications. An aqueous suspension of 30 wt.% titanium dioxide with an average individual particle size of around 30 nm was used as feedstock material. The spray parameters, such as suspension solid content, suspension feed rate, and spray distance, were optimized using an Ar/H2 plasma to retain a fraction of unmelted feedstock nanoparticles as the source of fine pores in the membrane microstructure. The microstructure, porosity, phase composition, and pure water permeability of the membranes were characterized comprehensively. The average pore size of the membrane was around 40 nm, which was very close to the particle size of the pristine titanium dioxide powder. The membranes demonstrated a high water permeability between 2000 and 7200 L m−2 h−1 bar−1, which was inversely proportional to the thickness. They also exhibited significant photocatalytic activity under visible light.

Li ion transport properties of amorphous/crystalline Li-La-Zr-Nb-O solid electrolyte thick films prepared by suspension plasma spraying

Amorphous Li-La-Zr-O films are considered very attractive as a solid-state electrolyte in future batteries due to their low processing temperatures and resistance to Li-dendrite formation. The knowledge of amorphous Li-La-Zr-O phases is limited and thick films and bulk samples of amorphous Li-La-Zr-O have yet to be explored. Only thin film forms (~0.5 μm) of these amorphous Li-La-Zr-O phases have been prepared. In this work, we investigated the Li-ion transport properties of amorphous/crystalline mixtures of Li-La-Zr-Nb-O thick films (30 to 55 μm) prepared by the suspension plasma spray process. The process was manipulated to alter the amorphous Li-La-Zr-Nb-O content in the as-deposited films. Properties of the films that contained mostly amorphous Li-La-Zr-Nb-O (~76 wt%) were compared vs. mostly cubic Li garnet-type oxide (~55 wt%). The latter showed Li-ion transport properties that were similar to previously reported properties of cubic Li-garnet type oxides whereas the amorphous Li-La-Zr-Nb-O films exhibited significantly different properties. Their AC conductivity spectra show a Jonscher power law (JPL) behavior with the dimensionless exponent of ~0.92 that is followed by superlinear power law (SLPL) behavior with the dimensionless exponent of ~1.65 in the high frequency regime. These behaviors have not been reported earlier for the amorphous Li-La-Zr-Nb-O phases. Both of the JPL and SLPL behaviors have thermally activated characteristic with the activation energies of 0.76 eV and 0.64 eV, respectively. A lower value of ~0.45 eV was evaluated for the activation energy by solid-state 7Li NMR spectroscopy. The effect of temperature on the Li-ion dynamic process was studied by scaling the conductivity spectra and it was found to be temperature independent.

Columnar-structured thermal barrier coatings deposited via the water-based suspension plasma spray process

Suspension plasma spray (SPS) has been developed as a rapid, facile and cost-effective process to deposit columnar-structured thermal barrier coatings (TBCs). In contrast to the most commonly used ethanol-based suspensions, water-based suspensions have not been used in the SPS process to deposit columnar-structured TBCs due to their high surface tension, although they are much cheaper and safer. In this work, a new water-based SPS process was prepared by adding surfactant to lower the surface tension. The optimum content of dispersant and surfactant added to the suspension was determined via measurements of viscosity, particle size, surface tension, contact angles, and atomized droplet size. Coatings deposited using suspensions with and without surfactant showed typical columnar-structured microstructures and vertically cracked microstructures, respectively. The coatings deposited using suspensions with surfactant also showed evolution from columnar-structured microstructures to mixed microstructures of columns and cracks, and to homogeneous microstructures with the increase in standoff distance. The formation of different coating microstructures was correlated to the size of droplets after aerodynamic breakup and the Stokes number of in-flight particles. The new water-based suspension together with the water-based SPS process show great potential to be a cheap and effective alternative to the ethanol-based SPS process.

Role of phase content on the photocatalytic performance of TiO2 coatings deposited by suspension plasma spray

In this work, suspension plasma spraying (SPS) with different hydrogen (H2) flow rates was employed to produce TiO2 coatings with various phase contents, oxygen contents, and roughnesses. To eliminate the role of the morphology and oxygen content on the photocatalytic activity, all coatings were polished to reach the same roughness followed by heat-treatment at 550 °C in air for 48 h. Then coatings were analyzed by X-ray diffractometer (XRD), confocal laser microscope, scanning electron microscope (SEM), UV–visible spectrometer, Raman microscope, and thermogravimetric analyzer. The XRD data indicated that the percentage of anatase decreased as function of H2 flow rates, and almost 46% of anatase transformed to rutile during SPS process at the highest H2 flow rate. Moreover, the photocatalytic performance was evaluated by monitoring the degradation of methylene blue under visible light irradiation, and the results indicated that anatase phase positively enhances the photocatalytic activity of TiO2 coatings.

Thermal decomposition and crystallization behavior of Yb/Y co-doped SrZrO3 precursor used in the suspension plasma spray process

A double rare-earth (Yb/Y) co-doped SrZrO 3 [Sr 1.0 (Zr 0.9 Yb 0.05 Y 0.05 )O 2.95 ] thermal barrier coating was prepared via suspension plasma spraying (SPS). The rare-earth nitrates [Zr(NO 3 ) 4 ·5H 2 O, Sr(NO 3 ) 2 , Yb(NO 3 ) 3 ·6H 2 O, Y(NO 3 ) 3 ·6H 2 O] and NH 4 (C 2 O 4 ) 2 ·H 2 O were used to prepare the precursor suspension by co-precipitation. The thermal decomposition and crystallization of the precursor suspension powders calcined at 1200 °C were characterized with X-ray diffraction and a synchronous thermal analyzer coupled with quadrupole mass spectrometry . Zr 2 (C 2 O 4 ) 2 (OH) 4 decomposed into Zr(C 2 O 4 ) 2 , ZrO 2, and H 2 O initially, followed by the decomposition of Zr(CO 3 ) 2 into ZrO 2 . The SrC 2 O 4 precursor decomposed into SrCO 3 and SrO consecutively. The ZrO 2 reacted with SrO (Yb 2 O 3 , Y 2 O 3 ) to generate the Yb/Y co-doped SrZrO 3 . And the Yb/Y co-doped SrZrO 3 coating with a columnar crystal structure was prepared by SPS, which was analyzed with scanning electron microscopy, an inductively coupled plasma atomic emission spectrometer, and a laser flash analyzer. The thermal conductivity of the as-prepared coating was 1.77 W·m −1 ·K −1 at 1000 °C, which was more than 19% lower than that of the SPS SrZrO 3 coating. • The precursor suspension was prepared by co-precipitation using Zr(NO 3 ) 4 ·5H 2 O, Sr(NO 3 ) 2 , Yb(NO 3 ) 3 ·6H 2 O, Y(NO 3 ) 3 ·6H 2 O and NH 4 (C 2 O 4 ) 2 ·H 2 O. • The phase evolution of the precursor suspension was investigated. • The Yb/Y co-doped SrZrO 3 coating was prepared by suspension plasma spray using the prepared precursor suspension. • The Yb/Y co-doped SrZrO 3 coating has a low thermal conductivity of 1.77 W·m -1 ·K -1 at 1000 °C compared to SrZrO 3 coating.

Investigating the in-flight droplets' atomization in suspension plasma-sprayed coating

A three-dimensional unsteady numerical model is employed to study the in-flight droplets/particles' atomization in the suspension plasma spraying (SPS) process. A user-defined function (UDF) written in C programming adds the electromagnetic fields to the fluid flow field. A two-way coupled Eulerian-Lagrangian technique simulates the sprayed droplets' interaction with the plasma flow. The developed model is applied to investigate the droplets' atomization behavior in the SPS process. Droplets' atomization is simulated by applying the Kelvin-Helmholtz Rayleigh-Taylor (KHRT) breakup model. This model considers the effects of both aerodynamic forces (Wave model) and Rayleigh-Taylor instabilities on the atomization process combing a liquid core region (Levich model). Previous works to estimate the KHRT breakup model's coefficients were performed on a liquid jet (e.g., fuel jet) into the air. Because the density ratio of suspension in the plasma is higher than that of the liquid jet into the air (suspension density is higher than a liquid droplet and plasma density is lower than air), the model's coefficients should be modified for the suspension atomization in the SPS process. For this reason, nine case studies are investigated to see the effect of KH and RT instabilities and the liquid core length on the droplets/particles' atomization. The results obtained from the suggested values show a good agreement compared to the existing data.

Incorporation of graphene nano platelets in suspension plasma sprayed alumina coatings for improved tribological properties

Graphene possesses high fracture toughness and excellent lubrication properties, which can be exploited to enhance tribological performance of coating systems utilized to combat wear. In this work, suspension plasma spray (SPS) process was employed to deposit a composite, graphene nano-platelets (GNP) incorporated alumina coating. For comparison, monolithic alumina was also deposited utilizing identical spray conditions. The as-deposited coatings were characterized in detail for their microstructure, porosity content, hardness, fracture toughness and phase composition. Raman analysis of the as-deposited composite coating confirmed retention of GNP. The composite coating also showed good microstructural integrity, comparable porosity, higher fracture toughness and similar alumina phase composition as the monolithic alumina coating. The as-deposited coatings were subjected to dry sliding wear tests. The GNP incorporated composite coating showed lower CoF and lower specific wear rate than the pure alumina coating. Additionally, the counter surface also showed a lower wear rate in case of the composite coating. Post-wear analysis performed by SEM/EDS showed differences in the coating wear track and in the ball wear track of monolithic and composite coatings. Furthermore, Raman analysis in the wear track of composite coating confirmed the presence of GNP. The micro-indentation and wear test results indicate that the presence of GNP in the composite coating aided in improving fracture toughness, lowering CoF and specific wear rate compared to the monolithic coating. Results from this work demonstrated retention of GNP in an SPS processed coating, which can be further exploited to design superior wear-resistant coatings.

A novel approach to prepare Li-La-Zr-O solid state electrolyte films by suspension plasma spray

In this work we investigated a novel approach to prepare Li-La-Zr-O solid-state electrolyte films by the suspension plasma spray process. This process offers several advantages that make it a promising low-cost, rapid and robust production method for garnet-type Li-ion conductors. A cubic garnet-type, Li6.75La3Zr1.75Nb0.25O12, ethanol-based suspension was plasma sprayed on stainless-steel substrates using two torch power levels, 30.9 and 77.1 kW, at different stand-off distances. Solid-state electrolyte films of ~14 μm thickness were deposited in ~0.1 h of spraying. Maximum Li-ion conductivity as high as 7.3·10−6 S cm−1 at 22 °C has been obtained for the samples sprayed at 30.9 kW and stand-off distance of 25 mm. These samples contained a majority of amorphous phase (67.0 wt%), 20.2 wt% of Li6.75La3Zr1.75Nb0.25O12, and the balance of 12.8 wt% of the pyrochlore phase (La2Zr2O7). We associate this result with the relatively high value of Li number density, 2.2·1022 cm−3, and the lowest content of La2Zr2O7. The higher torch power level and/or longer stand-off distance leads to a reduction in Li number density and higher content of La2Zr2O7, likely due to evaporative loss of Li species during the spray process. These factors also translate to a decrease in Li-ion conductivity. The knowledge that has been acquired in this preliminary study provides guidelines for further development and optimization of this rapid deposition technique of garnet-type solid-state electrolyte films.

Investigations on Particle Behavior at the Stagnation Zone for a Suspension Particle Jet in Plasma Spray Conditions

The suspension plasma spray process is now emerging at the industrial scale, and open questions remain regarding the formation of coatings through this process, especially regarding the relationship among particle impact, spreading and build-up into columns. Furthermore, concerns have been raised regarding the behavior of the suspension droplets in the plasma jet stagnation zone since it is a zone where plasma jet streamline directions and velocities are highly disrupted when the plasma jet impinges on a solid surface. In this study, the particle-laden jet streamlines were experimentally observed very closely to a flat surface using a particle image velocimetry technique. Submicron particles were collected in flight to determine which particles contributed to coating growth. The particle mean impact velocity against the surface was determined through image velocimetry and splat dimensions. The impact angles of the particles were also determined, and a correlation was identified with the growth angles of the columnar coating.

Numerical Study of the Effects of Twin-Fluid Atomization on the Suspension Plasma Spraying Process

Suspension plasma spraying (SPS) is an effective technique to enhance the quality of the thermal barrier, wear-resistant, corrosion-resistant, and superhydrophobic coatings. To create the suspension in the SPS technique, nano and sub-micron solid particles are added to a base liquid (typically water or ethanol). Subsequently, by using either a mechanical injection system with a plain orifice or a twin-fluid atomizer (e.g., air-blast or effervescent), the suspension is injected into the high-velocity high-temperature plasma flow. In the present work, we simulate the interactions between the air-blast suspension spray and the plasma crossflow by using a three-dimensional two-way coupled Eulerian–Lagrangian model. Here, the suspension consists of ethanol (85 wt.%) and nickel (15 wt.%). Furthermore, at the standoff distance of 40 mm, a flat substrate is placed. To model the turbulence and the droplet breakup, Reynolds Stress Model (RSM) and Kelvin-Helmholtz Rayleigh-Taylor breakup model are used, respectively. Tracking of the fine particles is continued after suspension’s fragmentation and evaporation, until their deposition on the substrate. In addition, the effects of several parameters such as suspension mass flow rate, spray angle, and injector location on the in-flight behavior of droplets/particles as well as the particle velocity and temperature upon impact are investigated. It is shown that the injector location and the spray angle have a significant influence on the droplet/particle in-flight behavior. If the injector is far from the plasma or the spray angle is too wide, the particle temperature and velocity upon impact decrease considerably.

Thermal Stability of YSZ Thick Thermal Barrier Coatings Deposited by Suspension and Atmospheric Plasma Spraying

Two types of segmentation-crack structured yttria-stabilized zirconia (YSZ) thick thermal barrier coatings (>500 μm, TTBCs) were deposited onto the stainless steel substrates using atmospheric plasma spraying (APS) and suspension plasma spraying (SPS) process, respectively. In this work, thermal aging behaviors, such as the microstructures, phase compositions, grain growth, and mechanical properties of APS TTBCs and SPS TTBCs, were systematically investigated. Results showed that both as-sprayed TTBCs exhibited a typical segmentation-crack structure in the through-thickness direction. APS coatings mainly comprised of larger columnar crystals, while a large number of smaller equiaxed grains existed in SPS coatings. Both of the coatings underwent tetragonal-monoclinic phase transformation after 155 °C/40 h heat treatment. The poorer phase stability of SPS TTBCs may have a connection with smaller grain size. Thermal-aged APS and SPS coatings exhibited a significant increase in H and E values with the rising of thermal aging temperature, and for the samples that thermal aged at 1550 °C, the H and E values increased sharply during initial stage then decreased after 80 h due to the phase decomposition. The segmented APS coatings had weak bonding between the lamellaes during thermal exposure, which caused the mean Vickers hardness value of APS TTBCs to be much lower than that of SPS TTBCs.

Phenomenological model of the suspension droplets evaporation in a plasma flow considering different mass transfer mechanisms

Suspension plasma spraying (SPS) technology allows the production of advanced coatings via deposition of micron and submicron particles, however its effective implementation requires a deep understanding of “droplet – plasma” interaction. Droplets of suspension in a jet drastically change their size due to fragmentation and evaporation of the liquid carrier, a change in the structure of particles occurs, and several processes of mass and heat transfer take place. This paper analyzes the time scales of the droplet breakup, convective (Hill vortex) and diffusion mass transfer of solid phase in a suspension, heating and evaporation of the material, vapor transport due to diffusion and filtration mechanisms. Basing on these analyses, a phenomenological model of the evolution of suspension droplets in the SPS process is proposed. The model includes the stages of a breakup, diffusion drying and the formation of a dry crust, the filtration exit of vapors, and the final heating and melting of the material. A 1-D simulation of the behavior of droplets of a ZrO2 suspension in a uniform air plasma flow was carried out, the influence of the velocity (500–2500 m/s) and temperature (3000–5000 K) of the plasma, the concentration of the suspension (1–60% wt) on the characteristics of the sprayed particles was studied. It was found that after formation of surface crust the vapor pressure inside the particles can reach 1 MPa, and filtration mass transfer of vapor must be considered when analyzing the problem. Equations have been obtained for estimating the size and temperature of particles and duration of each stage of droplet evolution.

Modeling the effect of droplet shape and solid concentration on the suspension plasma spraying

A three-dimensional unsteady magnetohydrodynamic model employing a two-way coupled Eulerian-Lagrangian method has been developed to simulate the suspension plasma spraying (SPS) process. In the current study, the developed model is employed to study the effect of droplets' shape and solid concentration (sub-micron yttria-stabilized zirconia (YSZ)) on the SPS process. Assuming the droplets as the sphere is an idealization. While a droplet moves through the plasma gas field, circulation of the internal liquid, which depends on the ratio of the dynamic viscosity of suspension droplets, and plasma gas, starts. Moreover, the droplets are deformed as a result of non-uniform pressure forces acting on their surface. As the droplets' shape distorts, the drag coefficient changes. Therefore, using a drag coefficient model, incorporating the droplets' distortion is crucial to achieving an accurate spraying model. In the current study, a dynamic drag law is applied to analyze the effect of droplets/particles' shape on the SPS process. As a result of the catastrophic breakup within the plasma core area, the breakup model, Kelvin-Helmholtz Rayleigh-Taylor (KHRT), is used for stimulating the droplets/particles' atomization. The inflight particles' conditions (temperature, speed, and size) are computed by tracking the sprayed droplets even after the solvent evaporates. It was concluded that the percentage of the molten particles in the case of applying dynamic drag law (non-spherical particles) decreases significantly compared to the case of using spherical particles. The effect of suspension concentration is also studied. It was shown that using a higher solid concentration (20 compared to 10 wt.% YSZ) provides denser coating as a result of the larger molten landed particles with higher velocities.