Splat formation during thermal spraying of polymer particles

2021 ◽  
Author(s):  
Milan Ivosevic
Keyword(s):  
Thermal Spraying ◽  
Polymer Particles ◽  
Splat Formation

scholarly journals Splat Formation Mechanism in Thermal Spraying

2011 ◽  
Vol 5 (12) ◽  
pp. 1001-1014 ◽  
Author(s):  
Masahiro FUKUMOTO ◽  
Kun YANG ◽  
Motohiro YAMADA ◽  
Toshiaki YASUI
Keyword(s):  
Formation Mechanism ◽  
Thermal Spraying ◽  
Splat Formation

The Effect of Substrate Preheating and Surface Organic Covering on Splat Formation

1998 ◽  
Author(s):  
C.J. Li ◽  
J.-L. Li ◽  
W.-B. Wang
Keyword(s):  
Stainless Steel ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Substrate Surface ◽  
Thermal Spraying ◽  
Splat Morphology ◽  
Organic Substances ◽  
Splat Formation ◽  
Molten Droplet ◽  
Preheating Temperature

Abstract The splashing usually occurs when a droplet impact on a substrate surface during thermal spraying, which results in the formation of splat with irregularly complicated morphology. In present study splats are formed on polished stainless steel substrate surface covered with different organic substances with different boiling points by plasma spraying under different preheating temperature of substrate in order to clarify the factors which control the splashing during droplet flattening in thermal spray process. The droplet materials used are aluminum, nickel, copper, Ah03 and molybdenum. Three kinds of organic substances used are xylene, glycol and glycerol which are brushed on the surface of substrate before spraying. It is found that when the preheating temperature exceeds 50°C over the boiling point of organic substance brushed on substrate surface the regular disk type splats are formed in the case that no substrate melting occurs by molten droplet. When the flattening of droplet causes the melting of substrate such as the combination of Mo droplet with stainless steel substrate, the preheating of substrate has no influence on splat morphology. The evaporated gas induced splashing and substrate surface melting induced splashing models are proposed to interpret the formation of the annulus-ringed splat

Microstructure Characterization and Modeling of Splat Formation during Air Plasma Spraying for Inconel 625 Superalloy

2007 ◽  
Vol 539-543 ◽  
pp. 1218-1223 ◽  
Author(s):  
F. Azarmi ◽  
A. Moradian ◽  
J. Mostaghimi ◽  
Tom W. Coyle ◽  
L. Pershin
Keyword(s):  
Plasma Spraying ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Thermal Spraying ◽  
Inconel 625 ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Three Dimensional Model ◽  
Splat Formation ◽  
Molten Droplets

There is a growing interest in use of the nickel-based alloy Inconel 625 coatings due to its ability to improve base materials high temperature properties. Thermal spraying methods such as Air Plasma Spraying (APS) can be considered as a convenient method to deposit this material. The present work deals with APS deposited Inconel 625 structures consisting of huge number of individual splats formed by impacting molten droplets on substrates during spraying process. It is clear that the splat formation mechanism which dominates its size, cohesion, and boundaries highly influences the microstructure of the coating. This paper presents a developed numerical technique performed to simulate splat formation using a three dimensional model. In this method flow field is solved by Finite Volume Method (FVM) and free surfaces are determined from Youngs’ Volume of Fraction method (VOF). Finally, the model prediction is correlated with the actual splat geometries.

scholarly journals Role of Ambient Pressure on Splat Formation and Coating Adhesion Strength during Thermal Spraying Process

2011 ◽  
Vol 29 (3) ◽  
pp. 151s-155s ◽  
Author(s):  
Kun YANG ◽  
Kazuhiro TANAKA ◽  
Takashi USAMI ◽  
Masahiro FUKUMOTO ◽  
Toshiaki YASUI ◽  
...  
Keyword(s):  
Adhesion Strength ◽  
Ambient Pressure ◽  
Thermal Spraying ◽  
Splat Formation ◽  
Coating Adhesion ◽  
Spraying Process

Analysis of Undercooling, Nucleation, Rapid Solidification, and Microstructure Formation in Thermal Spraying

2002 ◽  
Author(s):  
H. Zhang ◽  
X. Y. Wang ◽  
S. Sampath
Keyword(s):  
Thermal Spraying ◽  
Thermal Characteristics ◽  
Nucleation Theory ◽  
Scaling Analysis ◽  
Size Distributions ◽  
Splat Formation ◽  
Flat Substrate ◽  
Equilibrium Solidification ◽  
Grain Size Distributions ◽  
Molten Droplets

A splat formation model including undercooling, nucleation, and non-equilibrium solidification has been developed to study the thermal characteristics of molten droplets impacting on a flat substrate. The nucleation sub-model is based on the classic nucleation theory accounting for heterogeneous nucleation kinetic and crystal growth. The effects of contact angle on nucleation temperature and grain density have been investigated. The grain size distributions have been predicted and compared with experimental results for molybdenum (Mo) splats on different substrates. Based on scaling analysis, time scales of various sub-processes, e.g., the nucleation delay, recalesence, and total solidification time, have been derived, and compared with simulation results.

Effect of Substrate Temperature on Microstructural Characteristics of Thermal Sprayed Superalloys

2011 ◽  
Vol 495 ◽  
pp. 13-17
Author(s):  
Fardad Azarmi ◽  
Ghodrat Karami
Keyword(s):  
Substrate Temperature ◽  
Plasma Spraying ◽  
Steel Substrate ◽  
Substrate Surface ◽  
Thermal Spraying ◽  
Air Plasma ◽  
Microstructural Characteristics ◽  
Splat Formation ◽  
Vacuum Plasma Spraying ◽  
Porosity Level

Recently, there has been a huge interest in application of thermal spraying processes to apply a protective layer on the surface of engineering components. Thermal spraying as a near net shape forming technique has also found applications in manufacturing of advanced engineering components. Spraying methods such as High Velocity Oxygen Fuel (HVOF), Vacuum Plasma Spraying (VPS), and Air Plasma Spraying (APS) are among the most commonly used deposition techniques. Coatings are built up from impact of molten particles on the substrate surface and their flattening and solidification (splat formation). Deposition of millions of individual splats connected to each other at different layers will result in a lamellae type structure. This is a typical example of an anisotropic microstructure. The microstructural features such as porosity, oxide layers define the physical and mechanical properties of coating material. This study investigates the influence of substrate temperature on microstructural characteristics of APS deposited superalloy 625 on steel substrate. The coatings were deposited on substrates at different temperatures. The porosity level was measured using prosimetry. Both image analysis technique and Electron Probe Microanalysis (EPMA) was used to measure the amount of oxide phase. The results indicated that lower substrate temperature results in lower oxide in microstructure. There has been no significant change in porosity level due to substrate temperature.

Effect of wave processes on splat formation during thermal spraying

2000 ◽  
Vol 42 (5) ◽  
pp. 321-325 ◽  
Author(s):  
V.V Sobolev ◽  
J.M Guilemany
Keyword(s):  
Thermal Spraying ◽  
Wave Processes ◽  
Splat Formation

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

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Kun Yang ◽  
Min Liu ◽  
Kesong Zhou ◽  
Changguang Deng
Keyword(s):  
Formation Process ◽  
Thermal Spraying ◽  
Industrial Applications ◽  
Splat Formation ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Recent Developments ◽  
The Individual ◽  
Free Falling ◽  
Future Work

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.

Building of Protective Coating Against Corrosion by Flame Spraying of Mechanofused Composite Particles

2015 ◽  
Vol 1765 ◽  
pp. 37-44
Author(s):  
A. Molina-Díaz ◽  
J. Delgado-Venegas ◽  
F. Juárez-López ◽  
G. Velázquez-García ◽  
R. Cuenca-Álvarez
Keyword(s):  
Protective Coating ◽  
Steel Substrate ◽  
Salt Spray ◽  
Thermal Spraying ◽  
Corrosion Damage ◽  
Flame Spraying ◽  
Composite Particles ◽  
Substrate Roughness ◽  
Alumina Layer ◽  
Splat Formation

ABSTRACTA protective coating was built and assessed in order to reduce the degradation of metallic substrates caused by corrosion damage. Hence, a set of coatings with different configurations, in terms of layer arrangement, was produced by flame-spraying of composite powder (AISI 316L stainless steel coated with an α-alumina layer) onto an AISI 1018 steel substrate. In order to ensure a homogeneous dispersion of phases, a correlation was established between the operating parameters of thermal spraying (roughness and surface temperature of substrate, spraying distance, passing speed) and the splat formation. Then, corrosion damage caused in the coated samples by exposure to a salt spray was monitored through weight measurements and observations with optical and scanning electron microscopy. The results show that corrosion still remains in all cases; however, it proceeds at lower rates for coatings made with composite particles plus an α-alumina layer. The weight loss due to corrosion damage was reduced in approximately 94% as compared with the substrate without protection. Coating adhesion was also improved by an increased substrate roughness, with no need for an intermediate layer.

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