Thermal Spraying Process Kinematics

2021 ◽  
pp. 331-346
Author(s):  
Gaurav Prashar ◽  
Hitesh Vasudev ◽  
Lalit Thakur
2014 ◽  
Vol 682 ◽  
pp. 431-437 ◽  
Author(s):  
V.A. Petrova ◽  
A.A. Bakanov ◽  
A.V. Walter

The paper presents a pretreatment of the substrate material prior to the thermal spraying process. The ultrasonic finishing method allowed creation of a rolling topography comprising alternating projections and cavities, compressive stress, and increase of the number of defects on the surface. Optical profilometry and metallographic analysis allowed detecting of adhesion zones which form a strong physicochemical bond at the interface between the coating and the substrate material. This interfacial adhesion should provide a firm adhesion strength in end products.


2005 ◽  
Vol 502 ◽  
pp. 505-510 ◽  
Author(s):  
Masami Futamata ◽  
Xiaohui Gai ◽  
Toyokazu Mizumoto ◽  
Kimio Nakanishi

To fabricate thermal spraying coatings with good reproducibility, it is necessary to improve the process of the equalization of both thermal history and impacting behavior of the particles. In this study, the characteristics of the solution type plasma spraying using the hollow-cathode type torch are investigated. The physical and mechanical properties that are different from usual thermal spraying coatings are described. By using solutions including metal ingredients in a state of ion, colloid or sol, thinner coating that cannot be made by conventional plasma spraying methods is formed on various substrates. The coatings are uniform in appearance.


Author(s):  
K. Sakaki ◽  
Y. Shimizu ◽  
Y. Gouda ◽  
A. Devasenapathi

Abstract Effect of nozzle geometry (such as throat diameter of a barrel nozzle, exit diameter and exit divergence angle of a divergent nozzle) on HVOF thermal spraying process (thermodynamical behavior of combustion gas and spray particles) was investigated by numerical simulation and experiments with Jet KoteTM II system. The process changes inside the nozzle as obtained by numerical simulation studies were related to the coating properties. A NiCrAIY alloy powder was used for the experimental studies. While the throat diameter of the barrel nozzle was found to have only a slight effect on the microstructure, hardness, oxygen content and deposition efficiency of the coatings, the change in divergent section length (rather than exit diameter and exit divergence angle) had a significant effect. With increase in divergent section length of the nozzle, the amount of oxide content of the NiCrAIY coatings decreased and the deposition efficiency increased significantly. Also, with increase in the exit diameter of the divergent nozzle, the gas temperature and the degree of melting of the particle decreased. On the other hand the calculated particle velocity showed a slight increase while the gas velocity increased significantly.


2013 ◽  
Vol 234 ◽  
pp. 1-6 ◽  
Author(s):  
Denis Bémer ◽  
Roland Régnier ◽  
Yves Morele ◽  
Florence Grippari ◽  
Jean-Christophe Appert-collin ◽  
...  

2013 ◽  
Vol 371 ◽  
pp. 270-274 ◽  
Author(s):  
Stefan Lucian Toma ◽  
Diana Antonia Gheorghiu ◽  
Steluta Radu ◽  
Costică Bejinariu

The physic-chemical and mechanical properties of steel deposits obtained by thermal spraying depend on technological parameters of the spraying process. Generally, wear resistance of the deposits depends on the degree of porosity and the adhesion of the layer to the substrate. In the case of the deposits obtained by spraying, studies have shown that between deposited layer (SD) and substrate (S) there are the following types of adhesions: mechanical, metallurgical, superficial, physical and diffusive. Each type of adherence, enumerated above, works through a well-defined mechanism so that it can be said that the adhesion of the obtained deposits by thermal spray is a sum of mechanisms which interacting. How these mechanisms interact, as well the percentage of the influence is determined by: operating parameters, by the deposit material and thermal treatments after the deposit obtaining. This paper proposes to determine the influence of thermal treatment on adherence of 60T deposits obtained by thermal spraying in electric arc- as a thermal processing method after metallization. The assessment of adherence deposit 60T - in two ways, according to with EN 582 and DIN 27201/2005 in conjunction with the investigations of electron microscopy (SEM), XRD analysis, and image analysis performed at both the zone: Coating - Interface - Substrate (CIS) has revealed the presence of diffusion and the structural constituents. The graphs of adherence variation for 60T deposits with the concentration gradient of the alloying elements of the 60T layer respectively of adherence layer (75B) obtained experimentally by investigations carried out on the substrate have demonstrated the role of the secondary thermal treatment on the deposit adherence.


2005 ◽  
Vol 475-479 ◽  
pp. 2427-2430 ◽  
Author(s):  
Mu Qin Li ◽  
Da Shan Shang ◽  
Chen Ma ◽  
Shi Qin Yang

Ti/bioglass composite coatings on titanium alloy were prepared by a subsonic thermal spraying technology. Mixtures of titanium and bioglass powders with different proportions were used as feedstock. The effect of soaking of bioglass on the bond strength of between coatings and substrate was discussed. The bond strength and residual stress were investigated. The morphology was observed using scanning electron microscopy (SEM). The results showed that TiO2, CaTi4(PO4)6, CaTiO3, NaTi2(PO4)3 formed during thermal spraying process and the residual stress in the coatings was in compressive state. After the coatings were heat-treated, soaking of bioglass made some particles achieve metallurgical bond. Furthermore, new bioglass was formed and the compressive stress was increased. The phenomenon of bioglass healing up the cracks in the heat-treated coatings was observed through SEM, which reduced the porosity of the interface layer resulting in the significant increase of the bond strength.


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