Protective Plasma Sprayed Coating forThermo-Sensitive Substrates

Soufiane Oukach,Mohammed El Ganaoui,Hassan Hamdi,Bernard Pateyron,M El Ganaoui,S Morsli,R Bennacer,B Liu,M Darcherif

doi:10.1051/matecconf/202030701039

Abstract

Plasma spray is one of the surface treatment techniques that consist on the deposition of a thin coating onto a targeted substrate. Coating is built up by successive accumulation of layered splats resulting from impact and solidification of molten particles into thin ‘‘splats’’ onto the substrate. The process of droplet impact, spreading and solidification is then a crucial process in coating formation. This technique may be also used for thermo-sensitive materials such as wood by applying a metallic coating for protective or decorative purposes. However, when applying a ceramic coating which provides a high protection against hot temperatures like fire, wood may be damaged because of the high temperature at which the ceramic molten particles arrive at the substrate. In this paper, a numerical simulation based on the Finite Elements Method is carried out in order to simulate the process of the first splat formation onto a wood substrate under traditional plasma spraying conditions. The computations are carried out on a fixed eulerian structured mesh using the level set method to track the interface between the molten particle and surrounding gas. The effects of operating conditions as well as the droplet characteristics that allow applying ceramic coating onto a wood substrate without any damage to this thermo-sensitive material are investigated.

Highlights

Wood, which is an organic and heterogeneous material, represents an integral part of our usually life
When treating wood by plasma spray, it receives two thermal solicitations: the first one is the direct flow of the plasma jet and the other one is the average temperature at which the molten particles of the material to be deposited impact onto the substrate
The direct flow of the plasma jet may be avoided by blowing a cold high flow of air which cools the surface of the substrate and deflects the hot jet, while the thermal effect of the molten particles resulting from the thermal energy released from the droplets to the substrate leads to increase the surface temperature

Summary

Introduction

Wood, which is an organic and heterogeneous material, represents an integral part of our usually life. Wood currently attract particular attention owing to large demands for sustainable development This material may be further damaged by several factors such as moisture, microbial growth, UV light the fire that represents an important danger to this material leading to lose its basic properties, environmental quality and its durability. A relatively new technique in the domain of wood surface treatment which has become increasingly popular due to its increased performance is the plasma spray technique [5,6] This technique consists of the deposition of a metallic or ceramic hard coating having a physical thickness on the substrate to be covered. The choice of a ceramic coating such as alumina is due to its improved properties such as the superb resistance to high temperatures environment like fires

Numerical formulation

Results and discussion

Conclusion