Quo Vadis Thermal Spraying?

Abstract This paper is devoted to thermal spraying and presents the state of our current knowledge, as well as the research or development needs are in; spraying heat sources i.e., flame, HVOF, D-Gun, plasma torches; particle heat and momentum transfer (measurements and modeling), process on-line control, powder morphologies and injection within the hot jet and reactions with environment; coating formation i.e., particle flattening and solidification, splat layering, residual stresses, coating microstructure and properties; reliability and reproducibility of coatings.</jats:p

3D modeling of the plasma co-spraying of two dissimilar materials

International audienceThe co-spraying of a ceramic and a metallic powder for the manufacturing of functionally graded plasma-sprayed coatings is investigated by using a 3D commercial Computational Fluid Dynamics code, ESTET 3.2. The operating conditions of the plasma torch are kept constant and various configurations of the powder injection in the plasma flow are discussed

Modeling of Simultaneous Plasma Spraying of Two Powders

Abstract This paper presents a simulation of the simultaneous spraying of a metal and a ceramic powder with different configurations for the injection of the powder into the plasma jet. The plasma jet and the behavior of the injected particles were modeled with a commercially available computational model of the dynamics of liquid bodies. The particles are modeled as discrete Lagrangian objects. Three series of numerical tests were carried out: simultaneous spraying of the powder in a three-dimensional plasma jet in a stable state; simulation of the 3-D plasma flow, assuming that it fluctuates at the same frequency as the arc voltage; and simulation of the effect of the current fluctuation on particle behavior. A pre-calculation with an analytical model made it possible to determine the suitable gas flow rate so that the "average" trajectories of the metal or ceramic powders coincide at the same point on the surface. Paper includes a German-language abstract.</jats:p