The use of computational fluid dynamics (CFD) to model the operation of thermal-spray processes has gained interest in the thermal-spray community, able to provide an understanding as to how a process functions, and better how to make a process work better. Advancements to the science of modeling now permits the ability to create a comprehensive model of a plasma gun that not only simulates the dynamics of the gas, but also the mechanics of arcs (plasma), thermodynamics, and entrained particulates to form a nearly complete model of a working thermal-spray process. Work presented includes the methods and procedures used to validate the model to a Sulzer Metco TriplexPro TM -200 plasma gun and exploration of the operating regime to give an in depth and insightful look into the physics behind the operation of a triple-arc cascaded plasma gun.

Use of a comprehensive validated computer model of a thermal spray process enables an ability to improve, optimize, and fine-tune the performance of that thermal spray process. A validated model of the Sulzer Metco TriplexPro TM 200 plasma gun has been used to improve the performance of the actual gun in terms of enhancing gas flow dynamics, thermal management, and overall performance in terms of a robust design. Internal changes to the gun geometry using the model have extended the life of the hardware. In addition the model has permitted the investigation of the fundamental operation of the gun, specific to the behavior and path of the arcs, as well as the ability to operate the plasma gun, under simulation, in operating regimes that currently cannot be supported by the physical hardware. The model has been run at gas pressures above 1.4 Mpa and/or voltages above 300 V that currently cannot be obtained with the physical hardware due to equipment limitations to evaluate the potential to extend the operating window of the Sulzer Metco TriplexPro TM 200 gun beyond current levels in terms of particle velocity and temperature. The end result is an improved process tool for applying thermal spray coatings ranging from ceramics applied at high particle temperature and low particle velocities to carbides and alloys applied at lower temperatures and higher velocities.

Utilization of a comprehensive validated computer model of a thermal spray process enables an ability to improve, optimize, and fine tune the performance of that thermal spray process. A validated model of the Sulzer Metco TriplexPro 200 plasma gun has been used to improve the performance of the actual gun in terms of enhancing gas flow dynamics, thermal management, and overall performance in terms of a robust design. Internal changes to the gun geometry using the model have extended the life of the hardware beyond any current plasma gun. In addition the model has permitted the investigation of the fundamental operation of the gun, specific to the behavior and path of the arcs, as well as the ability to operate the plasma gun, under simulation, in operating regimes that currently cannot be supported by the physical hardware. The model has been run at gas pressures above 14 bar and/or voltages above 300V that currently cannot be obtained with the physical hardware due to equipment limitations to evaluate the potential to extend the operating window of the Sulzer Metco TriplexPro 200 gun beyond current levels in terms of particle velocity and temperature. The end result is an improved process tool for applying thermal spray coatings from high temperature ceramics to relatively colder and faster carbides and alloys.

Plasma spraying at low pressure conditions (LPPS) is a well established thermal spray process with a broad variety of important applications in different industrial segments. The operating conditions for LPPS processes can vary in a wide range from only a few mbar up to typically 200 mbar which imposes different characteristics of the corresponding spray conditions and resulting coating properties. Thermal spray processes have been approved being suitable for integrated fabrication of various layers for SOFC components. Depending on the process conditions, different layers used as functional coatings of SOFC components such as dense electrolyte layers as well as porous electrodes can be realized using the LPPS technology. Due to the flexibility of these processes, an optimized performance of the application on different target materials and geometries is possible with an increased technological and economical benefit compared to conventional thermal spray techniques. This paper presents an overview on the general potential and spray conditions of the LPPS process and its application for the deposition of various functional layers such as electrolyte and electrodes for SOFC components.

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