Simulation of Thermal Spraying in IPS Virtual Paint

A. Berce, Master thesis, Chalmers, supervisor B. Andersson, A. Mark, examiner L. Davidson, June 2011.

The plasma spraying process is used to coat surfaces which are subjected to extreme conditions, e.g. rocket nozzles in the aerospace industry. The basic outline of the process is to inject metal or ceramic particles into a plasma jet generated by an electric arc. The particles are melted by the high temperature and accelerated towards the component to be coated (the substrate) by the high fluid velocities inside the plasma jet. When impacting on the substrate the particles solidify in a few milliseconds to form a strongly bonded coating.

At Fraunhofer Chalmers Centre a software for simulating electrostatic rotary bell spray painting is being developed and used in the automotive industry. In this thesis it has been investigated how well this software, IPS Virtual Paint, can predict the results in a plasma spraying process.

Two test cases were defined and simulated. Data from previous detailed simulations of the plasma jet and its close surroundings was used to define the virtual plasma gun. Physical testing of the two cases was performed to calibrate and validate the results of the model. Also, a post-processing tool with the aim of calculating the coating thickness and temperature history of the coating and substrate was developed. The results from simulations and testing are given and compared, a satisfactory agreement has been reached.

Photo credits: Nic McPhee