TUTCRIS - Tampereen teknillinen yliopisto


Novel online diagnostic analysis for particle in-flight properties in cold spraying

Tutkimustuotos: Konferenssiesitys, posteri tai abstrakti


TilaJulkaistu - 2017
TapahtumaInternational Thermal Spray Conference & Exhibition 2017: Thermal Spray paves the Way to the Stars - CCD Congress Centre Düsseldorf, Düsseldorf, Saksa
Kesto: 7 kesäkuuta 20179 kesäkuuta 2017


ConferenceInternational Thermal Spray Conference & Exhibition 2017


In cold spraying, powder particles are accelerated by preheated supersonic gas to high velocities and sprayed on a substrate. The particle velocities depend on the equipment design and process parameters e.g. on the type of the process gas and its pressure and temperature. These, in turn, affect the coating properties. The particle velocities in cold spraying are known to be high and the particle temperatures low, which can, therefore, be a challenge for the diagnostic methods. A novel optical online diagnostic system, HiWatch HR, will open new possibilities for measuring particle in-flight properties in high-kinetic thermal spray processes such as cold spray processes. The system employs an imaging detector with the laser backlight illumination of the particle jet using telecentric optics. This technique enables an accurate small diameter particle size measurement with a large sample volume. The aim of this study was to evaluate the particle velocities of metallic particles sprayed with high-pressure and low-pressure cold spray systems and with varying process parameters. The measured in-flight particle properties of each spray condition were further linked to the resulting coating properties. In addition, the camera was able to provide information about variations during the spraying, e.g. fluctuating powder feeding. Such information is important from the process control point of view and can be used as a quality control tool.