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2853 |
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Wednesday, September 28, 2011, Saal B2.2 4:00 PM Process Diagnostics, Sensors & Controls 1 |
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Development of optical monitoring of the thermal spaying |
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Yuri Chivel* / Institute of Applied Physical Problems, Belarus Igor Smurov / Ecole Nationale dIngenieurs , DIPI Lab., France |
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Growing demands on the quality of sprayed coatings require reliable methods to monitor and optimize the spraying processes. The accurate determination of the particle temperature and velocity is necessary. Also the status of spraying surface under the spraying process is essential but parameters of surface are not measured in the majority of the thermal spraying. The velocity of particles in cold spraying can be experimental measured through using laser two-focus velocimetry or other laser aided diagnostic method. It is not an efficient and cost effective approach to under taking a systematic measurements such as in industry. A new approach has been made which based on the illumination of particles stream by broadband radiation in continuous mode of operation. The ParticleWatch system is designed and fabricated. This system serves to measure parameters of a high-speed particle stream including cold particles. Brightness temperature can be measured in the range of 11000- 35000 !. Particle speed and size can be measured for speeds up to 2000 m/s and 6 µm minimal size. Synchronously with the registration of the particles parameters surface temperature of the coating has measured with 2-channel pyrometer with a spatial resolution of 300 ¼m and a temporal resolution of 2 ms in the temperature range 2700 - 16000 C and 1 ¼s in the temperature range 8000 35000 C. ParticleWatch system have been used for the Cold Spray and D-gun spraying monitoring . As the result of experiments the influence of surface temperature on the delay time of Ti-particles deposit on Inox in Cold Spraying was established. During D-gun spraying of Ti- powder on Inox substrate two group of particles are formed during the pulse that causes the two peaks in the curve of surface heating .The obtained results are discussed. |