Study on the Acceleration Process of BaTiO3 Particles during Vacuum Cold Spraying
In this paper,the acceleration process of BaTiO3 ceramic particles under different vacuum cold spraying parameters was simulated,and the effect of process parameters on particle velocity was discussed.The results were verified using particle image velocimeter.BaTiO3 ce-ramic coatings were prepared using vacuum cold spraying method and their properties were tested.The simulation results showed that the parti-cle velocity increased with the increase of gas pressure and preheating temperature.It was observed that under the same gas pressure and pre-heating temperature,the smaller the diameter of the particle,the more it was affected by the bow shock wave.The acceleration pattern of multi-ple particles was found to be similar to that of a single particle.According to the results obtained from particle image velocimetry,under the condition of and 300 K and 373 K at 0.2 MPa,the velocity of BaTiO3 particles differed from the simulation results by about 10.2％and 8.1％,respectively.Under the process parameters,as indicated by the simulation results,the continuous and dense BaTiO3 coatings with a thickness around 2 to 3 μm were fabricated by vacuum cold spraying,and the binding force was found to be 8 N.The research results indicated that the process parameters and their influence laws,obtained through numerical simulation combined with particle image velocimetry,were reliable and could be used to guide the preparation of flexible ceramic films.
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