Low Porosity and Fine Coatings Produced by a New Type Nozzle ofHigh Velocity Arc Spray Gun

摘要

Providing for the DZ400 arc spray system, the new design high-velocity arc spray gun with three different nozzles isdeveloped to produce the coatings with the structure of superfine and low porosity. This system can be used tospray the three normal wires of 4Crl3, FeCrAl and 7Crl3 (flux cored wires). With the SEM to analysis shape andparticles size sprayed by the nozzles by different parameters, as well as with the S-3500N SEM (made by HITACHI)and the INCA ESA (made by OXFORD) identify the content of the oxides, porosity and thickness of the coatings.The result shows that the porosity in the coatings of solid wire is less than 2%, of the flux-cored wires is less than 4%,and the coating sprayed by the nozzle with the secondary supplementary airflow is typically shown to be distributedin the form of high-density lamellar splat structure and the average lamellar thickness is around 5μm.